Dezincification is a problem unique to brasses i.e. alloys of copper and zinc. Zinc is a relatively reactive metal, second only to magnesium in the galvanic series in terms of least nobility. Although alloyed with copper, the strength of the atomic bond between zinc and copper is relatively low. Therefore, under corrosive conditions, the zinc will be attacked and preferentially removed. This leaves behind a porous, copper-rich structure with negligible mechanical strength. Initially, white powdery deposits will appear on the surface, but left unchecked the part will ultimately fail.
The phenomenon can be prevented by reducing the zinc content in the brass alloy, adding tin, antimony, arsenic or phosphorus.
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