Preparation of Ni-SiC Composite Coating by Electrochemical Deposition

摘要:

采用电化学沉积法通过在电解槽中添加SiC颗粒制备Ni-SiC复合镀层。由于第二相颗粒SiC的加入改善了镀层的性能，使之具有高硬度、耐磨性和耐腐蚀性能等。Ni-SiC复合电镀改善镀层的组织结构并显著提高镀层的质量。采用NiSO4·6H2O（35 g/100 mL），NiCl2·6H2O（4 g/100 mL），H3BO3（3.5 g/100 mL），十二烷基硫酸钠（0.5 g/100 mL），SiC颗粒（0.4~1.0 g/100 mL）体系，在pH值为4，温度35~50 ℃时，通过电化学沉积法制备Ni-SiC复合镀层。实验探究了温度、电流密度、镀液中碳化硅颗粒含量以及超声波分散时间对镀层中SiC复合量的影响。通过扫描电镜和XRD对镀层进行分析，结果表明：在温度为35~50 ℃之间复合镀层中SiC的量随温度的增加呈现先增加后减少的趋势；在电流密度为0.026~0.06 A/cm2之间，复合镀层中SiC的含量随电流密度的增加呈现先增加后减小的趋势；镀液中SiC量在0.4~1.0 g/100 mL之间时，镀层中SiC含量随着镀液中SiC含量的增加而增加，超过一定值（0.6 g/100 mL）增加幅度变小；超声波分散时间在10~50 min之间, 镀层中SiC的含量随时间的增加而先增加后减少。镀层中碳化硅颗粒均匀分布有利于晶粒的细化

Abstract:

Ni-SiC composite coating was electrodeposited from the modified bath containing SiC particles. The system consisting of NiSO4·6H2O (35 g/100 mL), NiCl2·6H2O (4 g/100 mL), H3BO3 (3.5 g/100 mL), sodium dodecyl sulfate (SDS) (0.5 g/100 mL) and SiC (0.4~1.0 g/100 mL) was used at pH=4 and 35~50 ℃ to obtain a Ni-based composite coating containing SiC particles. The effects of temperature, current density, content of SiC in the electrolyte and ultrasonic dispersion time on codeposited content of SiC particles were investigated. The Ni-SiC composite coating was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The results indicate that the codeposited content of SiC particles increases with increasing of temperature and then decreases at 35~50 °C. When current density is between 0.026~ 0.06 A/cm2, SiC content increases with the increase of current density and then decreases. When the concentration of SiC is between 0.4~1.0 g/100 mL in the plating solution, it increases with the increase of concentration of SiC. When the content of SiC exceeds a certain value (0.6 g/100 mL), the rate increase becomes low. When the ultrasonic dispersion time is between 10~50 min, the codeposited content of SiC particles first increases and then decreases with increasing of time. Uniform distribution of SiC particles in the coating is beneficial to refine the grain size of deposit