Abstract
Hot corrosion behaviour of a β-NiAl coating induced by Na2SO4, K2SO4, and Na2SO4-K2SO4 deposits was investigated at 700 °C in air + 300 ppm SO2. To provide an insight into the corrosion mechanisms, phase equilibria of the Na2SO4-K2SO4-NiO-SO3 system were calculated using an in-house developed thermodynamic database. The attack rates and morphologies could be correlated with the deposit compositions and their reactions with oxides. K2SO4 and Na2SO4-K2SO4 deposits are more corrosive than Na2SO4. This is attributed to a reduction of the melting temperature of the deposit and the formation of Ni-containing mixed sulphate phases in the presence of K2SO4.
Original language | English |
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Article number | 110146 |
Journal | Corrosion Science |
Volume | 198 |
DOIs | |
State | Published - Apr 15 2022 |
Funding
The authors are grateful to Mr. H. Cosler for performing the hot corrosion tests, to Mr. V. Gutzeit and Mr. J. Bartsch for preparing the cross sections. Dr. E. Wessel and Dr. D. Grüner are kindly acknowledged for the SEM analysis. Mr. M. Ziegner is kindly acknowledged for the XRD analysis. This work was supported by China Scholarship Council (Grant number 201708440229 ); Federal Ministry of Economic Affairs and Energy and MTU Aero Engines AG (Grant numbers: 20T1522A , 20T1302A ).
Keywords
- Hot corrosion (C)
- Metal coatings (A)
- Modelling studies (B)
- Molten salts (A)
- Nickel (A)
- SEM (B)