Microstructure and performance of Nb-bearing Ni60A-Cr₃C₂ coatings manufactured by laser cladding

ABSTRACT

The Ni60A-Cr₃C₂ coatings with different Nb addition were prepared by laser cladding. The microstructure was observed by SEM and TEM. The chemical composition of phases was studied by X-ray diffractometer and Electron Probe Micro-analyzer (EPMA). Microhardness and wear behaviour were measured by microhardness tester and wear tester, respectively. The results show that the main phases in Ni60A-Cr₃C₂ coating are γ-Ni, Cr₇C₃, Cr₂₃C₆, Ni₃Si₂, Ni₃B and CrB. With Nb addition, the NbC phase appears in the coatings. The size and volume fraction of NbC increase with the increase of Nb addition. The hardness and wear resistance increase first and then decrease with the increase of Nb addition. The micro-hardness of coatings with 2 wt-% Nb addition is the highest, reaching 1046.6 Hv0.2. The relative abrasive resistance of coatings with 3 wt-% Nb addition is the best, and is 2.33 times that of Nb-free coatings.

KEYWORDS:

• Laser cladding
• Ni60A-Cr₃C₂ coatings
• Nb addition
• microstructure
• micro-hardness
• abrasive resistance

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors appreciate the financial support for this work from the National Natural Science Foundation of China under Grants No 51274016, and the Open Foundation of Key Laboratory of E&M (Zhejiang University of Technology), Ministry of Education & Zhejiang Province (No. EM2016070103).