| Designing High Temperature Protective Bondcoat for Ni-base Single Crystal Superalloys Zebin Bao1; Shenglong Zhu1; Fuhui Wang2; 1INSTITUTE OF METAL RESEARCH, CHINESE ACADEMY OF SCIENCES, Shenyang, China; 2NORTHEASTERN UNIVERSITY, Shenyang, China; PAPER: 216/Corrosion/Regular (Oral) SCHEDULED: 14:00/Tue. 29 Nov. 2022/Andaman 2 ABSTRACT: To meet the sustaining request of enhancing thrust-load ratio, single crystal (SX) superalloy, film cooling and thermal barrier coating system (TBCs) have been perspectively utilized in advanced areo engines. Usually, the coating system consists of an oxidation resistant bondcoat and a heat resistant top coat. During service of SX superalloy components at high temperature, the element interdiffusion between bondcoat and superalloy substrate may instigate serious deterioration of mechanical property (e.g., creep resistance and rupture life) of SX superalloy by forming topologically-close-packed (TCP) phases and second reaction zone (SRZ) [1]. Another impact of such interdiffusion is the loss of beneficial element and undesirable oxidation of refratory elements at surface [2]. Thus, to inhibit or mitigate the interdiffusion is one of the key points to design protective bondcoat for Ni-base SX superalloys [3]. In this study, a Re-base diffusion barrier (DB) has been sucessfully incorporated between the state-of-the-art bondcoat of (Ni,Pt)Al and the Ni-base SX superalloy. In contrast to normal (Ni,Pt)Al coating, the coating with Re-base DB showed better oxidation resistance and less interdiffusion, which further resulted in thinner formation of SRZ and TCP precipitates. Mechanisms responsible for the enhanced performance during the oxidation tests will be intensively discussed. References: [1] D.K. Das, K.S. Murphy, S. MA, T.M. Pollock, Formation of secondary reaction zones in diffusion aluminide coated Ni-base single-crystal superalloys containing ruthenium, Metall. Mater. Trans. A 39 (2008) 1647–1657.<br />[2] N. D. Souza, D. Welton, G.D West, I.M. Edmonds, On the roles of oxidation and vaporization in surface micro-structural instability during solution heat treatment of Ni-base superalloys, Metall. Mater. Trans. A 45 (2014) 5968–5981.<br />[3] C.A. Guo, W. Wang, Y.X. Cheng, S.L. Zhu, F.H. Wang, Yttria partially stabilised zirconia as diffusion barrier between NiCrAlY and Ni-base single crystal René N5 superalloy, Corros. Sci. 94 (2015) 122–128. |
