Electrical Conductivity And Tribological Property Of Nano-MoS₂/Cu Composite Coating Deposited By Brush Plating

The nano-MoS₂/Cu coatings were deposited by brush plating in this study.Nano-MoS₂powders with the average particle size of40nm and80nm were selected asthe second addition particle and2A12aluminum alloy was substrate. Scanning electronmicroscopy （SEM）, transmission electron microscope （TEM）, X-ray diffraction （XRD）,energy dispersive spectrometer （EDS） and X-ray fluorescent spectroscopy（XRF） wereused to characterize the microstructure, phase composition, component distribution ofcomposite coatings. The bonding strength and hardness of coatings were analysed byscratch test and nanoindentation test. The electrical conductivity and tribological propertyof composite coatings were explored by ApplentAT510DC resistance tester and GTM-3Evacuum ball on disk tribometer.It can be seen that nano-MoS₂/Cu coatings were successfully deposited by brushplating, of which the thickness is uniform, the porosity is about1%and the distribution ofnano-MoS₂is homogeneous. The optimum parameters are the plating voltage of8VandMoS₂concentration of10g/L in plating bath. The bonding strength adding40nm and80nm MoS₂composite coatings are13N and14N. Compared with the pure Cu coating,the bonding strength of composite coatings with addition of40nm and80nm MoS₂particles are improved30%and40%. The hardness of coatings with addition of40nm and80nm MoS₂particles are1.63GPa and1.50GPa, respectively.The electrical conductivity of nano-MoS₂/Cu composite coating is excellent. Whennano-MoS₂particle size is40nm and the electrolyte nano-MoS₂concentration is10g/L,the electrical conductivity is at the range of34⁴5%IACS. For80nm, the electricalconductivity is in the range of40⁴9%IACS. After vacuum heat treatment, the electricalconductivity of composite coatings is improved obviously. The electrical conductivity of40nm composite coating is improved by65%and reaches the peak of50%IACS forvacuum heat treatment at500℃and80nm composite coating is improved by25%andreaches the peak of59%IACS for vacuum heat treatment at400℃. When the electrolytenano-MoS₂concentration is15g/L, the electrical conductivity of the coatings of nano-MoS₂is much higher than coatings of micron-MoS₂and the highest value is46%IACS for80nm MoS₂.The tribological property of composite coating with the addition of nano-MoS₂isapparently improved. When the electrolyte nano-MoS₂concentration is15g/L, the frictioncoefficients of two nano-MoS₂coatings are all lower than that of the micron-MoS₂coating.The lowest friction coefficient is reached to0.06for the addition of80nm MoS₂. Thecomposite coating antiwear performance of80nm MoS₂is more excellent than40nm andmicron-MoS₂. The formation of MoS₂lubricant transfer film is the main reason for lowerfriction coefficient and ware rate. The wear mechanism indicates are slight abrasive wearand adhesive wear.