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Hot corrosion behavior and near-surface microstructure of a “low-temperature high-activity Cr-aluminide” coating on inconel 738LC exposed to Na2SO4, Na2SO4 + V2O5 and Na2SO4 + V2O5 + NaCl at 900 °C

Salehi Doolabi, M ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.corsci.2017.09.004
  3. Abstract:
  4. Hot corrosion is a serious problem in gas turbines due to poor quality fuels which contain Na, V, S and Cl. To resolve the problem, Cr-aluminide was coated on IN-738LC superalloy with a two steps pack cementation process. Oxidation behavior and near-surface microstructure of the coating showed consecutive increase in destruction by exposition to Na2SO4, 75Na2SO4 + 25 V2O5 and 70Na2SO4 + 25 V2O5 + 5NaCl (wt.%). Kinetic studies indicated parabolic corrosion rate in salt-less samples due to diffusion. Similar expression for salt-covered samples was assessed for oxide dissolution. Plate-like, broken-plate-like and cauliflower-like morphologies attributed to the corrosion products were observed after exposition to above three salts, respectively. © 2017 Elsevier Ltd
  5. Keywords:
  6. A. Metal coating ; A. Molten salts ; A. Superalloys ; C. Hot corrosion ; Corrosion ; Gas turbines ; Microstructure ; Salts ; Superalloys ; Temperature ; Corrosion products ; Hot corrosion ; Low temperatures ; Molten salt ; Near-surface microstructures ; Oxidation behaviors ; Oxide dissolution ; Pack cementation process ; Corrosion rate
  7. Source: Corrosion Science ; Volume 128 , 2017 , Pages 42-53 ; 0010938X (ISSN)
  8. URL: https://www.sciencedirect.com/science/article/pii/S0010938X16312550