UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The effect of oxygen on the reaction between copper and saphire O’Brien, Thomas Edward 1973

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1974_A7 O27.pdf [ 10.35MB ]
Metadata
JSON: 831-1.0078718.json
JSON-LD: 831-1.0078718-ld.json
RDF/XML (Pretty): 831-1.0078718-rdf.xml
RDF/JSON: 831-1.0078718-rdf.json
Turtle: 831-1.0078718-turtle.txt
N-Triples: 831-1.0078718-rdf-ntriples.txt
Original Record: 831-1.0078718-source.json
Full Text
831-1.0078718-fulltext.txt
Citation
831-1.0078718.ris

Full Text

THE EFFECT OF OXYGEN ON THE REACTION BETWEEN COPPER AND SAPPHIRE BY THOMAS EDWARD O'BRIEN B.A.Sc, U n i v e r s i t y of B r i t i s h Columbia, 1970 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n the Department of METALLURGY We accept t h i s t h e s i s as conforming to the req u i r e d standard. THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1973 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r a n a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l m a k e i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e H e a d o f my D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f M e t a l l u r g y  T h e U n i v e r s i t y o f B r i t i s h C o l u m b i a V a n c o u v e r 8 , C a n a d a D a t e October 8, 1974 ABSTRACT The e f f e c t of oxygen p o t e n t i a l on the wetting behavior and i n t e r f a c i a l energy between copper and sapphire was studied using the s e s s i l e drop technique i n a CO-CC^ atmosphere. A l i n e a r r e l a t i o n s h i p —6 —5 was found between Y c t and l o g p0„ from 10 to 10 atmosphere. Beyond 10 atmosphere Y q t approached a constant value a s y m p t o t i c a l l y . A b a r r i e r surface l a y e r was proposed to e x p l a i n t h i s change. The Gibbs' a d s o r p t i o n equation was used to evaluate the c h a r a c t e r i s t i c of the i n t e r f a c e s . Formation of a C^O f i l m at the l i q u i d -vapour i n t e r f a c e and a CuAlC^ f i l m at the s o l i d - l i q u i d i n t e r f a c e was suggested. The work of adhesion was found to reach a maximum at -2 approximately 10 atomic precent oxygen. Measurements of the b a s a l r a d i u s as a f u n c t i o n of oxygen content were used to evaluate the r o l e of oxygen i n promoting spreading. I t was found that spreading on sapphire was d i r e c t l y p r o p o r t i o n a l to the log a r i t h m of oxygen present i n the molten copper drops. E v a l u a t i o n of the pe n e t r a t i o n of copper i n t o sapphire was evaluated u s i n g the e l e c t r o n probe microanalyser. Data obtained i n d i c a t e d that i n absence of oxygen copper does not penetrate a p p r e c i a b l y . Between 0.13 and 1.39 wt.% [0] copper p e n e t r a t i o n was not dependent on oxygen content and time. I t was found that copper penetrates very r a p i d l y i n i t i a l l y and then appears to stop. An attempt has been made to obt a i n an equation based on the Young-Dupre equation, when the d i f f e r e n t en"-:»y values are a f f e c t e d by the oxygen p o t e n t i a l of the system. i i i TABLE OF CONTENTS gage TITLE PAGE , . . . i ABSTRACT i i TABLE OF CONTENTS i i i LIST OF FIGURES v i ACKNOWLEDGEMENTS v i i i CHAPTER I . INTRODUCTION 1 A. General D i s c u s s i o n 1 B. C u - A l 2 0 3 System 2 C. Copper-Oxygen System 4 ; D. Other Related Work - . 6 E. Aim of Present I n v e s t i g a t i o n 7 CHAPTER I I . EXPERIMENTAL 9 A. M a t e r i a l s 9 1. Sapphire 9 2. Copper 10 3. Cupric Oxide 10 4. Alumina and Cuprous Oxide 10 B. Apparatus f o r S e s s i l e Drop Experiments 1? 1. Furnace 12 2. Atmosphere C o n t r o l l e r . . . . . 12 3. O p t i c a l System. . ^ i v Page C. Apparatus f o r D i f f u s i o n Experiments 14 D. Specimen P r e p a r a t i o n 14 1. Sapphire 14 2. Copper Buttons 17 E. Experimental Procedure 17 1. S e s s i l e Drop Experiments 17 2. D i f f u s i o n Experiments 18 3. E l e c t r o n Probe M i c r o a n a l y s i s 19 4. M i c r o s t r u c t u r e Examination 20 5. Scanning E l e c t r o n Microscopy 20 CHAPTER I I I . RESULTS AND DISCUSSION 21 A. S e s s i l e Drop Experiments 21 1. Contact Angle Measurements . 21 2. I n t e r f a c i a l Energy 23 3. Adsorption Isotherms 25 4. Work of Adhesion 29 5. I n t e r f a c i a l Area. . , 29 6. Examination of S o l i d i f i e d Drops . 31 B. D i f f u s i o n Experiments 35 1. I n t e r f a c i a l Region 36 2. Copper P e n e t r a t i o n i n Alumina 38 3. Copper P e n e t r a t i o n Without Oxygen Present . . . . 43 V Page 4. Copper Aluminate D i f f u s i o n 44 5. I n t e r f a c e M i c r o s t r u c t u r e s 45 6. Copper M i c r o s t r u c t u r e s 48 C. A F i t of Data f o r Y C T 49 CHAPTER IV. CONCLUSION . 52 CHAPTER V. RECOMMENDATIONS FOR FUTURE STUDY 54 APPENDIX I . SESSILE DROP TECHNIQUE AND GIBBS 1 EQUATION . . . 55 A. S e s s i l e Drop Technique 55 B. Gibbs' Equation 57 APPENDIX I I . ZIRCONIA (CALCIA STABILIZED) FOR CONTROL OF OXYGEN ATMOSPHERE . 58 APPENDIX I I I . SESSILE DROP DATA 60 APPENDIX IV. SIEVERT'S LAW 61 APPENDIX V. ELECTRON PROBE MICROANALYSIS 62 APPENDIX V I . Y C T VALUES 63 APPENDIX V I I . X-RAY ANALYSIS. . 64 BIBLIOGRAPHY $ 6 v i LIST OF FIGURES Figure Page 1. 3 2. 5 3. E f f e c t of Oxygen on the Surface Tension of Copper (1200°C) 6 4. 11 5. 13 6. 15 7. 16 8. 18 9. 19 10. 22 11. 23 12. 24 13. 26 14. 27 15. 28 16. 30 17. 31 18. 32 19. 33 20. 34 21. 35 22. 36 v i i F i g u r e Page 23. X-ray Images 37 24. Copper P e n e t r a t i o n i n t o Alumina 39 25. " " " " . . . . . . . . . 39 26. 11 " " " 40 27. " " " " 40 28. " " " " 4.1 29. " " " " 41 30. Specimen w i t h no Oxygen A d d i t i o n 43 31. Copper P e n e t r a t i o n w i t h no Oxygen Present 44 32. Cu-CuA10 2-Al 20 3 Couple 45 33. F r a c t u r e Surface 46 34. I n t e r f a c i a l Void 47 35. S t r u c t u r e at Void . 47 36. Scanning E l e c t r o n M i c r o s c o p i c View of I n t e r f a c e . . . . 48 37. E u t e c t i c at 0.13 [0] wt.% 50 38. E u t e c t i c at 0.27 [0] wt.% 50 39. E u t e c t i c at 0.57 [0] wt.% 51 40. E u t e c t i c at 1.39 [0] wt.% 51 41. Contact Angle R e l a t i o n s h i p s 56 42. ASTM Standard X-ray Card . 64 43. D i f f r a c t i o n P a t t e r n f o r Sy n t h e t i c CuAlO- 65 ACKNOWLEDGEMENTS The author would l i k e to express h i s g r a t i t u d e to h i s research a d v i s o r , Dr. A.CD. Chaklader, f o r h i s v a l u a b l e advice. Thanks are a l s o due to other f a c u l t y , t e c h n i c a l s t a f f and f e l l o w graduate students f o r t e c h n i c a l a s s i s t a n c e and u s e f u l d i s c u s s i o n s . The f i n a n c i a l a s s i s t a n c e provided by the H.R. MacMillan Fello w s h i p i s g r a t e f u l l y acknowledged. The best l a i d plans of mice and men .•. R. Burns 1 I . INTRODUCTION A. General D i s c u s s i o n The combination of d i f f e r e n t types of m a t e r i a l s i s of ever i n c r e a s i n g t e c h n i c a l importance. I t may be p o s s i b l e w i t h such combinations to make use of the best p r o p e r t i e s of a l l m a t e r i a l s concerned. Of utmost importance i s the a b i l i t y to o b t a i n a good bond and matching between these m a t e r i a l s . According to Helgess^on^ the t e c h n i c a l l y important combinations of metals and ceramics can be it e m i z e d as f o l l o w s : 1. d i s p e r s i o n strengthened metals. 2. metal f i b r e r e i n f o r c e d ceramics. 3. ceramic f i b r e r e i n f o r c e d metals. 4. cermets. 5. ceramic coatings on metals and 6. metal coatings of ceramics. The bonding formed between the metal and the ceramic i n such systems i s o f t e n subjected to severe c o n d i t i o n s during use. Therefore i n v e s t i g a t i o n s of the s t a b i l i t y of t h i s bond are important from a t e c h n i c a l point of view. The s t a b i l i t y of the whole composite may depend on the s t a b i l i t y of the i n t e r -f a c i a l bond i t s e l f . In the case of a t h i n - f i l m deposit on a ceramic 2 substrate , the i n t e r f a c i a l r e a c t i o n and s t a b i l i t y of the t h i n f i l m and a l so i t s f u n c t i o n a l p r o p e r t i e s , such as r e s i s t i v i t y , may s o l e l y depend on the subsequent ox idat ion and d i f f u s i o n r e a c t i o n of the f i l m with the subs tra te . Much of the e a r l y work i n metal to ceramic bonding dea l t with metal to g lass s ea l s . The invent ion of the e l e c t r i c l i g h t b u l b and l a t e r 2 e l e c t r o n i c vacuum tubes prompted much research i n t o the product ion of s e a l s . E a r l y work. into c r y s t a l l i n e ceramic-metal seals employed a g lassy l ayer 1 2 between the ceramic and metal phases. Later developments ' employed ; var ious metals , oxides and s i l i c a t e s e i t h e r alone or i n mixtures to form a bond. Due to the complexity of the i n t e r f a c i a l r e g i o n , c h a r a c t e r i z a t i o n of many bonds, has not been c a r r i e d out. Many poss ib l e i n t e r f a c i a l , 3-10 react ions for var ious systems have been proposed , which can a f f e c t the bonding. There can be s o l i d s o l u t i o n by d i f f u s i o n , product ion of an i n t e r -mediate compound or g lass and so on. Reactions such as these lower the i n t e r f a c i a l tension and hence the surface free energy of the s o l i d , by . the formation of an i n t e r f a c i a l compound. Widman^ found t h a t • i n systems where a bond between an oxide and a metal was to be made, atmosphere c o n t r o l was very important. I n . a l l of the systems i n v e s t i g a t e d , he found be t t er adhesion was p o s s i b l e i f a c o n t r o l l e d amount of oxygen was added to the atmosphere. B. CU-AIQO-J System The use of p r i n t e d c i r c u i t s has r a p i d l y increased the i n t e r e s t i n copper-alumina bonding. Oxygen and i t s r o l e i n the bond formation between copper and alumina has thus become very important. 