Background

It has been estimated that the worldwide annual costs of metallic corrosion are over $500 billion per annum. Coatings are an effective solution to reduce corrosion activity, and are becoming more important with the introduction of new materials, and of new applications.

There is pressure to improve the environmental aspects of coatings, particularly by ending the use of heavy metals and chromate, and reducing the quantity of volatile organic chemicals (VOCs) used. This, with demands for improved performance has created serious challenges for the coatings industry.

The sol gel based system developed at Sheffield Hallam University is highly effective in corrosion resistance, whilst being chromate free very low in VOC content, and also requires low energy input for production and application.

The technology

A range of coatings have been developed, based on a silica organic/inorganic platform, doped with nanoscale materials to produce customised protective coatings, with varying characteristics.

Coatings are chromate free, and have a range of VOC content, from zero to 100 per cent solvent based. The platform technology is patented, individual formulations, involving composition and process parameters, are held as confidential information.

Benefits

Sheffield Hallam sol gel coatings demonstrate very high corrosion resistance with little evidence of change after extensive salt-spray tests. Flexibility is excellent with 180 degree (T0) bends produced without cracking. Low temperature and rapid cure is available.

A range of substrates can be coated including aluminium alloys (including Al 2024), carbon steel, stainless steel and hot dip Zn galvanized carbon steel. Adhesion and scratch resistance can be controlled dependent on curing temperature and time. A critical benefit is the adaptability of the sol gel, and customised coatings can be developed.

Development stage

The University is seeking licensing and joint development partners to upscale coating formulations to industrial scale processes.

Lead researcher(s)

Professor Bob Akid

Dr Heming Wang