The effects ofpH and electrical bias on abrasion of alumina in aqueous solutions

Abstract

Various coolant chemicals are known to have enhancing and suppressing effects on wear and the quality of finish, but little has been understood about the nature of these effects. Studies were performed to examine the effects of pH and surface bias on wear, subsurface damage, and the various theories of chemical interaction with the wear process. Results of this examination of wear suggest that chemical adsorbates can play a significant role in wear fracturing. Previous observations of plastic mechanisms in brittle wear have lead tribologists to suggest that chemically induced changes in plasticity are the cause of these effects. Instead, this thesis contends occurrence of plastic effects to be by-product of localized hydrostatic compression and insufficient stress intensity to cause fracture. Crack rates and stress intensities required for fracture to occur are known to vary with adsorption.