12 13 Cu^O was found ' to f a c i l i t a t e the formation of a second 14 phase which s t a b i l i z e d the g r a i n growth of Al o0„. Others have found that , i n the presence of oxygen during the treatment of mixtures of Cu and Al^O^, a complex phase was formed. Examination of the phase diagram f o r CuO-Ci^O-A^O^ i n d i c a t e s the p o s s i b i l i t y of two d i s t i n c t compounds being formed. These are CuAlC^ and CuAl^O^ (Figure 1 ). o o IK t-< CC liJ 0. LU 1 8 0 0 / / _ L i q u i d - { 1 6 0 0 — % m / • * • * • • • — L iqu id + A l 2 0 3 1 4 0 0 Liquid-*- a • • _ C u 2 0 / 1 • • • • • -»/••/• • • » • • • ~ I 2 6 0 ° c * -1 2 0 0 _J e m • • t jU 0 L iqu id +#Cu A I 0 2 • • • • • • • • • -> • • • • II65°C • * Cu A l 0 2 + A I 2 0 3 • C u - 0 + C u A I O , * • • • • 1 0 0 0 - 1 — * C u 2 0 9 0 0 8 0 0 i u » 1 y u • C u O + C u ( A I 0 2 ) 2 • C u A I 0 2 1 • A l 2 0 3 C u ( A I 0 | ) 2 + A I 2 0 3 • 700L . . C u O + A l 2 0 3 6 0 0 1 « i i 0 CuO 2 0 4 0 6 0 W t . % A l 2 0 3 8 0 100 A l 2 0 3 Figure 1. Phase Diagram f o r C u O - C u ^ - A l ^ 15 16 Chaklader et a l . have found that w i t h the a d d i t i o n of l a r g e amounts of cu p r i c oxide to l i q u i d copper drops r e s t i n g on alumina substrates CuA10 2 i s formed at the i n t e r f a c e . A l l the works mentioned p r e v i o u s l y d e a l t w i t h l a r g e oxygen a d d i t i o n s , u s u a l l y w e l l over the s o l u b i l i t y l i m i t . Such a d d i t i o n s would e f f e c t the e l e c t r i c a l p r o p e r t i e s of the copper, t h e r e f o r e i t i s important to consider smaller a d d i t i o n s of oxygen and what e f f e c t i t 4 may have on the f i n a l p r o p e r t i e s and as w e l l as on the s t a b i l i t y of the i n t e r f a c e . I t i s e s p e c i a l l y important to note whether the formation of CuAlO^ at the copper-alumina i n t e r f a c e can act as a b a r r i e r l a y e r to prevent subsequent d i f f u s i o n of copper i n t o the s u b s t r a t e . As f u r t h e r d i f f u s i o n may r e s u l t i n the l o s s of the e l e c t r i c a l p r o p e r t i e s of d e v i c e s , such as p r i n t e d c i r c u i t s . I t has a l s o been claimed"^ that CuAlO^ was observed to form w i t h the smallest c o n c e n t r a t i o n of oxygen a d d i t i o n (<v 1 wt.%). However, most of the data r e l a t e to the mechanism of copper-alumina bonding w i t h higher concentrations of oxygen, much above the s o l u b i l i t y l i m i t of oxygen i n copper. C. Copper-Oxygen System The phase diagrams f o r the copper-oxygen system are shown i n Figures 2(a) & (b). I t i s apparent from the most recent data of Osterwald"^k t h a t , under e q u i l i b r i u m c o n d i t i o n s , the s o l u b i l i t y l i m i t f o r oxygen i n copper i s 1.8 weight percent at 1200°C. In a d d i t i o n to the data a v a i l a b l e from the phase diagram the a c t i v i t y c o e f f i c i e n t of oxygen i n ; 18 19 20 19 d i l u t e l i q u i d Cu-0 a l l o y s has been found to be 0.205. ' ' Wilder a l s o determined that the f r e e energy f o r the d i s s o l u t i o n of oxygen i n l i q u i d copper i s -18.10 k c a l f o r the equation: k02 —• [0] (atm pet) 21 From t h i s value the S i e v e r t s law constant i s c a l c u l a t e d to be 485, that i s : °c 1400 1200 1083' 1000 800 600 400 Atomic Percentage Oxygen 10 20 30 40 50 200. h + L 1200° 1065° Cu 2 !&k 10.2 p-G+ 1075° y-p+.y " :!7\ 375°—20A y + ~G—I 6 + ' 1-2. y 8 12 16 20 Weight Percentage Oxygen 2200 1800 1400 1000 600 100 oxygen in atom %, » 2 oxygen i n wt % Figure 2(a) & (b). Copper-Oxygen System. 17a & b. 6 [0] (atm pet) 485 P 0 2 2 (atm) (see Appendix IV) The e f f e c t of oxygen on the surface t e n s i o n of copper has a l s o been evaluated (see Figure 3) LV ( e r g s , -6^ )1 12 11 XIO 2 10 8 01 0-2 0-3 0-4 0-5 0-6 [0] atm% 22 Figure 3. E f f e c t of Oxygen on the Surface Tension of Copper (1200°C). D. Other Related Work 23 2A 23 26 Eremenko ' ' et a l . and Knox and Baker have s t u d i e d the i n t e r f a c i a l energy of l i q u i d copper, n i c k e l and s i l v e r , i n contact w i t h alumina, at v a r i o u s oxygen p o t e n t i a l s . In the i n v e s t i g a t i o n of the silver-oxygen-alumina system 23 Eremenko and N a i d i c h suggested that the increase i n w e t t i n g of the alumina by s i l v e r , w i t h i n c r e a s i n g oxygen c o n c e n t r a t i o n , could be a t t r i b u t e d to a surface f i l m of oxide on the s i l v e r . This monolayer was reported to form both at the metal-ceramic i n t e r f a c e and at the metal-vapor i n t e r f a c e . They a l s o suggested that once the surface f i l m was formed no f u r t h e r spreading 26 occurred. Knox and Baker showed that f u r t h e r spreading occurred w i t h increase i n oxygen p o t e n t i a l beyond the re g i o n s t u d i e d by Eremenko and Na i d i c h . Knox and Baker explained t h i s behavior by suggesting e i t h e r the formation of a compound, AgAlC^ or the accumulation of Ag^O at the i n t e r f a c e . S i m i l a r l y i n t h e i r study of the nickel-oxygen-alumina system, 24 Eremenko and N a i d i c h found a r e d u c t i o n i n the i n t e r f a c i a l energy of n i c k e l w i t h the a d d i t i o n of oxygen. They a l s o a t t r i b u t e d t h i s to a surface f i l m of oxide. 25 Analogous r e s u l t s were reported f o r the copper-oxygen-alumina 2 system. I n t e r f a c i a l energy was found to drop from 1370 ergs/cm down to 2 530 ergs/cm as the oxygen increased from 0 to 0.88 percentage by weight. E v a u l a t i o n of t h i s data u s i n g the Gibb's equation suggests a surface l a y e r formation at the g a s - l i q u i d i n t e r f a c e to a maximum value of 34 x 10 ^ ^molqs/ 2 cm . E. Aim of Present I n v e s t i g a t i o n 15 16 25 26 Previous s t u d i e s ' ' ' have suggested that the a d d i t i o n of oxygen to l i q u i d copper tends to reduce the i n t e r f a c i a l energy and promote spreading. In these s t u d i e s the oxygen a d d i t i o n s were g e n e r a l l y i n l a r g e concentrations and l i t t l e attempt was made to c o n t r o l oxygen p a r t i a l pressure above the d r o p l e t s . Some of the i n v e s t i g a t o r s d i d not attempt to determine how much of the o r i g i n a l oxygen was l e f t a f t e r the experiments. A l s o some of the work was c a r r i e d out using p o l y c r y s t a l l i n e alumina p l a t e s , at the s u b s t r a t e . To overcome these problems i t was proposed i n t h i s study to s t a r t w i t h pure copper and melt t h i s on s i n g l e c r y s t a l sapphire (A^O^) d i s c s . In order to introduce a c e r t a i n amount of oxygen i n t o the copper and c o n t r o l the oxygen p o t e n t i a l , the atmosphere i n the closed chamber surrounding the specimen was r e g u l a t e d using a CO-CO^ gas mixture. With the use of thermodynamic r e l a t i o n s h i p s i t would be p o s s i b l e to determine the oxygen p o t e n t i a l i n the system and the amount of d i s s o l v e d oxygen i n the copper. I t was proposed a l s o t o use the s e s s i l e drop technique to determine the fundamental r o l e played by oxygen i n t h i s system. A f u r t h e r purpose of t h i s study was to i n v e s t i g a t e the pen-e t r a t i o n of copper i n t o sapphire. The dependence of copper p e n e t r a t i o n on pxygen p o t e n t i a l and time was to be evaluated. From t h i s study i t was hoped to determine whether the copper w i l l continue to penetrate, f o l l o w i n g the i n i t i a l m e l t i n g , and destroy the i n s u l a t i n g p r o p e r t i e s of the alumina and e l e c t r i c a l p r o p e r t i e s ( c o n d u c t i v i t y ) of the copper l a y e r . 