| HIGH COMPATIBILITY of NANOCRYSTALLINE COATINGS with SINGLE CRYSTAL SUPERALLOYS for HIGH TEMPERATURE APPLICATIONS Shenglong Zhu1; 1INSTITUTE OF METAL RESEARCH, CHINESE ACADEMY OF SCIENCES, Shenyang, China; PAPER: 215/Corrosion/Regular (Oral) SCHEDULED: 12:45/Tue. 29 Nov. 2022/Andaman 2 ABSTRACT: Strong interdiffusion between protective coatings and superalloy substrates at high temperatures leads to formation of secondary reaction zone (SRZ), which may seriously weaken the creep and fatigue properties of the coated components[1-3]. In this talk, a serial of nanocrystalline coatings will be introduced to show their high substrate-coating compatibility in addition to excellent oxidation resistance at 1100 ºC. The coatings were prepared on Ni-base single crystal superalloy Rene N5 using magnetron sputtering, and their chemical composition were derived from Rene N5. The thermally grown oxide (TGO) grew on the coating with chemical composition same as Rene N5 is alumina with dispersive TaOx, which is harmful to the oxidation resistance. Increasing the Al concentration to decrease the Ta content in the γ' phase of the coating can reduce the amount of the TaOx in TGO while either making a single γ' phase coating or decreasing the Ta in the coating can prevent the formation of TaOx in TGO. The β phase in the coatings should be prohibited, since it is the driving force to form SRZ. References: 1. T. Narita, A View of Compatible Heat-Resistant Alloy and Coating Systems at High-Temperatures, International Workshop on Advanced Material for New and Renewable Energy, Jakarta, INDONESIA, JUN 09-11, 2009; AIP Conference Proceedings 1169 (2009) 63-73. 2. F. H. Latief, K. Kakehi, Influence of thermal exposure on the creep properties of an aluminized Ni-based single crystal superalloy in different surface orientations, Materials and Design 56 (2014) 816–821. 3. A.G. Evans, M.Y. He, A. Suzuki, M. Gigliotti, B. Hazel, T.M. Pollock, A mechanism governing oxidation-assisted low-cycle fatigue of superalloys, Acta Materialia 57 (2009) 2969–2983. |
