SINTERED HARD ALLOY WITH HIGH CORROSION RESISTANCE AND HIGH WEAR RESISTANCE

摘要

PURPOSE: To improve oxidation resistance and corrosion resistance under the influence of high temp. oxidation and high temp. corrosion by adding an element having a prescribed free energy of carbide standard formation to a Cr-containing sintered hard alloy. ;CONSTITUTION: This sintered hard alloy consists of WC as hard phase substance, Co and/or Ni as binding phase metal, Cr, and the fourth element. The amount of (Co+Ni) in this alloy is regulated to 5-35wt.%, and the free energy of carbide standard formation of the fourth element is always higher than -3000cal/gmol in the temp. range between the ordinary temp. and 1200°C and is lower than dGf of Cr in a certain temp. range not higher than 1200°C. Further, Cr/(binding metal) is regulated to 0.05-0.2. Moreover, it is preferable that Ni/(Co+Ni) in this alloy is regulated to 0.1-0.7 and Ca or V is used as the contained fourth element, and further, its compositional weight ratio to Cr is regulated to 0.05-1.5.;COPYRIGHT: (C)1996,JPO