Dong-Lin Wu

Laser surface texturing (LST) was used to process circular patterns on silicon nitride (Si₃N₄) ceramic. The surface wettability of un-textured and textured Si₃N₄ ceramic was studied. It was found that all samples were hydrophilic. The hydrophilicity of the textured Si₃N₄ ceramic with a smaller interval was weaker. Effect of the interval on the tribological performance of Si₃N₄ ceramic was investigated under different reciprocating frequencies. As the reciprocating frequency increased, the coefficient of friction (COF) of Si₃N₄ ceramic showed an overall upward trend. And the COFs of textured Si₃N₄ ceramic were higher. At the reciprocating frequency of 0.5 Hz, the COFs of textured samples with different intervals were relatively close. At higher reciprocating frequency, the difference in COF gradually increased. This can be attributed to the change in lubrication state that occurs during the frictional process. Debris and plough were found at surface of all samples, and the original surface was cleaner. The surface damage of textured samples was more severe than that of un-textured samples. EDS analysis on the wear area was performed. The wear rate of the frictional pair at the interval of 250 μm was higher. It was consistent with the more significant wear marks on the surface of the Si₃N₄ ceramic at this interval. There were significant differences in the frictional process between un-textured and textured samples. For the un-textured surface, the debris was mainly concentrated at the edges of the friction trajectory. In contrast, textured patterns had the function of storing lubricant, while also generating micro-shear effects on debris and improving the status of lubrication, resulting in more complex frictional process.