Study On Trivalent Chromium Electroplating Process Of Environmental Protection

At present, trivalent chromium electroplating process has became one of the mostimportant techniques to taking place of the seriously pollutional hexvalent chromiumelectroplating process. Studing deeply on the trivalent chromium electroplatingprocess, mading it apply on mass production has highly realistic and strategicalsignificance to breaking through the overseas technical barrier and achieving the goalof Clean Production in Chinese electroplating industry.Starting from the three big technical problems in the trivalent chromiumelectroplating process, a deep study had been made on the ornamental trivalentchromium electroplating process in sulphate system and chloride system in thisdissertation. With the methods of Hull cell testing, small size cell rack-plating testingand scale-up experiment testing and so on, we made the Dimensionally Stable Anodefor trivalent chromium electroplating in sulphate system and graphite anode inchloride system, and entire process criterions for the two systems. At the same time, adetailed discussion had been conducted on the reaction mechanism of the anode andcathode in this dissertation. The process standards were showed as follow:(1) Process Standard for Trivalent Chromium Electroplating in Sulphate System (2) Process Standard for Trivalent Chromium Electroplating in Chloride System The measuring results indicated that, self-made Dimensionally Stable Anode hadhigh electrocatalytic activity for oxygen evolution, and good conductivity else. Thisanode had favorable capability to restraining Cr⁶⁺ creation. There was no seriousproblems such as Cr⁶⁺ creation or chlorine evolution in self-made products of the twosystems at the period of electroplating. The integrative performance of the self-madeproducts had reached the same level of overseas congeneric ones. The electrodepositsobtained from self-made trivalent chromium electrolytes had similar color withhexvalent chromium electrodeposit, but the grain in the former deposite was morefine. The hardness of trivalent chromium deposite was inferior to the trivalentchromium, at the same time the corrosion resistance had an advantage over the latter.