Copper-Zinc Dezincification Phenomenon
In copper-zinc brass, zinc leaches out during corrosion, leading to a porous and unstable copper network.
Physicochemical mechanism of action
Zinc is generally a more stable alloy component than copper. During corrosion, zinc is leached from the brass and forms a layer on the surface. This process can be selective, leaving copper behind and forming a porous network.
Metallurgical relevance & welding risks
The dezincification phenomenon leads to reduced strength and toughness of the weld. The resulting pores can cause cracks and fractures, especially under mechanical load. Furthermore, the porous copper network can reduce resistance to further corrosion.
Workshop practice & instructions
To avoid the dezincification phenomenon, proper weld preparation is important. This includes cleaning the surface and using suitable protective or insulating materials. For heavily loaded applications, using more stable brass alloys that are less susceptible to dezincification can also be considered.