EFFECT OF SURFACE-ROUGHNESS OF SUBSTRATES ON RESIDUAL-STRESS OF TIN COATING

Effect of film thickness and surface roughness of substrate on the residual stress of TiN coating prepared by are ion plating was studied, Chipping and spalling of TiN films increased with increasing surface roughness and film thickness. The thermal stress of TiN coating was calculated by finite element method (FEM) analysis. The results indicate that the thermal stress of TiN films increased with increasing surface roughness of substrates. From stress analysis by FEM and the X-ray method, it is concluded that chipping and spalling of TiN films occurrs when the total stress consisting of thermal and intrinsic stresses generated during the deposition process exceeds the mechanical strength of the TiN films.