Resistance of ceramic / metal Functionally Graded Materials in the flame of a combustion chamber under harsh thermal and environmental conditions

Ceramic/metal Functionally Graded Materials (FGM) are efficient systems to increase the performance of materials used in thrusters, which operate under harsh thermal and environmental conditions. In this context, an experimental study has been carried out to firstly develop the FGM using atmospheric plasma spraying process and secondly investigate the resistance of the materials in the flame of a combustion chamber under oxidising atmosphere. Several configurations of FGM have been tested, in order to analyse the influence of the different layer thickness and composition, on their resistance. The link between the different FGM configurations and their endurance in the combustion flame has been established. The best performance was demonstrated with a thin ceramic layer of rich yttria stabilised hafnia deposited on the top surface. All the configurations showed an excellent resistance with limited degradation signs.