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Experimental study of phase equilibria in the Al 2 O 3 –MgO–TiO 2 system and thermodynamic assessment of the binary MgO–TiO 2 system
Author(s) -
Ilatovskaia Mariia,
Saenko Ivan,
Savinykh Galina,
Fabrichnaya Olga
Publication year - 2018
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/jace.15748
Subject(s) - eutectic system , liquidus , isothermal process , phase diagram , ternary compound , differential thermal analysis , atmospheric temperature range , analytical chemistry (journal) , scanning electron microscope , materials science , phase (matter) , ternary numeral system , thermodynamics , solid solution , mineralogy , crystallography , diffraction , chemistry , microstructure , inorganic chemistry , metallurgy , physics , organic chemistry , chromatography , optics , composite material
Phase relations in the MgO–TiO 2 and Al 2 O 3 –MgO–TiO 2 systems have been studied experimentally using X‐ray diffraction, scanning electron microscopy combined with dispersive X‐ray spectrometry, and differential thermal analysis. The heat capacity measurements of the Mg 2 TiO 4 , MgTiO 3 , and MgTi 2 O 5 compounds have been carried out in the temperature range of 473‐1373 K using DSC . A new thermodynamic description of the MgO–TiO 2 system has been derived based on obtained experimental results, data from literature, and taking into account the cation disordering of the intermediate compounds Mg 2 TiO 4 and MgTi 2 O 5 . The liquid phase was described by the two‐sublattice partially ionic model (Mg +2 ,Ti +2 ,Ti +3 )(O −2 ,Va,O,TiO 2 ). For the Al 2 O 3 –MgO–TiO 2 system: the solid‐state invariant reaction involving the intermediate phase of pseudobrookite solid solution have been found at the temperature of 1433 K. On the liquidus surface, the eutectic invariant reaction has been established at 1843 K and the transitional one—at 2006 K. Based on the obtained experimental results isothermal sections within the range 1269‐1697 K of the ternary system have been predicted. The MgTi 2 O 5 –Al 2 TiO 5 section has been constructed.