Patent ID: 7575620

Claim:
A matrix powder comprising: (a) about 15 weight percent of −325 Mesh cast tungsten carbide particles; (b) about 2 weight percent −325 Mesh particles comprising one or more of iron particles and nickel particles; (c) about 2 weight percent +60 Mesh macrocrystalline tungsten carbide particles; (d) about 6 weight percent −60+80 Mesh macrocrystalline tungsten carbide particles; and (e) about 75 weight percent −80+325 Mesh hard particles comprised of crushed cemented tungsten carbide particles containing one or more of cobalt and nickel within at least one of the following particle size ranges: (i) −80+120 Mesh hard particles; (ii) −120+170 Mesh hard particles; (iii) −170+230 Mesh hard particles; (iv) −230+325 Mesh hard particles; (v) −325 Mesh hard particles; and wherein said crushed cemented tungsten carbide particles constitute between about 10 weight percent to about 50 weight percent of the matrix powder and the balance of (e) is comprised of macrocrystalline tungsten carbide particles.