Influence and effectivity of Sm2O3 and Cr3C2 grain growth inhibitors on sintering of WCoB–TiC based cermets

Abstract

With WC, TiB2 and Co powders as raw materials, WCoB–TiC based cermets were prepared by liquid phase reaction sintering (LPRS) in a vacuum furnace at 1400°C. In this work, the consolidation of WCoB–TiC based cermets with Sm2O3 or Cr3C2 as grain growth inhibitor was studied. The amounts of inhibitor are 0; 0.3; 0.6 and 0.9wt%. The effects of Sm2O3 and Cr3C2 on the grain growth of WCoB–TiC based cermets were studied. The microstructure and mechanical properties of WCoB–TiC based cermets were analyzed by field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). It is found that that Sm2O3 and Cr3C2 not only retard the densification of the WCoB–TiC based cermets, but also significantly suppress the growth of WCoB-grains and TiC-particles. Specimens doped with 0.3wt% Sm2O3 exhibit the optimum mechanical properties (hardness and wear resistance). Whereas mechanical properties (hardness and wear resistance) of specimens linearly increase with the increase of Cr3C2.