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Lubrication and chemical constitution 1923

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Lubrication and Chemical constitution by Stewart Robertson McDougall Lubrication and Chemical constitution by Stewart Robertson M c D o u g a l l A ? h « s l a • u b a l t t o d for tho Dogroo o f XA3TBB 0? APPLIED 3OI1H0S l a tho d o p a r t » « a t o f omaasTM THB tmXTSBSIK 0? BRITISH ICLI&BI* A p r i l , 1 9 2 3 . Introduction Purpcae of Reeeareh Barly Investigations {A) the Coefficient of friction of Dry Surfaces (b) 91M Coefficient of friction of Journal Bearings Recent Developments (a} Boundary lubrication and cillness t») ?iret Sxperiaents on Boundary Lubrication {oJ Tisoosity 2b«ory (d? 2fee Doeley &acblne (e) Hardy*s Metfto* and Results (fl Regions of lubrication Is a Soaring (gi Attempts to Measure Oiiinass by ?arlouo Methods Review of the Composition and Ohoaioal Satare of Lubricants Description of Apparatus Difficulties Bnaountared BSperinental Data (a) Steel on 3teel (1J Dry (11) Oleic Acid ( i l l ) Stearic &ei< ?AB;,E tf j e t r / s am. ( Jon t . ) ( I t ) Aayl Butyreta ( T ) ?he Bf fso t of Unaatnratloa (b) Babbitt of 3 teo l U ) i>*y (11) Olala Aold Dlsousalon of Reaulta Industr ia l v p p l l o a t l o n 3«usraary Bibliography I*£ft69tf3£l01! » t a the i o a t fear or fi*« yoare a gro^t &oal Of i a to reo t b&* boon &renoe& i n tbo onbjoot of labr inot ion* 1% boo boon a wall leaown faot OVOT oinao ©laoral i nb r tou t l ag o i l * aaao i a t o gonoral noo» t o o t thay woro ott tbo whola i n f e r i o r to a n i M l nan vogotafelo o l i o* tbo reaaoa for tfc'lo rtifforonoo on* aawo* loa**©" in to an t i l *a«t r e a o a t i ? . So far* hs»**o*» thoro baa baaa mm oa t la fao tory tbnory ooiroionoa In oxplanktioo of th i a <U»al»l lsr i t y . m*> novo wo Hon u n t i l aoa aa? sotho* of aotonainiag too Xnb*io&tln*$ proport ion of on o i l witfeoat t i y i a ^ i t out i n pmat ioo* aa attntspt baa boon n&do by ftavara), i av«at i«a tora to find a r e l a t i o n botwoon tha cthoalo&l nana t i to t ion and the i n b r l a a t i a g nan l i t ? of an o i l * ba t ao f iaa l r eao l t a have yet boon obtain*** i a tb la ronoarab aa attmapt hae boon mid© to ootormlaa the offoot of vary ia* maoosta of a lcohol*, e a t e r a , nana tore tn4 hydrocarbons nan f a t t y an Ida in e lnora l l ub r l ea t i ng o i l * , on tbo oe e f f i c i e n t of e t a t a f r i a t t o a of the l a t t e r whoa applied to d i f f e r en t metal earfana** i t we* aleo hoped t o develop a elctple «e»na for aeaar t&lalag tbo l o b r i o a t i a * qwaltty *f aa o i l a t t h e a t t r y tag i t i a p r a o t l o o . - z - SARLY IIYESfXfofXCVS - (a) Jho 3oefflolent of /rlotion of Dry Jurfuoes. ?he first recorded investigation of friction was ia 1699* whan AStontons (lie»*d. l*Aoad* Hoy. daa ŝciences, (16yy}» p. 236} found that resistance to relative notion varied with the nornal pressure, hut was Independent of the area of the applied surfaces* He expressed this re- lation as fellowss ? • u. p. where t • foroe aeoessary to oouse notion P • total pressure v * ooeffloleat of frlotloa la general he feuad that F was equal to one- third P* His theory was that frlotloa Is das to asperities la the surfaces, this view was later upheld by Suler (Berlin .load, HOBOire, ll748),p.l£2). thm aext experlnent along this lias was oon- duoted by Jouloab (Liei3.tl.l*.*o<ad.Hoy. des Sciences,(1765), vol.l0,p.l61). who in 1785 showed that there was a dlfferenoe between statlo and kinetio friotion* but that the above law held for both* ?hen la 1830, Uorln (Men* o.3oavanee Strangers IV.*(1833). pp.1. 591t VI* p.641) proved with a mere refiaed apparatus* that the kinetio was usually less than the etatlo friction* finally Jenkln and Ewing (Phil.Trans*A. 167, 509. (1877) dlsoovered that there was continuity from the stats of static to that of kinetio friction. - 3 - (b) The Coefficient of Friotion of Journal Bearings. A different line of experiments was commenced by B. rower (Proo. Inst, lleeh. Bng.t 1G83), p. 632; (1864) ,p.29), who determined the coefficient of friotion of a standard bearing and the effect of variations in pressure, speed* temperature, methods of lubrication and the kind of oil used. This marked the advent of the modern journal friction testing machine. Power used a 4 in. journal in a half bearing with load* from 100 lbs. to 500 lbs., and speeds ranging from 109 r.p.m. to 450 r.p.m. He found that the friotion was independent of the load, but proportional to the velocity. It was also affected by a change in temperature, and by different methods of lubrication. By using a similar method to lower, 0. Reynolds (Phil. Trans. ?ol,177, (1686), p. 157) showed that the friction depended on the viscosity of the lubricant. He improved the mathematical theory of lubricated bearings by the introduotlon of hydrodynamics. The mathematical end of the subject has also been highly developed by Jomnorfield Ueitscfcr. f. Kath.t.50.(1904), p.97) and Harrison (Jamb. Trans, vol. XXII, (1913), p.39). 5B3SST DSVEL0PHSIT3 - (a) Boundary Lubrication and Gillness. The mere important reeent investigations have - 4 - been carried out in a different field, namely "Boundary Lubrication". Boundary Lubrication occurs whan the solid faces are close enough together to infltience directly the properties of the lubricant, and is found in ordinary dry surfaces, This is quite different from the ordinary condition la bearings which is known as "Flooded Lubrication"* Here the metal surfaces are separated by an oil film of appreciable thioknoss which prevents metal to metal contact. In such oases the friction depends entirely upon the viscosity of the lubricant; while in the case of Boundary Lubrication, the it depends onAoiliness of the lubricant and the chemical nature of the metal surfaces* that in Flooded Lubrication, the value of the lubricant depends on viscosity is shown by the use of wolassee as a lubricant on sugar-making machin- ery, of air on spinning machinery and of water on the pro- peller shafts of boats. •The vital importance of Boundary Lubrication is because of its continual occurrence in the actual operation of all machinery* It is encountered under the following conditions s (1) The starting and stopping of bearings, which causes the perfect oil film to be squeezed out, thus allowing abrasion if an oil with a high degree oi* oiliness is not used* {Z\ Whoa the oil supply, due to negligence or a break in the lubricating system, has been allowed to get low* (8) Between the piston rings and cylinder walls, and also in the cross head of an engine. - s - (4} la oases where high pressures and slow speeds are asefi, such as in gears and la oatt lag and threading* In the l a t t e r case, lard and f ish o i l s era aaoti in preference to mineral o i l s * 01linesa la a new hypothetical property of as a l l which wakes I t a s e t t er lubricant than another o i l of the same v i s c o s i t y . I t Is the only difference between good* >>oor and a©n~lubrtoa»t»« Lord Saylei^h la 1916 (Pail* Kag* 3 .6 . Yoi.SS* l l*I*J# *m Sfttl studied the action of a glass bot t le e l iding on an inclined glass plane* Ha noticed that for • *ry* clean plate the bott le s l i d quits eas i ly ; but when he breathed on the plate or flooded I t with water* tfea #j|gU» earns lag s l i p wae much greater* On evaporation of the moisture he obtained his original values* 2 hen he tried the same experiment asiag paraffin o i l and a brass plate l a which he obtained similar resul ts to those with water* the conclusion* drawn frosa these determinations was that tha fr ic t ion was greater* thelarger the awount o lubricant present* and that in the dry s ta te the plate had a th i s film af about 10 "* 4 HUU in thiatoaeas ad- sorbed onto i t s surface* Shis film levered the fr ic t ion a large asoant. «Tast before he performed the above «e*k ^ord ftstfletgh went into an involved mathematical discussion of - * - the subject which Is given la detail la tho Philosophical Hagasino. 