Thermal barrier coating is one of the three key technologies of turbine blade, which is equal to advanced high-temperature structural materials and efficient cooling technology. Plasma spray-physical vapor deposition (PS-PVD) technology is known as the advanced preparation process of thermal protection coatings for the new generation engine.
Institute of New Materials，Guangdong Academy of Sciences focused on the slight changes in structure and mass of gun cathode, the core component of PS-PVD equipment. Combined with the low-pressure spectrum diagnosis technology of high-speed plasma flow, the plasma temperature and electron density were calculated by Boltzmann cartography and Stark broadening theory. The influence of the cathode state on the plasma jet characteristics in the low-pressure environment of 50~100Pa was investigated, and important conclusions were obtained by combining with the differences of the micro-morphology and typical properties of the prepared coating. The plasma jet produced by the cathode with medium loss has the highest temperature, the highest electron density and the most complete powder evaporation. High supercooling and supersaturation of gas phase particle resulted in high nucleation and crystal growth rates, resulting in uniform and complete columnar crystals with the best performance (FIG. 1).
The research findings have been published in Ceramics International vol. 46 (IF: 3.45). Yan Zhang, a master (jointly trained by Central South University), is the first author, and Jie MAO, a professor-level senior engineer, is the corresponding author. This work was supported by the General project of the National Natural Science Foundation of China (51771059).
The paper link: https://doi.org/10.1016/j.ceramint.2020.02.109
Fig.1 The coating morphology, electron density and temperature of plasma jet prepared by different cathode loss time of spray gun