A MoSi2-based composite coating by supersonic atmospheric plasma spraying to protect Nb alloy against oxidation at 1500 °C

A MoSi2-based oxidation resistant coating was directly deposited on Nb alloy substrate by supersonic atmospheric plasma spraying using pure agglomerated MoSi2 powders. The as-received coating mostly consisted of h-MoSi2, t-MoSi2 and Mo5Si3 in a typical layer structure. The cyclic oxidation test of t...

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Bibliographic Details
Published in:Surface & coatings technology Vol. 352; pp. 182 - 190
Main Authors: Sun, Le, Fu, Qian-Gang, Fang, Xiang-Qing, Sun, Jia
Format: Journal Article
Language:English
Published: Elsevier B.V 25.10.2018
Subjects:
Diffusion
MoSi2-based composite coating
Nb alloys
Oxidation
Supersonic atmospheric plasma spraying
MoSi2-based composite coating
Oxidation
Nb alloys
Diffusion
Supersonic atmospheric plasma spraying
ISSN:0257-8972, 1879-3347
Online Access:Get full text
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Summary:A MoSi2-based oxidation resistant coating was directly deposited on Nb alloy substrate by supersonic atmospheric plasma spraying using pure agglomerated MoSi2 powders. The as-received coating mostly consisted of h-MoSi2, t-MoSi2 and Mo5Si3 in a typical layer structure. The cyclic oxidation test of the MoSi2-based composite coating was evaluated at 1500 °C in air. The formed multi-layer of the coating included SiO2 outer layer, Mo5Si3 + MoSi2 + SiO2 middle layer and Nb5Si3 transitional layer after oxidation. The results show that the mass loss of the coated sample was 5.31 mg/cm2 after exposure at 1500 °C in air for 43 h. The excellent protective ability against oxidation of the MoSi2-based composite coating could be mainly attributed to a continuous protective SiO2 scale and an adhesive Nb5Si3 diffusion layer, which ensured the low oxygen diffusion rate and the strong bonding to the substrate. [Display omitted] •A MoSi2-based coating was directly deposited on Nb alloy by SAPS.•The cyclic oxidation test of the coated samples was evaluated at 1500 °C in air.•A protective SiO2 scale and a Nb5Si3 transitional layer were formed after oxidation.•The Nb5Si3 layer could reduce the thermal stress at the coating/substrate interface.
ISSN:0257-8972
1879-3347
DOI:10.1016/j.surfcoat.2018.07.091