抄録
To investigate the damage behavior of DLC (diamond-like carbon)-Si coating under high contact pressure, a series of experiments were carried out using the Vicker's hardness test. As substrate materials, alloy tool steel (SKD11) and high speed tool steel (SKH51) were used. In order to investigate the effect of coating thickness on coating damage, DLC-Si coatings with two thicknesses of 2.1μm and 4.0μm were prepared on SKD11. Coating damage was observed from the coating and cross-section surfaces. From observation of the coating surface, the indentation shapes of DLC-Si-coated tools were able to be sorted into 3 main types in terms of macroscopic coating damage level. For indentation shape type I, which shows no marked damage but a cross mark caused by the Vicker's indenter, cross-sectional observation was carried out, and a crack parallel to the coating surface was observed in all the DLC-Si coatings. It is inferred that the parallel crack in the coatings was generated by a force from the compressive residual stress of the coating.
