New Technology Could Expand Life Of Bridges, Airplanes (540)

 TULLAHOMA, Tenn. — Industry prays for a way to prevent rust and corrosion, and University of Tennessee Space Institute scientists believe they’ve developed the required technology.

 Corrosion-prone steel and aluminum surfaces can be transformed into a stainless steel-like material requiring no maintenance and possibly lasting forever, the scientists say.

 Dr. Mary Helen McCay, a metallurgist and deputy director of UTSI’s laser center, said the high-powered laser process has “enormous potential applications ranging from automobiles and ships to bridges, roofing, airplane fuselages and wings.”

Steel products that have required heavy maintenance at huge expense could be made rust- and corrosion-proof permanently, quickly and at relatively low cost, McCay said.

 Aluminum is subject to stress-corrosion which causes cracking, and the UTSI laser process can solve that problem by adding special components to the surface, she said.

 “I’m told that billions of dollars are spent annually on replacing corroded components. That’s a significant cost,” McCay said.

Dr. Narendra Dahotre, UTSI professor of materials processing and one of the investigators, said the process is not just a coating.

 “It’s a transformation of material, and once it’s converted, it should last forever,” Dahotre said. The process was tested last spring at nearby Arnold Engineering Development Center, where NASA’s Saturn V moon rocket was tested in the 1960s and where, more recently, engines and airframes of the space shuttle, the B-1 bomber and the F-16 fighter were tested.

“Those initial tests were successful,” said Dr. Dwayne McCay, UTSI vice president and laser engineer. “We’ll do some more technology work for a year and then return to the wind tunnel for more tests.”

 AEDC currently faces a problem of rust particles coming loose from the carbon-steel surface of the test tunnel ducts and flowing into the air and possibly into the engine being tested, AEDC officials said.

 “That skews the test data. Our process would eliminate that concern simply because the surface we would recreate will not corrode,” Dahotre said.

 “We take a high-powered laser beam and melt a small depth of surface material and add small amounts of metallic elements to change and improve steel surfaces,” he said.

 “In the AEDC wind tunnel tests, we melted a few millimeters of the carbon steel surface and simultaneously mixed various metallic elements with the melted carbon steel. That created a stainless steel equivalent,” Dwayne McCay said.

 A high-powered laser was mounted on computer-controlled equipment that traveled through the duct work, transforming the surface at the rate of about 30 square inches a minute.

 Mary Helen McCay said the new process had not been possible until now because lasers were not powerful enough to do the job. Also, she said, the process depends on the latest generation of robotics, computers and fiber optics.

 “The three technologies had to come together to make this process possible,” McCay said. Dahotre pioneered the application of the process to aluminum, she said.

 “I did this when I was a graduate student at Michigan State, but the lasers were just far too large to make it feasible,” Dahotre said. “Now we have a laser powerful enough, yet small enough, to do the job.”

 Dahotre, Mary Helen McCay and Dwayne McCay, through the UT Research Corporation, have filed for a patent on the rust-proofing laser technology.

 — End Adv For Monday

 Contacts: Dr. Narendra Dahotre (615-455-0631) Dr. Mary Helen McCay (615-455-0631) Dr. Dwayne McCay (615-393-7209) Cindy Calhoun (615-393-7521)