ABSTRACT
The friction and wear of polycrystalline silicon nitride has been measured in a sliding ball-on-flat apparatus in an environment containing water vapor at elevated temperatures. The friction coefficient and wear rate are typically high at the start of an experiment and then are significantly reduced at varying water partial pressures in the temperature range 300-800°C. The high friction and wear values are regained when the temperature is increased above 800°C. The high temperature transition depends on the water partial pressure.
