Thermal barrier coatings: Review

Thermal barrier coatings (TBC) are extensively used for high temperature applications like gas turbine blades, internal combustion engines, and pyro chemical reprocessing units. This leads to a considerable competition in development of TBC materials and as a result various materials are developed. Also parallel development in the coating technologies such as atmospheric plasma spray (APS), electron beam physical vapour deposition (EB-PVD) etc. helped in improving microstructure of the coating which in turn helps in increasing their life. In coating process, main focus is on increasing the life of underlying substrate. Continuous research and investigation in thermal barrier materials is done by evaluating and analysing its high temperature behaviour and various failure modes. This review paper gives a summary of the different thermal barrier coating materials used at present, advancements in coating materials, high temperature behaviour of TBC, residual stresses induced in the coating and its failure mechanism.