碱性脉冲电镀Zn-纳米SiC复合镀层工艺条件的优化

Optimization of process conditions for pulsed electroplating of Zn-nano-SiC composite coating in alkaline bath

采用由30 g/L氧化锌、180 g/L氢氧化钠、2.8 g/L香草醛、4 g/L硫脲、4 g/L三乙烯四胺、1 mL/L甲醛和0.15 g/L SiC(粒径约40 nm)组成的碱性镀液对Q235钢脉冲电镀Zn-纳米SiC复合镀层,通过优化得到较佳的工艺条件为:平均电流密度2.0 A/dm^(2),占空比30%,镀液温度20~30℃,脉冲频率125 Hz,搅拌速率250 r/min,电镀时间20~25 min。在该工艺下所得复合镀层结晶细腻,含碳化硅的质量分数为1.67%,耐蚀性比脉冲电镀纯锌镀层更好。

Zn-nano-SiC composite coating was prepared on the surface of Q235 steel by pulsed electroplating in an alkaline bath comprising ZnO 30 g/L,NaOH 180 g/L,vanillin 2.8 g/L,thiourea 4 g/L,triethylenetetramine 4 g/L,formaldehyde 1 mL/L,and SiC(about 40 nm in diameter averagely)0.15 g/L.The process conditions were optimized as follows:average current density 2.0 A/dm^(2),duty cycle 30%,bath temperature 20-30℃,pulse frequency 125 Hz,agitation rate 250 r/min,and electroplating time 20-25 min.The composite coating prepared is fine-grained,contains 1.67wt.% of SiC,and has better corrosion resistance than the pure zinc coating prepared similarly by pulsed electroplating.