Synthesis of WC and dense WC-5 vol.% Co hard materials by high-frequency induction heated combustion

Tungsten carbide (WC) and dense WC-5 vol.% Co materials, with grain size of similar to1 mum, were synthesized by high-frequency induction heated combustion synthesis (HFIHCS) method in one step from elemental powders of W, C, and cobalt (Co) within several minutes. Simultaneous combustion synthesis and densification were accomplished under the combined effects of an induced current and mechanical pressure. In the absence of cobalt additive, WC can be formed, but its relative density was low (about 70%) under simultaneous application of a 60MPa pressure and the induced current. However, in the presence of 5 vol. % cobalt, the density increased to 98.5% under the same experimental conditions. The percentages of the total volume shrinkage occurring before and during the synthesis reaction of WC-5 vol.% Co were 7 and 57%, respectively. The fracture toughness and hardness values obtained of WC-5 vol.% Co were 7 MPa m(1/2) and 2100 kg/mm(2), respectively. (C) 2003 Elsevier B.V. All rights reserved.