Hot pressed hard compacts contg. small diamonds - using very short sintering times to prevent soln. of diamonds in the matrix

Prods. contain diamonds with a size 1 mm which are mixed with a metal-carbide and hot pressed in graphite moulds at a temp. ca 1800 degrees C. Heating for pressing consists of heating the mould to 1200 degrees C by high-frequency induction at a rate of 1000-1100 degrees C per minute, followed by heating to the final sintering temp. at 3000-6000 degrees per minute by resistance heating of the carbide-diamond mixt. in addn. to heating the mould by induction. The mould is pref. maintained at 1200 degrees C for =2 minutes; but for is not >2-3 seconds at the final sintering temp. The prods. are cutting and drilling tools having wear-resistant surfaces. The short time at the final sintering temp. does not impair the props. of the diamonds but widens the range of alloys which can be used in the matrix.