Patent ID: 6057046
Filing Date: 2000-05-02
Classification: B22F,C22C,Y10T

Abstract:
A nitrogen-containing sintered alloy comprising a soft layer at an outermost surface of said alloy, a WC-depleted region immediately beneath said soft layer, and an internal core region beneath said WC-depleted region, wherein:said sintered alloy has an overall phase content comprising at least 75 wt. % and not more than 95 wt. % of a hard phase and at least 5 wt. % and not more than 25 wt. % of a binder phase,said hard phase comprises WC and (Ti.multidot.W.sub.x M.sub.y)(C.sub.u N.sub.1-u), where M represents at least one metal other than W selected from group 6A of the periodic table, 0<x<1, 0.ltoreq.y.ltoreq.0.9, and 0.ltoreq.u<0.9, with an atomic ratio of N/(C+N) being at least 0.2 and less than 0.5, with at least one of TiC, TiN, and TiCN making up at least 5 wt. % and not more than 60 wt. % of an overall composition of said sintered alloy, and with at least one carbide of at least one metal selected from group 6A of the periodic table including said WC making up at least 30 wt. % and not more than 70 wt. % of said overall composition,said binder phase comprises Ni and Co,said soft layer contains WC and said binder phase,said WC-depleted region contains said binder phase and (Ti.multidot.W.sub.x M.sub.y)(C.sub.u N.sub.1-u) and from 0 to 2 vol. % of WC, and has a thickness of at least 3 .mu.m and not more than 30 .mu.m, andsaid internal core region contains said binder phase and (Ti.multidot.W.sub.x M.sub.y)(C.sub.u N.sub.1-u) and more than 2 vol. % of WC.