Friction and wear behavior of pressureless liquid phase sintered SiC ceramic

• Friction and wear behavior of LPS SiC ceramic was investigated.
• Wear mechanism of LPS SiC ceramic was investigated.
• Microstructure evolution during friction was investigated.

Unlubricated friction properties of the pressureless liquid phase sintered SiC ceramics (PLPS SiC) at room temperature were investigated by a bar-on-ring tribometer. The results showed that the friction and wear behavior of PLPS SiC ceramics were closely related to the normal load and the microstructure. The friction coefficient increased with the rotation speed and normal load. Comparing to the rotation speed, the normal load had bigger influence on the friction and wear behavior of the PLPS SiC ceramics. The amorphous films existing between the SiC grains led to the easy spalling of SiC grains. The spalled SiC grains acted as abrasives, resulting in the formation of furrows on the surface first and causing severe wear subsequently. On the other hand, the spalled SiC grains were easily oxidized by the heat generated during the friction process due to their nanometer size. The worn process was the interaction of multiple wear mechanisms, and different worn mechanism was found under certain friction condition.