Thermodynamical and experimental conditions of hafnium carbide chemical vapour deposition

Ceramic films are increasingly used to coat a large variety of materials an d chemical vapour deposition is thus an appropriate process to get high per formance mechanical parts. In order to reinforce carbon foams for high temp erature applications, the possibility of covering such a substrate by a few micrometers thick deposit of hafnium carbide is investigated. The reason w hy is that hafnium carbide is the binary carbide that exhibits the higher m elting point (approximate to 3850 degrees C) whereas the temperature range for the expected application is as high as 3000 degrees C. The conditions o f HfC deposit are first studied by means of thermodynamical calculations. A few trends of the chemical system are pointed out which allow us to select appropriate gaseous precursors, experimental parameters and the associated variation range. Experimentally, the significant parameters are evidenced using experimental planning method. An attempt to correlate the experimenta l and calculated main results is discussed.