Low temperature synthesis of dense TiB₂ compacts by reaction spark plasma sintering

Abstract

In this study, the low temperature synthesis of dense titanium diboride (TiB₂) compacts by Reaction Spark Plasma Sintering (RSPS) of ball milled mixtures of titanium and boron powders is presented. The influence of milling time and sintering temperature on the in-situ reactive synthesis, densification, grain size and mechanical properties of TiB₂ was investigated. TiB₂ compacts with relative density above 99% have been obtained at a significantly low sintering temperature of 800°C. X-ray diffraction analysis confirmed the formation of TiB₂ along with a small amount of secondary TiB phase. The effect of TiB on the grain size and the hardness and fracture toughness was investigated. TiB₂ compacts processed were found to have a nanohardness > 26 GPa and an elastic modulus > 570 GPa and indentation fracture toughness more than 3.30 MP a.m^1/2. It is shown that RSPS can be an attractive route for synthesis of ultrahigh temperature ceramics at low temperatures.