3»d» Vol.35, (1918J, p.l. For two platas tho conclusion drawn wa« that »/$• S 4.091 h/e whore 7 a friction P • pressure h * distance between platea a s length of upper and shorter plate. Co) fti YtiflWaty fl»onr» Prof. 0. Faaai at Settlagan (a* phy*lk.ahea.e6, U n * U 9P* *?»•**) foand that the viscosity of ether, carbon bisulphide and ethyl, alcohol iacreased enormously far proseare» of £.000 atmosphere*, 4a shown by H.li. Martin (2>roe. rhys.3eo.¥ol.32, {1919~*Q) p. lis), it was believed, that la a aaae of imperfect lubrication, wear was das to a concentration of the lead In a few spots of Halted area, tans giving a very high pressure oa the oil film. This eaased a rise la the vleeoeity of the oil. whloh would then prevent metal to metal contact. Jhis led to the theory that animal and vegetable oils were batter lubricants than aiaeral oils la easts of Imperfect lubrication, because it was Believed that the viscosity ef ths latter did not increase as ouch as the former under pressure. This view was overthrown In 1919. by f, 3. Stanton. L. ̂ rohbatt and J. 0. Southooabe (Snginee ring 108# (1919) pp. 759-60) in measureaeats of the traneaisslon of power through a warm gear. ?hey found that, contrary to the above theory* an Increase in pressure to 900 atmospheres raised the viscosity of animal and vegetable oils four fold, and that of mineral oils sixteen fold* 2his showed that viscosity- could not he the only factor in lubrication* •?hey noticed th&t there was very little change in the efficiencies of aniraal and vegetable oils with a rise in temperature* but that It was accompanied by a rapid fall for mineral oils* X% was found that this fall In the latter could be prevented by the addition of small amounts of fatty aelds* From these results ©illness was believed to be due to chemical affinity between the metal surfaces and the lubricant* (d) ?fto Pce^ey Haohtat. *• *m Lesley (Proo. I»hyo. Soo* Vol. SI, (1919-20)* 9* 1 S«) concluded from the &bove investigation, that the property of oillness would show up best, by measuring the statio coefficient of friction for oils between different metal surfaaos* For this purpose he constructed what is now known as the Deeley Machine» • - e - _2 Q B f a l s xaaehiae ooaaiated of a saaooth, flat* olreular plat** 4 . of any deaired s e t a ! , whloh oould be rotated at varioae epe«de» OB i t res t s aaofcher p late , B, of adjustable weight* 2aia plate 1» supported by three eaal l ho»i*phsrleal pegs of any taetal. Whoa A i» rotated, B i s dragged aloag at the ease apeed by the fr lat iea be- tween the two aotal aurfasea, aa t i l the torque set ap la the o&librated epriag, Q9 overeoaes the resiataaoo to s l ip* 2o 3 la attached a polator, J>, whioh indieatea on a epeolal aoale the aoeff ioieat of f r io t ioa , *»at at the polat where a l lp oaeura the indicator giwea the ooeffioieat of a t i t l e f r la t loa , aad froa thoa oa the ooeff ioieat of kinetics frlotloa» 2© get auy ooaaisteat reaulte with thia aaohlao, i t haa been feand aeoesaary to rewov© the las t - 9 - traces of water. Beeley noticed, that with this machine for clean surfaces without any lubricant, the coefficient of static friction gets greater and greater as the surfaces are rubbed en each other*. For aild steel en oast iron, his coefficient at first was 0,164. while after running for tea minutes he got a value 0.417. He found very little difference between static and kinetic friction* but ob- served * marked differ ens* in the friction of the sane ell when need on different metals* fhis dissimilarity is •hews i« the following table* Kind of e n ft*B,31eelc e l l Bayoano e l l Typewriter o i l I letory Hod o i l ?*?*? .cylinder o i l llano has tor spindle o i l Oastor e l l Talvoline cylinder o i l sperm e l l t ro t ter o i l Olive e l l Hape e l l a u u m n M U H B II r B A A 7 7 Mild Steel Mild Steel on 0.271 0.213 0.211 0.196 0*193 0.183 0*183 0*143 0*127 0*123 0*119 0*119 0.275 0*234 0,294 0*246 0*236 0,262 0.189 o.ieo 0.152 0.196 0*136 M m mineral oil? V • vegetable oil; B m -blended oil m animal oil ?hls table brings out the fact that Bape and Olive oils are the best lubricants* with mineral oils the worst* and castor oil about half way in between* Hape - 10 - aad Ol ive o l i o aee* to redaee the f r l e t l e a the aa»e aoMMt for » l i d a tea l 01 oaat l r e a . h t the fomer to b e t t e r wi th a l l d a tee l oa load bronte . r rea theee r e a u l t a . Peelay ooaoladed that tho e e e f f l o l e a t of e t e t l o f r l e t l e a var lee aot o a l j w i th the l a b r l e a a t , hat also v i t a the a* tola l a eontaot* There fo ra , ellftaeae veald appear to be aa o f foot o f the a l l apoa the a e t a l aar faeea, ra ther thea aay phyeloal property of the l abr loaa t l t a e l f . ? M t , ha belteved.waa aao to tho eaeevaretea ae l e e * lee of tho labr loaat oa t o r i at* l a t a a f i r * payolao-ohoaleel maloa w i th tho ao ta l ear faeee, that f o r a l a f a f r l o t l e a red*olag aedlea oeapeaed of o i l aad a « t a l , vhleh veald appoar to ba aero than a aolooalo l a th lekaeaa. ( • I a a r a l * ! M t l h j j m l j a j i l U . hardy deteralaed tha a t e t l o f r l o t l a a by aeaaarlng tha fovea aeoeaeary to a t a r i a healephere a l l d l a g 9r»r a aaooth p l a t a . l a bla a r t l o l e , "A Arabian l a Lebr lea t lea" . ( J o a n , o f *eo* Jhea. l a d . Vol * 38 . ( 1 *11 ) , p . It) ha ototoo t h a t , "with a t rae labr leaa t tha f a a l l l t y far a l l p p l a g la aea laa l when a layar of soob axoosslra t a a a l t y oaparataa tha aa l ld faaaa that aathlaa l a aalaed by laoreaatac tha thlekaeaa of tho lay o r " . Thla f l l a ha faaaa to ho aboat I i 10 * T a a . l a thlahasaa. Ba v e r i f i e d - 11 - this statement by showing that some liquids were better lubricants in thin than in thiolc layers, as shown by the following results for glass on glass. Pull in grams Liquid Film Flooded Acetic Acid 40 47 Sulphuric Acid Vt 47 Aleie Acid 10 13 He believed this indicated that lubrication depends wholly on the chemical constitution of the liquid, and that films being better lubricants, pointed to the fact that lubrication is accomplished by a fluid adsorbed onto the solid face. In a paper published by the saae investigator in 1919, (Phil. Mag. Vol. 38, (1919), p. 32) it was pointed out that there is a variation in the surface energy at an interface between two liquids and a com- posite surfaoe, which Is closely related to the chemical constitution of these substances. If this interface is formed by chemical forces, we would expect that they could be saturated or neutralized. 