A smarter, safer way to reduce corrosion

The discovery provides a boost for the steel industry, helping it to retain its focus on high-quality steel meeting the very highest standards of performance and safety. The breakthrough is of particular importance because the industry needs an alternative to the corrosion inhibitor most widely used at present, hexavalent chromate, which will be banned across the EU from 2019.

Release coating outperforms hexavalent chromate

Corrosion inhibitors are commonly used in a wide range of sectors, including coated steel products used to construct industrial, commercial and other buildings; aerospace and aircraft; and the car industry. Led by Professor Geraint Williams, the team, based at the Swansea University’s College of Engineering, discovered a material and manufacturing process for a smart release coating which outperforms hexavalent chromate in laboratory tests.

Triggering on demand

The new method involves a stored reservoir of corrosion inhibitor. It works by channelling aggressive electrolyte anions into the coating, triggering the release of the inhibitor ‘on demand’, thus preventing corrosion. The product has been tested with salt spray, the standard test for corrosion, outperforming hexavalent chromate. Researchers used a scanning Kelvin probe, specially built by the team, which can detect the state of the metal beneath a coating without touching it. This allowed them to test different products much more quickly, with each test taking around 24 hours, rather than 500 hours as was previously the case.

Prize-winning discovery

The discovery could lead to the product taking a significant slice of a multi-million euro market. The market for coiled coated steel is potentially worth EUR3.8 billion per year in Europe alone. Initial discussions with industry have been extremely positive. The work has won the Materials Science Venture Prize of EUR31.720 awarded by The Worshipful Company of Armourers and Brasiers, and presented at the University of Cambridge.