PICKLING METHOD FOR COPPER OR COPPER ALLOY WITH SUPPRESSED GENERATION OF GASEOUS NOX DURING PICKLING

摘要

PURPOSE:To effectively suppress the generation of gaseous NOx during pickling by using a nitric acid bath into which a specific ratio of urea is incorporated for pickling of copper or copper alloy. CONSTITUTION:The copper or copper alloy is pickled by dipping the same into the nitric acid of 15-21% nitric acid concn. into which 2-5g/l urea is incorporated. The gaseous NOx generated in the stage of cleaning is decreased to about <=1/10 the amt. of the case in which the urea is not incorporated into the bath by adding a specific ratio of the urea to the bath.