Effect Of Mechanically Alloyed Sintering Aid On Sinterability Of Tib2

High-melting-point borides are attractive for structural and functional materials used in extreme environments. However, their poor sinterability due to their high melting point and strong covalent bonding have prevented their further applications. In this study, a new sintering process, called transient liquid-phase diffusion sintering (TLPDS), has been developed for high-melting-point borides. TiB2 compacts were fabricated by spark plasma sintering at 50 MPa for 15 min at temperatures of 1300 and 1600 degrees C via TLPDS of TiB2 powder with a eutectic TiB-Ti powder as the sintering aid, prepared via mechanical alloying (MA). Differential scanning calorimetry results indicated that the melting temperature of the obtained sintering aid was lower than its equilibrium melting point. MA of the sintering aid suppressed the open pore fraction to one-third of that in the compact sintered with the aid prepared without MA when sintering at 1300 degrees C. We also propose a possible mechanism for TLPDS of TiB2.