Electrodeposited Black Cr-C Nano-Composite Coatings

Nano graphite (50-60nm) displays excellent lubricating property and agglomerates easily into big particles in acidic electrolyte, which lead to its lower content in composite coatings. The influence of nano carbon particles concentration in bath, current density, temperature and agitating method on the properties of electrodeposited black Cr-C composite coating and wearing resistance of Cr-C coating were studied in this paper. The surface morphology and phase structure of the coatings were analyzed by means of scanning electronic microscopy (SEM) and X-ray diffractometer (XRD), and its microhardness was determined by micrometer. The results showed that the maximum microhardness of black Cr-C nano-composite coating was 10.8 Gpa, the maximum vol.% in coating was 8.82, which formed under current density of 100A/dm², temperature of 15°C, ultrasonic wave plus slow mechanical agitation. The optimum particle content in electrolyte was 10g/l. The black Cr-C composite coating has excellent wearing resistance.