Review of processing and design methodologies of environmental barrier coatings for next generation gas turbine applications

SiC-reinforced SiC ceramic matrix composites (SiC/SiC CMCs) are considered promising candidates to replace their super alloy counterparts due to higher temperature capabilities and lower densities. However, high-temperature and high-pressure water vapour sourced from the hydrocarbons' combustion reactions inhibit the potential of SiC/SiC CMCs by leading to rapid surface recession. In order to address this challenge, environmental barrier coatings (EBCs) have been developed. The emphasis of this review is on the materials and processing techniques for the development of EBC systems. In the first part of the review, the characteristics of the SiC/SiC CMCs and the most common EBC materials are summarised. Then, the interrelationship between processing methods, microstructures and the resulting properties is reviewed. Finally, an overview of the future directions is outlined to assist developments in advanced and novel EBCs for next generation gas turbines.