Advertisement

Corrosion Behavior of Inconel 625 Alloy in Na2SO4–K2SO4 at High Temperature

  • Yuan-Jun Ma
  • Yutian DingEmail author
  • Jian-Jun Liu
  • Yu-Bi Gao
  • Dong Zhang
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 217)

Abstract

The corrosion behavior of Inconel 625 alloy at 800 and 900 °C in the molten salt of 75 wt% Na2SO4–25 wt% K2SO4 was studied. The corrosion mechanism of Inconel 625 alloy after hot corrosion is mainly alkaline melting mechanism. The Cr2O3 on the surface of the alloy dissolved in molten salt as Na2CrO4, leading to the loss of the protective oxide layer on the alloy surface. With the decomposition of Cr2O3 on the surface of the alloy, Cr-depleted region appeared at the interface of the alloy matrix/corrosion layer, which inhibited the growth of the Cr2O3 oxide layer and resulted in the discontinuous oxide layer. This caused O and S to invade the substrate and corrode the alloy matrix. When the alloy was corroded at 800 °C for 120 h, the corrosion rate was about 3 mg/cm2. The corrosion layer was relatively complete, and it mainly consisted of flaky Cr2O3 and spinel-like NiCr2O4. When the alloy was corroded at 900 °C for 120 h, the corrosion rate was about 6 mg/cm2, and obvious shedding and faults appeared in the corrosion layer, which were mainly divided into three layers: the outer layer was composed of NiCr2O4 and NiO; the middle layer was a dense Cr2O3; the inner layer was composed of sulfides (Cr2S3 and Ni3S2), oxides (Cr2O3 and NiO), telluride, etc. Through thermodynamic calculation and analysis, it was found that SO2 decomposed from molten salt under high temperature could cause severe corrosion to the alloy. The main corrosion products were Cr2O3, Cr2S3, NiO, and Ni3S2.

Keywords

Inconel 625 Hot corrosion Na2so4–K2SO4 

Notes

Acknowledgements

The financial support by the National Natural Science Fund (51661019), Gansu Province Major Science and Technology Special Project (145RTSA004), National Key Laboratory of Nickel and Cobalt Resource Comprehensive Utilization (301170503).

References

  1. 1.
    G.P. Dinda, A.K. Dasgupta, J. Mazumder, Laser aided direct metal deposition of Inconel 625 superalloy: microstructural evolution and thermal stability. Mater. Sci. Eng. A 509, 98–104 (2009)CrossRefGoogle Scholar
  2. 2.
    E. Mohammadi Zahrani, A.M. Alfantazi, High temperature corrosion and electrochemical behavior of Inconel 625 weld overlay in PbSO4-Pb3O4-PbCl2-CdO-ZnO molten salt medium. Corros. Sci. 85, 60–76 (2014)CrossRefGoogle Scholar
  3. 3.
    S.J. Zinkle, G.S. Was, Materials challenges in nuclear energy. Acta Mater. 61(3), 735–758 (2013)CrossRefGoogle Scholar
  4. 4.
    P.S. Sidky, M.G. Hocking, The hot corrosion of Ni-based ternary alloys and superalloys for application in gas turbines employing residual fuels. Corros. Sci. 27(5), 499–530 (1987)CrossRefGoogle Scholar
  5. 5.
    D. Kim, H.J. Lee, C. Jang, D.J. Yoon, Corrosion characteristics of Ni-base superalloys in high temperature steam with and without hydrogen. J. Nucl. Mater. 441(1–3), 612–622 (2013)CrossRefGoogle Scholar
  6. 6.
    N. Eliaz, G. Shemesh, R.M. Latanision, Hot corrosion in gas turbine components. Eng. Fail. Anal. 9(1), 31–43 (2002)CrossRefGoogle Scholar
  7. 7.
    K. Misraa, Studies on the hot corrosion of a nickel-base superalloy, Udimet 700. Oxid. Met. 25(3–4), 129–161 (1986)CrossRefGoogle Scholar
  8. 8.
    W. Kai, C.H. Lee, T.W. Lee, C.H. Wu, Sulfidation behavior of Inconel 738 superalloy at 500–900 °C. Oxid. Met. 56(1/2), 51 (2001)CrossRefGoogle Scholar
  9. 9.
    R.D.K. Misra, R. Sivakumar, Effect of NaCl vapor on the oxidation of Ni-Cr alloy. Oxid. Met. 25(1/2), 83 (1986)CrossRefGoogle Scholar
  10. 10.
    S.R. Kameswa, The role of NaCl in the hot-corrosion behavior of nimonic alloy 90. Oxid. Met. (1/2), 33 (1986)Google Scholar
  11. 11.
    L. Jintao, Y. Zhen, L. Yan et al., Effect of alloying chemistry on fireside corrosion behavior of Ni–Fe-based superalloy for ultra-supercritical boiler applications. Oxid. Met. 12, 1–13 (2017)Google Scholar
  12. 12.
    H. Cui, J.S. Zhang, Y. Murata et al., Hot corrosion behavior of Ni-based superalloy with higher Cr contents-part II. Mechanism of hot corrosion behavior. J. Univ. Sci. Tech. Beijing 3, 91 (1996)Google Scholar
  13. 13.
    M. Li, High Temperature Corrosion of Metals (Metallurgical Industry Press, Beijing, 2001), p. 263. (in chinese)Google Scholar
  14. 14.
    J. Wang, C. Li, T. Zhang et al., Hot corrosion behavior of Ni-Cr-W based superalloy in molten salt environment. Aerosp. Mater. Technol. 44(6), 26–29 (2014). (in chinese)Google Scholar
  15. 15.
    J. Sun, The oxidation behavior of Ni-20Cr-Si and Ni-20Cr-Si-Al alloys at 1200 °C. J. Chin. Soc. Corros. Prot. (1), 53–58 (1993), (in chinese)Google Scholar
  16. 16.
    H. Chao, L. Yong, W. Yan et al., Hot corrosion behavior of Ni-xCr-6.8Al based alloys. Trans. Nonferrous Met. Soc. China 21(11), 2348–2357 (2011)CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Yuan-Jun Ma
    • 1
  • Yutian Ding
    • 1
    Email author
  • Jian-Jun Liu
    • 1
  • Yu-Bi Gao
    • 1
  • Dong Zhang
    • 2
  1. 1.State Key Laboratory of Advanced Processing and Recycling of Non-ferrous MetalsLanzhou University of TechnologyLanzhouChina
  2. 2.State Key Laboratory of Nickel and Cobalt Resources Comprehensive UtilizationJinchuan Group Co., Ltd.JinchangChina

Personalised recommendations