| 摘要: |
| 等离子物理气相沉积（PS-PVD）技术由于可实现涂层组织结构柔性调控及高沉积效率和高隔热、长寿命热障涂层制备而被广泛关注，但其粉体制备技术及工艺适配性研究进展较为缓慢。开展 PS-PVD 粉体材料工艺适配性研究，通过粉体成分及结构的有效控制，设计并制得一种采用化学共沉淀原料的 1~20 μm 的“双相”结构松散球形团聚 8YSZ 粉体，粉体具有高开孔率和一定自流动性。为了提高粉体的工艺适配性，系统研究 PS-PVD 工艺中不同喷涂距离、喷涂功率和偏离等离子射流中心不同位置的粉体沉积行为，发现通过粉体成分 / 结构的有效控制，在低喷涂功率、长喷涂距离和距离等离子射流中心的不同位置，均可实现良好的工艺适配效果及涂层气相沉积效果。通过粉体材料的优化控制可以降低气化过程中的耗能， 提高粉体气相沉积效果和拓宽 PS-PVD 喷涂沉积适配的工艺窗口，实现在高能、高速等离子体中的高气相比例沉积。在 PS-PVD 用高工艺适配性粉体及其可控制备技术等方面取得了突破，系统地开展了该工艺用粉体制备及性能调控、粉体工艺适配性规律等的研究。 |
| 关键词: 热障涂层 等离子物理气相沉积 粉体 沉积行为 工艺适配 工艺窗口 |
| DOI：10.11933/j.issn.1007?9289.20220818002 |
| 分类号:TQ174 |
| 基金项目: |
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| Process Suitability of Plasma Spray-physical Vapor Deposition with Fine Spherical Agglomerated Powders |
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HE Qing1,2, ZOU Han1,2, YOU Xiaoming1,2, ZHANG Yusheng1, ZHAO Qian2
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1.Chinese Academy of Agricultural Mechanization Science Group Co., Ltd., Beijing 100083 , China;2.Beijing Jinlunkuntian Special Machine Co.Ltd., Beijing 100083 , China
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| Abstract: |
| Plasma spray-physical vapor deposition(PS-PVD) is a novel technology providing a multiphase composite controlled deposition, which is highly flexible in terms of coating structure and performance adjustment owing to the multiphase deposition including solid, liquid, and gas. This process combines the advantages of Air Plasma Spraying(APS) and Electron Beam-Physical Vapor Deposition(EB-PVD). Coatings prepared by this process have the following characteristics, including high efficiency, reasonable cost, long thermal cycle life, and low thermal conductivity. The PS-PVD technology has been of interest owing to its characteristics. However, the progress in the preparation and development of suitable materials and compatibility between materials and process are still not satisfactory. The material used for the PS-PVD process is fine agglomeration granulation particles, which are scarce in the market. The primary focus of this review is the design and preparation of a material suitable for the PS-PVD process. To improve the process suitability of the powder, 8YSZ powders with a “dual-phase”, loose spherical agglomerated structure, and fine particles with sizes of 1–20 μm are developed by a chemical co-precipitation of the raw material. The powder consists of typical fine irregular dense particles, nanoscale and dense agglomerated particles, with a high rate of opening porosity and certain self-fluidity as well as good crushing strength as a key characteristic. The deposition behaviors of the powder and microstructural characteristics of coatings with different spray distances, thermal spray powers, and positions away from the jet center are systematically studied to improve the compatibility of powders and process. When the electric current is between 1.70 and 2.6 kA the spray distance is between 0.4 and 1.2 m, under various other process parameters, we can prepare columnar and quasi-columnar coatings composed of a single metastable tetragonal phase (t') by vapor deposition. A high-vapor-content deposition and excellent compatibility are realized by effectively controlling the powder content and microstructure during the spraying process, at a low thermal spray power, large spray distance, and different positions away from the jet center. By improving the spray powders, the consumption of plasma energy used for vaporing of powders decreases, the vapor deposition improves, and the suitable process parameters for PS-PVD are broadened, thus realizing a high-vapor-content deposition in a high-energy and high-speed plasma. The deposition of the material during the PS-PVD process is constructively analyzed. The deposition process is as follows. First, the powders are stably conveyed into the nozzle, and then the adherents in the powder evaporate and the fine agglomerated granulation particles collapse quickly. The collapsed materials then partially sinter, evaporate, and melt at the high-temperature zone of the anode. During the interaction between collapsed materials and plasma plume, the phenomenon continues in the chamber including a continuous evaporation, melting, atomization of a liquid drop, transmission of a gaseous phase, condensation of a gaseous phase, and ejection of sintered particles and melted liquid droplets from under the jet flow out of the plasma plume due to self-gravity. Finally, the coatings are deposited by a source of a vapor phase and reflected disturbing flow from the outskirts of the plasma plume. The ratio of the gaseous phase in the plasma jet and deposition efficiency are improved to some extent by controlling the powder microstructure, content, and existence of dense particles. The contributions of this study are the breakthrough in the design and controlled preparation of materials suitable for the PS-PVD process, spray powder preparation, property regulation, and compatibility between materials and deposition process. |
| Key words: thermal barrier coating plasma spray physical vapor(PS-PVD) powder deposition behavior process suitability process window |
