Densification, microstructure and properties of TiB2 ceramics fabricated by spark plasma sintering

This study reports the fabrication of high-density TiB2 ceramics at reduced temperatures (1500 °C) by using field assisted sintering technology/spark plasma sintering (FAST/SPS) technique. In-house processed TiB2 powders with high purity were employed as starting materials. The effects of SPS conditions on the sintering behavior and microstructure of TiB2 were investigated. Sub-micron character of TiB2 particles has a strong influence on the densification during SPS. Microstructural analyses revealed that the high pressure affected both the grain size and the shape of TiB2 crystallites. Elongated grains with average size of 6 μm were perceived in TiB2 sample fabricated by SPS at 1500 °C under 60 MPa pressure with a relative density of 96.7%. The microhardness and elastic modulus were measured as 27.4 GPa and 685.2 GPa, respectively. This sample revealed an improved oxidation resistance due to the formation of a thin oxidation layer on the surface when heated up to 1200 °C.