| 摘要 |
A cemented carbide article comprising a core of metal carbide grains and a binder selected from cobalt, nickel, iron and alloys containing at least one of these metals, and a surface layer which comprises (by weight) 5-25 % tungsten and 0.1-5 % carbon and a metal or alloy selected from the binder metals and alloys. The surface layer is substantially free of carbide grains as determined by optical microscopy or SEM. The cemented carbide article can be made by forming a mixture of metal carbide grains and a binder selected from cobalt, iron and nickel and alloys containing one or more of these metals, pressing the mixture to form the article, sintering the article and cooling the article to a temperature at which the binder is substantially solid in an inert gas, nitrogen, hydrogen or a mixture thereof in at least three cooling stages, the cooling rates being progressively lower rates. |
