Gelcasting of WC-8wt%Co tungsten cemented carbide

Nonaqueous gelcasting as a novel near-net process has been successfully developed to fabricate large size WC-8wt%Co cemented carbide parts with complex shape. In this paper, the effects of processing parameters such as type of monomers, dispersant and its concentration and solids loading on the theological behavior of WC-8wt%Co slurry based on nonaqueous system were investigated to obtain a flowable and stable suspension with a solids loading as high as possible. Moreover, the properties of green and sintered bodies were also studied. The results showed that the optimum amounts of monomer (HEMA) and dispersant (Solsperse-6000) is 1.71 wt% and 0.3 wt%, respectively, based on the weight of the powder, at which, a maximum solids loading of 52 vol% can be obtained, and the green strength can reach 25 MPa. The transverse rupture strength and hardness of specimens sintered at 1400 degrees C for 2 h achieve 2250 MPa and HRA90, respectively, which are similar to those of specimens made by conventional press/sinter or powder injection molding technology. (C) 2007 Elsevier Ltd. All rights reserved.