The Microstructure of Nanocrystalline TiB(2) Films Prepared by Chemical Vapor Deposition

Nanocrystalline titanium diboride (TiB(2)) ceramics films were prepared on a high purity graphite substrate via chemical vapor deposition (CVD). The substrate was synthesized by a gas mixture of TiCl(4), BCl(3), and H(2) under 1000 °C and 10 Pa. Properties and microstructures of TiB(2) films were also examined. The as-deposited TiB(2) films had a nano-sized grain structure and the grain size was around 60 nm, which was determined by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. Further research found that a gas flow ratio of TiCl(4)/BCl(3) had an influence on the film properties and microstructures. The analyzed results illustrated that the grain size of the TiB(2) film obtained with a TiCl(4)/BCl(3) gas flow ratio of 1, was larger than the grain size of the as-prepared TiB(2) film prepared with a stoichiometric TiCl(4)/BCl(3) gas flow ratio of 0.5. In addition, the films deposited faster at excessive TiCl(4). However, under the condition of different TiCl(4)/BCl(3) gas flow ratios, all of the as-prepared TiB(2) films have a preferential orientation growth in the (100) direction.