Fabrication of ultrafine binderless WC and WC-Ni hard materials by a pulsed current activated sintering method

Abstract

Using a pulsed current activated sintering (PCAS) method, the densitication of binderless WC and WC-Ni hard materials were accomplished using ultra fine powder of Ni and WC. The advantage of this process is that it allows very quick densification to near theoretical density and the prohibition of grain growth in nano-structured materials. Nearly fully dense WC and WCNi with a relative density of up to 97.6% could be obtained with the simultaneous application of 60 MPa pressure and electric current within 2 minutes without a significant change in grain size. The average grain size of WC was about 350 nn The hardness, fracture toughness, and the relative densities of the dense WC and WC-xwt.%Ni (x=8,10, 12) composites produced by PCAS were investigated.