| 摘要 |
PURPOSE:To obtain a surface-treated cemented carbide alloy member free from peeling of coating layer and excellent in machinability, by successively forming an intermediate softened layer, a surface semihard layer, and a coating layer each having a specific composition on the surface of a base material for a cemented carbide alloy with a specific composition to respectively specified layer thicknesses. CONSTITUTION:A base material of cemented carbide alloy has a composition consisting of, by volume, 5-30% Co and the balance WC and further containing, if necessary, 5-30% of NaCl-type crystalline structure of the carbides (excluding WC), nitrides, and carbonitrides of the group-IVa, -Va, and -VIs metals of the periodic table. On the surface of the above, an intermediate softened layer which has a composition consisting of 15-30% Co and the balance WC and further containing, if necessary, 5-30% of the same NaCl-type crystalline structure as mentioned above is formed to 2-50mum layer thickness. On the surface of the above layer, a surface semihard layer consisting of 3-15% Co and the balance WC and further containing, if necessary, 5-30% of the same NaCl-type crystalline structure as mentioned above is formed to 0.1-30mum layer thickness. Further, a single or multiple coating layer consisting of the same carbides, etc., as mentioned above and Al2O3 is formed to 1-20mum layer thickness on the above-mentioned layer. Moreover, by constituting the above-mentioned layers of structures having respectively proper hardnesses, the surface-treated cemented carbide alloy member can be obtained.
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