1?his seems to be the action of a lubricant in reducing the cohesion and re- sistance to slip between two surfaces. - 12 - Hard/ also found evidence of orientation of tho molecules of a lubricant, because at an Interface the sompoundi, such as, acids, bases -tnd asters, ah! oh produce the greatest surface energy changes are readily polarltall*. This orloatation of molecules at oarfaces was also pointed oat by Lengmalr. (Journ. Am. 3hen>. Joe. Vol. 56, (1916), p. 2221; vol.39, (1917), p.1646) According to Kardy, the theory of static friotlon which heat suits these facts Is that friction It dae to cohesion between the Dotal surfaces. 'Hm B. Hnrdy and *da Doubleday (Proa* Uoyal Joe. ?el. 110 A, March 1922, p. 560) carried oat numor- oas experiments in the field of Boundary fabrication, from which they case to the following conclusions: (1) that variation in the weight of the sliding hemisphere did not affoot their results, (2) that variation in the radius of curvature of the hemisphere had no effect (3) that for eteol, bismuth and rubbed quarts a change in temperature had no appreciable effect, U'rcc. ^oyal Joo, Vol. 101A, Sept. 1922, p. 46?) However, it wis actlooc that for glaseand oloan quarts, a rise In temperature lowers tho coefficient of friction. ?h« low valae obtained waa retained on cooling to the original temperature. ?hoy also found that for a lubricant, which is solid over part of the ran-re of temperature, there Is a rapid drop to a very lew value Just below and at the melting point, while Just above the melting point there Is a sadden rise to a constant value. - 13 - (4} t h a t the thlekaosa of the filra did not of foot the f r i c t i o n providing there was enctj^a of the l ab r i can t present to cover the whole su r face . *?he f r i c t i o n * however, gradually diminished as the concentrat ion of the lubr ican t increased, u n t i l a Btlnitatua was reached, when fur ther con- cen t ra t ion produced no change. IB) tha t an equation, such a s , «  s h - aE f i t t e d each oheigjqel ae r i e s inves t iga ted- a c coef f ic ien t of s t a t i c f r i c t i on % « Hcolecular weight of lubr icant c s a eeas taa t dependent on the cbesloal type of the s e r i e s . h * a constant dependent on the chenieal nature ef the so l id su r f aces . I t was noticed that the f r i c t i o n for the sarae lubr icant Varied when applied to di f ferent so l id substances , for s t e e l gave a higher coeff ic ient than bismuth, hat lower than f?laas. In the case of Eietala, the f r i c t i on wee found to vary d i r e c t l y as the hardness., while two d i f f e r en t aaetals on each other gave values intenaedl&te to those for each metal on i t s e l f . In the «Jouraal of the Jhenioal Society for December 1922 i p . 2875}, Uimm Ida Poubleday gives an account of setae E»easure©ents which she stade of the co- e f f i c i en t of s t a t i c f r i c t i o n for a ae r i e s of a p t i e a l l y ac t ive earbinols {3% H§ OHOH OJJ Ha« t U * She found t h e i r l ub r i ca t i ng p&ser te be Independent of the sign of ro ta t ion* or of any s p i r a l arrangement of the carbon a t o a s . - 1* - Th* Fourth Sepert on aollold ahe&istry (British Association for Advancement of iolenee (1922J, p. 185} contains an article by '• B. Hardy, In which he Indicates the affect of chemical constitution on the va3 «e of the coefficient of friction for pare liquids, when measured with Bismuth on Bismuth* In some chemical series, such as, the paraffins and benzenes, the static friction »aa shown to be a linear function of the molecular weight. In other series the effect of molecular weight was over- shadowed by that of chemical const!tatica. However, if he went high enough in any staple series of chain com- pounds, e*g* aloohols and fatty acids, he found a good lubricant, except in the ease of the aliphatic esters* It also became evident, that similar changes in the molecular structure of ring and chain compounds produced opposite effects en the two series* He ring compound was encountered which proved to he a really good lubricant. Hardy found that atoms placed symmetrically about a central careen atom produced very bad lubriaants, an example being carbon tetra chloride. ?he only generalisation whiah he could draw in the ease of bismuth on bismuth, was that the addition of a single VB. group to a molecule increases its lubricating power. However, a second or third group diminishes the effect of the firsts Single -OH groups on a ring or - 13 - oloaed chain aoapound appeared to bo sore effective than on an open chain. ^iso when he replaced Cl by H, or S by 3Hg a better lubricant was obtained. it) Pggftptta af ..WriaaUfttt 3.B a Bgartaff lober t B* i l son and Daniel P . Barnard UTcurn* Imd» and Bng. 3heta. Vol. 14, Mo.8 Aug* 1922, p.68£) •bowed froo experiments on a f r i c t i o n ^oaraal t e s t i n g naohlne* that for any bearing there are three regions of l u b r i c a t i o n , namelyi (al 4 region of f lnid filis l ub r i ca t i on where the oc t a l surfaces a r e held apa r t by a perfect filss of l i q u i d . Here v i s c o s i t y la of p r i s e importance, the o i l lneee of the lubr icant and the nature of the a e t a l having no e f fec t • (b) 4 region of p a r t i a l l ub r i ca t i on where the stetnl surfaces a re in c lose contact with each other* Sere , we a re not concerned with the v i scos i ty of the l u b r i c a n t , but «| tfc i t s o i l l n e s s and the nature Of the bearing t te tal* (o) 4 c r i t i c a l point Just between those two regions which i s lowered by an Increase in the o i l l n e s s of a l u b r i c a n t , and i s affected by the nature of the bear ing raet&l. Proa these r e s u l t s i t appears tha t the ordinary Journal f r i c t ion t e a t i a g sutoh ine operates in region & thus being nothing acre than a rougb viscometer* fhis was d e f i n i t e l y proven by Wiaslow H* Hereohel (3bea# * Set* Sng* Vol. 28, 3Jo* 13 , March 1923, p . 594) . - 16 ~ W AtlWPtg fco i n s u r e c i l inass by ?arlcu« Mathads v/llsoa and latttard {dearn* lad. . ffti—, ?*** t** I e . 