Study On Preparation And Performance Of Cu-SiC Nanocomposite Coatings Deposited On Carbon Steel

Cu-SiC nanocomposite coatings(Treating copper as the matrix coating,silicon carbide nanoparticles as the second phase particles,the silicon carbide nanoparticle is deposited with copper on Q235 carbon steel,Cu-SiC nanocomposite is shorted for it.)are prepared by ultrasonic-electro-deposition,the effect of cathode-current density,ultrasonic power,content of SiC nanoparticles,temperature and surfactant concentrations on surface morphology of coatings,content of particles of coatings and corrosion resistance are discussed.The parameter of electro-deposition is optimized by orthogonal experiment;the difference of performance between Cu-SiC nanocomposite and direct electro deposition copper coatings,ultrasonic electro deposition copper coatings is compared.The results show that:cathode-current density,ultrasonic power,content of silicon carbide nanoparticles,temperature and surfactant concentrations have significant effect on surface morphology of coatings and content of particles of coating.Through orthogonal experiment,the results show that the technological parameters affect the micro-hardness of coatings.The order from large to small is content of SiC nanoparticles>cathode-current density>ultrasonic power>temperature>surfactant concentrations.The optimal parameters are as follow:cathode-current density 6A/dm2,ultrasonic power 300W,content of SiC nanoparticles 12g/L,temperature 20?,surfactant concentrations 120mg/L.The surface morphology is observed by SEM,the surface morphology of direct current copper coating is lamellar structure,and the particle size range from 5?m to 10 ?m.The surface morphology of ultrasonic-electro-deposition is six of a pyramid shape,the particle size range from 3?m to 5 ?m.The surface morphology of Cu-SiC nanocomposite is cauliflower head shape,the particle size is 1 ?m.The elementary composition is analyzed by EDS,the direct current copper coating and ultrasonic electro deposition copper coating are consisted of cuprum,the Cu-SiC nanocomposite is consisted of cuprum,carbon and silicon.Through the analysis of XRD,the direct current copper coating and ultrasonic electro deposition are consisted of single copper-phase,and the Cu-SiC nanocomposite is consisted of copper-phase and carborundum-phase.According to Debye-Scherer formula,the grain size of Cu-SiC nanocomposite is smallest.The micro hardness of direct copper coating is 152.4 HV;the micro hardness of Cu-SiC nanocomposite is 294.6 HV,which is two times as much as direct current copper coating.In 3.5%NaCl solution,the corrosion rate of Cu-SiC nanocomposite is 0.0445 g·m-29h-1,the corrosion rate of direct current deposit copper coating is 0.2031 g·m-3·h-1.The results of polarization curve test show that the corrosion current density of Cu-SiC nanocomposite is smallest among the three type coatings.From the EIS test,the coating resistance of direct current copper coating is 823.2?cm2,the coating resistance of Cu-SiC nanocomposite is 1911.7?·cm2.Through the comparison,the corrosion resistance of Cu-SiC nanocomposite is best.