Chemistry – Metals - Corrosion of metals | e-Consult

A practical application of a barrier method is the use of paint to protect car bodies from corrosion. The car body is primarily made of steel, which is susceptible to rusting. A multi-layer paint system is applied to the car body. This system typically consists of a primer, an intermediate coat, and a topcoat. The paint acts as a physical barrier, preventing water and oxygen from reaching the steel. The primer provides adhesion to the metal and also acts as a barrier. The intermediate coat provides further protection and helps to seal the surface. The topcoat provides colour and protection from weathering. Even if the paint is scratched, the multi-layer system provides a degree of protection, as the corrosive agents must penetrate multiple layers to reach the steel. This significantly extends the lifespan of the car body and prevents structural failure due to corrosion.