Study on Porosity of Thermal-Sprayed Commercially Pure Aluminum Coating

作者：Bo Li, Lei Fan, Jie Bai, Jinhang He, Jianfeng Su, Song Wang, Chao Deng, Shifeng Liu, Zhiqing Zhang · 发表于：Materials · 年份：2023 · DOI：10.3390/ma16196612 · 被引用次数：12 · 研究领域：High-Temperature Coating Behaviors、Advanced ceramic materials synthesis、Metal and Thin Film Mechanics

Porosity is closely related to the corrosion and wear properties of a coating processed by thermal-spraying technology, and the quantitative characterization of porosity is a crucial part of the research on coating structures. The current image analysis method often uses the mechanical polishing method recommended by ISO to measure a coating porosity. This method has been proved to be an effective method for the characterization of oxide coatings. However, due to the significant differences in the physical and chemical properties between aluminum and oxides, this method may not be suitable for aluminum coatings, and a more appropriate approach needs to be explored. In this paper, the effects of three polishing technologies (mechanical polishing, argon-ion-beam polishing, and electrolytic polishing) on the porosity measurement of pure aluminum coatings were compared and studied. The research results showed that the commonly used mechanical polishing method and more advanced argon-ion-beam polishing method could not completely reveal the pore structure because SiC particles would be embedded in the pure aluminum coatings during mechanical polishing, filling large pores. Although electrolytic polishing technology had advantages in revealing the macroporous structure, it would introduce a microporous structure and oxides, which would affect the measurement of the coating porosity. The composite polishing technology (electrolytic polishing + argon-ion-beam polishing) could perfect...