Preparation of titanium diboride nanopowders of different particle sizes

Reactions between titanium and microcrystalline boron powders in a Na₂B₄O₇ ionic melt at temperatures from 700 to 850°C and those between TiCl₄ and NaBH₄ at temperatures from 300 to 750°C and hydrogen pressures of up to 10 MPa, with no solvent, have been studied by X-ray diffraction, scanning electron microscopy, thermogravimetry, and elemental analysis. The results demonstrate that TiB₂ formation occurs at t 〉 730°C and 550°C, respectively. According to scanning electron microscopy data, the TiB₂ powder consists of particles 70–75 and 35–50 nm size, and the crystallite size evaluated from X-ray diffraction data is 55 and 30 nm, respectively, in agreement with the equivalent particle diameters obtained from the specific surface area of the TiB₂ powders: 60 and 45 nm, respectively.