Microstructure and properties of HVOF sprayed Ni-based submicron WS2/CaF2 self-lubricating composite coating

• Published in: Transactions of Nonferrous Metals Society of China Vol. 19; no. 1; pp. 85 - 92
• Main Authors: ZHANG, Xiao-feng, ZHANG, Xiang-lin, WANG, Ai-hua, HUANG, Zao-wen
• Format: Journal Article
• Language: English
• Published: State Key Laboratory of Material Processing and Die and Mould Technology,Huazhong University of Science and Technology, Wuhan 430074, China 01.02.2009; School of Materials Science and Engineering, Huazhong University of Science and Technology,Wuhan 430074, China
• Subjects: self-lubricating composite coating; submicron tungsten disulphide; microstructure; HVOF spray processing
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(08)60233-2

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 deg C.