PURPOSE: To obtain a double layer valve seat showing excellent wear resistance over a long period and remarkably small in mate attackability as well by constituting it of an abutting layer of iron base sintered allays of three dispersion phases constituted of allays with specified hardness and compsn. and a backup layer of an iron base sintered alloy with specified hardness.

CONSTITUTION: This valve seat has a double layer of a valve abutting layer of iron base sintered alloys and a backup layer of an iron base sintered alloy integrally sintered and bonded with the valve abutting layer and is obtd. by infiltrating copper or a copper alloy into an iron series sintered allay matrix having 5 to 25% porosity. The valve abutting layer is constituted of a compsn. of 3 to 15wt.% primary dispersion phase of an Fe-Cr-W-Co alloy having 700 to 1800 MHv and 5 to 30% secondary dispersion phase of an Fe-Cr-Mo-W-V alloy having 400 to 800 MHv, and the balance an Fe-Co alloy base having 200 to 500 MHv. The backup layer is constituted of an Fe-Cr sintered alloy having 100 to 400 MHv.