The effect of manganese and silicon additions on the corrosion resistance of a polycrystalline nickel-based superalloy

•The service lives of nickel superalloys are often limited by environmental degradation.•Oxidation, sulfidation and hot corrosion of 3 variant policrystalline superalloys (baseline, 1wt% Mn and 0.5wt%Si) was assessed.•Mn reduced the oxidation rate without changing the scale morphology. The MnCr2O4 s...

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Bibliographic Details
Published inCorrosion science Vol. 176; p. 109042
Main Authors Anzini, E., Glaenzer, N., Mignanelli, P.M., Hardy, M.C., Stone, H.J., Pedrazzini, S.
Format Journal Article
LanguageEnglish
Published Amsterdam Elsevier Ltd 01.11.2020
Elsevier BV
Subjects
Aluminum oxide
Corrosion
Corrosion effects
Corrosion prevention
Corrosion resistance
Hot corrosion
Manganese
Morphology
Nickel
Nickel base alloys
Nickel superalloy
Oxidation
Oxidation rate
Polycrystals
Salt
Silicon
Sulfidation
Sulfur
Superalloys
Salt
Corrosion
Nickel superalloy
Silicon
Oxidation
Sulfur
Manganese
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Summary:•The service lives of nickel superalloys are often limited by environmental degradation.•Oxidation, sulfidation and hot corrosion of 3 variant policrystalline superalloys (baseline, 1wt% Mn and 0.5wt%Si) was assessed.•Mn reduced the oxidation rate without changing the scale morphology. The MnCr2O4 scale formed proved more protective against sulfidation and hot corrosion, but internal sulfides extended the damage depth.•Si modified the oxide morphology to a continuous Cr2O3-Al2O3 dual layer. This provided improved protection, reducing the sulfidation depth by 2/3 and the hot corrosion depth by ½. The service lives of nickel superalloys are often limited by environmental degradation. The present study compares oxidation, sulfidation and hot corrosion at 750 °C of three variants of a polycrystalline superalloy: a baseline alloy, a variant containing 1 wt% Mn and one containing 0.5 wt% Si. Mn reduced the oxidation rate without changing the scale morphology. The MnCr2O4 scale formed proved more protective against sulfidation and hot corrosion, but internal sulfides extended the damage depth. Si modified the oxide morphology to a continuous Cr2O3-Al2O3 dual layer. This provided improved protection, reducing the sulfidation depth by 2/3 and the hot corrosion depth by ½.
ISSN:0010-938X
1879-0496
DOI:10.1016/j.corsci.2020.109042