Coated cemented carbides and processes for the production of same

A surface-coated cemented carbide comprising

• (a) a cemented carbide substrate consisting of WC and at least one member selected from the group consisting of carbides, nitrides, and carbonitrides of Group IVb, Vb and VIb metals of the Periodic Table and a binder phase consisting of at least one member selected from the iron Group metals, in which
• (b) a binder phase-enriched layer is provided between 0.05 to 2 mm below the surface of the substrate;
• (c) a binder phase-depleted layer having a binder phase content less than the average quantity of the binder phase in the inner part of the binder phase-enriched layer is provided on the outer part of the said binder phase-enriched layer;
• said binder phase-depleted layer having B-1 phase depleted and said substrate having substantially no eta-phase;
• and
• (d) a monolayer or multilayer provided on the surface of said substrate consisting of at least one member selected for the group consisting of carbides, nitrides, oxides and borides of Group IVb, Vb and VIb metals of the Periodic Table, solid solutions thereof and aluminum oxide.