Coatings and Painting
Rust formation can be controlled with coatings, such as paint, that isolate the iron from the environment. Large structures with enclosed box sections, such as ships and modern automobiles, often have a wax-based product (technically a "slushing oil") injected into these sections. Such treatments also contain rust inhibitors
Covering steel with concrete can provide some protection to steel by the high pH environment at the steel-concrete interface. However rusting of steel in concrete can still be a problem. Rust can be avoided by controlling the moisture in the atmosphere. An example of this is the use of silica gel.