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| RIKEN Press Release | March 17, 2008 |
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RIKEN-JST team develops ceramic material with zero thermal expansionStability should make material ideal in ultrafine precision machining | |
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A team of researchers from RIKEN and the Japan Science and Technology Agency (JST) has succeeded in developing a ceramic material with zero thermal expansion in a wide range of temperatures, including room temperature. The material is expected to find wide use in such areas as ultrafine precision machining, where its stability could make it an ideal material and greatly reduce fabrication costs. Ordinarily, a material's volume increases as the temperature rises, a phenomenon known as 'thermal expansion.' This can lead to serious defects, and is often seen in daily life, such as when a glass cracks when hot water is poured into it. The research team working at RIKEN's Discovery Research Institute, present Advanced Science Institute, and led by Hidenori Takagi, investigated a manganese nitride with a 'reverse perovskite' crystalline structure and discovered that it exhibits a characteristic called 'negative expansion' - as the temperature rises, the volume becomes smaller. On the basis of this result, the team developed a ceramic material formed with manganese nitride only, and optimized the type, ratio and production conditions of the constituent elements for temperatures covering the 70°C range, which includes room temperature, and with a thermal expansion of zero. Until now, so-called 'zero expansion' materials have been composite materials in which substances with negative thermal expansion and those with positive thermal expansion were combined. Compared with these, in the newly developed zero expansion material, the distortion and defects are stabilized. In addition, because it is a single substance, production can be kept simple, and therefore costs can be kept low. It also exhibits the peculiar hardness of nitride, and compared with former materials, it is ground-breaking in that it can be utilized even in precision microprocessing where high power is applied. The new zero-expansion ceramic is expected to find strong demand in structural elements and in parts of a variety of industrial equipment, as well as in advanced industrial production of semiconductors and liquid crystal devices, in ultraprecise machining, and in precision optical instruments. The research result was reported in the annual meeting of the Japan Institute of Metals held in March, 2008. |
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| RIKEN, one of Japan's leading research institutes, conducts basic and applied experimental research in a wide range of science and technology fields including physics, chemistry, medical science, biology and engineering. Initially established as a private research foundation in Tokyo in 1917, RIKEN became an independent administrative institution in 2003. For more information, visit www.riken.jp | |
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