Brassing

Brassing is a term used in metallurgy and materials science to describe a phenomenon where a material, typically a copper alloy such as brass, undergoes a surface change due to selective leaching of one of its constituent elements. In the case of brass, which is an alloy of copper and zinc, brassing refers to the preferential removal of zinc from the surface.

This selective leaching can occur under various conditions, including exposure to certain corrosive environments, elevated temperatures, or electrochemical processes. The result is a surface that becomes enriched in copper, often with a reddish or reddish-brown appearance, while the zinc is depleted. This alteration of the surface composition can significantly affect the material's properties.

The consequences of brassing can include changes in mechanical strength, electrical conductivity, and corrosion resistance. For instance, the copper-enriched surface may be more susceptible to certain types of corrosion or may exhibit different frictional characteristics. Understanding and controlling brassing is important in applications where the surface integrity and composition of copper alloys are critical, such as in plumbing, electrical components, or decorative items. Methods to prevent or mitigate brassing often involve surface treatments, protective coatings, or careful control of the operating environment.