相图
摩尔分数
相(物质)
固溶体
焦绿石
鼹鼠
材料科学
衍射
结晶学
粉末衍射
分析化学(期刊)
热力学
化学
物理化学
冶金
有机化学
物理
光学
作者
J.L. Waring,Samuel J Schneider
出处
期刊:Journal of research of the National Bureau of Standards
[National Institute of Standards and Technology]
日期:1965-05-01
卷期号:69A (3): 255-255
被引量:41
标识
DOI:10.6028/jres.069a.025
摘要
The phase equilibrium relationships for a major portion of the Gd2O3-TiO2 system were determined in air, from a study of solid state reactions and from fusion characteristics. Three intermediate phases, a 1:2 compound, a 1:1 compound, and a face-centered cubic solid solution occur in the system. The solid solution phase is indicated on the phase diagram as existing from 33 to 40 mole percent TiO2, at 1750 °C. This phase melts incongruently over a range of temperatures and compositions, from 1840 °C, the peritectic temperature at 35 mole percent TiO2, to 1775 °C at 40 mole percent TiO2, the incongruent melting temperature of Gd2O3∙TiO2. The minimum temperature of stability for the phase is 1600 °C at 38 mole percent TiO2. The compound Gd2O3∙2TiO2 has a cubic pyrochlore structure type with a = 10.181 Å and melts congruently at 1820 °C. This phase apparently accepts up to about 3 mole percent TiO2 in solid solution at 1460 °C. The compound Gd2O3∙TiO2, melts incongruently at 1775 °C and has a reversible phase transition at 1712 °G. The x-ray powder diffraction pattern of the high temperature modification was indexed on the basis of a hexagonal cell a = 3.683 Å, c= 11.995 Å and is apparently related to the A-type rare earth oxide. The compositions Sm2O:TiO2 and Eu2O3:TiO2 gave x-ray diffraction powder patterns with marked similarity one to the other as well as to both the high and low polymorphs of Gd2O3∙TiO2. The composition Dy2O3:TiO2 formed several phases one of which is apparently related to the high temperature polymorph of Gd2O3 •TiO2.
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