Nanostructured HfC–SiC composites prepared by high-energy ball-milling and reactive spark plasma sintering

A novel route combining the reactive spark plasma sintering (R-SPS) and HfSi2-C powders was proposed for fabricating dense and nano-structured HfC–SiC composites. Ultra-fine and homogeneously distributed HfC (310 nm) and SiC (210 nm) grains were obtained after sintering at 1750 °C, which were attributed to the molecular-level homogeneity of Si and Hf in HfSi2, the high-energy ball-milling of raw powders and low sintering temperature by R-SPS. The fracture toughness of the composites was improved up to 3 MPa m1/2 because of the homogeneous distribution of HfC and SiC grains and consequent enhancement of crack deflection.