Advances on strategies for searching for next generation thermal barrier coating materials

Abstract

Thermal barrier coating (TBC) materials play important roles in gas turbine engines to protect the Ni-based super-alloys from the high temperature airflow damage. High melting point, ultra-low thermal conductivity, large thermal expansion coefficient, excellent damage tolerance and moderate mechanical properties are the main requirements of promising TBC materials. In order to improve the efficiency of jet and/or gas turbine engines, which is the key of improved thrust-to-weight ratios and the energy-saving, significant efforts have been made on searching for enhanced TBC materials. Theoretically, density functional theory has been successfully used in scanning the structure and properties of materials, and at the same time predicting the mechanical and thermal properties of promising TBC materials for high and ultrahigh temperature applications, which are validated by subsequent experiments. Experimentally, doping and/or alloying are also widely applied to further decrease their thermal conductivities. Now, the strategy through combining theoretical calculations and experiments on searching for next generation thermal insulator materials is widely adopted. In this review, the common used techniques and the recent advantages on searching for promising TBC materials in both theory and experiments are summarized.