High‐pressure synthesis of a 12CaO·7Al2O3–12SrO·7Al2O3 solid solution |
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Authors: | Masashi Miyakawa Kiyoshi Kobayashi Takashi Taniguchi |
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Affiliation: | Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan |
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Abstract: | Solid solutions of 12CaO·7Al2O3 (C12A7) and 12SrO·7Al2O3 (S12A7) crystals were synthesized under high pressure. X‐ray diffraction patterns revealed that the lattice constants of the synthesized samples depend linearly on the compositional ratio of C12A7 and S12A7. Electron‐probe X‐ray microanalyses show that the chemical compositions of the crystals are represented by xC12A7·(1?x)S12A7 (0<x<1). These results indicate that the variation in the lattice constants is originated from a difference in the ionic radii of Ca2+ and Sr2+ ions. From impedance measurements, it was found that S12A7 has the highest conductivity (~1 × 10?3 Scm?1 at 550°C) among the solid solutions in the C12A7–S12A7 system. |
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Keywords: | high‐pressure synthesis mayenite solid solution total conductivity |
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