Friction and wear tests of Si{sub}3N{sub}4 pin (sphere of 12.7 mm in diameter) in combination with ceramics of five kinds (SiC, TiC, ZrO{sub}2, Al{sub}2O{sub}3, and Si{sub}3N{sub}4) were performed in a nitrogen gas atmosphere under unlubricated conditions with temperature being changed from room temperature to 600℃. Also, mechanisms of friction and wear were considered by analyzing the topography of worn surfaces and the following results were obtained. (1) When sliding against a TiC disk, the specific wear rate of Si{sub}3N{sub}4 pin was on average lower than for disks of other materials. At 600℃, the specific wear of pin sliding against disks of all the types was lower than that observed in vacuum, but the specific wear rates of a Si{sub}3N{sub}4 disk and a SiC disk was higher. (2) With an increase of temperature, the application of Al{sub}2O{sub}3 disk and ZrO{sub}2 sliding against ZrO{sub}2 resulted in a decrease of the specific wear of both pin and disk. The above phenomenon was explained by the effect of preventing the growth of wear particles by adhesion and material transfer exerted by nitrogen gas. (3) The mean depth of micro-grooves S{sub}p/b and the depth of mean line lσ increased and with a reduction of the mean tip radius of protuberances of counterpart material r{sub}0, the specific wear rate of pin and disk increased. (4) Mild wear and severe wear could be determined by using parameters S{sub}p/b, lσ, and r{sub}0 and these parameters made it possible to make a qualitative estimation of the specific wear rate.
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