Tailoring coating composition for the associated microstructural stability of a single-crystal superalloy: An experimental and simulation study. (February 2023)

• Record Type: Journal Article
• Authors: Geng, Lilun; Zhao, Wenyue; Ru, Yi; Pei, Yanling; Li, Shusuo; Gong, Shengkai
• Is Part Of: Corrosion science. Volume 211(2023)
• Publication Date: 2023-02
• Subjects: A. Metal coatings -- A. Superalloys -- B. SEM -- C. Oxidation -- C. Interfaces -- C. Thermodynamic diagrams; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110916
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: Further application of protective coatings to superalloys is limited by the microstructure evolution of coating/superalloy interfacial area due to the significant interdiffusion of various elements. Here, a trade-off between oxidation resistance and microstructural stability at 1100 °C is made for a high-Mo single-crystal superalloy coated by NiAlHfZr or NiCrAlYSi. The complex mechanisms of Al and Cr affecting the protective oxide scale formation, interdiffusion behaviors and deleterious Mo-rich phases precipitation have been uncovered. An efficient route utilizing thermodynamic calculation and kinetics simulation has also been established to evaluate the coating-associated microstructural stability of superalloys and to tailor coating compositions further. Graphical Abstract: ga1 Highlights: The composition and microstructure at coating/alloy interface were investigated. The addition of Cr to coating improves the oxidation resistance. The precipitation of Mo-rich phases could be regulated by Al and Cr contents. The activity gradient of Al across the interface can be mitigated by lower Cr. An idea for coating design coupling experiments and simulations is established.