AP0821 Development of Robust Harder Composites from WC and TiC by Arc Plasma Melt-Cast Method

Abstract

This work develops robust composites from tungsten carbide (WC) and titanium carbide (TiC) with enhanced hardness for various hard-facing industrial applications. Here, we take advantage of the thermal arc plasma method to develop composites from the mixture of tungsten carbide–titanium carbide (0.5-4 wt.% %) at 10 min. of plasma treatment at an argon flow rate of 1 ltr/min, in the plasma reactor. Constituents of composites such as WC, W₂C, TiWC₂ (solid solution phase between WC and TiC), and C (graphite) were observed in XRD results. The composites were found to have a well-ordered crystalline structure. Melt-cast pure WC and 0.5 wt.% TiC reinforced WC composite shows an acicular type of morphology. Whereas in the case of 2 and 4 wt.% addition of TiC in WC, the morphology is found to be dendritic. No impurities are present in the post-processing of composites, confirmed by XRD and EDS studies. BET surface area and total pore volume of melt-cast WC and WC-TiC (0.5-4 wt.%) composites were found to be 0.14-0.22 m²/g and 0.0003-0.0031 g/cm³ respectively. The typical WC reinforced with 4 wt.% TiC composite shows an improved microhardness value of 3422 ± 10 VHN, which is more than 70 % of the microhardness value of plasma-treated WC (2010 ± 06 VHN). The WC-TiC composites are characterized by high Young's modulus in the 675-710 GPa range. The enhanced hardness and Young's modulus values of the composite are possibly developed due to the presence of solid solution phase (TiWC₂) and tungsten semi-carbide (W₂C), as well as the low porous nature of the samples. The robust composites have great scope for developing wear-resistant tools, cutting tools, coating material for abrasive steel bearings, etc.