Available Technology
New irradiation technology provides metal corrosion resistance
Technology:
Techniques for forming new oxide coatings, improving existing oxide coatings, and applying oxide coatings on surfaces immersed in water
Markets Addressed
Corrosion diminishes the performance and safety of almost every product made with metal, ranging from very small medical implants to large-scale naval vessels, aircraft, bridges, and pipeline structures. A 2002 study by the US Federal Highway Administration (www.tfhrc.gov) estimated that the direct cost of metal corrosion was $276 billion per year in the US, or approximately 3.1% of national US Gross Domestic Product (GDP), and that indirect costs of metal corrosion could be an additional $276 billion per year in the US.
Corrosion affects services and day-to-day operations throughout the country and across all economic sectors (www.corrosioncost.com). For example:
• Infrastructure: airports, pipelines, bridges, railroads, waterways
• Transportation: aircraft, motor vehicles, railroad cars, ships
• Utilities: transmission systems for electricity, water, sewerage, telecommunications, and gas
• Government: military equipment, nuclear waste storage
• Production and manufacturing: agriculture, food processing, home appliances, pharmaceutical, pulp and paper, mining, chemical and petrochemical industries
Any reduction in corrosion rates anywhere has the potential to achieve significant cost savings. Dr. Ramanathan’s new technology to improve metals’ natural corrosion protection layers has this potential, and more, because it could be applied to almost any metal, from nanoscale materials up to large-scale engineering structures such as naval vessels. By restoring metal surfaces, this technology could be a major corrosion control measure that could help reduce that $276 billion annual cost.
Innovations and Advantages
Dr. Ramanathan has developed an irradiation technology that improves a metal’s own corrosion resistance. The irradiation can be applied to new metal surfaces, to surfaces that already have oxide coatings or alloy surfaces, and to surfaces submerged in water.
Corrosion occurs when metals react to oxygen and start to break down. Initially, oxide coatings form and these natural coatings can prohibit further corrosion. Frequently, the oxide coatings themselves break down, losing their natural ability to protect metals against further corrosion.
This technology takes advantage of the natural oxide coatings to restore, strengthen, and extend their anti-corrosion capabilities. Metal surfaces are irradiated in the presence of oxygen, using light with one or more wavelengths in the range between about 100 and 365 nanometers and a power density greater than about 10 milliwatts per centimeter2. The irradiation forms a modified oxide layer on the metal surface that improves corrosion resistance, as follows:
• Increases impedance by up to 10 times greater than before irradiation
• Reduces the leakage rate by up to 400 times less than before irradiation
• Reduces the pitting potential by up to 40% less than before irradiation
The irradiation can be applied when the metal is submerged, allowing ships to be treated while still afloat. Irradiation is rather fast as well, ranging from about ten mintues to at most four hours, depending on the metal, the condition of the metal, and the existing oxide coatings.
Additional Information
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Inventor(s):
Chang, Chia-Lin
Ramanathan, Shriram
Categories:
For further information, please contact:
Sam Liss, Director of Business Development
(617) 495-4371
Reference Harvard Case #2875