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The System HfO 2 ‐TiO 2
Author(s) -
COUTURES JEAN PIERRE,
COUTURES JULIETTE
Publication year - 1987
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.1151-2916.1987.tb05655.x
Subject(s) - monoclinic crystal system , phase diagram , eutectic system , materials science , annealing (glass) , analytical chemistry (journal) , tetragonal crystal system , thermal decomposition , crystallography , solubility , phase (matter) , mineralogy , chemistry , crystal structure , microstructure , metallurgy , organic chemistry , chromatography
The system HfO 2 ‐TiO 2 was studied in the 0 to 50 mol% TiO 2 region using X‐ray diffraction and thermal analysis. The monoclinic ( M ) ⇌ tetragonal ( T ) phase transition of HfO 2 was found at 1750°± 20°C. The definite compound HfTiO 4 melts incongruently at 1980°± 10°C, 53 mol% TiO 2 . A metatectic at 2300°± 20°C, 35 mol% TiO 2 was observed. The eutectoid decomposition of HfO 2,ss ) ( T ) → HfO 2,ss ( M ) + HfTiO 3 4,ss ss occurred at 1570°± 20°C and 22.5 mol% TiO 2 . The maximum solubility of TiO 2 in HfO 2,ss ,( M ) is 10 mol% at 1570°± 20°C and in HfO 2,ss ( T ) is 30 mol% at 1980°± 10°C. On the HfO 2 ‐rich side and in the 10 to 30 mol% TiO 2 range a second monoclinic phase M of HfO 2 ( M ) type was observed for samples cooled after a melting or an annealing above 1600°C. The phase relations of the complete phase diagram are given, using the data of Schevchenko et al. for the 50% to 100% TiO 2 region, which are based on thermal analysis techniques.