Refinement of TiB2 Powders with High-speed Planetary Mill and Its Effect on TiB2 Sinterability

Titanium diboride ceramic was produced via spark plasma sintering (SPS) using finer TiB2 powder made by high-speed planetary ball milling. The effects of ball milling parameters on the composites and particle size of TiB2 powder were investigated. It was shown that the average particle size of TiB2 powder decreased from 5.8 to 1.59 mu m and the wear rate of WC balls was 1.58 wt%, when the ball-to-powder weight ratio (BPR), the rotary speed and milling time and were 10:1, 600 rpm and 20 min, respectively. The content of WC in TiB2 powder can be limited below 4.58 vol% by optimizing the milling conditions. The sintering temperature of TiB2 powder milled can be decreased obviously, and the mechanical properties are evidently improved and the microstructure becomes more homogeneous when the powder of TiB2 becomes finer. The relative density, hardness, bending strength, and fracture toughness of the TiB2 ceramic fabricated at 1 700 degrees C reach the optimal values, which are 98.13%, 19.14 GPa, 756 MPa, and 5.71 MPa center dot m(1/2), respectively. The decrease of TiB2 particle size and the introduction of WC are the potential reasons for the improvement of TiB2 ceramic performance.