Corrosion behavior of cold sprayed 7075Al composite coating reinforced with TiB2 nanoparticles

SURFACE & COATINGS TECHNOLOGY

卷:404

Article

Xie, Xinliang^1,2  Hosni, Bilel³  Chen, Chaoyue⁴  Wu, Hongjian¹  Li, Yuelin⁴  Chen, Zhe⁵  Verdy, Christophe¹  Kedim, Omar E., I³  Zhong, Qingdong⁴  Addad, Ahmed²  Coddet, Christian¹  Ji, Gang²  Liao, Hanlin¹ 

[1] Univ Bourgogne Franche Comte, CNRS, ICB UMR 6303, UTBM, F-90010 Belfort, France

[2] Univ Lille, CNRS, INRAE, Cent Lille,UMR 8207,UMET Unite Mat & Transformat, F-59000 Lille, France

[3] FCLAB Res Federat, FR CNRS 3539, F-90010 Belfort, France

[4] Shanghai Univ, State Key Lab Adv Special Steel, 149 Yanchang Rd, Shanghai 200072, Peoples R China

[5] Shanghai Jiao Tong Univ, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China

关键词: Particle reinforced Al matrix composites;    Cold spraying;    TiB2 reinforcement;    Aqueous corrosion;   

DOI  :  10.1016/j.surfcoat.2020.126460

来源: Elsevier

【 摘 要 】

Cold spray (CS), as a novel surface treatment technique, has been widely used for repairing damaged components and as protecting coatings, especially for the applications of aircraft and marine components. To further improve the mechanical properties, while maintaining the corrosion resistance of pure Al and Al alloy coatings, ceramic particles are commonly added into the Al matrix to produce particle-strengthened Al matrix composite (P-AMC) coatings. In this study, dense 7075Al composite coatings reinforced with uniformly distributed in-situ TiB2 nanoparticles (hereafter named TiB2/7075Al) were successfully produced by CS using a gas-atomized composite powder and the propulsive gases of air and helium. Following this, the corrosion behavior of the cold sprayed (CSed) TiB2/7075Al composites was investigated using Tafel polarization, electrochemical impedance, spectroscopy, and immersion tests in 0.1 M and 0.6 M NaCl solutions, and were compared to those of the CSed pure 7075Al coating and bulk 7075Al-T6 material. Electrochemical tests revealed that the composite coating exhibits a higher corrosion rate than the pure 7075Al coating, primarily caused by a galvanic coupling between TiB2 nanoparticles and the more active Al matrix. Compared to the air-processed coatings, the He-processed ones exhibit higher densities of defects, like dislocations, and precipitates due to larger plastic deformation of the sprayed particles, which result in more active sites for corrosion and thus lower corrosion resistance. Low-temperature annealing treatment (230 degrees C/6 h) reduces these defects to increase the corrosion resistance of the CSed coatings. Comparatively, high-temperature annealing treatment (412 degrees C/4 h) results in the coarsening of precipitates and grain growth to increase the corrosion rate of the coatings. Corrosion mechanisms of the CSed and annealed composite coatings related to the microstructure evolution were investigated in detail.

【 授权许可】

Free