Preparation And Properties Of Nickel Composite Coating By Electroplating Method

Due to its own unique property, wear-resistant material becomes the important part of new materials field today. The material surface modification technology is an effective means to improve construction component's wear-resistance and corrosion- resistance. The composite plating used for producing wear-resisting coating has been developed and used widely in engineering technology. The thesis is focused on the technology process of wear-resisting composite coating by composite plating method, based on the requirement of wear-resisting material and characteristics of electrochemical deposition technology.Ni-SiC composite coating is produced through adapting stainless steel as the substrate, SiC as second phase particles by composite plating. The effect of electroplating process parameters on composite coating morphology and structure are studied using nickel-sulfamic-acid as mail salt, and the composite coating is characterized by metallurgical microscope, XRD and SEM. The results show that current density, time of electroplating and concentration of plating solution component are key factors affecting the morphology and structure of composite coating. But the temperature is the secondary factor. The optimized technology parameters are obtained through the serials of experiments. The SiC wire saw is prepared by composite plating using above optimized parameters, which was characterized by SEM.Furthermore, Ni-CMS self-lubricating composite coating is produced through adapting stainless steel as the substrate, carbon microspheres as second phase particles, nickel-sulfamic-acid as mail salt. Ni-CMS composite coating is characterized by metallurgical microscope, XRD and SEM. Based on that, the effect of plating technology parameters on morphology and structure of Ni-CMS self-lubricating compound coating are studied. And the optimized technology parameters are obtained through the serials of experiments. The friction coefficient of stainless-steel-substrate, Nickel coating, Ni-SiC composite coating and Ni-CMS composite coating are studied. Results show that the friction coefficient of stainless-steel-substrate is about 0.80, the friction coefficient of Nickel plating coating is about 0.27, the friction coefficient of Ni-SiC composite coating is about 0.9 and the friction coefficient of Ni-CMS composite coating is about 0.20. It is confirmed that Ni-SiC composite coating has higher friction coefficient and is higher wear-resisting composite coating material; Ni-CMS composite coating has lower friction coefficient and is self-lubricating composite coating material. In the test of abrasion, Ni-CMS composite coating doesn't fret away in 30 minutes, but Nickel coating wear out in 2 minutes.