Dezincification Resistant Brass

Cu-Zn alloys containing more than 15% Zn are susceptible to a dealloying process called Dezincification where the selective removal of Zn leaves a relatively porous and weak layer of Cu and Cu oxide. Corrosion of a similar nature continues beneath the primary corrosion layer resulting in gradual replacement of sound brass by weak, porous copper. Unless arrested this corrosion mechanism eventaully penetrates the metal, weakening it structurally and allowing liquids or gasses to leak through this porous mass.

Additions of As (typically 0.02 - 0.25%) to alpha brasses effectively produces high resistance to dezincification at normal operating temperatures. A further addition of Sn (up to 1.5%) further enhances resistance to dezincification and has led to the development of Naval brasses with good resistance in marine environments.