Patent ID: 7070643

Claim:
A compositionally graded sintered alloy which comprises: 1 to 40% by weight of an iron group metal; 0.1 to 10% by weight of at least one specific metal element selected from the group consisting of Cr, Au, Ge, Cu, Sn, Al, Ga, Ag, In, Mn and Pb; a hard phase containing, as a main component, at least one compound selected from the group consisting of a carbide, a nitride and a mutual solid solution of a metal (s) which belongs to Group 4 (Ti, Zr, Hf), 5 (V, Nb, Ta) or 6 (Cr, Mo, W) of the Periodic Table; and inevitable impurities, wherein the content of the specific metal element gradually increases from a surface of the sintered alloy toward an inner portion thereof, and a ratio of the average concentration of the specific metal element in a region which is at least 1 mm inside from the surface of the sintered alloy, to the average concentration of the specific metal element in a region between the surface and the position which is 0.1 mm inside the surface, of the sintered alloy, is 1.3 or more.