Citation

Lu XD, Wang HM. Acta Materialia 2004; 52(18): 5419-5426.

Copyright

(Copyright © 2004)

DOI

10.1016/j.actamat.2004.08.006

PMID

unavailable

Abstract

Mo2Ni3Si/NiSi wear-resistant metal suicide composite coatings consisting of Mo2Ni3Si primary dendrite and interdendritic Mo2Ni3Si/NiSi eutectic were fabricated on substrate of an austenitic stainless steel AISI321 by laser cladding using Ni-Mo-Si elemental powder blends. The high-temperature structural stability of the coating was evaluated by aging at 800°C for 1-50 h. High-temperature sliding wear resistance of the as-laser clad and aged coatings was evaluated at 600°C.

RESULTS indicate that the Mo2Ni3Si/NiSi metal silicides coating has excellent high temperature phase stability. No phase transformation except the dissolution of the eutectic Mo2Ni 3Si and the corresponding growth of the Mo2Ni 3Si primary dendrite and no elemental diffusion from the coating into the substrate were detected after aging the coating at 800°C for 50 h. Aging of the coating at 800°C leads to gradual dissolution of the interdendritic eutectic Mo2Ni3Si and subsequent formation of a dual-phase structure with equiaxed Mo2Ni3Si primary grains distributed in the NiSi single-phase matrix. Because of the strong covalent-dominated atomic bonds and high volume fraction of the ternary metal suicide Mo2Ni3Si, both the original and the aged Mo 2Ni3Si/NiSi coating has excellent wear resistance under pin-on-disc high-temperature sliding wear test conditions, although hardness of the aged coating is slightly lower than that of the as-clad coating. © 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Language: en

Keywords

Diffusion; Silicon compounds; High temperature effects; Coatings; Phase transitions; Ternary systems; Laser cladding; Coating; Austenite; Cladding (coating); Composite coatings; Laser applications; Metal silicide; Metal silicides; Phase stability; Stainless steel; Tribology; Wear resistance