Microstructure and properties of HVOF sprayed Ni-based
submicron WS2/CaF2 self-lubricating composite coating
submicron WS2/CaF2 self-lubricating composite coating
(1. State Key Laboratory of Material Processing and Die and Mould Technology,
Huazhong University of Science and Technology, Wuhan 430074, China;
2. School of Materials Science and Engineering, Huazhong University of Science and Technology,
Wuhan 430074, China)
Huazhong University of Science and Technology, Wuhan 430074, China;
2. School of Materials Science and Engineering, Huazhong University of Science and Technology,
Wuhan 430074, China)
Abstract: Ni-based submicron WS2/CaF2 self-lubricating composite coatings were produced on carbon steel substrate by high velocity oxygen fuel(HVOF) spray processing, and the microstructure and mechanical properties of the coatings were investigated. Non-uniform microstructure characterized by some pores and microcracks is observed in the produced composite coatings, which leads to low microhardness value, low adhesive strength and low frictional coefficient. For Ni45-5%CaF2-10%WS2 (mass fraction) and Ni45-10%CaF2-5%WS2 (mass fraction) coatings, under the test condition of load 40 N and speed 2 m/s, the friction coefficients obtained at room temperature are in the range of 0.35−0.48 and 0.31−0.41, respectively. The friction coefficients of two kinds of coatings increase to 0.4−0.63 and 0.35−0.46, respectively, at the test speed of 1 m/s. And the Ni45-10%CaF2-5%WS2 coating presents the minimum friction coefficient of 0.32−0.38 and good anti-wear properties at 400 ℃.
Key words: HVOF spray processing; submicron tungsten disulphide; microstructure; self-lubricating composite coating