Corrosion performance of bi-layer Ni/Cr2C3–NiCr HVAF thermal spray coating

•The intermediate dense layer of Ni declined the corrosion rate of Cr2C3–NiCr coating.•Higher acidity of the electrolyte leads to higher corrosion rate and tendency for pitting.•Bi-layer Ni/Cr2C3–NiCr coating was the best system to protect the steel substrate.•Bi-layer HVAF thermal spray coating ser...

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Bibliographic Details
Published in:Applied surface science 2016-04, Vol.369, p.470-481
Main Authors: Sadeghimeresht, E., Markocsan, N., Nylén, P., Björklund, S.
Format: Article
Language:English
Subjects:
Bonding
Coatings
Corrosion
EIS
Flame spraying
HVAF
HVAF Corrosion
Immersion test
Manufacturing and materials engineering
Nickel
Polarization
Production Technology
Produktions- och materialteknik
Produktionsteknik
Spray coating
Sprays
Thermal spray
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Summary:•The intermediate dense layer of Ni declined the corrosion rate of Cr2C3–NiCr coating.•Higher acidity of the electrolyte leads to higher corrosion rate and tendency for pitting.•Bi-layer Ni/Cr2C3–NiCr coating was the best system to protect the steel substrate.•Bi-layer HVAF thermal spray coating serves as a critical approach to extend the life of components. The corrosion behavior of three HVAF thermal spray coating systems (A: single-layer Ni, B: single-layer Cr2C3–NiCr coatings, and C: bi-layer Ni/Cr2C3–NiCr coating) was comparatively studied using immersion, salt spray, and electrochemical tests. Polarization and EIS results showed that the corrosion behavior of Cr2C3–NiCr coatings in 3.5wt.% NaCl solution was significantly improved by adding the intermediate layer of Ni. It was illustrated that the polarization resistance of the bi-layer Ni/Cr2C3–NiCr and single-layer Cr2C3–NiCr coatings were around 194 and 38kΩcm2, respectively. Microstructure analysis revealed that the bond coating successfully prevented the corrosion propagation toward the coating.
ISSN:0169-4332
1873-5584
1873-5584
DOI:10.1016/j.apsusc.2016.02.002