8 , 4.ngr« 19££» p.. 663} give as account of several different methods whiah they usod In an attempt to measure c l l ineso* Beeley'a method was employed f irs t* because with i t both the s t a t i c and kinet ic fr ict ions ooaid be -.hair conclusions were that* (11 **• k iaet le f r lo t l ea i s lower than the s ta t i c jfjftatioa (2) far metals thare t» a continuous change from s t a t i c to kinocio fr ic t ion $Ml ftowmmv en the bearing had far? l i t t l e affect | 4 l Aaimal sad Ve&e table o i l s have a lower coeff ic ient ©f f r i c t ion than refined >rsl o i l s (ft! the addition of a easel 1 emetrnt af fatty aold# or a aoaalftar&bly larger ameaat af a neutral v© X© o i l to a mineral oll» predness a «arkad lowering af the coeff ic ient of f r i c t ion . (6) the maximum dlfTerence on metal aurfaoes between the f r i o t i e * af different o i l s Is ŝ t sera ve loc i ty . This would s a f e s t the eaafflatant of s ta t io fr ic t ion to be • the best s ingle measurement af ©Illness* fhey considered oI l lness ta ha due to a tenatieusly adsorbed film of the lubricant to the metal snrfaees, the presence of which diminishes or prevents Hiatal to metal contaot. ?ho a b i l i t y of this film to - 17 - withstand t h e high and prolonged pressures to wljich i t I s exposed without being squeeaed out would ind ica te that i t was sore than ssonft-aolecular aad saore of the nature of a p l a s t i c sol id than of a l i q u i d . 7h&y next used Laagouir 's Inclined Plane Method with s imi l a r r e s u l t s to those obtained above. However, p-*orec~el, which i s known to lower the surface tension of watar*. did not give a low coef f ic ien t of f r i c t ion* ?his shows that an adsorbed f l l a can not be the only necess i ty of a lub r i can t and that i t s chemical structure vast have SONS e f fect* ?fcls i s brought eat l a the following table . — ' • ii * w i » S t a t i c Fr i c t ion Incl ined Plaae itsthod .. Lead m 100 on. 31yoorol Veloa i te "B" o i l V e l o e l t e »B" + z£ S t ear i c acid 7 e l o e i t e "B- -r £,l Irea 3 tearate Heutral lard o i l Ve loe l t e *B* r &,l p - creso l Ve loe l t e «*" treated twice with Fe by M Measurements Spherical Segment S l ider i n e f f i c i e n t of Fr ic t ion Speculum Speculum on ^tee l xmmm ., 0*20 o*isa 0.120 0*120 0.125 a.186 0*190 ©a Spec- 0*20 0 . 173 0.121 0.120 0.126 0*178 o.ieo ^l loy 3 on J tae l 0.152 0.123 0.09S a • a *> a • a a a a a - 18 - Measurements of the lowering of the surfaoo tension between lubr ican t s and mercury were alao made. Mercury was used codetta© I t la the only pare metal in the l i qu id s t a t e under ordinary cond i t ions . From t h i s they only found tha t t h s lowering of the surface tension indicated a tendency for some substance to concentrate oa a oc ta l su r face , and that the film formed was a so l id fa ther than a f l u i d , and of co l lo ida l ra ther than jaoleonlar dimensions* 4 method was then devised to measure the e l e e t r i o s l r e s i s t ance of an adsorbed f i lm. 2hey took two hardened, polished s t ee l surfaces sad held theia firmly together by a d e f i n i t e p res su re , while t h e i r r e - s i s tance was mm&auT*4 by means of a wheatstone bridge* fhen the surfa#ea were exposed to some o i l and t h e i r r e s i s t ance again measured. Xt was not ioed, that the lender the faces were kept In contact with the o i l , up te a period of about twenty-four hours , th© higher was the res i s t ance obta ined. ?hls ind ica tes that i t takes sofiirt t i a e for en adsorbed film to build up. I t took longer for the film of mineral o i l to foaa than for aa amiaal or vegetable o i l , due, i t was bel ieved, to the small amount of film forming cons t i tuen ts present in the former and the time I t takes for them to diffuse to the metal surfaces* - 19 - file rate of clogging of taetal and glass c a p i l l - aries was also studied* yielding the fact , that on s tee l and glass mineral o i l s gave a thicker film than lard-oil* therefore the thickness of an adsorbed film ie no indie- ation of the o i l i ae s s of a lubricant. ?he films in the capillary tuboa proved to be of the order of 0*1 mm* in thickness* She film forming tendency of o i l s which had been f i l t ered through Ful ler's Barth was the same as before the treatment* f ina l ly an attempt v&s made to separate the "oi l iaess" of a lubricant by treating It with very finely divided iron formed by the reduction with hydrogen of a ferric hydroxide gel at 450° 3. 2his iron seemed te ad- sorb to I t s e l f e l l the film lb rains constituents of the e l l leaving behind an inferior lubricant as shown by the table em page ^7 *&d by the following* Original concentration of s tearic acid in o i l , percent 0.S0 j Steario ae ld l e f t a f t e r t r e a t i n g 50 gms* e f s o l a * with 10 gtsa* of reduced Iron 0*28 S t e a r i c acid removed per gta* f i r o n . spas* 0.016 In the bibliography are listed quite a number of other recent articles on the subject which come to about the same conclusions as the above* - 20 - \alaal and Vegetable olio are known to ooaeiat of eatera of the flyaerll *roup -33 H3. ?hle glvea eoaponada of the for* 33 H3 *3, whore H la the fatty aold radlele. la aolld fits, stearin and Palaltla pro- doalaate, while In llqaida, wo nanally find u 1 .!•<{• mount of Clein. ?ho ooapoeitlon of thoae ooaaon eatera lot Trijlyoeryl Stoarate - J3 H5 ( 0 3je H35 0) 3 ?rl glyceryl Palaltato - 03 H6 ( 0 ;16 H3l 0 ) a frlglyeeryl oloato - 1) Us ( 0 1̂6 H33 °*S 3pera oil ooataiaa oatera of mono- and trl-valont aloohola iaetead of glyoeril. mineral olio* on the other hand, are hydro- oarbona, the ultimate otruotnro of whloh very little la known* Dunatan and ?hole (Journal of the Inatltutloa of Potrolena Teoaaologleta, Yol. IV, (1918),pp. 191-220) oay that all mineral oils whloh are good lubrlonnta oon- tain unsaturated aoleouloa. They alao atnte thati "la no oaao haa the ohoaloal oonetltotion of a aoapound of a lubrioating oil boon eetubllahod, but the ohemloal bo- navloar of thooo olio lndloite that aoong the ooopononto are nnaatorated hydrooarhona {poeelbly open ohaln, bat aore probably aaphthonlo aad polynnolear, or perhapa both typea), oataratod hydrooarbeaa (aapthonio aad * -. 21 - probably to some extent polynuolear. but not to any appreciable extent paraffiaold)* and aromatic hydrooarboas (to aa unknown and possibly a limited extent)* 2he un- saturated compounds constitute between 20 and 40 per cent* Of fssost lubricating oils* It appears then, that the true lubricant is an unsaturated compound, possessing all the attributes of such a compound, i. o*t - (1) Capacity to absorb Iodine* broialna, oxygen and so on. {£) Sol ability In strong Sulphuric /.old. {5} Bigier l/ti ratio th&u the saturated derivative* ^Apparently the same facts hold ^oed la regard to fatty lubricants* Bapo oil* castor oil and olive oil contain in their sjcleoulos double bonds, and are superior to enoh a saturated product as, for example, tallow. *»!» recent years the progress of organic chemistry has largely been due to the realisation that ansaturntlon, or the possession of residual affinity, plays aa all important part In the reactivity and the very personality of a oompownd* Colour, odour, tagto. physiological activity* and* in a word, all the character- istlo properties of bodies are influenced by this con- dition* It appears now that ??e stay add lubricating ability to the already long list of effects proceeding from this one prise cause. cause of 3 re • ¥ • led J e l l o l d concentrate Isorbtioa* Thole say is to the late gory of . I the d i e - » ae th« irded an c o - e x i s t s ting o i l spended in •no tare*" 0 rk done oh to ose I Btof seed three a s o l i d - , - . ^ r ^ ^ r ^ t t t l ng, ground g l a s s , top . ?he stetal