Phase equilibria and crystal chemistry in the ternary system BaO-TiO/sub 2/-Nb/sub 2/O/sub 5/, I

Journal Article · Wed Apr 01 00:00:00 EST 1987 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(87)90362-8· OSTI ID:6545547

Millet, J M; Roth, R S; Ettlinger, L D; Parker, H S

A partial subsolidus phase diagram is presented of the BaO-TiO/sub 2/-Nb/sub 2/O/sub 5/ ternary system. Ten compounds or solid solutions in the ternary system are described. BaTi/sub 3/Nb/sub 4/O/sub 17/, BaTi/sub 5/Nb/sub 4/O/sub 21/, BaTi/sub 7/Nb/sub 4/O/sub 25/, and BaTi/sub 9/Nb/sub 4/O/sub 29/ belong to a chemically and structurally homologous series AB/sub 2n + 1/O/sub 4n + 5/ with 3 less than or equal to n less than or equal to 6, the first member of which is isomorphous with KTi/sub 2/Ta/sub 5/O/sub 17/. They all crystallize in the orthorhombic system, space group Cmcm with essentially constant a and b parameters. The c parameter varies approximately linearly with composition. A nonstoichiometric phase with a composition close to 3BaO : 5TiO/sub 2/ : 3Nb/sub 2/O/sub 5/ crystallizes in the monoclinic system, space group P2/sub 1//c. Two other new phases are solid solutions extended on the quasi-binary join BaTiO/sub 3/-Ba/sub 5/Nb/sub 4/O/sub 15/. Three solid solutions Ba/sub 3/Ti/sub 4/Nb/sub 4/O/sub 21/ (Ba/sub 3/Ti/sub 4 + %x/Nb/sub 4-4x/O/sub 21/ with 0 less than or equal to x less than or equal to 0.3), Ba/sub 6/Ti/sub 2/Nb/sub 8/O/sub 30/ (Ba/sub 6-x/Ti/sub 2-2x/Nb/sub 8+2x/O/sub 30/), and BaTiO/sub 3/ (BaTi/sub 1-5x/Nb/sub 4x/O/sub 3/ with 0 less than or equal to x less than or equal to 0.02) were confirmed and further studied.

• Research Organization: National Bureau of Standards, Gaithersburg, MD
• OSTI ID: 6545547
• Journal Information: J. Solid State Chem.; (United States), Vol. 67:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
CRYSTAL STRUCTURE
PHASE DIAGRAMS
NIOBIUM OXIDES
TITANIUM OXIDES
EXPERIMENTAL DATA
LATTICE PARAMETERS
SPACE GROUPS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
DATA
DIAGRAMS
INFORMATION
NIOBIUM COMPOUNDS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
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& Refractories- Structure & Phase Studies