UH’s corrosion lab fights the inevitable
Entropy, the second law of thermodynamics, holds that everything breaks down sooner or later. In Hawaiʻi, the form of entropy known as corrosion seems to happen sooner—just ask any driver negotiating Hawaiʻi roads after a three-day pounding by a tropical deluge or any windward homeowner contemplating pitting on fixtures exposed to trade breezes.
Professor Lloyd Hihara (top) tests the durability of materials and effectiveness of preventive measures under laboratory-controlled conditions and in the field in Hawai'i's ultra-corrosive environments. Among the myriad of materials tested is an experiemental metal matrix composite wire developed by industry for telecommunications (bottom).
From Campbell Industrial Park to Haleakala, Hawaiʻi’s rain forests, oceans, deserts, volcanoes and snow-capped mountains offer the perfect environments in which to study the natural corrosion rates of just about anything, from high tech metals to rubber tires. Lloyd Hihara has turned this natural "advantage" into a premier laboratory focused on stalling the inevitable. The research engineer heads the Hawaiʻi Corrosion Research Lab at the University of Hawaiʻi at Manoa, one of the best-equipped facilities in the country for testing how new materials and coatings stand up to the elements.
Military and industry support anti-corrosion work
Indeed, the research promise inherent in Hawaiʻi’s uniquely ultra-corrosive climes have prompted the Department of the Army, Northrop Grumman and others to spend $3.5 million over the last three years to support Hihara’s anti-corrosion quest. The money spent on research represents just a fraction of the approximately $276 billion in corrosion-related losses sustained by American industry each year. "The military alone estimates it loses $20 billion a year," Hihara says.
The Army has supplied the majority of Hihara’s funding to date, so much of what’s discovered over the next few years will benefit them directly. "We hope to become the number one testing site in the Pacific for the Department of Defense," Hihara says. But the lab also relies on the largess of private industry, and Hihara’s findings will eventually filter down to a mass market.
"The metals we test are so expensive that we have to rely on the help of private industry for samples," Hihara says. Some are made only in small quantities. For example, 3M, which brought the country Scotchgard, has supplied samples of a telecommunication wire made of a prototype metal matrix composite that 3M hopes will energize America’s congested transmission grid, bringing more reliable communication networks to the world.
Innovative new metals are tested in lab and field
Samples are meticulously categorized and gingerly strapped to large test racks, and then exposed to various climate conditions in locations around the state. Many of the test sites are on properties owned by Hawaiian Electric Company, which has a strong interest in the 3M wire and has formed a partnership with Hihara for corrosion research.
What happens to the 3M product generally happens to all Hihara’s samples—they are beaten and buffeted by Hawaiʻi’s weather. Conditions at each site are electronically monitored every 30 minutes, and Hihara and his small staff of engineers and graduate students record the electro-chemical processes that chisel away at the samples. It takes about a year to gather useful data.
The benefits can be profound. "Not only does this research save money, it’ll saves lives," Hihara explains. That’s because everything we drive, fly, ride or work with, corrodes. Guns jam, sports gear fails, computers stall, bridges groan, planes get grounded. Everything relies on a combination of performance and reliability. Industry demands greater performance from complex combinations of metals, yet it often lacks practical long-term data about their reliability and sustainability in the field.
New metals are lightweight, strong. . . and untested
"One of the ongoing challenges is that, while metal matrix composites are lightweight and strong, we often don’t understand how they hold up under natural conditions," Hihara says. "The rush to move these super-products into the marketplace needs to be tempered by sound research."
And it’s not just rust, we’re talking about, he adds. "Microbes and biological factors often come into play with these metal matrix composites." So the lab works with other departments around the university, including chemistry and biology, "to bring as much as we can to the table."
In the sterile, brightly lit lab in Manoa’s Pacific Ocean Science and Technology building, tiny slivers of metal matrix composites are poked, prodded and analyzed under powerful microscopes. A walk through the security-enhanced digs reveals microscopes, computers and other expensive equipment. Submerged in rows of gurgling fish tanks are countless samples of metals in various states of controlled, induced corrosion. White-coated lab technicians monitor tanks with the concern and efficiency of nurses in an intensive care ward. Samples dispersed for field-testing will eventually be returned to the lab for analysis.
Corrosion barriers could enhance vehicle performance
Thin ceramic films, such as silon gel and silane-based carbons, are being developed here, to be used as corrosion barriers on metal substrates that will one day make planes fly faster, farther and longer or give new life to an old bicycle. Projects may go by such esoteric names as thermogalvanic corrosion of copper or scanning-vibrating electrode technique for localized corrosion and modeling, but the benefits of Hihara’s research are extremely practical.
"I really love this work," he says. "What I’m doing here may not look like the most exciting work, but it’s incredibly challenging and produces benefits for every industry." Hihara’s career interest stems from an undergraduate engineering class in corrosion that he took while studying for his BS at Manoa. He earned a PhD from the Massachusetts Institute of Technology, learning from (and competing against) the brightest minds in the field. When a position opened in the mechanical engineering department at Manoa, the Pearl City native jumped at the chance to come home.
"Funny thing," he muses. "I’m now teaching the undergraduate course that first got me interested in corrosion 20 years ago." And doing it well, apparently. In addition to his research accomplishments, Hihara is a 1995 recipient of the Regents’ Medal for Excellence in Teaching.
How to conquer corrosion
Corrosion control technology can reduce or eliminate many forms of corrosion, but remedies may be very specific to the metal and environment in question. Nevertheless, University of Hawaiʻi Professor Lloyd Hihara offers these suggestions as good general practices.
- Moisture is necessary for the corrosion process; mitigate corrosion by reducing moisture.
- Dust can be hygroscopic (attract moisture); keep bare metal surfaces clean, dry and well lubricated.
- For indoor environments where humidity can be controlled, keep the relative humidity below 60 percent.
- In marine environments, wash off accumulated sea salt, which is very corrosive.
- Avoid putting dissimilar metals in intimate contact to reduce galvanic action. For example, a brass pipe will accelerate corrosion of a galvanized pipe if they are in direct contact.
- If using coatings for corrosion protection, surface preparation is of primary importance; surfaces to be coated must be free of grease, oil, dirt and existing corrosion products.