p la te ased I s neasurlag - 22 - Another view held by some as to the cause of oiliness of lubricants is their colloidal nature* '*• Ostwald (Introduction to theoretical and ...polled aolloid Jheralstry, 1917} says that a colloid tends to concentrate on the surfaces, the phenomena being called adsorbtion. In their article mentioned above Bunstan and Thole say thatj "Recent work on colloid ohemlstry points to the fact that heavy oils must be Included in the category of . ieo-colloids, i.e., polyphase systems in which the dis- perse component is ef the sane chemical nature as the dispersion Medium, ^ust as water Must be regarded as a system in which molecules,such as, (S2 Q)~ co-exists with simple H2 0 molecules, so la a lubricating oil the dlsperee phase is a molecular aggregate suspended in a dispersion medium of simpler and similar structure." From consideration of the previous work done one this subject it was decided In this research to use the method employed by .v. B. Hardy. She apparatus used is shown in Plate I. it consists of a glass case set on a three legged levelling stand, which in turn rests on a solid table* She glass ease Is covered by a tightly fitting, ground glass, top. ?he metal plate used In measuring - 23 - the coefficient of static friction ia placed Inside the case by smsas of a pair of tongs, after which, the apparatus is carefully levelled. Ca the plate is set a spherical segment of any desired Metal* *hie is connected* by means of a fine thread over a veil balanced pulley running on ball bearings, to a beaker into which mercury is run In a very fine stream front a burette* When the weight of the beaker becomes great enough the hemisphere is pulled along the plate* &t the instant movement is first noticed the stream of mercury is Immediately shut off* Then the beaker is detached and weighed, to the second decimal place* with that part of the string which Is below the pulley. During all the experiments a stream of care- fully dried and filtered air was passed through the apparatus by means of a water pressure ptu;p. ?hla precaution was taken to prevent the cleaned plate from •*»ortlng a film of grease from the atmosphere, the drying and filtering of the air was accomplished by passing it through six wash bottles of concentrated sulphuric acid* an absorption tower containing solid sodium hydroxide, two tubes of phosphorous pentoxide and finally a tube of glass wool. ?he sulphuric acid, as well as acting as a drying agent, took up a con- siderable amount of dust from the air ana was renewed - 24 - whenever i t became dark l a c o l o r . ?he purpose of the Sodium Hydroxide wa» to prevent any aulphuric acid spray from being carr ied through. M m o i l UQ«, ffnoountared, A s c a l e pan on which weights were placed was firstt used t o determine the force necessary to cause taoveaent, but proved u n s a t i s f a c t o r y . 2his was due to the i n e v i t a b l e j a r caused by adding and removing the we ight s , which s t a r t e d the hemisphere sieving too soon, t h i s d i f f i c u l t y woe overcome by rep lac ing the s c a l e pan with a beaker i n t o which a f i n e stream of mercury was run u n t i l the necessary weight was obtained. ?he weight e f the beaker and mercury was then found fcy weighing en a ba lance . Sue s t e e l p l a t e s and hemispheres*f irst used, and were mild s tee l A caused a great deal e f trouble by not g iv ing any c o n s i s t e n t r e s u l t s se shewn by the fo l low- i n g f igures i n table I* 3?ull in 3ra»s . (Bry Surfaces} Mild S tee l Hand fool J t ee l 34.23 75.69 S0.14 7$.3£ 4S.12 77.20 32,72 77.00 87.78 7d.47 - 2$ In t M i 3i,io a a seal fcotaisphoro of 214 ipsa* i a weight •*»« usod tee a dry s t e e l plat©* ft*© t roable was) elissiastod 'by ge t t i ng a p l a t e of hard tool s t e e l whiah %ns of t he iaB9 aosipeaition as th# faeiai sphere . ~hi» asw p l a t e g©ve iM»ry l i t t l e t rouble freta jrast lag a f t e r i t wa* alenned where an the e thers rusted v©ry r e a d i l y . 2ke r e s u l t s for t he ae® p l a t e are a lso given in t a* l e I* J leaa iag the p l a t e s and hemispheres turned out t e «eA41ff lanl t task* 2he p l a t e s «ere .ground by rubbing two of thara together with very f ine eaery and water* ?h<s etaer? was then reaowed and the p l a t e polished ey mehiag with a fresh aorlr l a clean flawing water* a f t e r whieli the p l a t e wae rufchsd vigorously by the fiagera -with a l i t t l e inure snap l a the running »**«* un t i l a alingla& feeling- was produced* hen the p l a t e was elean water weald ©ever i t s e n t i r e ettrfaee* the rea l t e s t for a eleaji etfTfeee i s a oatiatant walae for fcfie oeeff ioieat ei* f r i c t i on whl3h ana b« reproduced* After cleaning the p la te was plaeee in the glass ease ;m& dried by a rapid atreara of dry a i r* She hemisphere was aieaned aad dr ied in a e i&i la r manner* hen so lu t ions of Stear in Asia l a Liquid fetrol&tuo ware need the fejsser so l i d i f i ed an* and aould net he leapt i n solut ion* i*his riiifioaity wee - 26 - surnounted by p lac ing an o l e i t r i o r n d l a t l m heater next tha TIISB o a i e t so tha teiroernture could ba kept hijh enough to s a l t tha 3 tear io * o l d . Howtter, for s o l u t i o n s o?«r t h i r t y par oont . s to . ir io aoid tha teraporature ea l not high enough so recourse was had to d i l u t e other s o l u t i o n s . ?he a taar io aoid and l i q u i d potrolatun war* hen tea l a a f lane and thoroughly n ixed . \ ssmll port ion of th i s s o l u t i o n was dissolTad In sons ather which was poured onto tba pi at a and allowed to evaporate, ihlm a left^wery th in f i lm on tha p l a t a on whioh measurements aoald ba aa&e* 3trrt«titan - rha feroa necessary to oanaa tha string to BOTC ewer tha pulley whan it was loaded was found to ba 0*5 gas* fhia amount has bean subtracted frost all tha values given in this artiole. c A oouroe of error ar l so s in tha angle *B3 over tha pul l ey not being a r ight angle thus oanalng a vary s l i g h t l i f t i n g atotlaa on tha hemisphere, 'fha angle SUA was measured by taking two points tan inches apart d l r e o t l y beneath the thread on tha tab le and measuring - 2? - the difference in height of the string at point* above the ends of the l ine , fhis difference *?as found to average 0,29 in. which gives for the tangent of the angle BAQ a value 0.029. HJhis the angle BA3 1B 1° 43*. a© the value of the desired force A3 equals «.£. cos BAG • AB X 0.9996, whloh gives a negligible oouireotion and therefore has been omitted. tftl Bfttit - U ) ti.Ufll OB Stttf l - (1) Measurements were first made to determine the force necessary to oause steel to move on dry steel ?he coefficient of friction was calculated by means of Anontons* equation* fhe results are given in Table 11. for ;3teel on 3 tool (firy) Full in Oram* Joefficlent of Static 'riotion 75.69 0.353? 76.3,2 0.3567 7 7 , 2 0 0.3606 77.00 0.3596 76.4? 