Thin Solid Films, Vol.308-309, 310-314, 1997
A practical method for the determination of the Young's modulus and residual stresses of PVD thin films
In a previous article [R.O.E. Vijgen and J.H. Dautzenberg, Thin Solid Films, 270 (1995) 264-269], it is shown that the residual stress of thin hard physical vapour deposited (PVD) coatings can be easily measured by the thin foil method. With this method, TiN is deposited an a thin circular stainless steel foil. Sectioning of this foil into narrow strips results in an easily measurable radius of curvature from which the residual stress can be calculated. In this paper, it is shown that the same strip can also be used to determine the Young's modulus of the coating. For this purpose the strip is heated up while its curvature change is observed. To ensure a homogeneous temperature of the strip, Oil is used as a heat exchange medium. A calibrated video camera and image processing software are used to measure the curvature of the strip. The results show a linear relationship between the curvature and the temperature of the strip. From this the Young's modulus can be calculated. This method is used to determine the Young's modulus and residual stresses of magnetron sputtered TiN coatings with different deposition parameters.
Keywords:COATINGS