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Thermal stability and oxidation resistance of FeCrxCoNiB high-entropy alloys coatings by laser cladding

Authors :
Shuai Li
Bingjie Cai
Pinqiang Dai
Chong Zhang
Fa Chang
Biao Huang
Source :
Surface and Coatings Technology. 359:132-140
Publication Year :
2019
Publisher :
Elsevier BV, 2019.

Abstract

The FeCrxCoNiB (x values in molar ration, x = 0.5–3) high-entropy alloys coatings were prepared by laser cladding on an AISI 1045 steel substrate. Annealing and high temperature oxidation experiments were performed on the FeCrxCoNiB (x = 0.5–3) coatings at 900 °C. The phase structure, morphology, and composition of the coatings and oxidation layers were analyzed by XRD, TEM, SEM, and EDS. Results demonstrated that the FeCrxCoNiB coatings are composed of simple face-centred cubic (FCC) phase and boride. The hardness value of the coatings is significantly improved due to the boride, which is achieved 860 HV at x = 0.5. Cr is conducive to inhibiting the coarsening of boride and enhancing the resistance of coatings to high-temperature softening. The oxidation kinetics curve of FeCrxCoNiB coatings basically follows oxidation dynamic the parabolic law. The selective oxidation in the FeCrxCoNiB coatings changed from the oxidation of Fe to the oxidation of Cr as an increase in Cr content, and finally formed continuous Cr2O3 film. The high temperature oxidation resistance of the FeCrxCoNiB coatings dropped with adding boron into the coatings, which improved contributing to Cr increasing. FeCrxCoNiB coatings gain a better high temperature oxidation resistance as x ≥ 2 (33.3 at.%).

Details

ISSN :
02578972
Volume :
359
Database :
OpenAIRE
Journal :
Surface and Coatings Technology
Accession number :
edsair.doi...........94b22aa880f1eb70b1a379d95f99ce9d
Full Text :
https://doi.org/10.1016/j.surfcoat.2018.12.072