Preparation of TiB<sub>2</sub>/C Composites in a CVI Reactor

Titanium diboride (TiB2) appears to be an attractive candidate for a high-temperature fiber reinforced composites. Chemical Vapor Infiltration (CVI) has been carried out for the preparation of TiB2/C composites. Titanium diboride has been deposited from the gas mixtures of TiCl4, BCl3, and H2 in the furnace at the reaction temperatures between 850 to 950 °C and about 20 torr. Effects of infiltration parameters such as temperature, reaction time, and concentrations of BCl3 and H2 have been studied. Analyses with SEM, TGA and XPS were carried out. The amount of deposition in the preform increased with the increases of the reaction time, temperature and the flow rate of BCl3. The activation energy of the whole deposition reaction could be estimated from the Arrhenius plot.