磁场辅助射流电沉积Ni-SiC纳米复合镀层耐蚀性的研究

Study on Corrosion Resistance of Ni-SiC Nano-composite Coatings Prepared by Magnetic Field-Assisted Jet Electrodeposition

采用磁场辅助射流电沉积方法在45#钢表面制备了Ni-SiC纳米复合镀层,并研究了镀层的表面形貌、耐蚀性及物相组成。结果表明:当电流密度为4 A/dm2时,镀层的腐蚀失重最小为3.2 mg/cm2;当磁场强度超过0.8 T后,镀层的腐蚀失重基本保持不变;当喷射速率达到3 m/s时,镀层的腐蚀失重最小为3.5 mg/cm2。经SEM分析可知,当磁场强度达到0.8 T时,腐蚀产物最少,晶间腐蚀较轻。由极化曲线及电化学阻抗谱分析可知,当磁场强度达到0.8 T时,镀层的耐蚀性最好。由XRD分析证实了Ni、SiC两相的存在,并且随着磁场强度的增加,衍射峰变矮、变宽,说明镀层晶粒细化,改善了镀层的耐蚀性。

Ni-SiC nano-composite coatings were prepared on the surface of 45#steel by magnetic field-assisted jet electrodeposition,and the surface morphology,corrosion resistance and phase composition of the coatings were studied.The results showed that the corrosion weight loss of coating reached the minimum value of 3.2 mg/cm^2 when the current density was 4 A/dm^2.The corrosion weight loss was unchanged when the magnetic field intensity exceeded 0.8 T.When the jet velocity was 3 m/s,the corrosion weight loss reached the minimum value of 3.5 mg/cm^2.The SEM analysis showed that the corrosion product was the least with lighter intergranular corrosion when the magnetic field intensity was 0.8 T.The Tafel curve and electrochemical impedance analysis showed that the corrosion resistance of coating was the best when the magnetic field intensity was 0.8 T.The existence of Ni and SiC phases was confirmed by XRD analysis,and the diffraction peak became shorter and wider with increasing of magnetic field intensity.In addition,the corrosion resistance of coatings was improved due to the refinement of grains.