Effect of hot-pressing temperature on densification and mechanical properties of titanium diboride with silicon nitride as a sintering aid

The effect of hot-pressing temperature on the densification behavior and mechanical properties of titanium diboride (TiB₂) was investigated. TiB₂ specimens were hot-pressed for 1 h at temperatures in the range of 1500°-1800 °C, with an addition of 2.5 wt % of silicon nitride (Si₃N₄) as a sintering aid. The density increased markedly at temperatures in the range of 1500°-1600 °C and remained constant thereafter. The formation of a eutectic liquid at 1550 °C was attributed to the steep increase in density. The hot-pressing temperature also improved the mechanical properties, such as the flexural strength, Vickers hardness, and fracture toughness of the specimens. Similar to the density, the mechanical properties improved remarkably at approximately 1550 °C, so that optimum properties were obtainable at temperatures as low as 1600 °C.