Improving stability of thermal barrier coatings on magnesium alloy with electroless plated Ni–P interlayer

• Published in: Surface & coatings technology Vol. 206; no. 21; pp. 4471 - 4480
• Main Authors: Fan, Xizhi, Gu, Lijian, Zeng, Shuibing, Zhu, Ling, Wang, Chunjie, Wang, Ying, Zou, Binglin, Huang, Wenzhi, Chen, Xiaolong, Khan, Zuhair Subhani, Cao, Xueqiang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-06-2012; Elsevier
• Subjects: Applied sciences; Bond strength; Coatings; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Failure analysis; Magnesium alloy; Materials science; Metallic coatings; Metals. Metallurgy; Nonmetallic coatings; Physics; Production techniques; Surface treatment; Surface treatments; Thermal shock resistance; Bond strength; Coatings; Thermal shock resistance; Failure analysis; Magnesium alloy; Interfacial layer; Nickel base alloys; Stability; Mechanical strength; Surface treatments; Non metal coating; Adhesion; Metal coating; Thermal shock; Chemical deposition; Thermal barriers
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2012.05.004

Thermal barrier coatings (TBCs) of zirconia stabilized by 8wt.% yttria (8YSZ) on MB26 rare earth–magnesium alloy with MCrAlY as bond coat were prepared by air plasma spraying (APS). In order to improve the thermal shock resistance of the coatings, an interlayer of Ni–P alloy between the substrate and bond coat was prepared by electroless plating. The preparation, microstructure, bond strength and thermal shock resistance of the coatings were investigated. The results indicate that Ni–P interlayer not only has favorable effects on the protection of Mg alloy substrate from thermal oxidation during thermal spraying, but also significantly improves the bond strength of TBCs. The thermal shock life of TBCs was enhanced from 5cycles to longer than 130cycles with the application of Ni–P interlayer. The failure of TBCs in thermal shock test was mainly induced by the corrosion of Mg alloy substrate.
► Ni–P interlayer is designed to improve the stability of TBCs on Mg alloy. ► Ni–P interlayer has favorable effects on the protection of Mg alloy during APS. ► The thermal shock resistance of the TBCs with Ni–P interlayer is greatly improved. ► The corrosion of substrate mainly leads to the failure of the TBCs.