Abstract
Phase transition of solid solution phases of (Ndx,Sm1 - x)AlO3 was investigated by powder X-ray diffraction technique. The transition temperature Tc from orthorhombic to trigonal structure is linearly related to x in (Ndx,Sm1 - x)AlO3 with the relation of Tc(°C) = -1043.4x+785.8 as an approximation at ambient pressure. This transition is reversible against the change of temperature. At room temperature, the structural change from orthorhombic to trigonal system takes place at around x=0.73 when x varies from 0.0 to 1.0 in (Ndx,Sm1 - x)AlO3. Thus, the average ionic radius of R3+ plays an important role to decide the structure of RAlO3, and an appropriate selection of ionic radius rR for R will function so as to control temperature and/or pressure for the structural change. As a result, structural diagram of RAlO3 given by temperature condition and atomic number of R, which implies a phase diagram under pressure and temperature conditions, was proposed. Change of molar volume of a series of RAlO3 was also discussed based on both effects of temperature and ionic radius R3+.
Original language | English |
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Pages (from-to) | 104-110 |
Number of pages | 7 |
Journal | Journal of Alloys and Compounds |
Volume | 266 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 1998 Feb 20 |
Keywords
- Phase diagram of RAlO
- Phase transition
- Structure of (Nd,Sm)AlO
- X-ray diffraction
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry