Effects of CO2 Laser Surface Processing on Fracture Behavior of Silicon Nitride Ceramic

Abstract

Surface defects generated by grinding deteriorate the flexural strength of the silicon nitride (Si3N4) ceramic. In this paper, CO2 laser surface processing was applied to eliminate the grinding-induced defects. SEM micrograph showed that the surface integrity of Si3N4 samples was improved after laser processing. Four-point bending tests and fractographic analysis indicated that the flexural strength and fracture origins were affected by the change of surface integrity in laser-treated Si3N4 samples. The effect of grinding-induced residual stress on flexural strength of laser-treated samples was discussed. It was concluded that laser surface processing had significant effects on fracture behavior of flexure Si3N4 samples.