Materials Performance

JUN 2016

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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6 JUNE 2016 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 55, NO. 6 UP FRONT —Kathy Riggs Larsen Oxidation Research Could Lead to More Corrosion- Resistant Water Pipes Using state-of-the-art in situ microscopy techniques, scientists at Binghamton University (Binghamton, New York) were able to watch the oxidation of copper— the primary building material for mil- lions of miles of water piping—at the atomic level as it was happening. What they observed could help create pipes with better corrosion resistance. "Oxidation of metals [the loss of elec- trons at the molecular or atomic level] is a universal reaction caused by the simple fact that the oxide of most metals is more stable than the metal itself. Resistance to corrosion or oxidation is one of the most important properties for materials ex- posed to air or water," says Guang wen Zhou, associate professor of mechanical engineering at the university. Water is naturally corrosive, espe- cially in pipes carrying hot water because the elevated temperature accelerates the oxidation/corrosion rates. "The most common reason for water utilities to add corrosion inhibitors is to avoid copper corrosion. The research f indings of our study on the oxidation of copper alloys can facilitate the development of new al- loys with improved resistance to corro- sion in water," Zhou adds. Using atomic-resolution electron mi- croscopes, the scientists demonstrated that the oxidation of copper occurs via layer-to-island grow th of copper oxide on f lat copper surfaces with copper atoms evaporating from the surface. Solid oxide, made of copper and oxygen atoms mixing thermally above the original surface, is deposited back on the surface. This is dif- ferent from the long-held idea of a solid- solid transformation. They note the ob- servation is counterintuitive because a surface can resist oxidation better if it can be made more uneven. According to Zhou, not all oxidation is a bad thing. "[Oxidation] can lead to the formation of a protective layer against corrosion attack," he says. "Our results establish the principles of pre- dicting the trend for promoting or sup- pressing the oxidation of materials, which is much needed for smarter utili- zation to steer the reaction toward the desired direction for real applications such as corrosion resistance or improved chemical catalysis." For more informa- tion, v isit binghamton.edu. Carnegie Science Center Kiosks Show Effects of Corrosion The USS Requin. At the Carnegie Science Center (Pitts- burgh, Pennsylvania), an interactive kiosk connects viewers to the Cold War-era USS Requin submarine moored outside the center. When visitors touch a digital display, windows open to depict how elements of the submarine succumb to corrosion. This exhibit is one of the sci- ence center's three new kiosks sponsored by the Department of Defense (DoD) Corrosion Policy and Oversight Off ice. "Military aircraft, ships, and vehicles operate in myriad environments and are always susceptible to corrosion," says Daniel J. Dunmire, director of the DoD Corrosion Off ice. "This kiosk allows any- one to appreciate what we're up against as we f ight to preserve our aging military f leets around the globe." The other exhibits include a "City Tour" kiosk that allows guests to see Pitts- burgh through the sharp eyes of a corro- sion engineer and get an inside look at how the environment degrades the city's archi- tectural treasures. Additionally, a corro- sion coupon rack—placed outside the sci- ence center near a window—shows viewers how experts simulate real-time environmental testing on sample materi- als to evaluate how they weather the envi- ronment, and gives them an idea of how corrosion might affect their home or per- sonal car. For more information, visit carnegiesciencecenter.org. Biomaterial Impedes Bacteria on Metal Surfaces Researchers at Ben-Gurion University of the Negev (BGU) (Be'er Sheva, Israel) have developed an innovative anti-biof ilm coating that has signif icant potential for a variety of medical and industrial appli- cations. Anti-adhesive patches developed from a naturally occurring biomaterial (algal- secreted polysaccharide [Ps]) and a copper metal complex f ilm can prevent destructive bacterial biof ilms from form- ing on metal surfaces when they are im- mersed in water and other damp environ- ments. The researchers found the anti-adhesive surface brought about bac- terial migration that impeded bacteria's transformation to an irreversibly at- tached state. According to the research- ers, the solution addresses a pervasive need to design environmentally friendly materials to obstruct dangerous surface bacteria grow th and holds tremendous potential for averting biof ilms formed by surface-anchored bacteria. To learn more, visit aabgu.org.

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