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Thursday | 17 December, 2015 | 11:35 am

Armed for life

By Gretchen Salois

Above: Modumetal’s patented manufacturing method uses electricity, not heat, to produce ultra-high performance, nano-layered metals.

Breakthrough in affordable corrosion resistance that lasts decades longer

December 2015 - In 2007, Modumetal CEO Christina Lomasney and co-founder John Whitaker were working on lightweight armors for several defense agency projects in the United States. The challenge was to come up with lighter weight armor that registered better toughness and hardness measurements than conventional steels. The caveat, however, was that any breakthrough solution couldn’t cost more than what was then available. It was during this search the team found themselves investigating coatings derived from existing formulas that could protect metals as well as new structural alloys. 

MM 1215 coatings image1Lomasney knew she had a tough task ahead. The easiest approach to improve performance is to change the chemical composition of coatings, but this would significantly add to the expense. “We could come up with stronger coatings by adding tungsten or higher grade alloys, but those come at significant differential cost,” she says.

Instead of attempting to come up with an entirely new chemical composition to combat corrosion, Modumetal began exploring the same raw materials, but to modify them in a different manner. To keep the upfront cost the same, Modumetal needed to take a common raw material and manipulate it to produce “a coating that gives you ten times better performance.”

“The first applications were structural,” Lomasney says. From there, what they found particularly intriguing was laminating metals together on a nanometer scale. “If you can architect the material or control the nature of its nanolayer interface, you can dramatically affect its performance. You can control that interface. It’s an entirely new way of affecting performance and is complementary to chemistry and microstructure.”

Zinc is a widely used element to protect against corrosion for a variety of different steel grades. Zinc is also cost effective compared with other coatings. 

“We configured zinc to better protect the substrate,” explains Lomasney who, alongside her team, discovered that working with readily available and relatively inexpensive raw materials helped to control costs while simultaneously resulting in a significantly extended performance life cycle. 

“There are a lot of properties we can influence in a large-scale manufacturing environment. We’re looking at configuring current coatings today and layering them to enhance performance by virtue of the layered structure itself,” she says.

Before Modumetals struck upon these facts, “performance differentiation was either through manipulation of chemistry or microstructure of the metal, but that’s it,” she continues. “Those are the only things about the alloy that you can change that will affect performance. There was nothing else. We are saying there is something else.” 

Trial and error

The principles of nanolamination are well-documented in academic literature but had never been applied to industrially relevant alloys, says Lomasney. Once Modumetal had established the right mix to achieve successful coatings, it sought to file the necessary patents. The company found that Delphi Automotive, then a subsidiary of General Motors Co., had already developed the process intended for large-scale applications in automotive manufacturing. At the time, Delphi was going through bankruptcy so Modumetal bought the patents. 

In some areas, Modumetal originated both the science and products, especially in the case of corrosion resistance, she says. “We pioneered industrial developed alloys and how architects can use those alloys. We try to see what works, then come back and derive our formulas around that performance characteristic. We’re at the beginning of a higher field of science. There’s a lot more we can do in terms of enhancing performance with nanolaminated alloys.”

MM 1215 coatings image2

Modumetal’s nanolaminated parts, such as these heavy bolts, perform better against corrosion and at a competitive price.

Modumetals’ enhanced coatings were tested under the same conditions as those already in service. Such trials as exposure to salt water sprays and exposure to hot, humid environments help determine the useful life expectancy of the nanolaminated materials versus conventional materials of the same chemistry.

Samples are exposed to salt water, moisture and heat in accelerated corrosion chambers for years until they fail—that is, the coating has worn away, allowing the substrate to corrode. Lomasney cites the conventional G90 weight zinc coating, which will fail an ASTM B117 standard salt spray test after 1,000 hours. “To put that in perspective, our coating is undergoing the same salt test and has so far run for 15,000 hours and still has not failed. Those samples have been undergoing constant testing since October 2013,” she says.

Modumetal also uses a laboratory to run live tests of its coatings on outdoor panels in the extreme climates of Arizona and Florida. “Those samples will sit out there for a long time,” adds Lomasney. Coatings are also being tested in such aggressive environments as offshore oilrigs, buffeted by high and low tides and waves.

Practical performance

Increasing the lifespan of material used for infrastructure is of particular interest as U.S. public facilities are in dire disrepair. It will cost approximately $2 trillion to replace existing structures due to corrosion alone or, as the American Society of Civil Engineers estimates, $3.2 trillion of U.S. GDP by 2020. “This technology can extend the life of assets and hold significant savings potential,” says Lomasney. “If you’re saving that kind of capital, this technology can potentially change national budgets.”

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Modumetal’s nanolaminated metals are lighter, stronger and more durable even in extreme environments.

Beyond bridges and ports, multiple industries such as oil and gas face corrosion problems. “As that industry has evolved, it has turned to operating in more aggressive environments,” she says. “Having a higher corrosive threshold means you don’t have to replace components as frequently, which means reduced downtime and improved return on assets.”

When dealing with standard galvanized sheet, the goal will be to reduce the thickness of the coating to deliver the equivalent of G90 but at significantly reduced cost—or have the value directly tied to performance. 

Adapting electrochemistry in a specific way will allow scientists to produce corrosion resistant coatings on a very large scale. The breakthrough occurs where scientists can control electric fields across long stretches of rolling raw material at a competitive cost. “It was an interesting day when we realized we had achieved our goal,” says Lomasney.

Altering chemistry and electric microstructures could launch a resurgence in metallurgy and metal alloy design into very different types of applications, a common theme for materials development over time, she says.

The long-term potential is staggering. “For the next 100 years, this new way of configuring alloys will dramatically change performance in metals and metal alloys,” predicts Lomasney. MM

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