TRIBOLOGICAL CHARACTERISTICS OF ALPHA-ALUMINA IN HIGH-TEMPERATURE WATER

The effects of temperature, sliding speed, and contact load on the tribological behavior of an alpha-alumina ceramic sliding on the same material in water were investigated in the range from room temperature to 300-degrees-C under the corresponding saturated vapor pressures. The specific wear rate increased remarkably at elevated temperatures. The primary wear mechanisms in high-temperature water are considered to be microfracture, promoted by the solution of grain boundary layers, and stress corrosion cracking. A film containing gamma-alumina particulates appeared on the worn surface with increasing sliding speed and increasing contact load in 300-degrees-C water.