Dezincification of a siphon made of CW506L | CuZn33 | C26800

The pipe section sat horizontally under a sink and was replaced after about 25 years due to a leakage. During the removal, the brass pipe crumbled because, due to massive dezincification in many places, the entire wall thickness consisted only of copper sponge and corrosion product. When dezincification occurs, the brass (yellow) dissolves, the zinc (blue-gray) corrodes, and the copper is precipitated as a pure but now spongy metal (reddish). This is a selective corrosion mechanism. The brass here has a pure α structure, and the surface is nickel-plated.