| 摘要: |
| 在热喷涂制备微米 / 纳米双结构涂层的工艺优化研究中缺乏对颗粒状态与喷涂工艺和涂层结构性能之间关系的综合分析。针对大气等离子喷涂制备双模态微观结构的热障涂层过程开展工艺参数优化研究。首先基于试验测量和数值仿真模拟所获得的颗粒状态以及射流信息，计算可表征飞行粒子受热状态的熔融因子分布，同时开展试验研究获得给定喷涂工况下涂层微观结构和沉积效率。最后以熔融因子为中间参数，研究并建立喷涂工艺-飞行粒子状态-涂层结构特性相关关系。结果表明， 数值仿真模拟得到的纳米团聚颗粒状态与试验测量结果基本一致。纳米结构涂层微观结构主要缺陷为未熔纳米团聚粒子及微裂纹。在纳米结构涂层制备过程中，随着喷涂距离增加，飞行粒子的熔融因子先增大后减小，涂层沉积效率先增加后降低， 孔隙率和未熔粒子数则先减小后增大。主气流量的增加则会导致熔融因子减小。在喷涂功率相近情况下，采用低电流高电压的组合会使得飞行粒子熔融因子分布取值较大，进而使得涂层沉积效率增加、孔隙率降低。使用熔融因子分析喷涂工艺参数对纳米团聚粉末颗状态和涂层结构特性的影响关系，可用于指导纳米双结构涂层制备过程工艺控制。 |
| 关键词: 等离子喷涂 飞行颗粒 熔融因子 微观结构 孔隙率 |
| DOI：10.11933/j.issn.1007-9289.20211108001 |
| 分类号:V261 |
| 基金项目:国家自然科学基金(52031010)；国家科技重大专项(2017-Ⅶ-0007-0100)资助项目 |
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| Optimization of Process Parameters for the Preparation of Nanostructured Coatings Based on Melting Index |
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ZHU Jinwei1, WANG Shixing2, ZHENG Lili1, ZHANG Hui3, HE Jing2
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1.School of Aerospace Engineering, Tsinghua University, Beijing 100084 , China;2.Beijing Jinlunkuntian Special Machine Co., Ltd., Beijing 101113 , China;3.Department of Engineering Physics, Tsinghua University, Beijing 100084 , China
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| Abstract: |
| In the study of process parameters optimization of nanostructured coating prepared by thermal spraying, comprehensive analysis of the relationship among particle status, spraying parameters, and coating properties is lacking.The process parameter optimization is carried out for the preparation of nanostructured YSZ coatings by atmospheric plasma spraying. Based on the particle state and jet information obtained by experimental measurement and numerical simulation, the melting index (M.I.) distribution that can characterize the heating state of in-flight particles is calculated. Experimental research is carried out to obtain the coating microstructure and deposition efficiency under given spraying conditions. M.I. is used as an intermediate parameter to study and establish the correlation between process parameters, in-flight particle states, and coating characteristics. The results show that the state of nano-agglomerated particles obtained by numerical simulation is consistent with the experimental measurement results. The main defects in the microstructure of nanostructured coatings are un-melted nano-agglomerated particles and microcracks. During the preparation of nanostructured coatings, as the spraying distance increases, M.I. of in-flight particles and the coating deposition efficiency first increase and then decrease, and the porosity and the number of un-melted particles first decrease and then increase. The increase of argon flow rate can lead to the decrease of M.I.. When the spraying power is similar, the combination of relatively low current and high voltage can make M.I. distribution of in-flight particles larger, which can increase the deposition efficiency and reduce the porosity of coatings. The effects of spraying parameters on agglomerated particle status and coating characteristics are analyzed by M.I., which can be used to guide the process optimization of nanostructured coatings. |
| Key words: plasma spraying in-flight particle melting index microstructure porosity |