0.3573 AT. 0.3576 ?he weight of the steel hemisphere used throughout ell the determinations was 214 gms. • 28 - U ) 3 t e e l on a t — 1 - ( c o s t ) U i ) \Ui<3 AflU ~ 2»he c o e f f i c i e n t of s t a t i c f r i c t i o n for s t e e l en s t e e l , u s i n g l i q u i d p e t r o l a t u m with v a r i o u s p e r c e n t - ages e f o l e i o ac id a s a l u b r i c a n t , was next measured* t h e l i q u i d was a p p l i e d to t h e p l a t e by deans of a c l e a n g l a s s t ube i n such anounts t h a t t h e hemisphere s tood i n a v i s i b l e f i l m . The r e s u l t s ob ta ined a re given i n 2able. XXI and t h e i r ave rages p l o t t e d i n 3raph X. ?A£L3 XXI• S t e e l on S t e e l , o i e l e Acid 0,i c i s i o *oid 0 .655 Liquid re tro l a tun 100.1 Liquid P e t r o l a t u s 99.35/* . 5 5 . 8 6 5 5 . 0 0 56 .67 5 5 . 4 8 5 0 . 7 6 0 . 2 5 0 7 0 . 2 6 0 7 0 . 2 6 0 1 0 . 2 5 9 2 0 . 2 6 0 6 AY.Q.2599 4 6 . 9 3 4 7 . 1 8 4 7 . 5 6 4 5 . 9 7 4 7 . 4 0 0 .2193 0 .2205 0 .2223 0 .2146 0 .2216 AV.0.2197 Oleic Aold 0 .97^ Liquid P e t r o l a t u n 99.03/5 Oleio Acid 1.73,S Liquid Pe t ro la tum 96 .27* y 4 3 . 1 4 4 2 . 6 4 4 3 . 5 6 44*19 4 3 . 8 6 0 , 2 0 1 6 0 . 2 0 0 2 0 . 2 0 3 6 0 . 2 0 6 3 0 . 2 0 4 0 AV.0 .2033 4 1 . 6 0 4 0 . 5 1 41*56 4 0 . 1 4 4 0 . 2 9 .V 0*1946 0 . 1 6 9 3 0 . 1 9 4 2 0 .1675 0 . 1 6 8 2 , 0 . 1 9 0 0 1 u. O.Z600 ( i O.ZZOO > O ISOCi . o.tq-oo 1 O.IOOQ O.0600 0.02.00 0.0000 rrr^ ==z 4 4 E=r P*- IP747 1 ; 7414 -" —i .___ •r:x- . _— _ i_ , . 777: m riti: 774 5*7 7 4 ~'t.^ — : r - — ™ - 7-77.74 ~™.4 ^ V VQ 777777 " : :. s i :.._i _ p4 ; 7 r r 777: 4 4 t :4 • 7:7*7 . •:.:-:;irr. : ^ ^ : : .'. ..4.::.. 774747 44i .74 -__---.- - • -:... -- '.:..: —.- 4 4 4 4 1 477x774 it— ™£ : s : : r : : ."—..47 • — - : p̂= 7E474: %,=:-» -r.::p.;-.£ :4^fe .. .. ...... . . . J 4 7 4 : - :-::. ,4v 477 : - r ..__:r -_-" 77 :;:.-:../ ...Lr ..... _ _:.:::-.- — 1 4 — — , ^. . . . i r i-r : ; :.=±.— J - - - - - r - ' ' - I- . . .1 - r ~ :...._ .__.._ 777:4^ 777^44 .. __... .. .. _ . . -. : " .: 4 l . . : ...• . . - . . • ; . _ . . - - ! - • _ - ••—-J ~fe ^ 77474.7 — - - _ - — ._-L ~.." ! - . -"."".""7 • !. — 4 5 ~ ~ §7f747 ' '_'_ ' 4 : : 4 4 4 7 ^ 7 4 • [ '""' " "*" . . . " . , . } . . . : . . . • . ; . : . ,.. ' v. 44-47: --:r*.--r 777(477 ~ 1 — ; —-" ;' r 1 — —". . . - . . . . ' : . _ • ~~J!p7: rE: : = P ~ ; 7535H : .477 ;::J 747;:4. 47.777 . . J . 774"*- ". • . • . : : : : _ _ • _ - - - _ - : : ::..._:.::-: —— 7--7777: - • ' • - ' ! " - • ' " • ' .̂. , ; - - - - ; ^ | : . i : • 4 •:- •;.::~z:-\: .:.:_.:_.:_: '4. \ - - • • • • • • - ..-::... ! S t e a r i c # c O l e i c 4 4 4 4 - ___::',:'."rr:: :.:.:.:.-.:_ 0 :-—--•-_-,. " • : : : : ' . : . . ' •vr-'T.'-.-iFvVE-i:: . ....... ..._|... ....-,— • " 1 ;; • ' } " " ; T ~ 4 : :_.:.- F - — - 77444. ^ • 7 7 :z_r.t::::. - - m& B n t Wf7 \: WgZ, . - ^H +*- ^ 1 it" m : . . - [ • : W& — BEE -' Wm 1 m flctd. 7-4777 77::_::7 • . • . . . . • . : : :"'"'.'.',.:._: r.-777- . :77"|7-.7 ;:: . 747777: ::.--- ;. 4: 4 . 4 ... • • . ..• . 7~ - :' . 1 747 : . ; ; ; . ; • ; • . ; ; ; ; ..: . . r .. .... :..::.: ."' 4 7 7 . 4 : --;. . . . . .. 777:----- . . . . • i - - ;_ 77:;.-:.: 7: •7 77::::: 4 4 4 4 • - - . : . " • 747: . : . . . - . 4:477" :.::--..:. .~:";";'-:~ 47774 • • • • - - • - • 77-.. : . - - L t . . : : : ; : " . . . ••-• - ' - - ' ^ B t "B&U- , -4 :44 . / : | ; • -7-7.77 '-.- •-.- .-7- - 4 4 .": : 777:4 :._ .:.:_:: :::.::,.::- . .7 '••-.' '• ft tr ' ' ' ' Br "̂ - - — -:-S J -::. I ""Hi: ._;. 1 . ] | | m;~^mmm 0 A? -?° 30 40 J O Grt> 1PH 1. • - :  . ;_ .. .. 777 :' -i :--•::;..-.-::.--: - ! .__" * — ' - :~^ZL—-.. EE7:747r- : r - i - = _ j 774ir7'7 iTT:^: 7 4 4 : v : ^ r : : - . : .--•-: > ' r * :: ;; EJ. .-. .- 447777 ' 74.44:: | 4 4 11 ". 7.4. 1 ~-̂ 77". ___ ^_": •-' : -: - ::, : JtTr:,; 4 tr ' - 7 7';777 i . • +i ----- i ' 1 .._:•;._ - T_ -.- : L ...:.:..: . " {j -:::•-!•.. ' | ; 4 7 4 7 ^ L . : : . . : • : • • 7^7447 : — 6 0 29 - ?*.BLS I l l . t o o n t . Stool t Ololo i.old 3.33/J Liquid Potrolatua 96*67,* 3 41*67 41*30 42*21 41*01 41*79 a 1.1947 0*1991 0.1969 0.1916 0.1961 ±•.0.1943 Ololo aola 60.99,5 Liquid Potrolatua 39.01* -* 37.99 97*06 96*90 97*99 37*94 « 0.1776 0*1732 0.1780 0*1796 0.1749 ,.•.0.1746 >n 3tool. cloi Liquid •-* 36*29 37.26 38.22 36.80 38.49 Cloi Liquid ft' 36.77 39.72 38.66 37.21 39.04 o -aid 31.79,.» Potrolatua 67.21.» u 0.1787 0.1741 0.1786 0.1720 0*1799 «.•.0.1767 0 *oId 100 * Potrolatuo 0,» u 0.1012 0.1836 0.1806 0.1749 0.1624 .**• 0.1609 m {mil l a (jramo u m ooof f io iont of s t a t i o f r i o t i o n to) j t i f t r U **aifl * o i a l l a r oxporiaont wno outdo,using varying amounts of s toar lo aoid in l iqu id petrolatum, to rtotor- a l no tho of foot o f tho unoatnratoti bond. ?ho rooulto aro givon l a fablo IT and tho aoorat;oo plot tod in ttrayh I . - 30 - *A5LB IV. •" ".I i i i ! • • . » . i - . . . . fei*l n 3t«*l S t e a r i o A* 14 0 . 4 2 * L i q u i d P e t r o l a t u m 9 9 . 5 6 , 3 i 4 9 . 9 6 4 9 . 3 1 5 1 . 1 1 4 9 . 9 9 S t a a r l e a 0 . 2 3 3 4 0 . 2 3 0 4 0 . 2 3 0 0 0 . 2 3 3 6 A T . 0 . 2 3 4 1 A o i d 2 * 7 3 i L l q a i d P e t r o l s tout 9 7 . 2 7 4 1 4 3 . 6 3 4 4 . 1 6 4 4 . 8 1 4 4 . 0 2 4 4 . 9 0 S t e a r i c « 0 . 2 X 8 5 0 . 2 0 6 4 0 . 2 0 9 5 0 . 2 0 5 7 3 . 2 0 9 8 A T . 0 . 2 0 9 0 AC Id 2 4 . 3 , 2 L i q u i d P e t r o l a t u m 7 5 . 7 , 1 ¥ 4 3 . 7 6 4 4 . 6 1 4 4 . 3 4 4 4 . 0 1 4 3 . 5 0 a 0 . 2 0 4 5 0 . 2 0 6 4 0 . 2 0 7 2 0 . 2 0 5 6 0 . 2 0 3 3 AT. 0 . 2 0 5 6 • S t e a r i o AOld 0 . 9 7 / 1 L i q u i d • W 4 8 * 0 6 4 6 . 0 6 4 8 . 0 3 4 0 . 6 1 P e t r o l a t u m 9 9 , a 0 . 2 2 6 3 0 . 2 2 8 4 0 . 8 2 4 6 0 . 2 2 7 2 AT. 0 . 2 2 7 1 s t e a r i c A o l d S . 7 6 ( l L i q u i d £J • 4 2 . 5 6 4 3 . 0 0 4 2 . 3 2 4 3 . 8 7 4 2 . 1 5 P e t r o l a t u m 9 4 . '' t» 0 . 1 9 9 0 0 , 2 0 1 0 0 . 1 9 7 7 0 . 2 0 5 0 0 . 1 9 7 0 A T . 0 . 2 0 0 0 03,5 • ' ,Z&& S t e a r l e A c i d 5 4 . 9 9 , 1 L i q u i d » 4 3 . 5 7 4 2 . 7 6 4 3 . 4 6 4 2 . 3 6 4 3 . 1 6 e t h e r e o l a t i o n P e t r o l a t u m 4 5 . •u 0 . 2 0 3 6 0 . 1 9 9 9 0 . 2 0 3 1 0 , 1 9 7 9 0 . 2 0 1 6 AT. 0 . 2 0 1 2 01,4 ! .' ' I i i l i . i l in" ' ' in I I i l l i in ' i " i " i' " I I 'i < i ' " "i 31 * SAJJLS I?„ (Oont.) 3t*ario j i c i d 1 0 0 $ Liquid Petrolatuia 0% W 82.01 82.77 33,35 33.32 ether eolation « 0.1495 0.1531 0.1553 0.1557 AV. 0.1535 4 2he of foot of the addi t ion of an • • t o r to a o i l Mineral .was s tudied by melag Tarious auoanta of j;rjl fintyrate in Llqald r«trolatn& with the r e s u l t * g iven In ?a»l« 7 ana p l o t t e d i n Graph I I . SPOT U. xr-r. O.2600 Q 0-ZZOQ 0.1&00 O-WOO O-IOOO 0-0600 =£ m- I L T L Q ^ J r 1 o ozoo X: > V * W o * :;. •• G8/?PH IT. • 32 m fABLB ?. Steel Amy I Butyrate 1*06,* Liquid Petrolatum 98.94,i on steel. imyl Butyrate 2*19 I Liquid Petrolatum 97. ei,£ 54»se 5 4 . 1 1 53*92 54*19 53*96 0 . 2 5 5 0 0 . 2 5 2 9 0*2520 0*2532 0*2583 AT* 0*2533 52*23 52*53 5 1 . 6 1 5 2 . 6 6 5 1 . 1 2 AT. 0 .2440 0 .2454 0 . 2 4 1 2 0 . 2 4 6 1 0 .2389 0 .2431 Aayl Butyrate 8«8,i Liquid Petrolatum 9 1 . 2 1 A»yl Butyrate 20.33,1 Liquid ^etrolatuta 79.67> v/ 90*01 4 9 . 2 9 49*08 49*76 4 9 . 9 9 0 .2337 0*2304 0 . 2 2 9 4 0*2326 0*2336 AT. 0 . 2 3 1 9 49.16 49.34 50.08 50.63 49-99 „Y< 0.2292 0.2306 0.2340 0.2366 0.2336 0.2326 4»yl Butyrate 50.49p Liquid Petrolatum 49.51,1 Amyl Butyrate fi6«99% Liquid Petrolatum 13.01/2 5 0 . 