Selective leaching (also called dealloying) is a type of corrosion where one element is removed from an alloy, leaving behind a weakened, porous structure.
This process typically occurs when an alloy is exposed to an electrolyte that preferentially dissolves one metal. A common example is dezincification, where zinc is leached out of brass, leaving behind copper. The remaining material becomes brittle, porous, and structurally compromised.
Selective leaching reduces the mechanical strength, durability, and conductivity of the metal, making it a major concern in piping systems, valves, marine environments, and chemical processing equipment.
To learn how to prevent this form of corrosion, see our FAQ on how to prevent selective leaching.