Cutting method for hard metals brings atomic world into focus
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TOKI, Gifu Prefecture–Cutting edge technology has allowed researchers to slice super hard metals and other materials to fragments of less than 100 nanometers, the thinnest level achieved anywhere in the world to date.
To get an idea of how precise that measurement is, one nanometer is equal to one-millionth of a millimeter.
Masayuki Tokitani, an associate professor of fusion reactor materials science at the National Institute for Fusion Science, headed a team that managed to slice tungsten steel, touted as a future material for nuclear fusion reactors, to less than 100 nanometers.
The technology allows researchers to closely examine atoms inside the materials, a development bound to be embraced by automakers and other manufacturers to detect flaws in their products earlier.
To estimate the lifespan of components or develop new materials, items need to be sliced so the atoms can be observed with electron microscopes.
Although conventional techniques can cut materials to at least several hundred nanometers, the thickness of the slices does not them sufficiently permeable to electron beams from electron microscopes, resulting in blurred images.
Tokitani and his colleagues abandoned the idea of cutting materials evenly and tried to slice them into a terraced shape as only the thinnest part needs to be examined.
“I had a sudden flash of inspiration,” said Tokitani, referring to the moment he came up with the innovative idea.
The team members repeatedly applied 30-nanometer-diameter gallium ion beams from two angles diagonally. After changing the beam application point and direction, they succeeded in cutting tungsten into a fragment thinner than 100 nanometers.
“With this technique, atoms can now be examined in detail,” Tokitani said.
The will also likely be adopted in auto parts development and other fields.
Components wear down small cracks on the surface start spreading. Being able to examine atoms of metal parts will make it possible to take steps before the surface cracks get really serious.
“The strength of the new technology is that it can be applied to not only tungsten but also semiconductors, carbon materials, ceramic materials and any other substances, no matter how hard they are,” Tokitani said. “I will keep trying to improve the accuracy to get a better result.”
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