7 7 5 0 . 0 3 5 1 . 0 1 5 1 . 1 5 5 0 . 2 7 A T . 0 .2373 0 . 2 3 3 8 0 . 2 3 8 4 0 . 2 3 9 0 0 . 2 3 4 9 0 .2367 53.57 53.61 52.69 53 .11 53.72 AT. 0.2504 0*2506 0.2471 0.2482 0.2510 0.2495 S=k - 5 5 • ?ABI»E 7* ( J o n t . ) i .1 • » . i ^ • xmfl B u t y r a t e 95 •9,1 L iqu id Potr©latum 4 . l i Aayl Batyra te 9 7 . 3 5 J Liquid £ o t r o l a t u » 2*65,a a 55«7? 55*24 5 5 . 1 1 54.3ft M,n 0 .2560 0*2583 0*2*76 0*2541 0*255? A*.0*2565 Aflgrl Butyroto 100 » ; Liquid l e t r o l a t u w j 0,> * » 55*45 ft.** 55*55 5 t * 5 5 •t.n « 0*27«0 0 . 2 7 5 5 0*2755 5*5752 5*5720 Av*0.2762 56*22 5 5 . 7 2 5 6 . 6 0 5 5 . 9 6 5 6 . 3 1 o . 1 6«3 2 0*2604 0 . 2 6 4 3 0 . 2 6 1 5 0 . 2 6 3 1 &••0 .2625 J • 1 • (•) **• »fg«at of Unaaturatlon Tlie coefficient of static friction of mineral oil e*»B different iodino nuabcrs to find the effect of unsat- urated hydrocarbons. ..'he reeulte are found in 2ablo VI and Oraph III* - 34 - 'Sa.hUl 7 1 . O i l # 7 3 I o d i n e So V 55*58 58 . 6 6 5 8 . 1 5 57*97 55*18 O i l #79 I o d i s e V 57*55 56*51 57*42 56*57 5 6 . 2 5 . 1 7 AT* »o. A * . P o l a r i s e #2 I o d i s e B e . y a 0 . 2 7 2 8 0 . 2 7 4 0 0 . 2 7 1 8 0 . 2 7 0 9 0*2719 0 . 2 7 2 5 4 0 •a 0*2695 0*2646 0 . 2 6 8 3 0 . 2 6 3 4 0 . 2 6 2 9 0*2657 2 3 ti 3*90 L.fifi ,31po.ol. O i l #78 I o d i s e S o . y 5 6 . 2 4 5 8 . 2 0 56*50 58*06 5 8 . 1 9 AT* P e l e r i n e I o d i s e s o . 5 7 . 3 2 5 8 . 4 6 5 7 . 6 4 5 7 . 9 6 5 7 . 2 4 AY 2 0 Q 0 . 2 7 2 1 0 .2719 0 . 2 7 2 4 0 . 2 7 1 2 0 .2719 0 . 2 7 1 9 2 . 5 u 0 . 2 6 7 9 0 . 2 7 3 1 0 .2695 0 . 2 7 0 9 0 . 2 6 7 5 . 0 . 2 6 9 7 I 1 . :• | 55 .32 5 5 , 0 0 5 5 . 1 7 5 6 . 1 3 0 . 2 6 2 7 0*2585 0 . 2 5 7 0 0 . 2 5 7 7 0*2635 AT. 0*2596 - - ••-•••m4\ : : i t T : : : ± a ,—U4--4---WC w 1 ! -H -rt-i T • { 1 '" 1 | i'i' l l ^ f S jjgmT-SH- .... .. . g3te?3= - i PPB Bin FT 1 ten -H-rt- -h-r : / Eii i i l / •'•'•tstrHf^ i ' 1 " . - i . .:. 1 / r: r ' ! j ^ 1 '"' 1 / "sir u ^ / 1 K ' " 1 LJ— _— •*7 % • ' +- j j i t „ •••* H - [j i T ^5? .x-xxn .. .. - - 1:1 " - - -- _ — ;— j 1 ! 1" T H r . r 1 f i'i r ffi • • —r+--H •4- :4 1X1.-7 -::.: -XtV- _ - —1—f—i—j— m m : - j-j -- ,- - pi ; * —- TTTf. . L -̂V-i-" ^—- — : — iE-"t 5j 4CT -; m r - - - •f-i— .... 1 .,.: 4*4- - .:s:. J I •1 vrrr - - : • • :•':: .... 1+ i .,._. f.rl :r:i: .:,.... ... ,. • & r;:.. - :"__ - • I " f _ - i : - - ; • • ; . i — .... '"  ;: X " r " . h — - 1 : : — HE ::r;.; _!.:"!' - j t~ - _ : - p - 1 - —̂— ' " ! • ".- ._ ...... .. .. ' • ... " ._... :".'.... ." | ± - — —... - • - + — : . " u : . '. 1, :.: . ..: ' J ' • M "44- 4 • — ! T .:.:! ']••"," t t r : ....... !+•* *•• S i 44- j : -- id-. ~;TT . . ; . : • ;.: ^^^ !—.' — ...J:.'„ -a S 3 11 o 5s ^ * O o K5 —< 9 6 o o 6 O o o o N 6 - 35 - A test was also atterapted with Butyric told but bad to "be abandoned as it attacked the steel even la very dilate solutions. (tl Dry -> The coeff ic ien t of babbi t t on s t e e l with out any lubr ican t was measured with d i f f i cu l t y* She soft babbi t t was abraded so badly by the hard s t e e l that-" I t was had to get cons i s ten t r e s u l t s with the dry surfaces* the wei^xt of t he babb i t t hemisphere was 135.? pas* ?he r e s u l t s for dry surfaces a re given in Table ?XX« ?ABia m * Babbitt en Steel. {Vryl Pull i» Srims Ooeffielent of Static Friction |H»I|»».I«IIISMMI> I M M — J * W W — J S • i . H l l l | » I P i W W W l i * l i H W i W W . i l < M l . n . l « « » i — I I « I « . W I • •»«•——mi — III! • » — < W — W — W t * » 77.52 0*5043 76*80 0,5126 78.00 0.5075 a*. 0.5081 U i ) QU\Q »gl4 - la order so ascertain the affeot of different a&tals on the coefficient of static friotlon of a lubri- cant the same solutions of oleic aoid used on the steel were tired with the babbitt. 2he results obtained are given la fable 7111 aa* plotted in Uraph IV. (1 1 0.3-9 00 a 300 0 QZ&OO r o.zzoo O. /30O Q.tyoo 0.1000 £ • • 7 - J & - t i f: 5 :Fi : :.i . . . . . i 4 -%- ; • ' ..:'.. $ t7. -"• 1 A \ . r:. • . • ) <o_ . . . . . : '-1: ' • i'-l 0 ^ !• ; .. —.. .1 ~ ' - - : . t ^ ::•'• i ... " . 1 ... • ! - 1 • • • " \ ' — i ~" " - zz: ^ — . . . i ; . . ^ — ;._L [••* i ' . ! • • • ./ :¥\ •>.:.: - V . | . : 1 . : . 1 - 1 •• _" '7~T—" 1 - ..! • 1 1 •• 1 j . . . . . ..... " I . . . . • j • • 0 ..... : | ' • , . | . :. ..'- ' ;" -... r~~\—~ :  . " i - . . ; • " • • 1 - • [ •j . i • j •- z . _. . 1 ; _ j .:•• : j . . . " ^ ' - • • i - .": 1 :. "I :  i • : 1 | 0 71-& . - J ' [••-•-:• i .. :i-:_: ' • - ! > ' " " — - ; • ! **»5i'l i ' ; — ! — ••.[•••• : • - i • i - .:. U-' Z : ....  ( - - . • 1 I - •1 i ~"~~T~ . - i i ... i . • i " i ; " ..... a [-.': 0 • ~ - l ••;•;•• • • ! : . i — ~ i i i . . - . . i ; • • • • • • • ! ' 1 4 F • ~:s " ! - . ; : - . , ; - . . ! • , : - • i • • ' i ' .: — ~ - i . i • \ : • ' ! -.- j - • . ' : . : 0 ' • : ' ; . : " , i • • . ^ ' - -. . r ... • • . | . " • . ! . . • • • .. L . . " • ! • •i ••. ....... — . ..':. . . £i£ ::-- 5 ' tt • 444 - - Sffl •"  : "f"ii +tj±t ^ r 4 f t ~ 1 — : i l • •: \ J r • .. _ " * = p £ l l - - • r S t ^ " T :c f i ffi ••'••i ffi S I ' l l I | j ! - & • j i :: : ' .1 'fs : If 0 - t * ..H-F i+ — 4:^-. IH!J ... i f-:;. | ^ ^tft^t sS ^m ~T— T - T T J T l j t is J i; -x:"" Z-t "fh"; 2 •.•*—- Fit IfF ; ; - • • . ; , j . . - J •H J ; •i- j ' " i i ; - - 4^.:: - i ; ' ::":'...': 4-T'̂ T.-' S-U4-'- mm d -:: " "•.: .".." V. "̂  '_ 3.;"^. -1 TL.:.. • rn r j :, zu i tS :̂ 5 f*7tr - ; - i . n9— ^ .-jS: ;• . . . . . ~~ — . . '•'.- "*"."- .... _ — . _ ) . . :S~JL: Z'.TtZ. _:..:. rrrrrt • . - - . : - ' . .-"" : ' :! - © , i • • • i . i • '. . • . - 0 .-. . V - -.; ; : : ." — - • • • ' GR/JPH IS 1 - 36 - ?iBL3 Till. Babbitt on Steel d o l e L i q u i d l o l d OS P o t r o l a t u n 100 > a 57 55 5 6 57 5 6 Ol f t io L i q u i d . 7 2 . 2 5 . 8 6 . 9 7 • 9 5 \ o l d J . 0, 0 . 4 V . 0 , 0 . 9 7 * . 3 7 i 6 . 3 5 9 4 .3699 3 7 7 2 , 3705 3 7 0 5 P a t r o l f t t a a 9 9 . 0 3 , 1 O l o l o . L i q u i d vV 5 3 * 1 1 5 2 . 7 7 5 3 . 0 4 5 3 * 4 3 5 3 . 2 7 t o l d 0 .651 P e t r o l a t u m 9 9 •vv* 0 1 * Id a o l d 1 L i q u i d u 0 . 3 4 5 5 0 . 3 4 3 3 0 . 3 4 5 1 0 . 3 4 7 5 0 . 3 4 6 5 0*£456 .73,J P a t r o l a t u a 98 • 3 5 * . .27;* X-i 4 7 . 1 0 46*38 4 6 . 3 3 4 6 . 8 4 4 6 . 5 8 u 0 . 3 0 6 4 0 . 3 0 1 7 0 . 3 0 1 4 0 .3047 O.3031 AV* 0 .3035 O l e i c -o ld 3*33> Liquid P « t r o l a t u a 9 6 . 6 7 J ",' 4 2 . 7 3 4 3 . 2 8 43*49 4 3 . 3 7 a 0 . 2 7 8 0 0 . 2 6 1 6 0 . 2 8 2 9 0 . 2 6 2 2 J.V. 0 . 2812 \ ' 4 1 . 5 9 40*51 4 0 . 7 8 41*56 AT. OXeio to ld 3 Liquid Potro u 0 . 2 7 0 5 0*2636 0 . 2 7 5 3 0 . 2 7 0 3 0 . 2 6 7 4 2 . 7 9 1 latUK» 67.21,* u 4 0 . 6 3 4 0 . 2 2 40*25 «.v 0 . 2 6 4 3 0 .2617 0 .2619 . 0 . 2 6 2 6 '—— - 37 - ?iUBLS VIII. (Gent.) O l e i o Acid d o . 99 5 Liqu id *>etroIatuia 3 9 . 0 l i .: 4 0 . 1 2 39 . 25 3 3 . 0 6 4 0 , 4 3 4 0 . 2 9 *v. u 0 . 2 6 1 0 0 . 2 9 5 4 0 . 2 5 4 2 0 . 2 6 3 0 0*2621 0 . 2 5 9 1 O l e i c i .Liquid IS 4 0 . 4 1 3 9 . 7 6 39 .28 4 0 . 4 2 3 8 . 6 9 void ioo | Petrolatum oj a 0 . 2 6 2 9 0 . 2 5 8 7 0 . 2 3 5 6 0 . 2 6 2 9 0 , 2 5 3 0 A** 0 . 2 5 8 6 Oleic 4old was observed to attach the babbitt when evtr 3.33 par seat* was used ia the liquid petrolatata. 