Performance of thermal barrier coatings produced by smart plasma processing

Abstract

Thermal barrier coating typically comprising of bondcoat and yttrium stabilized zirconium topcoat, has been used to improve the efficiency of turbine engine by providing the capability to sustain significant temperature gradient across the coating. Alumina and zirconia composite coating was proposed as a potential candidate to improve the qualities of thermal barrier coating system due to its low melting point and high hardness. The gas tunnel type plasma system, which has high energy density and also high efficiency, is useful for smart plasma processing. The characteristics of the obtained ceramic coatings such as Al₂O₃ and ZrO₂ coatings were superior to the conventional ones. The ZrO₂ composite coating has the possibility of the development of high functionally graded TBC (thermal barrier coating). In this study, the performance such as the mechanical properties, thermal behavior and high temperature oxidation resistance of the alumina/zirconia functionally graded TBCs produced by gas tunnel type plasma spraying was investigated and discussed. The results showed that the alumina/zirconia composite system exhibited the improvement of mechanical properties of thermal barrier coatings and oxidation resistance.