9 I I . EXPERIMENTAL A. M a t e r i a l s 1. Sapphire The s i n g l e c r y s t a l d i s c s of sapphire (aluminum oxide) used throughout the i n v e s t i g a t i o n were s u p p l i e d by Adolf M e l l e r Company. Specimens were cut from 0.6 cm diameter s i n g l e c r y s t a l rods, so as to give two p a r a l l e l s u r f a c e , the top surface being p o l i s h e d to an o p t i c a l f i n i s h . The p o l i s h e d working surface was approximately p a r a l l e l to the (1012) plane. I The sapphire rods were produced from gamma-alumina powder having a maximum impurity of 200 ppm. During f a b r i c a t i o n the i m p u r i t y l e v e l was decreased, as s p e c t r o g r a p h s a n a l y s i s , c a r r i e d out i n the Geology Department of the U n i v e r s i t y revealed the f o l l o w i n g i m p urity l e v e l i n a t y p i c a l d i s c : Ca < 5 ppm, Cr ^ 4 ppm, Cu ^ 3 ppm Ga < 1 ppm, Mg 5 ppm, Mn ^ 8 ppm Na < 10 ppm, Pb ^ 1 ppm, S i 'V 15 ppm i .' } • This a n a l y s i s i n d i c a t e s i m p u r i t y of approximately 51 ppm maximum, a considerable improvement over the o r i g i n a l i m p u r i t y l e v e l of 200 ppm i n the alumina powder. 10 2. Copper Copper was su p p l i e d by the American Smelting and R e f i n i n g Company i n the form of 99.999+% copper rods. S p e c t r o g r a p h s a n a l y s i s s u pplied w i t h the rod l i s t e d i m p u r i t y l e v e l s as f o l l o w s : Fe < 0.7 ppm, Sb < 1 ppm, Pb < 1 ppm, Sn < 1 ppm N i < 1 ppm, B i < 0.1 ppm, Ag < 0.3 ppm, As < 2 ppm Cr < 0.5 ppm, S i < 0.1 ppm, Te < 2 ppm, Se < 1 ppm, S < 1 ppm. Swaging and machining were c a r r i e d out on the rods to produce c y l i n d r i c a l l y shaped specimens. These were 0.2 cm diameter f o r the we t t i n g experiments and 0.6 cm diameter f o r the d i f f u s i o n s t u d i e s . 3. Cupric Oxide Cupric oxide employed i n the d i f f u s i o n s t u d i e s was 99.999+% p u r i t y . I t was su p p l i e d by Johnson Matthey Chemicals L t d . , who reported the a n a l y s i s of i m p u r i t i e s as f o l l o w s : Cd = 5 ppm, Ba = 2 ppm, Bo < 1 ppm, Ca < 1 ppm, Mg < 1 ppm, Na < 1 pm. 4. Alumina and Cuprous Oxide To produce the s y n t h e t i c copper aluminate (CUAIO2), alumina and cuprous oxide (Ck^O) were used. The alumina (99.99+% p u r i t y ) was su p p l i e d by Koch and L i g h t Company and had i m p u r i t i e s l i s t e d as: Fe < 10 ppm, Na < 10 ppm, S i < 10 ppm, a l l others < 1 ppm The cuprous oxide was su p p l i e d by Rocky Mountain Research In,c. and was s p e c i f i e d as 99.999+% p u r i t y . Figure 4. Furnace f o r S e s s i l e Drop Experiments. These components were combined i n a s t o i c h i o m e t r i c mixture, blended and heated at 1000°C f o r twenty-four hours to produce CuAlO^ (See Appendix V I ) . Hot-pressing was used to give a dense button from which smaller c y l i n d r i c a l specimens were cut us i n g an u l t r a s o n i c c u t t e r . The f i n a l specimen diameter was 0.6 cm. B. Apparatus f o r S e s s i l e Drop Experiments The apparatus f o r c a r r y i n g out the s e s s i l e drop experiments c o n s i s t e d of three major components - furnace, atmosphere c o n t r o l l e r and o p t i c a l system. 1. Furnace S e s s i l e drop specimens were melted i n the furnace of the dilatometer apparatus (Theta I n d u s t r i e s , D i l a t r o n i c V, see Figure 4 ) . The alumina d i s c s were placed on a hi g h p u r i t y (99.9%) Al^O-j p l a t e r e s t i n g on alumina powder i n the tube of the furnace. Once the furnace was turned on i t took about 30 minutes to reach 1200°C. 2. Atmosphere C o n t r o l l e r In order to c o n t r o l the oxygen p a r t i a l pressure i n the furnace, carbon monoxide and carbon d i o x i d e gases were mixed. The mixture was regulated using flow meters. This mixture was then fed i n t o the furnace c o n t a i n i n g the specimen and back through a second furnace tp which was attached a c a l c i a s t a b i l i z e d z i r c o n i a oxygen probe (See Appendix I I ) . By measuring the p o t e n t i a l across the z i r c o n i a probe, between the furnace atmosphere and a i r , i t was p o s s i b l e to determine the oxygen p a r t i a l pressure i n the system. Figure 5 shows the atmosphere c o n t r o l l e r . 13 Figure 5. Atmosphere C o n t r o l l e r . 3. O p t i c a l System In order to a s c e r t a i n the exact shape of the molten copper drop on the sapphire s u b s t r a t e an o p t i c a l system f o r d i r e c t observatipn was constructed. This system c o n s i s t e d of a 300 mm telephoto lense mounted on the end of a 54 cm long s t e e l tube (Figure 6). An 8X o b j e c t i v e lense was a f f i x e d half-way along the tube and a 35 mm.single lense r e f l e x camera at the other end. Use of the s i n g l e lense r e f l e x camera allowed f o r d i r e c t observations as w e l l as to photograph the s e s s i l e drop. For t h i s purpope Kodak plus-X f i l m (ASA 125) was used w i t h exposure times of 1 to 2 seconds. C. Apparatus f o r D i f f u s i o n Experiments For the d i f f u s i o n experiments the CENTORR furnace was used. , This furnace was a tungsten f i l a m e n t surrounded by molybdenum heat s h i e l d s i n a water cooled copper chamber (Figure 7). A helium atmosphere was uped i n the furnace; under s l i g h t l y more than one atmosphere pressure. A c a l c i a s t a b i l i z e d z i r c o n i a oxygen probe was used to determine the p a r t i a l . pressure of oxygen i n the atmosphere above the specimens. D. Specimen P r e p a r a t i o n 1. Sapphire As the sapphire c y l i n d e r s arrived, w i t h two p a r a l l e l f a c e s , one o p t i c a l l y p o l i s h e d , very l i t t l e p r i o r p r e p a r a t i o n was r e q u i r e d . The sapphire c y l i n d e r s were washed w i t h e t h a n o l , d r i e d i n a bla^st of a i r , and weighed p r i o r to use. Figure 6. O p t i c a l System. Figure 7. CENTORR Furnace. 17 2. Copper Buttons Once machined the copper buttons were washed i n t r i c h l o r e t h e n e to remove machine o i l and stored i n a d e s i c c a t o r f i l l e d w i t h n i t r o g e n . Just p r i o r to use they were r i n s e d i n 50% HNO^ to remove surface contami-n a t i o n , washed w i t h water and ethanol and d r i e d immediately w i t h a b l a s t of a i r . A f t e r weighing the buttons used i n the s e s s i l e drop work were placed i n the furnace. The buttons used i n the d i f f u s i o n experiments were weighed and then had c u p r i c oxide placed i n t o the c a v i t y machined i n t o the specimen. These were subsequently weighed again to determine the amount of oxide added, and placed i n the furnace. E. Experimental Procedure 1. S e s s i l e Drop Experiments An alumina support p l a t e was placed at the bottom of the tube furnace i n order to give a h o r i z o n t a l base on which to r e s t the specimens. The sapphire c y l i n d e r s were then placed on the p l a t e and l e v e l was checked using a s t e e l sphere. Once l e v e l was achieved the smaller copper buttons were placed on top of the sapphir e , ( F i g u r e 8) the furnace r o l l e d i n t o p o s i t i o n and the s e a l s tightened. Gas va l v e s were turned on to give a fl o w of a de s i r e d mixture of C0-C0 2 and the over a l l flow was regulated w i t h an o i l bubbler. An approximate equal volume of gas flow was used f o r each t e s t . The fl o w was allowed to purge the system f o r one hour, checks were mac^ e to f i n d the oxygen p a r t i a l ;pressure i n the system and s l i g h t a d j u s t -ments were made to achieve the d e s i r e d atmosphere i f necessary. Once s t a b i l i t y was reached the furnace was switched on and allowed to reach 1200°C (h hour r e q u i r e d ) . Observations and photographs were taken of the 18 drop along w i t h checks of the oxygen p a r t i a l pressure. The furnace was switched o f f and allowed to c o o l down. A f t e r t h i s the gas flow was turned o f f , and the specimen was removed and weighed. Figure 8. S e s s i l e Drop Specimen P r i o r to M e l t i n g . 2. D i f f u s i o n Experiments A f t e r CuO a d d i t i o n s to the c a v i t y of the copper button (Figure 9) i t was placed on the sapphire and an alumina sleeve was placed over them. This sleeve prevented the molten copper from f a l l i n g o f f the sapphire. The copper-sapphire couples were placed i n a small alumina c r u c i b l e and lowered i n t o the heating zone of the furnace. The l i d of the furnace was b o l t e d on _3 and vacuum was a p p l i e d to out gas the system. Once the vacuum of 10 19 Figure 9. D i f f u s i o n Specimen P r i o r to M e l t i n g . atmospheres was obtained the system was purged w i t h helium. This procedure was repeated three times and then the chamber was f i l l e d w i t h helium u n t i l one atmosphere was reached. A s l i g h t flow of helium was maintained through-out the experiment u s i n g an o i l bubbler to assure a pressure s l i g h t l y h igher than one atmosphere. Once one atmosphere of helium was reached the furnace was switched on and allowed to reach 1200°C (approximately 15 minutes). The specimen was held at 1200°C f o r v a r i o u s periods of time. The furnace was switched o f f and the specimen was allowed to c o o l down (approximately h hour). A f t e r t h i s the helium flow was turned o f f and the specimen was removed and weighed. 