Effect of laser surface texturing on friction performance and surface damage of silicon nitride ceramic

Laser surface texturing (LST) with different patterns was performed on silicon nitride (Si3N4) ceramic. Effect of patterns created by LST on coefficient of friction (COF) and surface damage under dry friction was investigated. Results indicated that fluctuation of COF decreased with the increasing loading force for both un-textured and textured samples. Under the same loading force, COF of Si3N4 ceramic with textured patterns was more stable than the samples with smoothly finished surface. The COF of textured samples was not always lower than that of un-textured samples. This may be caused by differences in the distribution of debris and the continuity of surface contact. The worn surface existed damages of plow and crack. However, peeling was observed on un-textured samples only. The surface damage of textured samples was slighter than un-textured samples. Especially under the high loading force, catastrophic damage appeared on the smooth surface. The worn surface of textured samples still maintained the similar state. This could be mainly due to the more complex friction process on the surface of textured sample. The wear rate of the frictional pair was also studied. The mechanisms of friction process for smooth and textured surface were analyzed.