Effect of TiN particle size on wear behavior of SiAlON-TiN composites

SiAlON ceramics and their derivatives are potential materials for tribological applications where wear and friction are very crucial. TiN is a reinforcement phase and solid lubricant for SiAlON used to improve mechanical and tribological properties. In this study, α :β -SiAlON composites incorporating nano- and micron-size TiN particles were produced by a gas pressure sintering method. Tribological behavior of the composites was investigated based on reinforcement particle size and physico-mechanical properties. Tribology tests were performed with a computer-controlled tribometer under dry unlubricated conditions with ball-on-disk configuration. It was found that the TiN particle size has an effect on surface roughness and hence the coefficient of friction. When the TiN particle size decreased to nano size, the wear mechanism was tribochemical, whereas, when the particle size increased to micron size, severe mechanical wear was observed besides tribochemical wear.