3. E l e c t r o n Probe M i c r o a n a l y s i s A f t e r weighing, the alumina sleeves were removed and the sapphire p o r t i o n of the couple was cut lengthwise by a diamond saw. The copper p o r t i o n of the couple was then cut usi n g a j e w e l l e r s saw. A f t e r mounting 20 and p o l i s h i n g (to l u diamond paste) a carbon f i l m was deposited on the surface to avoid charge build-up d u r i n g examination i n the e l e c t r o n probe microanalyser. A n a l y s i s was then c a r r i e d out on the JOELGO E.P.M. A number of runs were made p a r a l l e l to the i n t e r f a c e and si n c e no appreciable change was noted i n p e n e t r a t i o n across the specimen, f i v e random l o c a t i o n s were chosen across the i n t e r f a c e . From these l o c a t i o n s , a n a l y s i s was c a r r i e d out f o r copper i n the alumina i n steps perpendicular to the i n t e r f a c e . Both copper and aluminum were monitored and counts over ten second i n t e r v a l s were recorded. In order to determine the amount of copper present i n the sapphire, comparisons were made w i t h standards of copper, and alumina. Considering oxygen as the only other element present, c o r r e c t i o n s were a p p l i e d to convert counts i n t o weight percent copper u s i n g the MAGIC (Microprobe A n a l y s i s General I n t e n s i t y C o r r e c t i o n ) computer program. S i m i l a r analyses were a l s o c a r r i e d out on some of the sapphire-copper specimens produced during the s e s s i l e drop experiments. 4. M i c r o s t r u c t u r e Examination The specimens prepared f o r a n a l y s i s on the e l e c t r o n probe microanalyser were a l s o examined us i n g an o p t i c a l microscope, I n t e r f a c e regions as w e l l as i n t e r n a l s t r u c t u r e s were observed and i n a l l cases r e p r e s e n t a t i v e photographs were taken. 5. Scanning E l e c t r o n Microscopy A number of the beads produced during the s e s s i l e drop exper-iment were examined i n the ETEC scanning e l e c t r o n microscope. Also some of the i n t e r f a c e regions of the d i f f u s i o n couples were examined. Representative photographs were taken. 21 I I I . RESULTS ANJJ DISCUSSION. , , , A. S e s s i l e Drop Experiments 1. Contact Angle Measurements From the photographs of the molten copper drop on the sapphire d i s c s (Figure 10) the contact angle was measured, at a s p e c i f i c oxygen p a r t i a l pressure (Appendix I I ) . The decrease In contact angle w i t h i n c r e a s i n g oxygen p a r t i a l pressure Is obvious from these photographs. The angle goes from an obtuse angle at a p a r t i a l pressure of oxygen at 3.98 x —16 —5 10 (10.a) to about a r i g h t angle at a p a r t i a l pressure of 3.22 x 10 ( l O . f ) . Complete r e s u l t s are t a b u l a t e d i n Appendix IV. On the b a s i s of these tabulated r e s u l t s a p l o t of contact angle versus pO^ was produced, on a semi-log s c a l e (Figure 11). I t appears from Figure 11 that; the r e l a t i o n s h i p i s l i n e a r over the range s t u d i e d . The maximum contact angle found was at a p a r t i a l pressure of oxygen of 3.98 x 1Q and was 123°-125°. This value i s c o n s i d e r a b l y lower than the reported e q u i l i b r i u m 27 value of 163° f o r supposedly pure copper, on sapphire, i n vacuum. Probably thijS d i f f e r e n c e i s due to the a d s o r p t i o n of CO to the surface of the molten copper. In f a c t the values f o r surface tension of l i q u i d copper 15b 22 2 2 i n vacuum and CO have been reported as 1172 ergs/cm and 1250 ergs/cm r e s p e c t i v e l y . 22 e - P „ 2 - 1.48 x 1(T 6 f - Po 2 - 3.22 x W' Figure 10. S e s s i l e Drops at Various Oxygen P o t e n t i a l s . (17x) 2. I n t e r f a c i a l Energy Taking the values of 9 at v a r i o u s p a r t i a l pressures of oxygen (Figure 11) the i n t e r f a c i a l energy can be c a l c u l a t e d u s i n g the Young-Dupr r e l a t i o n s h i p Y S L = YSV " YLV C O S 6 where y C T = copper-Al„0„ i n t e r f a c i a l energy y = A1_0_ - vapour i n t e r f a c i a l energy Y T„ = copper-vapour i n t e r f a c i a l energy. 23(a) To solve t h i s equation, the v a l u e f o r the s o l i d - v a p o r i n t e r f a c i a l 2 28 energy was taken as 748 ergs/cm. , a t 1200°C. The va l u e s f o r l i q u i d - v a p o r i n t e r f a c i a l energies were found u s i n g the Bashforth and 40 Adams a n a l y s i s . The values found employing t h i s technique had a rat h e r l a r g e s c a t t e r and th e r e f o r e were compared to those values found by Monma and Suto (from f i g u r e 3 ) . Figure 11-a shows that the values found i n the present study agreed reasonably w e l l w i t h those r e p o r t e d by Monma and Suto. F i g u r e 11-a Y T T 7 versus l o g [0~] 24 From these data a p l o t of i n t e r f a c i a l energy as a f u n c t i o n of l o g a r i t h m of the oxygen p a r t i a l pressure has been produced (Figure 12). 14 X I O 2 12 1 0 -8 10-16 |Q-<4 | 0 " 1 2 I 0 " 1 0 I 0 " 8 I 0 " 6 I 0 " 4 I0" 2 pOg (atm) Figure 12. y g L Versus pG^ ( l o g s c a l e ) -16 —3 From a p a r t i a l pressure of oxygen of 3.98 x 10 to 5.07 x 10 2 2 the i n t e r f a c i a l energy v a r i e s from 1429-1465 ergs/cm to 667-798 ergs/cm . This v a r i a t i o n would e x p l a i n the change i n contact angle from a c o n d i t i o n of very l i t t l e w e t t i n g to p r o g r e s s i v e l y b e t t e r w e t t i n g as the oxygen p a r t i a l pressure increases. The r e l a t i o n s h i p appears to be l i n e a r ( i n a semi-l o g a r i t h m i c p l o t ) up to a p a r t i a l pressure of oxygen of approximately 10 , beyond which the Y g L values tend to approach a constant a s y m p t o t i c a l l y . This could be due to the formation of an i n t e r f a c i a l b a r r i e r J e i t h e r a 16 25 d i s t i n c t compound or an oxygen l a y e r . 3. Adsorption Isotherms 22 Monma and Suto have found that the surface t e n s i o n of l i q u i d copper v a r i e s w i t h oxygen content (Figure 3). From t;heir curve, oxygen i 29 adsorption on the l i q u i d - v a p o u r i n t e r f a c e was c a l c u l a t e d u s i n g Gibbs' equation (see Appendix I) i n the form: RT 8C 2 where: Y TT 7 = surface t e n s i o n (ergs/cm ) JjV C = [0] at % R = gas constant T = temperature (°K) 2 T = coverage (mol/cm ) The use of t h i s form of the equation i s v a l i d f o r low c o n c e n t r a t i o n of surface a c t i v e elements, which i s the case when oxygen i s d i s s o l v e d i n a l i q u i d metal. Values of . were found by d i f f e r e n t i a t i n g the curve of surface t e n s i o n versus composition and from these values the adsorption isotherm was evaluated (Figure 13). , The a d s o r p t i o n isotherm goes through a maximum of about -10 2 14.3 x 10 mol/cm at an oxygen concentration of about 0.14 a t . % [ 0 ] . I f t h i s value was taken as being equal to the surface c o n c e n t r a t i o n , then i n t e r f a c e the surface occupied by one oxygen i o n on the l i q u i d - v a p o r / c a n be c a l c u l a t e d from the expression where N = Avogadro's number. —16 2 This value was found to be 11.6 x 10 cm . r 1 IV (mol [0] otm% Figure 13. Adsorption Isotherm ( l i q u i d - v a p o r ) . An oxygen i o n i n the s t r u c t u r e of a densely-packed f i l m on a O =2 surface has an i o n i c r a d i u s of 1.32A. Hence one 0 i o n occupies 6.04 x —16 2 10 cm . Taking i n t o account the discrepancy between t h i s value and that derived from the experimental r e s u l t s , and the f a c t that r e p u l s i v e forces e x i s t between oxygen ions i t i s not l i k e l y the f i l m was densely packed oxygen i o n s . I f i t i s assumed that each oxygen i o n was a s s o c i a t e d w i t h two C u + i o n s of r a d i u s 0.96A then the oxide f i l m would have occupied a l a r g e r area per oxygen i o n . The area occupied i n a densely packed f i l m 16 2 16 2 H~ i s 3.19 x 10 cm or 6.38 x 10 cm f o r 2 Cu i o n s . Therefore the + = —16 2 t o t a l area f o r 2 Cu ions and one 0 i o n i s 12.4 x 10 cm , which agrees —16 2 w i t h the experimental value of 11.6 x 10 cm . I t appears that on phe b a s i s of t h i s c a l c u l a t i o n the l i q u i d - v a p o r i n t e r f a c e was covered w i t h a f i l m of Cu^O, at and beyond an oxygen content of 0.14 a t . % The s o l i d - l i q u i d i n t e r f a c i a l energy can be p l o t t e d as a f u n c t i o n of d i s s o l v e d oxygen by i n v o k i n g S i e v e r t ' s Law to evaluate the amount of d i s s o l v e d oxygen (Figure 14). . r S L (ergs - cm2) 14 XIO 2 12 10 8 10"? ICf 4 IO"3 I0"2 10"' 10° 10' [0] a t m % Figure 14. Y g L Versus [0] atm.