Phase Equilibria in the TiO₂‐Rich Region of the System BaO‐TiO₂

Abstract

Phase relations in the system BaO-TiO, from 67 to 100 mol% TiO, were investigated at 1200" to 1450°C in 0,. Data were obtained by microstructural, X-ray, and thermal analyses. The existence of the stable compounds Ba,Ti,,O,,, Ba4TiI3O3,,, BaTi40,, and Ba2Ti9OZ0 was confirmed. The compound BaTi205 is unstable and either forms as a reaction intermediate below the solidus or crystallizes from the melt. The compounds Ba6Ti,,040 and Ba,Ti,,O,, decompose in peritectic reactions, and BaTiO, and Ba,Til,04, react to form a eutectic. Special conditions are required for the formation of BaZTi,O,,, which decomposes in a peritectoid reaction at 1420°C. The new phase diagram is presented.

Preparation of BaTi<SUB>2</SUB>O<SUB>5</SUB> Single Crystal by a Floating Zone Method

“…In those papers, the thermal stability of BaTi 2 O 5 has been discussed. Figure 1 shows 4,[8][9][10][11][12] however, no electrical property of single crystalline BaTi 2 O 5 has been reported. In this study, single crystalline BaTi 2 O 5 specimens were first synthesized by a FZ method, and the relationship between crystal orientation and dielectric property was investigated.…”

“…Many researchers have investigated on the BaO-TiO 2 phase diagram, 4,[7][8][9][10][11] because the BaO-TiO 2 system includes several useful dielectric and ferroelectric materials. In those papers, the thermal stability of BaTi 2 O 5 has been discussed.…”

Phase Diagramm, Cristallization Behavior and Ferroelectric Properties of Stoichiometric Glass Ceramics in the BaO-TiO2-B2O3 System

“…~450°C in the binary B 2 O 3 -TiO 2 system [Pavlikov et al, 1976]; compositions content 30÷35 mol% BaO around eutectic area e 7 (~31.5 mol% BaO) with m.p. 1317°C in the binary BaO-TiO 2 system [Rase & Roy, 1955;O'Bryan &Thomson, 1974], which include BaTi 2 O 5 composition. Area of glass formation from both these areas moves to eutectic areas e 1 (16,5 mol% BaO) with m.p.…”

“…Binary BaO-TiO 2 and BaO-B 2 O 3 systems are investigated rather in detail by various authors. The following eight binary barium titanates known in the BaO-TiO 2 system are: Ba 2 TiO 4 (2BaT), BaTiO 3 (BaT), BaTi 2 O 5 (Ba2T), Ba 6 Ti 17 O 40 (6Ba17T), Ba 4 Ti 13 O 30 (4Ba13T), BaTi 4 O 9 (Ba4T), Ba 2 Ti 9 O 20 (2Ba9T) and BaTi 5 O 11 (Ba5T) [Rase & Roy, 1955;O'Bryan & Thomson, 1974]. Levin with co-authors have studied the BaO-B 2 O 3 system and constructed its melting diagram.…”

Effect of fluxing additive on sintering temperature, microstructure and properties of BaTiO3

“…It is also used in positive temperature coefficient resistors (PTCR) such as thermistors, electroluminescent panels and pyroelectric elements. Its global production is ∼11×10 6 kg/annum and the MLCC industry alone is a multi-billion dollar industry in which more than 10 billion units are produced annually (O'Bryan and Thomson 1974;Scott 1993;Swartz and Shrout 1997;Bell 2008).…”