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Phase Relations and Ordering in the System Erbia‐Hafnia
Author(s) -
DURAN PEDRO,
PASCUAL CARMEN,
COUTURES JEANPIERRE,
SKAGGS SAMUEL R.
Publication year - 1983
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1983.tb09983.x
Subject(s) - hafnia , solid solution , phase diagram , fluorite , diffraction , materials science , crystallography , phase (matter) , lattice (music) , thermal expansion , analytical chemistry (journal) , chemistry , physics , metallurgy , optics , cubic zirconia , ceramic , organic chemistry , chromatography , acoustics
The system erbia‐hafnia was investigated using thermal expansion measurements and room‐temperature X‐ray diffraction of quenched and annealed samples. The range of existence of the solid solutions based on HfO 2 and Er 2 O 3 was determined by the precision lattice parameter method. Three compounds with hexagonal structure are reported: the first is an ordered fluorite‐related phase with the ideal formula Er 4 Hf 3 O 12 and decomposes with increasing temperature at ∼1500°C into a solid solution of the fluorite type; the second is formed at ∼55 mol% Er 2 O 3 , corresponding closely to the formula Er 5 Hf 2 O 11.5 , and undergoes a transformation at ∼1650°C into cubic solid solutions to fluorite and C type. The third compound is formed within the concentration range between 60 and 90 mol% Er 2 O 3 . This compound, Er 6 HfO 11 , decomposes at ∼1700°C into a cubic solid solution of the C type. A proposed phase diagram for the system erbia‐hafnia is presented.