% ( l o g scale) Again applying the Gibbs' equation i t i s p o s s i b l e to construct the adsorp-t i o n isotherm f o r the s o l i d - l i q u i d i n t e r f a c e (Figure 15). Comparing the two adsorption isotherms i t appears that the oxygen was f j.rst adsorbed at the l i q u i d - v a p o r i n t e r f a c e and then at the s o l i d - l i q u i d i n t e r f a c e . A maximum of the s o l i d - l i q u i d adsorption isotherm was taken to be at 18.78 -10 2 atomic percent oxygen as 5.37 x 10 mol/cm . Determining the area occupied by each adsorbed species (S = —•) gave an apparent area per i o n I I I | l I I I I. IO" 5 I 0 " 4 I0" 3 IO" 2 10"' 10° I0 1 [0] atm % Figure 15. Adsorption Isotherm ( s o l i d - l i q u i d ) [ 0 ] atm.% - l o g s c a l e ) . Comparing t h i s value to the area occupied by each adsorbed species at the g a s - l i q u i d i n t e r f a c e , i t i s apparent that the i n t e r f a c e i s not as densely packed i f only a monolayer of oxygen or Cu 20 i s considered. However, i f i t i s assumed that Cu 20 i s adsorbed and t h a t f o r each molecule C^O one of A^O^ i s associated w i t h i t then the area a s s o c i a t e d w i t h the adsorption of eaeh oxygen i o n from the atmosphere can be c a l c u l a t e d . The area f o r each —16 I I I molecule of Cu o0 i s 12.4 x 10 and s i n c e the i o n i c r a d i u s of AI 29 o -16 2 i s 0.51A i t s area w i l l be 0.9 x 10 cm . Two aluminum ions and three —16 2 oxygen ions w i l l then occupy 19.9 x 10 cm . The t o t a l area a s s o c i a t e d —16 2 w i t h each adsorbing oxygen i o n i s then 32.3 x 10 cm . This value i s i n —16 2 good agreement w i t h the experimental value of 32.1 x 10 cm . The agreement between experimental and c a l c u l a t e d values f o r the two i n t e r f a c e s i n d i c a t e s that a Cu^O f i l m e x i s t s at the l i q u i d - v a p o r i n t e r f a c e and a CuAlGv, f i l m e x i s t s at the s o l i d - l i q u i d i n t e r f a c e , (Note: Cu„0 + A l 0 —>• 2CuA10 o). 1 2 3 2 4. Work of Adhesion By lowering the surface t e n s i o n at both l i q u i d i n t e r f a c e s ( l i q u i d -vapor and s o l i d - l i q u i d ) the bond strength between the metal and ceramic would i n c r e a s e , as i n d i c a t e d by the increase i n wetting. The work r e q u i r e d to rupture t h i s bond, w h i l e the metal i s i n the l i q u i d s t a t e , i s c a l l e d the work of adhesion. By d e f i n i t i o n i t i s given as: W A = YLV + YSV ~ Y S L ^ S 6 e A P P e n d i x I ) This d e f i n i t i o n was a p p l i e d to data p r e v i o u s l y reported and the r e l a t i o n -ship of the work of adhesion to oxygen content was found (Figure 16). I t appears that the maximum adhesion of the copper to the sapphire substrate occurs at about 0.01 atomic percent oxygen. 5. I n t e r f a c i a l Radius Considering the spreading of the drop w i t h oxygen a d d i t i o n s can a l s o i n d i c a t e what r o l e the oxygen takes i n promoting w e t t i n g . The ' 2 i n t e r f a c i a l area can be expressed i n terms of the b a s a l r a d i u s as Trr . 2 2 The increase i n t h i s area [ i . e . tr(r - r )] should be a f u n c t i o n of the o 500-. !—j ; — — : — u , — : 1 - , , 10 10 [ 0 Z IO1 [0] atm % Figure 16. Work of Adhesion Versus, [0] atm.% ([0] atm.% - l o g scal§). a c t i v i t y of oxygen. Since the a c t i v i t y can be approximated, at low con-c e n t r a t i o n s by the co n c e n t r a t i o n , then a l i n e a r r e l a t i o n s h i p should e x i s t between the d i f f e r e n c e i n area and l o g [0 ] . The r a d i u s , and hence the degree of spreading, was measured as 2 2 a f u n c t i o n of log^IO]. These data are p l o t t e d as r r versus l o g e [ 0 ] as i s Figure 17. This p l o t i n d i c a t e s that as expected the spreading was d i r e c t l y p r o p o r t i o n a l to the lo g a r i t h m of oxygen c o n c e n t r a t i o n , and hence the l o g a r i t h m of a c t i v i t y at low concentrations of oxygen. Which means that the i n t r o d u c t i o n of oxygen i n the system a l t e r s the chemical p o t e n t i a l , which enhances spreading by i n c r e a s i n g the i n t e r f a c i a l area. This i s p o s s i b l e , i f the y i s higher than y ( i n t h i s case spreading w i l l J _ i V t>J-i decrease the t o t a l f r e e energy of the system) or i f oxygen being a surface a c t i v e agent lowers the surface t e n s i o n of the l i q u i d copper (which was confirmed by Monma and Sato) and as c a l c u l a t i o n showed that the i n t e r f a c i a l area i s covered by a surface l a y e r which can i n t e r a c t w i t h A^O-j to lower 27 the Y S L J as AF f o r the r e a c t i o n between Cu ?0 and A1 90^ i s h i g h l y negative. 31 E 00100 00050 -16 -12 • 8 log, [cj ( [of in atm- °/9) Figure 17. Spreading Versus l o g e [ 0 ] 6. Examination of S o l i d i f i e d Drops A number of the s o l i d i f i e d drops were examined i n an o p t i c a l microscope, i n the scanning e l e c t r o n microscope and i n the e l e c t r o n probe microanalyser. On examination i n an o p t i c a l microscope i t was found that upon s o l i d i f i c a t i o n some of the oxygen was trapped i n the copper and formed an e u t e c t i c . The amount of e u t e c t i c formed was o b v i o u s l y dependent on the p a r t i a l pressure of oxygen i n the system and hence on the d i s s o l v e d oxygen (Figure 18). Examination of the tops of the specimens a l s o showed a marked d i f f e r e n c e i n the e x t e r n a l s t r u c t u r e of the drops as w e l l (Figure 19). Upon s o l i d i f i c a t i o n the specimens w i t h higher oxygen content had a very i r r e g u l a r s u r f a c e , due to the formation of l a r g e copper g r a i n s w i t h copper-oxygen e u t e c t i c at the g r a i n boundaries. In f a c t i r r e g u l a r i t i e s i n the 32 Figure 18. Eutectic Structure Sessile Drops. (350x). a. pC>2 = 3.98 x 10 ^ atmospheres. -6 b. pC^ = 2.16 x 10 atmospheres Figure 19. Top Surface of S o l i d i f i e d Drops. (lOOx) surfaces were observed i n specimens subjected to an atmosphere of oxygen greater than 10 ^ atmospheres. Cut and p o l i s h e d specimens examined on the e l e c t r o n probe microanalysers i n d i c a t e d that copper penetrated i n t o the alumina. Copper was detected up to approximately 100 microns. An approximation of the pen e t r a t i o n under the drops appeared as i n Figure 20. L_J i _ , i , i centre 0 05 010 015 distance (cm) Figure 20. Copper P e n e t r a t i o n Under S e s s i l e Drop. Figure 20 i n d i c a t e s that the copper penetrates d i r e c t l y under the drop, and not to the si d e of i t . More p e n e t r a t i o n occurs toward the centre of the drop as compared to the edges. 35 B. D i f f u s i o n Experiments In order to determine i f the copper penetrates by a d i f f u s i o n a l process, to determine the dependence of the penetration on time and oxygen content and to examine f u r t h e r the copper microstructures upon s o l i d i f i c a t i o n , l a r g e r d i f f u s i o n couples were prepared. Experiments were c a r r i e d out at 5, 20, 60 and 240 minutes, w i t h oxygen a d d i t i o n s of 0.13, 0.27, 0.57 and 1.39 wt.% f o r each time. A n a l y s i s of the helium atmosphere above the specimens, using a zirconium oxygen sensor s i m i l a r to that used f o r s e s s i l e drop work, i n d i c a t e d a very low oxygen p a r t i a l pressure. The oxygen p a r t i a l pressure -13 was of the order of 10 atmospheres i n a l l runs regardless of the amount of oxide added to the copper specimens. A t y p i c a l specimen upon removal from the furnace appeared as i n Figure 21. Figure 21. A D i f f u s i o n Specimen 36 1. I n t e r f a c i a l Region The cut and p o l i s h e d specimens were examined under the e l e c t r o n probe microanalyser. I n s p e c t i o n of the absorbed e l e c t r o n image (Figure 22) i n d i c a t e d that a d i s t i n c t i n t e r f a c i a l zone was formed. I t appears that two d i s t i n c t regions e x i s t i n the i n t e r f a c i a l zone. One region immediately adjacent to the alumina surface appears to be f a i r l y narrow and i s p o s s i b l y an adsorbed f i l m . In a d d i t i o n to t h i s region another l a r g e r region i n the copper adjacent to the f i r s t r e g ion appears to have a r e l a t i v e l y l a r g e amount of copper-oxygen e u t e c t i c . Monitoring the X-rays f o r copper and aluminum (Figure 23) i n d i c a t e s that at the i n t e r f a c e the copper p o r t i o n i s s l i g h t l y d e f i c i e n t i n copper, having a l a r g e r amount of e u t e c t i c . This d e f i c i e n c y suggests the formation of a f i l m at the i n t e r f a c e , of e i t h e r oxide or copper aluminate. a. Aluminum Figure 23. X-Ray Images (2075x). The production of a surface l a y e r f i l m was at lower oxygen concentrations than p r e d i c t e d by the s e s s i l e drop work. This was probably due to the decrease i n r a t i o of l i q u i d - v a p o u r i n t e r f a c e i n comparison to the l i q u i d - s o l i d i n t e r f a c e due to the d i f f e r e n c e i n shape of the specimens and due to the use of an alumina sleeve. 