US Patent 7939013 Coated cemented carbide with binder phase enriched surface zone

The present invention relates to a coated cemented carbide comprising WC, a binder phase based on Co, Ni or Fe and gamma phase and with a binder phase enriched surface zone essentially free of gamma phase. The gamma phase has an average grain size less than about 1 μm. In this way a binder phase enriched cemented carbide with improved toughness and essentially unchanged resistance against plastic deformation is obtained.