In Situセラミックコンポジットに適したAl^<3+>置換LaM型ヘキサフェライトの合成

概要

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La(Fe, Al)_<12>O_<19> powder was synthesized by the two-step solid-state reaction of La(Fe, Al)O_3 with α-Fe_2O_3 and α-Al_2O_3 powders. The stability and the formation rate of LaFe_<12>O_<19>-based magnetoplumbite compounds are greatly improved by the formation of a solid solution with La_xAl_<12>O_<19>. The highest value of the saturation magnetization(52.9 emu/g)was obtained at the composition of 95 mol% LaFe_<12>O_<19>(LaM95)in La(Fe, Al)_<12>O_<19>. In Ce-TZP(ceria-stabilized tetragonal zirconia polycrystal)ceramic matrix, 90 mol% LaFe_<12>O_<19> in La(Fe, Al)_<12>O_<19>(LaM90)was stable in a wider temperature range than LaM95. Platelike LaM90 crystals were successfully grown in situ in Ce-TZP matrix at temperatures ranging from 1350 to 1375℃. The formation of anisotropic La(Fe, Al)_<12>O_<19> crystals was found to depend upon the preferential diffusion of La^<3+> ions through the initially formed magnetoplumbite lattice.
社団法人日本セラミックス協会の論文
1999-03-01