Abstract: A hard metal or cermet body has a 2 to 100 ?m thick first layer having a binder metal proportion of 2 to 25 mass % and up to 25 volume % of a nitride or carbonitride of one or more metals of Group IVa of the periodic system or up to 10 volume % of a carbide or carbonitride of V, Nb, Ta or Cr, balance WC, whereby the amount of nitride, carbonitride or carbide of the afore-mentioned metals amounts to at least 0.01 volume %. Under the first layer is a 2 to 40 ?m thick second layer with an enhanced nitrogen proportion relative to the first layer, is disposed. Thereunder is a transition zone with a thickness of 2 to 100 ?m in which the composition gradually changes to a homogeneous composition in the inner core of the hard metal or cermet body.

Abstract: The invention relates to a hard metal or cermet body with a hard material phase consisting of WC and/or at least one carbide, nitride, carbonitride and/or oxicarbonitride of at least one of the elements from group IVa, Va, or VIa of the periodic table and a binding metal phase consisting of Fe, Co and/or Ni, said binding metal phase making up 3 to 25 mass %. In particular, WC crystallites should protrude beyond the hard metal or cermet surface of the by 2 to 20 &mgr;m in order to improve the adhesion of surface layers that are applied.

Abstract: A hard metal or cermet body, especially as a cutting insert, has a WC content in the hard phase making up at least 10% and at most 96% thereof and three layers or zones between the interior of the body and the surface formed by the heat treatment to which the sinterable body is subjected. In the outermost layer hard material with limited binder content can be formed underlain by an intermediate layer of a substantially pure WC--Co composition, the innermost layer having a tungsten content falling to the value in the body interior and a binder phase and Group IVa and Group Va metal which increased progressively to the levels in the body interior.

Abstract: A cermet including a cermet core zone in which the content of a binder amounts to at most 90% by mass in relationship to a cermet hard phase is formed with a 0.01 to 3 um deep surface layer having an increased resistance to wear compare to the cermet core zone.