NH_4(Al,Cr)CO_3(OH)_2の合成とその熱分解によるAl_2O_3-Cr_2O_3固溶体の生成過程

概要

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Cr-containing compounds with crystal structures similar to AACH (Ammonium Aluminum Carbonate Hydroxide) were synthesized. Synthesized compositions were Al/(Al+ Cr) (atomic ratio) =1, 0.5 and 0. These compounds were examined by infrared spectroscopy and X-ray diffractometry. Infrared absorption bands in the lattice vibration region shifted to the lower wave number direction and X-ray diffraction peaks shifted to the lower angle direction with increasing Cr content. Al atoms in AA CH were considered to be substituted by Cr atoms. The compound with the composition Al/(Al+ cr) = 0.5 was considered to be a solid solution of Al and Cr compounds. The Formation process of α-(Al_2O_3-Cr_2O_3) solid solutions from Al/ (AI + Cr) = 0.5 compound was also investigated. The samples heat-treated below 500℃ were considered to be γ- (Al_2O_3-Cr_2O_3) solid solutions. A part of chromia crystallized as α-Cr_2O_3 about at 600℃. The γ-(Al_2O_3-Cr_2O_3) solid solution remained up to 1100℃ and transformed to α- (Al_2O_3-Cr_2O_3) solid solution containing about 60 mol% Al_2O_3 above 1100℃. The final α-(Al_2O_3-Cr2O_3) solid solution was formed below 1300℃.
社団法人日本セラミックス協会の論文
1988-08-01