Materials Performance

MAY 2015

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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Page 8 of 100

6 MAY 2015 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 54, NO. 5 Continued on page 8 UP FRONT Electron Microscope Reveals Aluminum Oxidation Process A new study conducted by researchers at Binghamton University (Binghamton, New York) and supported by the U.S. Depart- ment of Energy Office of Science shows that the oxidation process could be stopped by certain features of metal sur- faces. The knowledge may be used to bet- ter understand and possibly control oxida- tion in a variety of materials. A low-energy electron microscope (LEEM) was used by the team to observe surface changes in a Ni-Al alloy as metal oxide stripes formed and grew under a range of elevated tem- peratures. The crystal surface of the Ni-Al alloy is a step-like structure with a series of f lat terraces of different heights with a one-atom-high step between them. The study showed that the aluminum atoms in- volved in forming aluminum oxide (Al 2 O 3 ) stripes came exclusively from the steps, not the terraces. The growing oxide stripes were confined to the f lat terraces and pushed the steps away as oxygen grabbed aluminum atoms from the edges. This forced the steps to bunch closer and closer together until the growth rate of the Al 2 O 3 stripes slowed and then completely stopped. To learn more, visit discovere. NHTSA Investigates Brake Pipe Failure from Corrosion Brake pipe corrosion from left to right: a) no corrosion, b) corrosion without scaling, c) corrosion with scaling, and d) severe scaling corrosion with leakage. NHTSA photo. The Department of Transportation's Na- tional Highway Traffic Safety Administra- tion (NHTSA) (Washington, DC) reports vehicles from model year 2007 and earlier may be susceptible to brake pipe corrosion that can occur after seven to eight years of exposure to winter road salts, and issued a broad safety advisory urging owners of older sport utility vehicles (SUVs) and pickup trucks to take steps to prevent brake failure resulting from corrosion. If the corrosion is not properly addressed, potential brake pipe failure could result in a crash. The advisory was issued in con-

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