不定比性プロブスカイト型化合物ScRh_3B_xの硬度と耐酸化性

概要

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Polycrystalline samples of ScRh_3B_x, which consists of reactive Sc and high melting point Rh and B elements, have been successfully synthesized by the arc melting method. ScRh_3B_x has the perovskite cubic structure (space group Pm3m). Perovskite-type ScRh_3B_x exists in the range of 0&lnEx&lnE1.000 (0 to 20 mol%B). ScRh_3 has the AuCu_3 type structure (space group Pm3m). The lattice parameter a in annealed ScRh_3B_x depends on x, and varies linearly from a=0.3903(1)nm (x=0) to 0.40799(3)nm (x=1.000). The micro-Vickers hardness of the annealed ScRh_3B_x increases with increasing B content in the range x=0-1.000, from 1.9(±0.1) GPa for ScRh_3 (0 mol%B) to 9.9(±0.1) GPa for ScRh_3B_<1.000> (20 mol%B). TG analysis indicates that the onset temperature of oxidation for ScRh_3B_<1.000> is 595℃. The sharp exothermic peak of the DTA curve is found at 797℃. Weight gain of the sample by heating in air up to 1200℃ is 12.7%. The sample changed to Rh plus Sc_2O_3 and ScBO_3 after oxidation. The weight gain of the sample decreases with decreasing boron content.
社団法人日本セラミックス協会の論文
1999-06-01