The paper describes an alternative high temperature coating for carbon fibre reinforced carbon and carbon fibre reinforced silicon carbide. Hafnium carbide layers were obtained in a thermally stimulated chemical vapour deposition (CVD) reactor on non-porous substrates by reaction of hafnium tetrachloride, methane and addition of hydrogen. Thermodynamic modelling of the reaction HfCl4 + H, + CH4 --> HfC, HfCl4-x, C, HCI shows the possibility of depositing a nearly carbon-free hafnium carbide layer. These theoretical calculations could be proved experimentally in a thermally activated CVD process. The important carbon content in the hafnium carbide layers could be measured by means of secondary-neutral mass spectrometry, which was employed because of its outstanding capability to provide elementary concentrations at the parts-per-million level with a depth resolution of a few nanometres. The carbon-to-hafnium ratio of the deposited layer closely agreed with the thermodynamic predictions.