Discovery stops the rot

A new method of protecting the surface of steel could cut material costs for metals that need protection from corrosion. Developed in the

at the

(PNNL),

, it covers relatively low-cost stainless steels with a layer of aluminium that bonds irreversibly with the base metal.

Lead researcher Chuck Henager said the method imparts the anti-corrosive properties of aluminium to steel. Aluminium, although a chemically reactive metal, is useful in anti-corrosive applications; the metal surface reacts with oxygen in the air, creating a layer of aluminium oxide that resists most corrosion. The metal is more expensive and weaker than steel, so combining their properties is an ideal solution.

Henager starts by making the initial coating: a mixture of aluminium powder and a liquid polymer called polysiloxane, dissolved in the organic solvent cyclohexane. Polysiloxane is a preceramic: when heated under the correct conditions, it forms cross-links and becomes a solid ceramic.