| Copper-tin alloy coatings have good gloss, better corrosionresistance and suitable hardness, so in many electroplating applicationfields, electroplating cupronickel tin is the best choice of platingsubstitute for nickel. At present electroplating copper-tin alloy containthree types of cyanide，low-cyanide and cyanogens. The research focusedon the composition of cyanogens solution with system of focalpHospHate，and discussed the influence of the solution composition, pHvalue, temperature and other factors on the thickness, the composition ofalloy coatings. The main research contents for:Through orthogonal test, the better concentration of alloyelectroplating is obtained: Cu2P2O730g/L; Na2SnO355g/L; K4P2O7280g/L; C7H13O8Na30g/L; Gly25g/L; KNaC4H4O640g/L; KNO340g/L;Zn1g/L; Mn10g/L; Operation condition was:temperature30℃;pHvalue8.5; current density Dk=2.0A/dm2. Then, the concentration ofcomponent influenced the coating was discussed, the bath scatteredability and cathodic current efficiency were calculated. Finally, thebrightening agent influenced of the coatings was discussed, makingbrightening agent with the optimal concentration, ranges of theconcentration of components were gained by experiments.The bettersolution was: Cu2P2O725~40g/L; Na2SnO345~60g/L; K4P2O7260~300g/L; C7H13O8Na25~40g/L; Gly25~35g/L; KNaC4H4O630~45g/L; KNO330~40g/L;Zn1~3g/L; Mn8~11g/L; FJ-2was:4~6mg/L.Process condition is: temperature was25to30℃, pH was8.2~9.0, thecurrent density was1.0~2.5A/dm2. The coatings of alloy were depositedfrom the solution.The alloy components contain copper49~60%; tin38~47%; manganese1~2%; zinc0.6~2.5%. Besides, the factors of pHvalue, temperature, current density influenced the main ingredients wasdiscussed with brightening agent comparing without it.The tests showed that the cupronickel tin in performance can achievethe effect of nickel plating, which had similar plating nickel burnish, good corrosion resistant performance, high hardness, so it can completelyreplace nickel plating. |
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