1996 Volume 45 Issue 10 Pages 1119-1124
Residual stress is generated in coating films due to difference in thermal expansion between film and substrate. Since the residual stress influences the mechanical properties of coated material, it is important to measure the residual stress in the film and the substrate. In this study, 5μm thick TiN and TiC films were deposited on the spring steel substrates by multi-arc (M-A) and dynamic mixing (D-M) PVD methods. In the TiN films deposited by the M-A method, the compressive residual stress of -5.5--4.0GPa was measured, and its absolute value decreased with increasing depositing temperature. Similarly the compressive residual stresses of -2.0GPa and -7.2GPa were measured in the TiN film deposited by the D-M method and TiC film deposited by the M-A method, respectively. In the substrate near the film/substrate interface, small compressive residual stress of -25--10MPa was measured under the as-deposited condition. The residual stress change during the repeated bending stress was measured in the substrate and the film. In the substrate of TiN coated specimen, the residual stress increased in the early stage of repeated bending stress and saturated at the stress value of -110--40MPa. the saturated stress increases with increasing applied stress. On the other hand, the residual stress did not change in the substrate of TiC coated specimen. In addition, the residual stress in the films did not change during the repeated bending stress in all the coated specimens.
