UBC Theses and Dissertations
Effect of strain on corrosion rates of copper in sulfuric acid solutions Johnston, Hugh Alex
The corrosion rate of copper in deaerated aqueous, sulfuric-acid solutions, with regard to the effect of strain, temperature and electrolyte concentration was studied. Copper in the form of wire was subjected to applied stresses of 1728, 8640, and 17,280 pounds per square inch. Five temperatures in the range 15°C to 75°C. were investigated for electrolyte concentrations of 0.1, 0.5 and 1.0 molar sulfuric acid. The rate of corrosion was followed by noting the rate of copper uptake by the solution through a polarographic analysis run periodically for up to 30 hours. Reproducible results were obtained, it was found that: 1. The rate of reaction for the dissolution of copper in sulfuric acid was first order with respect to cupric ion concentration. 2. Experimentally, the reaction rate was pseudo-first order with respect to hydrogen ion activity. 3. Stress, in general, increased the reaction rate slightly, the effect becoming less at higher temperatures. 4. The activation energy for unstressed corrosion was 10.6 Kcal. for the temperature range 15-75 degrees. 5. For 1.0M and 0.5M acid solutions, stress decreased the activation energy and hence increased the reaction rate. 6. The average increase in reaction rate for 10 degree changes in temperature between 15 and 75 degrees was about 1.5. 7. A diffusion controlled mechanism could be proposed for the dissolution of copper in sulfuric acid solutions.
Item Citations and Data