抄録
The aim of this investigation was to clarify the fatigue behavior of steel coated with TiN by the physical vapour deposition (PVD) or chemical vapour deposition (CVD), in order to apply the ceramics coatings to machine components and structures. Cantilever-type rotating bending fatigue tests in air were performed by using the round specimens of 0.37% carbon steel normalized, JIS S35C, coated with TiN by PVD or CVD. From the experimental results, 16-23% increase of fatigue strength was observed for the TiN coated specimen, as compared with that of the base metal. Also the fatigue crack propagation rate observed on the surface of coated specimen was equivalent to that without coating. It is suggested that the fatigue crack may initiate at the surface of base metal under the coating film. The increase of fatigue strength of the TiN coated material is attributed to the retardation of crack initiation due to the restriction of dislocation movement in near surface of substrate by hard thin film.
