Microstructure and wear behaviors of laser clad NiCr/Cr3C2–WS2 high temperature self-lubricating wear-resistant composite coating

• Published in: Applied surface science 2012-02, Vol.258 (8), p.3757-3762
• Main Authors: Yang, Mao-Sheng, Liu, Xiu-Bo, Fan, Ji-Wei, He, Xiang-Ming, Shi, Shi-Hong, Fu, Ge-Yan, Wang, Ming-Di, Chen, Shu-Fa
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; High temperature wear-resistant composite coating; Laser cladding; Physics; Solid lubrication; WS2
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2011.12.021

► WS2 is utilized to produce high temperature self-lubricant wear-resistant composite coating by laser cladding. ► Noticeably, the coating added withWS2 has a higher microhardness because of the formation of the hard phase (Cr,W)C. ► The average friction coefficients both decrease with the rising of temperature, but the wear rates both increase. ► The coating added with WS2 has a lower friction coefficient whatever at ambient, 300°C, 600°C, and a lower wear rate only at 300°C. The high temperature self-lubricating wear-resistant NiCr/Cr3C2–30%WS2 coating and wear-resistant NiCr/Cr3C2 coating were fabricated on 0Cr18Ni9 austenitic stainless steel by laser cladding. Phase constitutions and microstructures were investigated, and the tribological properties were evaluated using a ball-on-disc wear tester under dry sliding condition at room-temperature (17°C), 300°C and 600°C, respectively. Results indicated that the laser clad NiCr/Cr3C2 coating consisted of Cr7C3 primary phase and γ-(Fe,Ni)/Cr7C3 eutectic colony, while the coating added with WS2 was mainly composed of Cr7C3 and (Cr,W)C carbides, with the lubricating WS2 and CrS sulfides as the minor phases. The wear tests showed that the friction coefficients of two coatings both decrease with the increasing temperature, while the both wear rates increase. The friction coefficient of laser clad NiCr/Cr3C2–30%WS2 is lower than the coating without WS2 whatever at room-temperature, 300°C, 600°C, but its wear rate is only lower at 300°C. It is considered that the laser clad NiCr/Cr3C2–30%WS2 composite coating has good combination of anti-wear and friction-reducing capabilities at room-temperature up to 300°C.