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[December 2004]
Scientists Find Atomic Clues to Tougher Ceramics
A collaboration of scientists led by researchers with the US Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab, Berkeley, CA, USA) has uncovered clues at the atomic level that could lead to a new generation of much tougher advanced ceramics to be used in applications like gas turbine engines.
Working with the unique facilities at Berkeley Lab's National Center for Electron Microscopy (NCEM), the collaboration has produced atomic-resolution images of silicon nitride ceramics that were sintered with oxides of rare earth elements to toughen them up and prevent cracks from spreading. These images revealed, for the first time, the exact location of each rare earth atom in the final material and how their presence affected its toughness.
"Our findings are a prime factor in understanding the origin of the mechanical properties in advanced ceramics and should make it possible to do the precise tailoring in the future that will critically improve the performances of these materials over a wide range of applications," said Robert Ritchie, a materials scientist who holds a joint appointment with Berkeley Lab's Materials Science Division and the University of California at Berkeley's Department of Materials Science & Engineering.
Robert Ritchie and Alexander Ziegler, a member of Ritchie's research group, were the principal authors of a paper by the collaboration which appeared in the 3 December 2004 issue of the journal 'Science'. The other co-authors were Christian Kisielowski and Nigel Browning of Berkeley Lab, Juan Idrobo of UC David and Michael Cinibulk of the Air Force Research Laboratory in Ohio.
www.lbl.gov
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