Electroplating Copper-nickel Alloy Plating Bath Salt Concentration Of Metal Ion Analysis Methods

The development of cupronickel plated steel coin is an important project for China Banknote Printing and Minting Corporation.This project is significant for improvement of minting technology.Owing to the similar characteristics between copper(Ⅱ~+)and nickel (Ⅱ~+)and their big electric potential difference,the formation of bath solution is complex. Complexing agents in bath solution will directly influence the content determination of copper(Ⅱ~+)and nickel(Ⅱ~+),besides,some components in additives have special influence on the content of copper(Ⅱ~+)and nickel(Ⅱ~+),which can not be ignored. Therefore,choosing a suitable method to assay the content of copper(Ⅱ~+),nickel(Ⅱ~+) and main salts accurately and quickly has become an essential part of the project for China Banknote Printing and Minting Corporation.In this paper,the author made a series systematic experiment on standard solution, plating bath solution by using flame atomic spectrometry,chemical analysis,and electrochemistry method.By comparing the experimental result,the author research that how the content of complexing agents influence the results of determination.The author ascertains suitable analysis kit and parameters,analyze the main factor which will influence the result of determination.,and put forward a way to diminish or even eliminate error.Large amounts of experimental results shows that the methods of using flame atomic spectrometry or chemical analysis still have error.However,this is system error,which can be diminished by emendation.Considering parallel experiments by different person,we can conclude that by adopting these two methods,the result of content determination of metal ions is stable.In other words,the error is small.Therefore,the determination result by using these two methods will not lead to misjudge of metal ions content in bath solution, so especially suitable for sample analysis(the concentration of main salts in plating bath needs to be analyzed every two hours).These two method can be used in on-line assay, especially flame atomic spectrometry which is fast to analyze,easy to operate and can calculate the concentration of main salts in accordance with determination result,so as to adjust the formulation of bath solution and provide advantageous guarantee for producing satisfactory products.