The influences of nano-carbon particle concentration in bath

current density

temperature and stirring method on the properties of electro-deposited Cr-C composite coating have been investigated.The surface morphology and phase structure of the coating were analyzed by scanning electronic microscopy（SEM） and X-ray diffractometer（XRD）

and its micro-hardness was determined by micrometer.The results indicate that the black Cr-C composite coatings with compact and uniformly distribution structure can be generated by adjusting the processing parameters

where the maximum micro-hardness can reach 10.8 GPa and maximum particle volume fraction in the coating can reach 8.82%.The optimized processing parameters for electro-depositing composite coating are as follows:current density of 100 A·dm-2

temperature of 15 ℃ and nano-carbon concentration in bath of 10 g·L-1.In addition

ultrasonic disperse was used to assist slowly mechanical stirring.