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Protective Coating Made to Self-Heal

Friday, July 20, 2012

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Nanoscale materials maker NEI Corp. has introduced a two-layer coating designed to significantly improve the corrosion resistance of zinc-plated and hot-dip galvanized steel.

A drop-in replacement for trivalent chromium, the new technology is designed to protect zinc-plated and galvanized steel surfaces from rusting under severe environmental and operating conditions.

NEI Corp.

The steel bars on the right show no appreciable white or red rust after 1,000 hours in salt-spray test (ASTM B117). The coating thickness is ~ 10 microns (0.4 mil).

The process consists of applying Nanomyte PT-100, a self-healing conversion coating, followed by Nanomyte TC-5001, a barrier coating designed to work synergistically with PT-100.

Both liquid formulations can be applied by dipping, brushing, and spraying.

Field tests of the system are now underway in these applications:

• Infrastructure (pipelines, buildings, transmission towers, bridges)

• Military armaments

• Aerospace components

• Marine vessels

• Automotive parts

• Electronic circuits

Corrosion Testing

In salt-fog exposure experiments (ASTM B117), Nanomyte-coated, zinc-plated steel panels showed no white rust after 840 hours and no red rust after 1,200 hours, according to the manufacturer. In contrast, NEI said, uncoated, zinc-plated panels showed white rust in 24 hours and red rust after 168 hours.

Salt-spray testing can be used with field testing and online life predictors for coatings on HDG, as prescribed by the American Galvanizers Association (AGA), NEI noted.

“Our thin, double-coat solution for zinc-plated and HDG steel represents a significant advancement in the state of the art that could eliminate the need for using thicker primers and topcoats,” said Dr. Fred Allen, president of NEI’s Anticorrosion Coatings Division.

NEI says the new technology reflects its continuing efforts to develop corrosion-resistant pretreatments, primers, topcoats and other coating systems to protect steel, aluminum and magnesium.

Said Allen, “Our goal is to engage customers as partners in developing new corrosion-resistant coating products.”

Founded in 1997 and based in Somerset, NJ, NEI Corporation develops, manufactures, and distributes protective coatings and other nanoscale materials for a broad range of industrial customers around the world.

More information: http://www.neicorporation.com/.

Comment from Tom Schwerdt, (7/23/2012, 9:59 AM)

Results would be more interesting with a prohesion (cyclic) salt fog, or natural weathering in a coastal environment. Zinc always performs badly in a continuous-wet environment like B117, as it never gets to form its protective patina.