Acta Metallurgica Sinica (English Letters) ›› 2022, Vol. 35 ›› Issue (6): 975-984.DOI: 10.1007/s40195-021-01310-5

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Temperature Effect on Early Oxidation Behavior of NiCoCrAlY Coatings: Microstructure and Phase Transformation

A. Ullah1,2, A. Khan1,3, Z.B. Bao2(), Y.F. Yang4(), M.M. Xu2, S.L. Zhu2, F.H. Wang5   

  1. 1University of Chinese Academy of Sciences, Beijing 100049, China
    2Shi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    3Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials, Ministry of Education, School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243000, China
    4Institute of Advanced Wear and Corrosion Resistant and Functional Material, Jinan University, Guangzhou 510632, China
    5Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang 110819, China
  • Received:2021-05-23 Revised:2021-07-02 Accepted:2021-07-06 Online:2022-06-10 Published:2022-06-15
  • Contact: Z.B. Bao,Y.F. Yang
  • About author:Y.F. Yang, yfyang@jnu.edu.cn
    Z.B. Bao, zbbao@imr.ac.cn;

Abstract:

Initial oxidation behavior of NiCoCrAlY coating prepared by arc-ion plating has been studied in air at 900, 1000 and 1100 °C. The results showed that phase transformation from transient θ-Al2O3 to α-Al2O3 was highly related to the temperature and oxidation time. The oxide scale in the initial stage was mainly composed of θ-Al2O3 at 900 °C. Instead, more amount of α-Al2O3 emerged out with increasing oxidation temperature. The elemental distribution after oxidation confirmed that faster chromium diffusion to the oxide scale played an important role in the speedy transformation from θ-Al2O3 to α-Al2O3. Y segregation at scale/coating interface resulted in less cavity formation and hence improved the oxide scale adherence.

Key words: MCrAlY coating, Phase transformation, Isothermal oxidation, Temperature effect