Dip a chunk of a gold and silver alloy into acid, and the silver quickly dissolves. This process--called dealloying--leaves behind an unusual form of gold whose surface is filled with near-atomic size nooks and crannies, giving it a spongelike appearance when viewed through a high-powered microscope. Why dealloyed gold adopts this odd structure has long puzzled scientists. Now, researchers from Johns Hopkins and three other universities, writing in the journal Nature, say they've solved this materials science mystery. By capturing near-atomic scale images of the metal with a scanning electron microscope and by constructing computer models of the dealloying process, the researchers produced a series of mathematical equations describing how the porous gold evolves.
The above story is based on materials provided by Johns Hopkins University. Note: Materials may be edited for content and length.
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