METHOD AND DEVICES FOR INCREASING THE SERVICE LIFE OF A PROCESS SOLUTION FOR CHEMICAL-REDUCTIVE METAL COATING

摘要

The invention relates to a method and devices for increasing the service life of a process solution used for chemical-reductive metal deposition. In said method, the pH-value is adjusted and the ions of the coating metal are replenished without interfering counter-ions by feeding the process solution, optionally after dilution, to at least one weakly acidic cation exchanger that is charged with ions of the coating metal. The reduction medium is replenished either in an auxiliary circuit or in a diluted process solution. Preferably, interfering cations originating in the reduction medium are eliminated with the aid of a strongly acidic, proton-charged cation exchanger and interfering anions with the aid of a weakly alkaline anion exchanger. During the metal deposition process, interfering cations that accumulate in the process solution are preferably eliminated with the aid of a strongly acidic, proton-charged cation exchanger. Said method permits a practically constant composition of the process solution with a negligible impurity content, producing a coating of exceptional quality. The increase in the service life of the process solution improves the cost-effectiveness and environmental compatibility of the chemical-reductive metal coating.