Formation of point defects in calcium titanate

George, William L.; Grace, R. E.

doi:10.1016/0022-3697(69)90284-4

Cited by 51 publications

(9 citation statements)

References 9 publications

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“…They also determined the enthalpy of the mobility of electron holes (22 kJ/mol). The latter reported by George and Grace [7,8] was lower (16.7 kJ/mol). They also determined the activation energies of (i) the mobility of oxygen vacancies (54.4 kJ/mol) and (ii) the mobility of electrons.…”

Section: Introductioncontrasting

confidence: 43%

Electronic and ionic conductivity in CaTiO3

Бак

Nowotny

Sorrell

et al. 2004

Ionics

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Abstract. The present work describes the electrical conductivity of undoped CaTiO 3 in terms of the electrical conductivity components corresponding to electrons, electron holes and ionic charge carriers in the temperature range 973 K -1323 K and under controlled oxygen partial pressure (10 Pa -72 kPa). These data are considered in terms of the transference numbers of the respective charge carriers. It appears that the ionic conductivity component assumes maximum at the n-p transition when the ionic transfer number reaches 50% of the total conductivity value at 1323 K. The present study also includes the determination of the activation energy of the conductivity component related to ions (162.1 kJ/mol), electrons (134.2 kJ/mol) and electron holes (86.2 kJ/mol). The data obtained in this work indicate that undoped CaTiO3 exhibits a substantial level of ionic conduction that cannot be ignored in a quantitative analysis of electrical conductivity data.

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Section: Introductioncontrasting

confidence: 43%

Electronic and ionic conductivity in CaTiO3

Бак

Nowotny

Sorrell

et al. 2004

Ionics

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“…CaTiO3-based oxides with perovskite structure show mixed ionic-electronic conductivity [1] that makes it possible to use them as catalysts, electrode materials for high temperature solid oxide fuel cells and other electrochemical devices, membranes for oxygen separation, hydrogen production, etc. Doping of calcium titanate with different impurities allows to vary the ionic and electronic structure and therefore the electrical properties of these compounds in a wide range.…”

Section: Introductionmentioning

confidence: 99%

Crystal structure and electrical conductivity correlation in CaTi1−xFexO3−δ system

Dunyushkina

Горбунов²

2002

Ionics

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Abstract. The structural refinements of CaTil.xFexO3_ ~ (x = 0 -0.4) were performed by means of the X-ray data full-profile analysis method on the basis of the orthorhombic perovskite structure (space group Pbnm). The lattice parameters, atomic coordinates, occupancies and equivalent isotropic temperature factors were refined. The characteristic Debye temperature value was determined for the composition x = 0.25 by analysis of the temperature dependence of X-ray reflections intensity. Using the structural refinement results, the model of oxygen vacancy formation, ordering and transport under acceptor doping was proposed. The dependence of the ionic conductivity on the iron concentration in CaTil_xFexO3_ ~ calculated in the frame of proposed model describes well the experimental data.

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“…5a for CO x = 0.4 sample together the transfer band centred at 300. These bands can be associated to Fe 3+ in octahedral coordination: 480 nm to 6 A 1g ! 4 A 1g , 650 nm to 6 A 1g !…”

Section: Samplementioning

confidence: 99%

“…These bands can be associated to Fe 3+ in octahedral coordination: 480 nm to 6 A 1g ! 4 A 1g , 650 nm to 6 A 1g ! 4 T 2g , and 880 nm to 6 A 1g !…”

Section: Samplementioning

confidence: 99%

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Iron and chromium doped perovskite (CaMO3 M = Ti, Zr) ceramic pigments, effect of mineralizer

Gargori

Cerro

Galindo

et al. 2012

Ceramics International

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Solid solutions Ca(D x M 1Àx )O 3 (M = Ti, Zr and D = Fe,Cr), have been studied as ceramic pigment in conventional ceramic glazes using 0.5 mol/ mol of NH 4 Cl as flux agent by solid state reaction and by ammonia coprecipitation route. Ca(Cr x Ti 1Àx )O 3 compositions obtained without addition of NH 4 Cl as mineralizer, produce pink color in glazes at low x but CaCrO 4 crystallizes when x increases, producing undesired green colors. The crystallization of chromates can be avoided using NH 4 Cl as mineralizer, giving a complete solid solution that produce pink color in glazes at low x and dark blue shades at high x. Coprecipitated sample produce blue colors at low x and at low temperature than ceramic sample (1000 8C instead 1200 8C for CE sample). Cr 4+ ion acts as red chromophore, but at higher x values (blue samples) Cr 3+ ion entrance affects the color. Ca(Fe x Ti 1Àx )O 3 system crystallizes perovskite CaTiO 3 and pseudobrookite Fe 2 TiO 5 together with rutile as residual crystalline phase, glazed samples change from a yellow to a pink color associated to the increase of pseudobrookite with firing temperature. Ca(Fe x Ti 1Àx )O 3 and Ca(Cr x Zr 1Àx )O 3 systems crystallize perovskite CaZrO 3 and zirconia (ZrO 2 ) in both monoclinic and cubic polymorphs, but iron or chromium oxides are not detected in the powders. Coprecipitated sample stabilises cubic form. The solid solution is not reached completely in these samples and is not stable in glazes. #

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Formation of point defects in calcium titanate

Cited by 51 publications

References 9 publications

Electronic and ionic conductivity in CaTiO3

Electronic and ionic conductivity in CaTiO3

Crystal structure and electrical conductivity correlation in CaTi1−xFexO3−δ system

Iron and chromium doped perovskite (CaMO3 M = Ti, Zr) ceramic pigments, effect of mineralizer

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