Physical and mechanical properties of plasma-sprayed thermal barrier coatings at room and high temperatures

Abstract

Thermal barrier coatings (TBCs) are applied widely in the field of aviation. The physical and mechanical properties of single top coatings are significant for the numerical simulation and the prediction of service life of turbine blades. In this research, a new method of fabricating thick single top coatings was performed. In order to investigate the high temperature behavior of the coating materials, three groups of heat treatment temperature (1200°C, 1400°C and 1600°C) were implemented to specimens. The physical and mechanical properties of plasma-sprayed (PS) TBCs with different heat treatment times (HTTs) were tested at room temperature. The Young's modulus of TBCs at room temperature increased with the heat treatment time (HTT), while decreased with the porosity. The relationships between Young's modulus and porosity of all three temperatures were linear approximately.In addition, the mechanical properties of PS-TBCs at 1200°C in air were obtained through three-point bending experiments. The relationships between Young's modulus at 1200°C and porosity were different from those obtained at room temperature. The Young's moduli of TBCs at room temperature and 1200°C can be calculated directly by their porosities, with the help of the fitting formulae obtained in this research. The bending stiffness and strengths at 1200°C with different HTTs were also investigated.