Microstructure and wear resistance of low temperature hot pressed TiB 2

Abstract

Fine-grained TiB 2 compacts have been hot pressed to 98–99% theoretical density at 1400 °C. The compacts were consolidated from sub-micron powders prepared by a high-energy ball milling technique. Titanium diboride (TiB 2) powders were obtained from the milling of commercially synthesized TiB 2 and also from the mechanical alloying (MA) of Ti and B precursors. The formation of TiB 2 from Ti and B powders by mechanical alloying was found to reach completion after 3 h, and wear debris from steel mill vials and media introduced 0.8 to 1.5 wt% Fe in the sintered compacts. The dry erosion resistance of the highest density compacts was examined using an ASTM standard test with an abrasive jet of Al 2O 3 impinging at a normal angle of incidence. Steady-state erosion rates of 0.5 mm 3/kg of erodent compare favorably with the measured value of 9 mm 3/kg for commercial, fine-grained WC–Co cermets under identical conditions. Microstructures, fracture surfaces, and erosion craters were also examined by electron microscopy.