| 摘要 |
PROBLEM TO BE SOLVED: To prevent the warpage of a substrate from being generated due to the internal stress of a hard-carbon coating film itself by forming more than 2 layers of a diamondlike hard carbon layer consisting of hydrogen-contg. amorphous carbon on the substrate and arranging an internal stress relaxing layer between the layers. SOLUTION: A hard-carbon coating layer 2 contains 5-40 atomic % of a hydrogen density and shows >=3,000 Hv hardness. An internal stress relaxing layer 3 formed between the hard carbon layers 2 is a hydrogen-free carbon layer or a layer consisting of Si, W, Zr, Hf, Ti, Cr, Ge, Mo, Ru or their oxide, nitride or carbide. Further, when the thickness of the hard carbon layer 2 is denoted by (a) and that of the internal stress relaxing layer 3 by (b), a/b=1 to 1,000. Further, the thickness of the hard carbon layer 2 is preferably made to 50Åto 5μm and that of the internal stress relaxing layer 3 to 5Åto 5μm.
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