| Copper and its alloy has been widely used in many fields for their favorable physical andmechanical performance. To enhance the corrosion resistance and decoration, it's necessary tocolor the surface.The technology of chemical coloring the copper is researched in the paper. In order toimprove the coloring effect, the polishing technique as a key step is studied by orthogonal test.Chemical polishing is an easy-going and applicable preparation treatment compared to theother treatments, so it is used to polish copper and copper and brass. The optimal polishingtechnique is obtained. The optimal polishing of copper technique is 700 mL·L-1 of H2O2, 40g·L-1 of H2SO4 (p=1.84 g/dm3),160 g·L-1 of glycol, a bit of OP-10,5 g·L-1 of brightener A,operating temperature is 40℃and polishing time is 5-10min.The optimal polishing of copperand zinc alloy is approximately same with copper, but the operating temperature is 25℃andthe polishing time is reduced to 1-3min. The parameter of coloring of copper which influencesthe coloring effort is studied. The optimal coloring technique is gained finally. It is 120 g·L-1of NaOH, 17 g·L-1 of K2SO4·KHSO4·2KHSO5, 10 g·L-1 of Na2SO4, operating temperature is25℃and the coloring time is 15 min. The result of electrochemical test of colored coppershows the coloring treatment improve the anodic deliquescence and corrosion resistance andhas little effect to the cathode.The technology of electrochemical coloring the cupronickel is also researched. Atechnique of coloring cupronickel is developed in the end by orthogonal test and parameteranalysis. The optimal technique of yellow coating is 44 g·L-1 of (NH4)2MoO4, 95 g·L-1 ofNaH2PO4, 19 g·L-1 of NaOH, cathodic current density is 1.2 mA·cm-2, operating temperature is28℃and coloring time is 1min. The optimal technique of purple coating is 42 g·L-1 of(NH4)2MoO4,106 g·L-1 of NaH2PO4,25 g·L-1 of NaOH, cathodic current density is 2.2mA·cm-2,operating temperature is 50℃and coloring time is1.5min. The optimal technique ofblue coating is 42 g·L-1 of (NH4)2MoO4,106 g·L-1 of NaH2PO4,25 g·L-1 of NaOH, cathodiccurrent density is 2.2 mA·cm-2,operating temperature is 50℃and coloring time is 2min. Theresult of XPS of yellow and purple coating is shown yellow coating is composed of MoO3 andNa2HPO4. In the process of coloring, the surface of cupronickel is not only release hydrogenbut also reduce (NH4)2MoO4 to Mo2O5. The purple coating is composed of Mo2O5 andNa3PO4.
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