The dezincification of brasses in concentrated ammonia

Abstract

The dezincification of three commercial brasses, of composition 70 30, 63 37, and 60 40 (Cu/Zn), in 15.7 N ammonia was evaluated using immersion tests, solution analysis, and potentiostatic polarization measurements. All the three brasses undergo corrosion and dezincification in ammonia. The 60 40 brass exhibits the fastest rates while 63 37 shows the slowest rates. Corrosion and dezincification rates increase with the copper concentration of the corrodent, reaching maximum values at 2-5 mg cm-3 of copper. Plastic deformation by 50% cold rolling reduces considerably the amount of dezincification from 60 40 brass but causes only minor changes in 70 30 and 63 37 brasses. © 1982.