THE FORMATION OF ALUMINUM HYDROXIDE IN THE SLIDING WEAR OF ALUMINA

The wear of ceramics is often affected by tribochemical reactions with the surrounding environment. This paper examines the development of aluminium hydroxide interfacial layers in the wear of alumina at intermediate wear rates and the effect of these layers on wear and friction. Since the humidity of the surrounding atmosphere promotes the formation of these layers, a dramatic effect of humidity on the wear rate is brought about by the changes in layer formation. In supporting experiments, it was found that alpha-alumina reacts directly to form boehmite (Al(OH)) under moderate pressures and high temperatures.