Ga_2O_3-Sm_2O_3系の高温状態図

概要

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In the phase diagram study on the system Ga_2O_3-Sm_2O_3, the liquids and eutectic temperatures were measured from the cooling curves of specimens by the specular reflection method with a heliostat- type solar furnace. Quenched specimens from the melt were examined by X- ray diffractometry and chemical analysis. In the system, four compounds were found ; garnet- type 3Sm_2O_3・5Ga_2O_3, perovskite-type SmGaO_3, monoclinic 2Sm_2O_3・Ga_2O_3 and orthorhombic 3Sm_2O_3・Ga_2O_3. These compounds, showed no phase transition during repeated heating and cooling cycles. The compound 3Sm_2O_3・Ga_2O_3 was found to melt incongruently at 1755±20℃. The lattice parameter were determined to be a_o=12.431 A^^° for 3Sm_2O_3・5Ga_2O_3, a_o= 7 658 A^^°, b_o=10.856 A^^° c_o=11.560 A^^°, β=109.240 for 2Sm_2O_3・Ga_2O_3 and a_o=11.400 A^^°, b_o=5.515 A^^°, c_o=9.070 A^^° , for 3 Sm_2O_3・Ga_2O_3, The solidification points of 3 Sm_2O_3・5 Ga_2O_3 and 2 Sm_2O_3・Ga_2O_3 were determined as 1680±20℃, and 1708±20℃, respectively. The phase diagram shows three eutectic points at 1555℃, 1640℃, and 1690℃ with 22.5. 55, and 70 mol% Sm_2O_3 composition, respectively. A high temperature phase diagram for Ga_2O_3-Sm_2O_3 system was proposed.
社団法人日本セラミックス協会の論文
1989-11-01