7a« above results show that the coefficient ef •tatlo friotlon of mineral lubricating oils ia materially layered by the addition of fatty acids, frem the oarres far olaio and stearic acid it appears that the oheaioal constitution materially affects the degree of lowering. Beth these acids are of practically the same molecular weight the only difference being that stearic aaid eon- tains two mare hydrogen atoms than clele acid. Bowerer, the latter is unsaturated and contains one double hood which seems te be the cause of its greater effect. 2hls would Indicate that the double bond contains some residual - 38 - affinity, whioh is attracted by foroes on the srufaces of the solid, thus forming a very tenacious film. /rota the differenoe in the lowering of the friotion due to the addition of the olelo and atearlo uoids and that of the arayl butyrato it is seen that the nolo- oular weight of the conpound added is of priao iaportonoe* for irayi butyrate has a molecular weight of 156, while olelo and atearlo aolds It is 262*36 and 284.36. respectively, thus showing that the greater the noleoular weight of the substance added te the mineral oil, the sore the ooefflolent of friotion Is lowered. Also, from the curves for the aolds, it is seen that the ooefflolent of friction varies inversely as the amount of acid present, until a concentration of about five per oent of aoid Is obtained in the oil. For greater conoentratione of aoid there is no appreciable lowering of the ooefflolent of friction. The -00H group of the aoid is practically insoluble in the oil while the hydrocarbon end is vory soluble, ^his causes the add to oonoontrate at the surface of the oil so the «0)H group is free to be adsorbed onto the metal surface. /hen the concentration of acid is such that tho surface of the oil contains all the molecules it can, the effect is the same as if pure acid were being used. - S9 - "Slam curve for aayl bntyrate Is an exception to this theory and none has so far been suggested to account for it. However* when tested with different metals its behaviour may suggest an explanation. Iraph IY shews that the metal surfaces with which the lubricant is la contact have a very decided influence en the coefficient of friction, whieh mast be dae te the ohemioal nature of the metals themselves* It is seen quite distinctly that for the name lubrieant steel oa steel gives a much lower value than does babbitt ea steel* fhe latter pert of the stearlo sold ourve Is dis- continuous due to the stearlo acid becoming solid on the plate* ?he experiments with mineral oils of different iodine numbers shown that there is a slight deorease in the friction for an increase la iodine number* 2his is undoubtedly dae to an iacrease in unaaturation* it is thought that this increase in unsatoration has a similar off eat to the addition of a fatty acid* If the oil to begin with had ao iodine number and the aasataratloa was gradually Increased a ourve similar to that for oleic aeld would likely be obtained. - 40 - LtiHftTaRsftfc .rftkM.iLU* 2he above Information coo Id bo used in compound- ing of l u b r i c a t i n g o i l s * If i t i s des ired to obtain a aheap o i l with the same l u b r i c a t i n g propert ies of SOBS expensive animal or vegetable o i l , i t i s only necessary fr© take a mineral o i l and add to i t not more than f i v e to per cent* of an animal or vegetable aoidAproduoe a l u b r i - cant of the required Qual i ty . In some oases where a f a t t y ac id in the pure s t a t e a t tacks the bearing* i t s f a l l e f f e c t can be obtained without injury to the bearing, by us ing a d i l u t e s o l u t i o n of the acid i n a mineral o i l * as shown above In the case of babbit t and o l e i o acid* ajaauax- The above results may be summarised as followst (1) ?he coefficient of static friction of a mineral lubricating oil is lowered by the addition of asters and fatty acids* (2) fhe addition of an unsaturated compound lowers the coefficient of friction more than does the corresponding saturated compound* (3) fhe coefficient ef a lubricant is affected by the metal*a surfaces with which it is in contact• (4) Five per cent of an acid added to a mineral oil gives as low a coefficient as the pure acid* - i l - ls) Xaore&se In iodine aw1t«r of an oil lowers Its coefficient of friction. In conclusion, the writer wishes to express his thanks and appreciation to 3>r« 7* F. Jeyor for his assist' anoe and advice in directing this work. »;,flw<m*'m. Amontons: Ilea. d . l ' & o a d . Boy. des S o l o n o e s , ( 1 6 9 9 ) , p . 2 0 6 . S a l o n B o r l i n Aoad. U e o o l r s , ( 1 7 4 8 ) , p . 1 2 2 . Ooulozab: Ham. d . l*Aoad. Soy* d e s S o l o n o e s , ( 1 7 8 5 ) , T O I . 1 0 . p . 1 6 1 . Horlnj *J«Q. d . 3oa-rans s t r a n g e r s I V . , ( 1 8 3 3 ; , PP«1. 5 9 1 | VI . p . 6 4 1 . Jonkin and Swing* P h i l . Traus . . . . 1 6 7 , ( 16770 , p . 5 0 9 B. Towors ? r o o . I n s t , tiooh. 3ng« ( 1 6 6 3 ) , p . 6 3 2 ; ( 1 6 6 4 ) , p . 2 9 . G. Reynold*i P h i l . Trans . V o l . 1 7 7 , ( 1 6 6 6 ) . p . 1 5 7 . Sosnaorfioldj Z o l t s o h o r . f . l i a t h . t . 6 0 , ( 1 9 0 4 ) , p . 9 7 . Harrison* J a a b . Trans* v o l * XXII. ( 1 9 1 3 ) , p . 3 9 . 0 . Pauott &, p h y s i k . ah o n . 8 6 , (1914) p p . 4 7 9 - 9 4 . Lord K a y l o l g h j P h i l * l a g . s . 6 . V o l . 3 5 . ( 1 9 1 8 ) , p p . 1 , 1 5 7 . 2 . 3 . S t a n t o n , L• ^rohbutt and « • K. Southaoiabe* Eng ineer ing 1 0 8 , (1919) p p . 7 5 9 - 6 0 . K. K. o i l s and » . 3 . 3on*hooobei Petroleum ^iinos 3 , p p . 1 7 3 - 5 , 2 0 1 - 3 , ( 1 9 2 0 ) . v o u r n . 3 o o . Ohen. I n d . 3 9 , p p . 51 - 60 * (1920) l.angnralrt *Jonnr. Ata. Jheia. 3 o o . v o l . 3 8 , (1916) p . 2221* • o l . 3 9 , ( 1 9 1 7 ) , p . 1 6 4 6 . Trans . Faraday 3 o o . 1 5 , I I I (1920) p . 6 2 . .; . B . Hardy: J o n r n . 3 o o . Ohem. I n d . V o l . 3 6 , ( 1 9 1 9 ) , p . 7 « P h i l . Hag. V o l . 3 8 , ( 1 9 1 9 ) , p . 3 2 . 7 o l . 4 0 , ( 1 9 2 0 ) , p .201 Fourth Boport on C o l l o i d Chemistry B r i t i s h A s s o c i a t i o n for .dTanoeaent o f S o i e n o o , ( 1 9 2 2 ) , p . 1 6 5 . '«. B. Hardy and Ida Doublooay t Froo. Hoy.3oo.Vol.100A (l922)p.550» Vol. 101* (192^), p. 467. BIBLloqiUPHY ( J o a t . ) Ida Doa"bleday: Jonrn* 3heia. Uoa. (1922) p . 2875 B. K. Deoloyj ? r o o . P a y s . 3oc . Vol . 32 , (1919-20) p . i a Duastaao and Tholoj lOmrn. I n s t . P e t . ?och. Vol . 17 . (1918) , p p . 191-228. Jhon. ?and l o t . 3a*?. Vol . 2 e . l o 7 (1923) , F . 299 A. Beuoket S e l f o a s i a d e r - « t g . 4 7 , (1920) p . 759 3 . ? . HoDortshawt P e t r o l o a a -Hraos, 3 , (1920) p p . 441-2 , 4 8 9 - 7 1 , 511-2 . 3 . 3 . Bfaatnagar and . a . 3 . Sarn«r* J o a r a . Soc . 3hea. l a d . 3 9 , (1920) , p p . 185-7 ? . J . H. Hyd«« £ a g l a « e r l a g I I I . , (1921) p p . 708-9 ^ . E . 311* oa aad ]}. P . Ba#aard: J . 3oo . ^atora. Sag* 1922 J m i r a . l a d . Bng.Ohen. Vol . 14, (1922) p p . 682* 883 . « • B . Horaohelt Jhsss. sad Sl«t. Sag . Vc l . 2 8 , (1923) , p p . 302 , 594,

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