PROCESSING OF ULTRA-HIGH TEMPERATURE CERAMIC MATRIX COMPOSITES (UHTCMCS) THROUGH RF ENHANCED CHEMICAL VAPOUR INFILTRATION (RF-CVI)

Carbon fibre (Cf) reinforced Ultra High Temperature Ceramic (UHTC) Matrix Composites (UHTCMCs) have proven to be excellent materials that can survive nearly 3000°C in highly oxidizing environments along with a good specific strength. Consequently, they have excellent potential for use in aerospace applications such as rocket nozzle throats and thermal protection systems (TPS). Due to the presence of the carbon fibres, UHTCMCs offer high strength and modulus combined with excellent thermal shock behaviour whilst the presence of the ultra-high temperature ceramic phase protects the carbon fibres at the application temperatures. High temperature oxidation, thermal ablation behaviour and mechanical properties of the UHTCMC’s relies heavily on the bonding between the carbon fibre and matrices especially the oxides formed to avoid any progressive failure and predict the life of the components. In the present investigation, a radio frequency assisted chemical vapor infiltration (RF-CVI) technique has been used to make the 2.5D Cf reinforced ZrB2, ZrB2/carbon matrices composites with various interphase materials. The advantage of RF heating is that it creates an inverse temperature profile in the sample, which means that the infiltration starts from inside and progresses outwards. This allows the time needed for processing to be reduced very significantly compared to the conventional CVI process. This presentation will report on the latest results from the research that has been undertaken at the University of Birmingham, including the results from a wide range of testing that has been undertaken at both DLR in Germany and the University of Naples in Italy.