2. Copper P e n e t r a t i o n i n Alumina P r e l i m i n a r y runs c a r r i e d out p a r a l l e l to the i n t e r f a c e i n d i c a t e d that p e n e t r a t i o n of copper i n t o alumina was constant from one s i d e of the specimen to the other. F i v e random l o c a t i o n s were chosen across each specimen. C h a r a c t e r i s t i c X - r a d i a t i o n f o r copper and aluminum was monitored and recorded f o r ten second counts at steps p e r p e n d i c u l a r to the i n t e r f a c e . These values were analysed using the "MAGIC" program (See Appendix V) and c a l c u l a t i n g the concentration of oxygen by d i f f e r e n c e . Figures 24-29 i n c l u s i v e are p l o t s of the copper concentrations p r o f i l e s beyond 20u i n the alumina. The region from the i n t e r f a c e to 20u was not i n c l u d e d as the s c a t t e r of data and the f a i l u r e of c o r r e c t i o n procedures i n these regions allowed only q u a l i t a t i v e a n a l y s i s . S c a t t e r was due i n part to the i r r e g u l a r nature of t h i s r e g i o n . From Figur e s 24-29 i t appears that the p e n e t r a t i o n of copper i n t o alumina i s constant w i t h time and oxygen co n c e n t r a t i o n . Further i t appears that copper i s d e t e c t a b l e up to about 300u. The l a c k of dependence of the c o n c e n t r a t i o n p r o f i l e s on time i n d i c a t e s that the p e n e t r a t i o n of copper i n t o alumina was not a t r u l y d i f f u s i o n a l process. I t appears that the copper penetrated i n t o the alumina, w i t h i n the f i r s t f i v e minutes (they wpre i n c o n t a c t ) , and then stopped. Further p e n e t r a t i o n probably occurs, but t h i s w i l l be very slow as i t would p o s s i b l y be due to d i f f u s i o n . The p e n e t r a t i o n of cppper as noted i n 40 Figure 27. Copper P e n e t r a t i o n i n t o AI 0 ([0] =r 1.39 wt.%; time = 60 min). 0 8 0 6 0 4 0 2 h [0] (wt%)=OI3 time =240 min -L 4 0 80 120 160 200 240 280 distance (microns) Figure 28. Copper P e n e t r a t i o n i n t o A1 20 ([0] = 0.13 wt.%; time = 240 min) 10 08 ? I 06| 04 02 oL [o] ( w t % ) = l 3 9 time = 240 min-4 0 80 120 160 ^ 2 0 0 240~ distance (microns) 280 Figure 29. Copper P e n e t r a t i o n i n t o A1 20 ([0] = 1.39 wt.%; time = 240 min) 42 Figures 26-29 i s probably c o n t r o l l e d by some r e a c t i o n which occurs r a p i d l y as soon as the copper melts. The e x i s t e n c e of a r a p i d r e a c t i o n at f i r s t m e l t i n g i s supported by the obs e r v a t i o n of the s e s s i l e drops. These specimens were noted on mel t i n g to form a rounded drop which changed shape w i t h i n the f i r s t few seconds and then assumed a shape which d i d not a l t e r w i t h time. The l a c k of dependence of p e n e t r a t i o n on oxygen content, i n the region of 0.13-1.39 [0] wt.%, i n d i c a t e s that very l i t t l e oxygen i s r e q u i r e d i n order to a l l o w p e n e t r a t i o n to occur. A l s o w i t h i n the given range of compositions f u r t h e r copper p e n e t r a t i o n does not occur w i t h increased oxygen concentrations. This f a c t allows f o r the s e l e c t i o n of the most advantageous oxygen con c e n t r a t i o n (up to 1.8 wt.%) to be based s o l e l y on co n s i d e r a t i o n s of bond stre n g t h and copper m i c r o s t r u c t u r e s . ; 43 Copper P e n e t r a t i o n Without Oxygen Present In order to determine i f any p e n e t r a t i o n occurs without any oxygen, two experiments were c a r r i e d out w i t h no oxygen added. With no oxygen present the copper d i d not wet the alumina, as i n d i c a t e d by the curvature of the copper c l o s e to the alumina i n t e r f a c e (Figure 30). Figure 30. Specimen w i t h no Oxygen A d d i t i o n (4 hours h o l d i n g time). 44 Once removed from the alumina sleeve the copper drop could be e a s i l y separated from the alumina drop w i t h very l i t t l e e f f o r t . Once cut and po l i s h e d the alumina i n d i c a t e d v i r t u a l l y no p e n e t r a t i o n of copper (Figure 31) 0 8 0 4 0 2 4 0 8 0 120 - l 160 2 0 0 2 4 0 distance (microns) 2 8 0 Figure 31. Copper P e n e t r a t i o n w i t h no Oxygen Present, The s l i g h t c oncentration of copper noted r i g h t at the i n t e r f a c e i s probably due to some s t i c k i n g at the alumina surface due p o s s i b l y - t o oxygen i m p u r i t i e s or roughness at the i n t e r f a c e . 5. Copper Aluminate D i f f u s i o n In order to determine the e f f e c t of a CuAlO^ phase at i j:he i n t e r f a c e , s y n t h e t i c CuAK^ was produced (see Appendix V I ) . A couple w i t h copper-CuA102-alumina was produced and hel d at 1200°C f o r four hours. Very l i t t l e p e n e t r a t i o n occurred as i n d i c a t e d by the ease of p u l l i n g the 45 v a r i o u s phases apart (Figure 32). The l a c k of p e n e t r a t i o n of copper i n t o Figure 32. Cu-CuAlO -AI 0 Couple. the copper aluminate and the subsequent l a c k of p e n e t r a t i o n of copper i n the alumina i n d i c a t e s that i f CuA10 2 was produced at the i n t e r f a c e then no p e n e t r a t i o n of copper would occur. Any p e n e t r a t i o n that does occur must have been p r i o r to the formation of t h i s phase at the i n t e r f a c e . This statement i s i n agreement w i t h the p r e v i o u s l y noted r e s u l t s , that copper penetrates r a p i d l y and then stops. The p e n e t r a t i o n was probably during the spreading of the oxygen across the i n t e r f a c e p r i o r to the formation of an intermediate phase. 6. I n t e r f a c e M i c r o s t r u c t u r e s Examinations were c a r r i e d out on the scanning e l e c t r o n and o p t i c a l microscopes. A number of specimens were f r a c t u r e d w h i l e being removed from the alumina sleeves. The copper appeared to have a good bond with the alumina as pieces of alumina were s t i l l attached to the copper. I t 46 appeared that the i n t e r f a c e was at l e a s t as strong as the alumina. In f a c t i n areas where a crack was propogated along the i n t e r f a c e , i t would stop and continue through the alumina c r y s t a l (Figure 33). The zone on the l e f t s i de of Figure 33 represents f r a c t u r e through the i n t e r f a c e and the zone to the r i g h t through the alumina. Figure 33 t Fracture Surface. Fracture through the i n t e r f a c e was probably promoted by voids which were developed on some specimens (Figure 34). A c l o s e r examination of these h o l e s ' ( F i g u r e 35) i n d i c a t e d a very s i m i l a r s t r u c t u r e as found on -6 the top of s e s s i l e drops above 10 atmospheres oxygen (Figure 19(b)). This would i n d i c a t e that a l o c a l pocket of oxygen was probably trapped i n t h i s area causing formation of the v o i d and the subsequent s t r u c t u r e during s o l i d i f i c a t i o n . 47 Figure 35. S t r u c t u r e at Void. (800x) 48 Further examination, i n the scanning e l e c t r o n microscope, of the i n t e r f a c e of a specimen cut by a diamond saw i n d i c a t e d that i n a zone adjacent to the i n t e r f a c e the s t r u c t u r e i s d i f f e r e n t than i n the bulk of the copper. This wide region i s very s i m i l a r to the one observed on the e l e c t r o n probe absorbed e l e c t r o n image. Unfortunately the region immediately adjacent to the i n t e r f a c e i s not observable i n t h i s photograph. Figure 36. Scanning E l e c t r o n Microscope View of I n t e r f a c e . (3000x - 1.39 [0] wt.%) 7. Copper M i c r o s t r u c t u r e s Observations of the changes i n s t r u c t u r e of the copper with oxygen a d d i t i o n s were c a r r i e d out on the o p t i c a l microscope. The amount, of e u t e c t i c formed was increased w i t h i n c r e a s i n g a d d i t i o n of oxygen. Figures 37 to 40 show the e f f e c t of added oxygen on the m i c r o s t r u c t u r e of the copper. From these photographs i t i s obvious that w i t h progressive a d d i t i o n s of oxygen the conducting p r o p e r t i e s of the copper w i l l probably decrease due to increase i n the amount of copper-oxygen e u t e c t i c . On the b a s i s of the observations of the copper m i c r o s t r u c t u r e s i t i s obvious that to have a r e l a t i v e l y c l e a n copper p o r t i o n of the couple as l i t t l e oxygen as p o s s i b l e i s the most d e s i r a b l e . Considering t h i s f a c t w i t h the work of adhesion (Figure 16) i t would appear that an oxygen - 2 content of about 10 atomic percent i s probably optimum. This could be achieved by mel t i n g the copper on the alumina su b s t r a t e i n an atmosphere - 8 w i t h a p a r t i a l pressure of oxygen of about 10 atmosphere. C. A F i t of Data f o r y L>J_| A f i t of the data f o r Y CT t e r m s of constants and oxygen was found to be: YSL - Y S V - Y L V Q cos (95.5 - 2.20 l o g e 10=]) f o r l o g e I 0 = ] < —3.75 and Y S L = Y S V " Y L V -{126(3,65 + l o g ^ O " ] ) }{cos (95.5 - 2.20 l o g j p " ] ) } f o r l o g e [ 0 = ] > —3.75 These equations are based on the Young - Dupre1 equation, and show the e f f e c t of oxygen on the s o l i d - l i q u i d i n t e r f a c i a l energy. I t may be p o s s i b l e to apply t h i s equation to other s i m i l a r systems. 