Process for producing brown covering layers on copper

摘要

A method for producing a uniform and adherent brown covering layer (brown patina) on surfaces of semifinished products made of copper, particularly on rolled tapes or sheets used in building construction. The surface of the copper semifinished product is first roughened by means of a mechanical treatment. The copper semifinished product is then heat treated at a temperature lying within the temperature range of 150 degrees to 650 degrees C. for the duration of 0.1 to 30 minutes. The copper semifinished product can be advantageously subjected to a chemical postoxidation treatment immediately following the heat treatment.