Low-Temperature Spark Plasma Sintering of Pure Nano WC Powder


Author to whom correspondence should be addressed: e-mail: johannes.poets chke@ikts.fraunhofer.de


For the first time we have demonstrated the densification of high-purity nanostructured (davg ≈ 60 nm) tungsten carbide by High Pressure Spark Plasma Sintering (HPSPS) in the unusually low temperature range of 1200°C–1400°C. The high-pressure sintering (i.e., 300 MPa) produced dense material at a temperature as low as 1400°C. In comparison with more conventional sintering techniques, such as SPS (80 MPa) or hot isostatic pressing, HPSPS lowered the temperature required for full densification by 400°C–500°C. High Pressure Spark Plasma Sintering, even in absence of any sintering aid or grain growth inhibitor, retained a very fine microstructure resulting in a significant improvement in both hardness (2721 HV10) and fracture toughness (7.2 MPa m1/2).