**7.6 Selective leaching**

Selective leaching is the removal of an element from an alloy by corrosion. Selective removal of zinc from brass is a prime example of this form of attack. A similar attack has been observed with other alloys in which iron, aluminum, cobalt and chromium are removed. This type corrosion is undesirable as it yields a porous metal with poor mechanical properties (**Figure 7**)**.**
