Reinforcing behavior and microstructure evolution of NbC in laser cladded Ni45 coating

• Published in: Applied surface science Vol. 455; pp. 160 - 170
• Main Authors: Sun, Shuting, Fu, Hanguang, Ping, Xuelong, Lin, Jian, Lei, Yongping, Wu, Wenbo, Zhou, Jianxin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2018
• Subjects: In-situ NbC; Laser cladding; Microstructure evolution; Ni45 composite coatings; Wear resistance; Ni45 composite coatings; Wear resistance; In-situ NbC; Laser cladding; Microstructure evolution
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.05.199

[Display omitted] •Ni45 composite coatings were reinforced by the in-situ synthesized NbC particles in laser cladding.•The in-situ NbC particles exhibited the homogenized influence on microstructure and microhardness.•The wear resistance of coating was promoted to 4.43 times than that of the original coating.•The detailed in-situ synthesized NbC mechanism was proposed. The microstructure evolution, microhardness and wear resistance of Ni45 composite coatings reinforced by in-situ NbC were investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe microprobe analyzer (EPMA), transmission electron microscopy (TEM), digital microhardness tester and wear test machine. The results showed that the matrix was mainly composed of γ-Ni(Fe) solid solution, and the reinforcement phases consisted of Cr23C6, NbC, Cr7C3, Cr2B and little content of Cr3C2. In-situ NbC particles were homogeneous and heterogeneous nucleation from the Nb and C atoms dissolved in the molten pool, which was first precipitated from the Ni45 alloy liquid. With the increase of NbC designed content, the microhardness of coating increased gradually. When the designed content was 20%, in-situ NbC particles were regular and distributed homogeneously, and the composite coating exhibited excellent wear resistance which was higher 4.43 times than that of the original coating.