Simulation of thermal stress in magnetron sputtered thin coating by finite element analysis

Stresses due to thermal mismatch develop in thin coatings deposited by physical vapour deposition (PVD) processes when cooled down to room temperature from deposition temperature. Despite having lower processing temperature, thermal stress can be significant when a large difference in physical and thermal properties of the bonded materials exists. A 2D finite element (FE) model for coating substrate system (TiN on stainless steel) has been investigated to simulate thermal mismatch stress. Several parametric effects i.e., deposition temperature, substrate thickness, coating thickness, Young's modulus, and thermal expansion coefficient were studied to get the description of the thermal stress states. The effect of interlayer material on thermal stress has also been studied. FEA results in terms of radial, shear and axial stress were compared with the analytical results and good agreement was found.