Analysis of thermal stress in magnetron sputtered TiN coating by finite element method

The thermal stress generated in the sputter deposited TiN coating on glass and silicon substrates was investigated by finite element analysis (ANSYS). The four-node structural and quadratic element PLANE 42 with axisymmetric option were used to model the thermal stress induced in the TiN coating. The influence of substrate temperature, Young’s modulus, substrate and coating properties on thermal stress were analyzed. It was found that the thermal stress in TiN coating, for the planar substrate, exhibits a linear relationship with substrate temperature, substrate thickness and Young’s modulus of the coating, but showed an inverse relationship with the coating thickness. The simulated thermal stress of TiN coating was in tandem with the analytical method. The thermal stress induced in the coatings for the rough substrate is higher as compared to that of the planar substrate. The radial stress and shear stress distribution of the coating–substrate combination were calculated. The low and high compressive shear stresses observed in the TiN coating on glass and Si substrate, respectively indicate a low adhesive strength of the coating on the former than that of the latter.