A Modeling Tool for Predicting the Durability of Environmental Barrier Coatings (EBC) for Ceramic Matrix Composites (CMC)

CompuTherm, LLC proposes a pilot project to develop a modeling tool that can be used to assess the durability of environmental barrier coatings (EBCs) for ceramic matrix composites (CMCs) under combustion environment. The modeling tool includes a thermodynamic database for the gas phase, a thermodynamic database for the silicate system (EBCs), and a computer software package that deals with thermodynamic equilibrium, gas-solid reaction, and volatile kinetics of silica. In particular, this tool would predict, given an EBC system and an environmental combustion condition, the partial pressure of each gaseous species in the system, the activity of silica in the EBC, the flux of volatile silicon species, such as SiO(g), and Si(OH)4(g), and the recession and glass formation of the EBC. This modeling tool would provide valuable guidance to the US Air Force and private sectors in the development of advanced EBCs for CMCs. CompuTherm, LLC has significant capabilities for developing modeling tools from its past experience with software and thermodynamic database development. In Phase I, we will examine the feasibility of developing such a tool using a simplified system, whilst a powerful tool, which can be applied to practical complicated systems, will be developed in Phase II. BENEFIT: A major breakthrough in gas turbine engine performance requires a new generation of hot-section structural materials having a temperature capability considerably higher than the current metallic hot-section structural materials. Si-based ceramics, such as ceramic matrix composites (CMCs), exhibit superior high-temperature strength and durability, which indicates their potential to revolutionize gas turbine engine technology. However, their usage as turbine engine hot-section components is limited due to their lack of environmental durability in the high velocity combustion environment. Development of advanced EBCs for CMCs is therefore an essential, yet challenging task for materials scientists/engineers due to the complexity of the system. Traditional trial-and-error approach is costly and time-consuming. Computational approach, on the other hand, becomes more and more important in materials development/enhancement and durability assessment. Successful completion of the proposed work will provide DoD, other federal agencies, aerospace, and related industries with a valuable tool to accelerate the development of advanced environmental barrier coatings (EBCs) for ceramic matrix composites (CMCs) to be used in high temperature combustion environment. In addition, research centers such as government laboratories and universities will find this tool useful for basic materials research. This will result in significant cost saving for the US government and aerospace industry in the development of next generation hot-section structural materials.