50 Figure 38. E u t e c t i c at 0.27 [ 0 ] wt.%. Figure 40. E u t e c t i c at 1.39 [0] wt.%. IV. CONCLUSION An i n v e s t i g a t i o n on the i n t e r f a c i a l r e a c t i o n , d i f f u s i o n and wetting behavior between molten copper and sapphire has been c a r r i e d out —3 —16 under c o n t r o l l e d oxygen p a r t i a l pressure i n the range 10 to 10 atmosphere. It was found that the contact angle (0) was d i r e c t l y p r o -p o r t i o n a l to log p 0 2 w i th in the range of p 0 2 used. S i m i l a r l y the s o l i d -l i q u i d i n t e r f a c i a l energy was evaluated and found to be d i r e c t l y p r o -p o r t i o n a l to log p 0 2 up to a value of approximately 10 ^ atmosphere. Beyond 10 atmosphere,the s o l i d - l i q u i d i n t e r f a c i a l energy approaches a constant value asymptot ica l ly i n d i c a t i n g the formation of a b a r r i e r l a y e r . The Gibbs' adsorpt ion equation was used to evaluate the adsorpt ion of oxygen to the l i q u i d - v a p o r and s o l i d - l i q u i d i n t e r f a c e s . C a l c u l a t i o n s , based on the Gibbs' adsorpt ion equat ion, ind ica ted that the l i q u i d - v a p o r i n t e r f a c e was covered with a Cu 2 0 l a y e r and the s o l i d - l i q u i d i n t e r f a c e wi th a C u A l 0 2 l a y e r . These r e s u l t s were confirmed iis,ing t h e o r e t i c a l i o n i c r a d i i to determine coverage per i o n . Using the values of energies assoc iated with the two i n t e r f a c e s the work of adhesion was c a l c u l a t e d as a funct ion of concentrat ion of oxygen. -2 This showed that the work of adhesion reached a maximum at abput 10 atm.% oxygen. 53 The e f f e c t of oxygen on the b a s a l r a d i u s was a l s o used to evaluate the e f f e c t on spreading. I t was found that the change i n the contact area was d i r e c t l y p r o p o r t i o n a l to the l o g a r i t h m of oxygen content. Hence spreading was p r o p o r t i o n a l to the l o g a r i t h m of oxygen a c t i v i t y i n the system. Further i t was found that a d i s t i n c t i n t e r f a c i a l r e g i o n was e s t a b l i s h e d between copper and alumina, and that copper penetrated i n t o the alumina. The p e n e t r a t i o n was not dependent on time or oxygen content. Copper appeared to penetrate w i t h i n the f i r s t few minutes and the d i f f u s i o n -9 2 c o e f f i c i e n t was approximately 10 cm /sec. With no oxygen present, p e n e t r a t i o n was almost non-existent. The bond at the i n t e r f a c e was strong except i n regions where voids were formed. F i n a l l y the m i c r o ^ t r u c t u r e of the copper was found to vary w i t h oxygen content. From the Cu-0 phase diagram, i t i s expected that the amount of e u t e c t i c formed should increase w i t h i n c r e a s i n g oxygen a d d i t i o n and t h i s was experimentally confirmed. An attempt has been made to o b t a i n an equation based on the Young-Dupre equation, when the d i f f e r e n t energy values are a f f e c t e d by the oxygen p o t e n t i a l of the system. V. RECOMMENDATIONS FOR FUTURE STUDY Since i t has been shown that oxygen a d d i t i o n s a i d the we t t i n g of copper to alumina, i t would be u s e f u l to i n v e s t i g a t e the mechanical s t r e n g t h of the bond formed on s o l i d i f i c a t i o n of the drops. Further i t would be u s e f u l to study the mechanical p r o p e r t i e s of copper-alumina cermets as a f u n c t i o n of copper oxide a d d i t i o n s . I t should be p o s s i b l e to increase the stren g t h of these bodies w i t h only s l i g h t a d d i t i o n s of oxygen. Use of oxygen as a bonding agent f o r m i c r o c i r c u i t s could a l s o be i n v e s t i g a t e d . Of importance would be the e f f e c t of oxygen on the c o n d u c t i v i t y of t h i n copper f i l m . S i m i l a r work as c a r r i e d out i n the present study would a l s o be u s e f u l i n the n i c k e l - a l u m i n a system. Nickel-alumina composite would be more u s e f u l i n a p p l i c a t i o n where mechanical strengths at elevated temperatures are of importance. 55 APPENDIX I SESSILE DROP TECHNIQUE AND GIBBS' EQUATION A. S e s s i l e Drop Technique The theory of we t t i n g of ceramics by l i q u i d metals has been 31 o u t l i n e d i n d e t a i l by Taylor. Considering the shape of a molten drop on a s o l i d s u r f a c e , an e q u i l i b r i u m w i l l develop so that the i n t e r f a c i a l tensions w i l l tend to form a minimum o v e r a l l energy c o n f i g u r a t i o n . For small drops the true e q u i l i b r i u m at a s o l i d - l i q u i d metal-vapor i n t e r f a c e can be shown d i a g r a m a t i c a l l y as i n Fi g u r e 41(a) where: ffc„ = YCTT = i n t e r f a c i a l t e n s i o n between the s o l i d and vapor. OVJ b V a = y = i n t e r f a c i a l t e n sion between the l i q u i d and the vapor. cr = y T c = i n t e r f a c i a l t e n s i o n between the l i q u i d and the L o LD 1.1 s o l i d . 6 = contact angle - angle through l i q u i d , between l i q u i d and plane of s o l i d . ty = angle through l i q u i d , between l i q u i d and s o l i d -l i q u i d i n t e r f a c e . Thus the balance of for c e s when resolved h o r i z o n t a l l y i s : YSV = YLV C O S 9 + YLS C P S * and when v e r t i c a l l y i s : YLS S i n * = YLV S i n 6 56 Gas q f i (G) Q Liquid -Jjf-lU ?^"~~*Osi Solid (S) (a) °s t S o l i d ( S ) Figure 41. Contact Angle R e l a t i o n s h i p s . 31 (a) w i t h balance of v e r t i c a l components. (b) without balance of v e r t i c a l components. Under p r a c t i c a l c o n d i t i o n s the s o l i d can accomodate s t r e s s and the v e r t i c a l f orces seldom occur, and hence i n the m a j o r i t y of cases w e t t i n g described by the pseudoequilibrium c o n f i g u r a t i o n shown i n Figure 41(b). Thus the pseudo-e q u i l i b r i u m c o n d i t i o n can be s t a t e d as f o l l o w s : YSV = Y L S ' YLV C ° S 32,33. From the above r e l a t i o n s h i p the work of adhesion i s defined as f o l l o w s : ^ YLV + YSV^ Y S L = Y L V ( 1 + cos 6) Hence the work of adhesion can a l s o be derived from the pseudoequilibrium contact angle 0. B. Gibbs' Equation The e f f e c t of a d d i t i o n s to the l i q u i d melt i s d i c t a t e d by the change i n f r e e surface energy caused by the a d d i t i o n . P r e f e r e n t i a l surface adsorption of the a d d i t i o n r e s u l t s i r i a minimum f r e e surface energy. 2 9 Q u a n t i t a t i v e l y t h i s adsorption i s expressed by the Gibbs' adsorption equation r . - = 3 i i RT3(ln a±) and at low concentrations: r a# _ 3 Y 1 RT3(ln c ± ) 9c. and s i n c e : 3(In C J ) = - —— c 5 8 APPENDIX I I ZIRCONIA (CALCIA STABILIZED) PROBE FOR CONTROL OF OXYGEN ATMOSPHERE The design and operation of the oxygen probe have been o u t l i n e d 34 i n d e t a i l p r e v i o u s l y . B r i e f l y , t h e probe c o n s i s t e d of a closed c a l c i a s t a b i l i z e d z i r c o n i a tube w i t h platinum contacts on the i n t e r i o r and e x t e r i o r of the cl o s e d end. When the cl o s e d end was placed i n contact w i t h the gas to be measured and a reference gas of known oxygen content ( a i r 0 . 