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On the Existence and Formation of Y 4 Al 2 O 9
Author(s) -
Papadopoulos Ilias
Publication year - 1991
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170260407
Subject(s) - sintering , stoichiometry , phase (matter) , materials science , nucleation , yield (engineering) , oxide , analytical chemistry (journal) , atmospheric temperature range , crystal (programming language) , crystallography , mineralogy , chemistry , thermodynamics , metallurgy , chromatography , organic chemistry , physics , computer science , programming language
For the preparation and transformation sequence in the system Y 4 O 3 –Al 2 O 3 the sintering of homogeneously mixed oxide powders was chosen. The constituents of the Y 4 Al 2 O 9 phase were determined by quantitative phase analysis with the method of inner standards. Corresponding gauge curves for the conditions of the temperatures of sintering were drawn. At low temperatures appears as first in the whole molar range the (2:1) phase, i.e. Y 4 Al 2 O 9 . With increasing temperature and sintering time the yield of this mixed crystal phase depends on the concentration of the oxide components in the powder mixture of the start materials. In flux mixtures of the components PbO, PbF 2 , and B 2 O 3 and despite suitable nucleation it was not possible to obtain this compound. In the melt the compound Y 4 Al 2 O 9 was prepared frequently in near molar conditions. Also a glass was prepared with (2:1) stoichiometry. Single crystals were identified by X‐rays.