The chemical vapor deposition of TiB2 from diborane

In this paper we describe an experimental study of the chemical vapor deposition of titanium diboride on graphite using the reaction of TiCl₄ with B₂H₆ in a hydrogen atmosphere in the temperature range 600–900 °C. Dense and adherent coatings were obtained varying in composition from boron rich at 600 °C (TiB_3.12) to stoichiometric above 700°C. There was a gradual increase in crystalline size with increasing deposition temperature. Chlorine tended to remain incorporated in the deposit (1.86 at.% at 600 °C decreasing to 0.51% at 900 °C). The coatings were very hard ($\text{HV = 3715 kgf mm}{}^{\mathrm{?2}}$).