2 1 atm) a p o t e n t i a l was e s t a b l i s h e d across the z i r c o n i a tube. From t h i s p o t e n t i a l the oxygen p a r t i a l pressure i n the system could then be c a l c u l a t e d u s i n g the f o l l o w i n g thermodynamic r e l a t i o n s h i p : E = — • In o nF where: ^ ^ 2 ^ s = o x y S e n p a r t i a l pressure i n the system (atmospheres) ( p 0 2 ) r = reference oxygen p a r t i a l pressure (atmospheres) R = gas constant (calories/mole) T = temperature (°K) F = Faraday constant ( c a l / e q u i v . ) n = no. of molar equivalent (4 f o r 0^) The C 0 2 - CO gas e q u i l i b r i u m can be considered u s i n g the f o l l o w i n g equation: co 2 ^=±: CO + ho2 ( P V s ( P o 2 ) r [1] 59 from which: p(CO) • p ( 0 2 ) 2  K o plcOJ [2] s o l v i n g f o r p(C>2) g i v e s : p(o 2) K q p(C0 2) H2 p(CO) [3] 35 reported value f o r K q i s given as: l o g 1 0 K o = _M^57 + 4 > 5 2 8 [4] s u b s t i t u t i n g t h i s i n t o the above equation and t a k i n g logarithme y i e l d s : l°g 1 0 P 0 2 = 2 l o g p(co 2) P(CO) + 2 ( - 1 4 , 7 5 7 + 4.528) [5] S u b s t i t u t i n g [5] i n t o equation [1] gives the r e l a t i o n s h i p : E = o 2.30 RT nF p(co 2X l o g 1 0 ( P 0 2 ) r - 2 l o g 1 ( ) ^ 2( - 1 4 , 7 5 7 + 4.528) [6] P(C0 ) I t i s now p o s s i b l e to c a l c u l a t e the value of . * from equation [ 6 ] , p (.00) S u b s t i t u t i n g t h i s value i n t o equation [3] and s o l v i n g gives the oxygen p a r t i a l pressure i n the system. APPENDIX III SESSILE DROP DATA Run No. Measured 8 (deg) wt.AI2O3 (g) wt. Cu (g) F i n a l wt. (g) O2 probe Voltage Probe Temp.°C p(C0 2) P(C0) P o 2 X 201 1110-115° 0.6344 0.1145 0.792 0.707 941 1.90 1.81 X IO " 1 1 X 202 84°- 91° 0.6350 0.1122 0.7476 0.360 896 3.18 x 1 0 4 5.07 X 10" 3 X 203 108°-111° 0.6344 0.1156 0.7507 0.953 904 0.234 2.74 X IO " 1 3 X 205 112°-117° 0.6344 0.1054 0.7400 0.894 858 1.16 6.79 X IO" 1 2 X 206 109°-114° 0.6373 0.1131 0.7422 0.805 866 6.57 2.16 X IO " 1 0 X 207 H 5°-120° 0.6338 0.1093 0.7438 1.005 871 0.108 5.85 X IO" 1 4 X 208 123°-125° 0.6359 0.1060 0.7436 1.131 861 8.91 x IO" 3 3.98 X IO" 1 6 X 209 107°-110°' 0.6372 0.1113 0.7487 0.775 862 1.27 8.08 X IO" 1 2 X 210 107.5°-109° 0.6349 0.1147 0.7479 - 0.736 863 2.78 3.87 X IO " 1 1 X 211 100°-105.5° 0.6348 0.1142 0.7492 0.687 849 91.65 4.21 X IO" 8 X 212 90°- 94° 0.6369 0.1174 0.7548 0.591 862 5.43 x 1 0 2 1.48 X IO" 6 X 215 94°- 96° 0.6374 0.1100 0.7477 0.509 870 2.53 x 1 0 3 3.22 X IO - 5 APPENDIX IV SIEVERT'S LAW 19 Using the value f o r AF as given by Wilder y i e l d s the f o l l o w i n g : AF = 18,100 %0 y [0] at.pet. i n AF = RT InK -AF K = exp - ^ r R = 1.987 cal/mole °K T = 1200 + 273 °K K = 485 @ 1200°C 21 Hence S i e v e r t ' s Law can be w r i t t e n as f o l l o w s : [0] = 485 P 0 [at. % ] z 62 APPENDIX V ELECTRON PROBE MICROANALYSIS The use of the e l e c t r o n probe microanalyser to determine 36 concentrations of v a r i o u s species has been reviewed by Brown. In the present study counts taken f o r ten second i n t e r v a l s were analysed u s i n g 37 ^8 the "MAGIC" program, of Colby as adapted by O'Brien (Feb. 1970). This program c o r r e c t s raw microprobe X-ray i n t e n s i t y data f o r dead-time l o s s e s , background adsorption ( H e i n r i c h , Duncumb-Shields, P h i l i b e r t ) c h a r a c t e r i s t i c fluorescence (Reed), b a c k s c a t t e r l o s s e s (Duncumb) and i o n i z a t i o n - p e n e t r a t i o n l o s s e s ( P h i l i b e r t - T i x i e r ) , but uses the Berger-S e l t z e r values f o r the mean i o n i z a t i o n p o t e n t i a l . Use of t h i s program i s reported by Colby to give r e s u l t s to w i t h i n ± 4% ( r e l a t i v e ) of chemical a n a l y s i s . In the r e g i o n l e s s than ^ 20um from the s u r f a c e , the determin-a t i o n of the concentration of Cu was very u n r e l i a b l e due to two reasons. One - due to d i f f e r e n c e s i n the t h i c k n e s s of the i n t e r f a c e l a y e r l a r g e amounts of s c a t t e r occurred i n the data. Second - c o r r e c t i o n f a c t o r s i n t h i s r e g ion were very high (over 30% and c l o s e to the copper w e l l over 100%) and as a r e s u l t f i n a l composition would not be r e l i a b l e . Beyond ^ 20 microns however, s c a t t e r and c o r r e c t i o n f a c t o r s were acceptable. APPENDIX VI Y O T VALUES Run Number 6 (deg) * 2 Y L V (ergs/cm ) Y S L ( e r g £ 3/cm ) X 201 111 - 115 1250 1196 - 1276 X 202 84 - 91 776 667 - 798 X 203 108 - 111 1250 1134 - 1196 X 205 112 - 117 1250 1216 - 1315 X 206 109 - 114 1235 1155 - 1256 X 207 115 - 120 1250 1276 - 1373 X 208 123 - 125 1250 1429 - 1465 X 209 107 - 110 1250 1113 - 1176 X 210 107. 5- 109 1250 1124 - 1155 X 211 100 - 105.5 1080 935 - 1035 X 212 90 - 94 852 748 - 950 X 215 94 - 96 775 802 - 829 * see Figure 3. APPENDIX V I I X-RAY ANALYSIS The ASTM standard X-ray card f o r CuAlC^ i s given below. Comparison of the peaks on the d i f f r a c t i o n p a t t e r n taken (as on the f o l l o w i n g page) i n d i c a t e s that the m a t e r i a l produced was CuA10 o. 9-185 d 2.38 2.82 2.44 5.61 C U A L0 2 I/I. 100 80 80 30 COPPER ALUMINATE FUd. CuKa A 1.542 Filter Nl Dia. ? Cutoff I/I, V I S U A L Ref. HAHN AND LORENT, Z. ANIORG. A L L G E M . CHEM . 279 241 (i95f; Sys. RHOMB a,, 5.896 o 28.1° Ref. I B I D . OHEDRAL bo S S.G. D' 3 D - R3M Co A C y Z 1 Ox iQ 2V Ref. n IU & rnp Color Sign "HEXAGONA D 4.897 ISOSTRUC L: A0=2.849, C0=16.98, C=5.95, Z=l; D X 5.104, TURAL * I T H C U F E 0 2 ; N A H F 2 T Y P E . d A I/I. nil d A I/I, hkl HEXAGONAL 0.974 20 1.0.16 1NDICES .939 5 0.0.18 5.61 30 003 .93B 10 (211,212 2.82 80 006 (1.0.17 2.437 80 101 .912 10 214 2.376 100 102 2.133 50 104 1.877 20 009 1.732 10 107 1.612 50 108 1.426 40 110 1.401 30 1.0.10 1.274 40 116 1.225 20 202 1.188 10 204 1.14B 20 119,0.0.1! 1.089 10 1.0.14 1.069 30 208 1.00B 30 j 1.1.12 1 2.0.10 Figure 42. ASTM Standard X-ray Card. ure 43. D i f f r a c t i o n P a t t e r n f o r S y n t h e t i c CuAlO 66 BIBLIOGRAPHY 1. Helgesson, Claes I . , "Ceramic-to-Metal Bonding", Boston Tech. Pub. Inc., Cambridge, Mass. (1968). 2. van Houten, CR. , "A Survey of Ceramic-to-Metal Bonding", Am. Cer. Soc. B u l l . 38, (6) 301 (1959). 3. A l l e n , B.C. and Kingery, W.E., Trans. A.I.M.E. 215, 30 (1959). 4. S h e v l i n , T.S., J . Am. Cer. Soc. 37_, 140 (1954). 5. C a r t e r , R.E., i b i d . 44, 116 (1961). 6. Adams, R.B. and Pask, J.A., i b i d . 44, 430 (1961). 7. Campbell, J.B., M a t e r i a l s and Methods 31 (5) 59 (1950). 8. Kingston W.E., "The Physics of Powder M e t a l l u r g y " , 1st ed., McGraw-Hill, N.Y., (1951). 9. Pask, J.A. and F u l r a t h , R.M., J . Am. Cer. Soc. 45, 592 (1962). 10. Pincus, A.G., i b i d . 57, 359 (1953). 11. Widman, H., Glas-Email-Keramo-Technik 14 (6) 205 (1963). 12. Bron, V.A., Ogeneupory 16 (7) 312 (1951). 13. Comstock, G.E., (Norton Co.), U.S.P. 2, 618, 567 (1952). 14. Komatsu, N. and Grant, N.J., Trans A.I.M.E. 224, 705 (1962). 15a. M i s r a , S.K., M.A.Sc. t h e s i s , U n i v e r s i t y of B.C., p.34 (1964). b. i b i d . , p.22. 16. Chaklader, A.CD., Armstrong, A.M. and M i s r a , S.K., J . Am. Cer. Soc. 51 (11) 630 (1968). 17a. Metals Handbook, 7th ed. p.1199. b. Osterwald, J . , Z. M e t a l l . , 59, 573 (1968). 18. D i a z , CM. and Richardson, F.D., Trans. I.M.M. (Sect. C), 7_6, 196 (1967). 19. Wilder, Thomas C., Trans. A.I.M.E., 236, 1035 (1966). 67 20. Fruehan, R.J. and Richardson, F.D., Trans. A.I.M.E., 345, 1721 (1969). 21. Darken, L.S. and Gurry, R.W., P h y s i c a l Chemistry of Metals, McGraw-H i l l , N.Y., p.256-258 (1953). 22. Monma, Kaizo and Suto, Hajime, Trans. J.I.M., 2_, 148 (1961). 23. Eremenko, V.N. and N a i d i c h , Y.V., Akad. Nauk. Ukr. SSR, I n s t . M e t a l l . i Spets. Splav., p.100 (1961). 24. Eremenko, V.N. and N a i d i c h , Y.V., Ukr. Khim. Zhur. 23, 573 (1957). 25. Eremenko, V.N. N a i d i c h , Y.V., and Nosonovich, A.A., Russ. J . of Phys. Chem. 3A ( 5 ) , 1018, t r a n s l . p.484 (1960). 26. Knox, B.E. and Baker, E.H., J . of Mat. Sc. 7_, 476 (1972). 27. Gaddalla, A.M.M. and White, J . , Trans. B r i t . Cer. Soc. 63 (1) 39 (1964). 28. Rhee, S.K., J . Am. Cer. Soc. 55 (6) 300 (1972). 29. Gibbs, W.J., S c i e n t i f i c Papers, Dover, N.Y. V^JL (1961). 30. O i s h i , Y. and Kingery W.D., J . Chem. Phys. 33_ ( 2 ) , 480 (1960). 31. T a y l o r , J.W., Progress i n Nuclear Energy, S e r i e s V. M e t a l l u r g y and  F u e l s , eds. F i n n i s t o n and Howe, Pergamon Press, N.Y. V.2, 398 (1959). 32. Young, T., P h i l . Trans. 1805, p.74; Young, T., miscellaneous work, London, J . Murray, 1855, V.I. (ed. Peacock), p.432. 33. Duprd, A., "Thdorie mdchanique de l a chaleur'J P a r i s , G a u t h i e r - V i l l a r s , 1869, p.369. 34. Barton, R.G., M e t a l l u r g y 455 Report, Department of M e t a l l u r g y , U n i v e r s i t y of B r i t i s h Columbia, 1972. 35. Hagemrk, K. and B r o l i , M., J . Inorg. Nucl. Chem., V.28, 1966, p.2840. 36. Brown, L.C. and Thresh H., Tools and Techniques i n P h y s i c a l M e t a l l u r g y ed. Weinberg, F., Marcel Dekker, Inc., N.Y. V.2, p.600 (1970). 37. Colby, J.W., "MAGIC I I I - A Computer Program f o r Q u a n t i t a t i v e E l e c t r o n Microprobe A n a l y s i s " , B e l l T e l . Lab., Allentown, Penn. (1969). 38. O'Brien, T.E., "MAGIC Program" Dept. of M e t a l l u r g y , U n i v e r s i t y of B r i t i s h Columbia (1970). 39. P a l a d i n o , A.E. and Kingery, W.D. , J . Chem. Phys. 37_ (5) 957 (1962). 40. Bashforth, F. and Adams, J.C., "An Attempt to Test the Theories of C a p i l l a r y A c t i o n " , Cambridge, U n i v e r s i t y Press, 1883. 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0078718/manifest

Comment

Related Items