NEW FRIENDLY ENVIRONMENTAL ETCHING TECHNOLOGIES FOR SOME STEELS AND COPPER ALLOYS

New compositions containing some organic inhibitors were tested in the carbon steels and copper alloys etching processes. The analysis of the etching efficiency and harmful products emission proves that significant reduction in the specific discharge of the waste waters and emission of nitrogen oxides can be achieved at the appropriate etching quality. This reduction is caused mainly by adsorption of the organic inhibitors on the metal surface by decreasing its excessive dissolution. On the other hand, the effective aggregation and dispersion of the corrosion products promotes faster transportation of the rust and dross particles away from the treated metal surface reducing the total processing time.