新型无氰镀镉工艺的研究与应用

Study and Application of Novel Cyanide-free Cadmium Plating Process

引进了新型无氰氯化钾镀镉工艺,在实验室和生产线上对其工艺性能和镀层性能进行了研究。镀液组成为35~40 g/L氯化镉,140~180 g/L氯化钾,120~160 g/L配位剂,25~35 m L/L辅助剂,1.5~2.5 m L/L光亮剂,p H为6.0~7.0,挂镀JΚ为0.5~1.5 A/dm2,θ为15~35℃;滚镀槽电压4~7 V,θ为15~30℃,滚筒转速3~7 r/min。在JΚ为1 A/dm2下电镀,镉的沉积速率为0.23μm/min,电流效率为72.3%。镀层经过低铬彩色钝化后进行中性盐雾试验96 h无白锈生成,504 h无红锈生成,其耐蚀性高于氰化镀镉。实验表明,该镀液的均镀能力和深镀能力、镀层的氢脆性和耐蚀性、结合力均满足HB 5036-92《镉镀层质量检验》的要求,废水处理后镉离子满足GB21900-2008《电镀污染物排放标准》的要求。

A novel cyanide-free potassium chloride cadmium plating process was introduced,and studies on the process performance and coating performance were done in laboratory and production workshop.The plating bath composition was： cadmium chloride 35 ～ 40 g / L,potassium chloride 140 ～ 180 g / L,coordination agent 120 ～ 160 g / L,adjuvant agent 25 ～ 35 m L / L,brightener 1. 5 ～ 2. 5 m L / L,p H 6. 0 ～ 7. 0,JΚ= 0. 5 ～ 1. 5 A / dm2 and temperature 15 ～ 35 ℃ in rack plating bath. In barrel plating bath： voltage was4 ～ 7 V,temperature was 15 ～ 30 ℃,and the barrel revolving speed was 3 ～ 7 r / min. The cadmium deposition rate was 0. 23 μm / min and the current efficiency was 72. 3% under the condition of JΚ= 1 A / dm2.White rust did not generate on the coating processed by low chromium iridescent passivation after 96 h neutral salt spray test,and red rust did not generate after 504 h neutral salt spray test,the corrosion resistance was better than that of cyanide cadmium plating process. Experimental results showed that： throwing power and covering power of the plating solution,hydrogen brittleness performance,corrosion resistance and binding force of the coating,all could meet the HB 5036-92 《Cadmium coating quality inspection》requirements. After treatment,cadmium ions in the plating wastewater could meet the GB 21900-2008《Emission Standard of Pollutants for Electroplating》requirements.