Wear and friction behavior of alumina ceramics in aqueous solutions with different pH

摘要

It is well known that the wear and friction behavior of ceramics can be significantly improved by using them in water or humid air rather then a dry atmosphere. Accordingly, various ceramics have found many water-lubricated applications. In spite of this, the effect of the pH of the aqueous media on the wear and friction behavior has not been investigated in detail. In this study, we have investigated the wear behavior of alumina ceramics in different water-lubricated conditions with a range of pH values from 0.85 to 13. Based on the results of reciprocating sliding tests, we found that the wear can vary by as much as one order of magnitude and the coefficient of friction between 0.2 and 0.6, depending on the conditions. We also observed that significantly different wear surfaces are generated for different pH values, and these surfaces have a diverse effect on the wear and friction behavior. Wear mechanisms were established by employing surface topography analyses and scanning electron microscopy (SEM). The chemical and electrochemical effects under the selected tribological conditions are discussed to help explain the observed behavior. Our findings suggest that by varying the pH of a solution we can obtain low-wear and/or high-wear of alumina ceramics to suit the requirements of the process.