Phase transformation in Na1+xSixZr2P3−xO12 compounds

Boilot, J.P.; Salanié, J.P.; Desplanches, G.; Potier, D. Le

doi:10.1016/0025-5408(79)90091-6

Cited by 200 publications

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“…As already explained, the ionic conductivity of these materials exhibit an anomalous peak near x ) 2 when plotted as a function of composition. 1,9 This compound at x ) 2 has a conductivity of σ ) 0.35 Ω -1 cm -1 at 573 K which is comparable to that of the -alumina (Na 2 O‚ xAl 2 O 3 ). 1,2 The Nasicons have certain important advantages, such as near isotropic (three-dimensional) mobility of ions, easier synthetic roots, lower sintering temperature, low thermal expansivities, etc., over -alumina.…”

Section: Resultsmentioning

confidence: 98%

“…A particularly interesting aspect of Na 1+x Zr 2 Si x P 3-x O 12 is that as the composition, x, increases the conductivity initially increases, by many orders of magnitude, up to an x ≈ 2. Beyond this it decreases showing 9 an anomalous peak near x ) 2. This anomalous variation in conductivity with composition is associated with a similar anomalous variation of the c-axis of the rhombohedral unit cell.…”

Section: Introductionmentioning

confidence: 94%

“…5 The low-temperature structure of Na 1+x Zr 2 Si x P 3-x O 12 for x < 1.6 and x > 2.4 is rhombohedral (hexagonal) with an R3 hc space group. 2,9 The compounds in the above range of compositions are not known to exhibit any phase transitions up to their melting points (>1650°C). At low temperature, the members of Na 1+x Zr 2 Si x P, 3-x O 12 in the range 1.6 < x < 2.4 (the SICs) show a slight distortion to the monoclinic structure and the space group is B2/c.…”

Section: Introductionmentioning

confidence: 99%

“…The transition is also accompanied by an increase in conductivity and over the transition region (400 K < T t < 460 K) the activation energy gradually reduces to half its value in the monoclinic phase. 9,10 The high-temperature rhombohedral R3 hc-phase is the one of particular interest here, due to its high ionic conductivity. A particularly interesting aspect of Na 1+x Zr 2 Si x P 3-x O 12 is that as the composition, x, increases the conductivity initially increases, by many orders of magnitude, up to an x ≈ 2.…”

Section: Introductionmentioning

confidence: 99%

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Structure, Conductivity, and Ionic Motion in Na₁₊_xZr₂Si_xP₃_-_xO₁₂: A Simulation Study

Kumar

Yashonath

2002

J. Phys. Chem. B

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Constant-pressure, constant-temperature variable-shape simulation cell Monte Carlo and microcanonical ensemble molecular dynamics simulation of superionic conducting rhombohedral phase of Nasicon, Na 1+x Zr 2 Si x P 3-x O 12 , 0 e x e 3, at a temperature of 600 K is reported. Changes in structure, conductivity, hop path, site occupancies, bond lengths of framework atoms with composition are discussed. Average Na(1)-O distance shows a peak at x ) 2, while Na(2)-O distance shows a monotonic increase. Sum of the sodium occupancies at Na(1) and mid-Na sites adds up to a constant value of one which supports the conclusion of Boilot et al. 1 based on X-ray diffraction. Occupancy of Na(1) site attains a minimum at x ) 2. The predominant conduction channel (which carries more than 90% of the sodium ions) is found to be the one connecting Na(1)-mid-Na-Na(2). Density contours for sodium, depicting this conduction channel, are reported. Free energy profile along the conduction channel suggests that entropy contribution cannot be neglected. The mid-Na site is not associated with a free energy minimum.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structure, Conductivity, and Ionic Motion in Na₁₊_xZr₂Si_xP₃_-_xO₁₂: A Simulation Study

Kumar

Yashonath

2002

J. Phys. Chem. B

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“…Among them, solid electrolyte-type CO 2 sensors are of particular interest from the viewpoint of low-cost, high-sensitivity, high-selectivity and simple-element structure [45]. Most researches concerning the use of NASICON as active element for gas sensors have been focused on the Na 1+x Zr 2 Si x P 3-x O 12 formula, in the composition range of 1.8 < x < 2.4, because in this range, conductivity shows the largest value [46][47][48]. A commercial NASICON with a nominal-composition Na 3 Zr 2 Si 2 PO 12 has been investigated as a CO 2 electrochemical sensor [49,50].…”

Section: Co 2 Gas Sensormentioning

confidence: 99%

Gas Sensors for Monitoring Air Pollution

Yoo¹

2011

Monitoring, Control and Effects of Air Pollution

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Thermoresponsive Inorganic Materials

Evans

2002

Encyclopedia of Smart Materials

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The effect of temperature on the vast majority of materials is well known—as materials are heated, they initially expand in volume before eventually melting, subliming, or decomposing. Thermal expansion is often viewed as a deleterious property. Thermal expansion can, however, also be put to good use. It has long been known that the walls of bowed buildings can be pulled back into shape by a cooling iron bar; steel tires can be shrink‐fitted onto the wheels of railway carriages. Although these examples represent a technologically useful response to the stimulus of increased (or decreased) temperature, they do not quite fall into the category of “smart.” However, the very simple concept of coupling together two materials, one that has a large and one a smaller coefficient of thermal expansion to produce a bimetallic strip can certainly be considered to create a smart composite body. Here, the strains induced by the higher expansion of one material cause the strip to bend as temperature is increased, leading to a simple temperature‐sensing/responsive device. The vast majority of materials known and used in technological applications have a positive coefficient of thermal expansion; the reasons for this behavior are discussed. Certain materials, however, display the opposite property and contract in volume when heated. These materials thus have a negative coefficient of thermal expansion, which has led to their somewhat confusing description as “negative thermal expansion” (NTE) materials. The properties of these materials and the origin of these effects form the main topic of this article. Materials that have this unusual thermoresponse have a number of important technological applications. Applications related to specific materials are discussed. The first major area of application is in producing composite bodies. By mixing normal materials with a negative thermal expansion phase, one can achieve a composite that has a precisely controlled positive, negative, or even zero coefficient of expansion. Second, certain of the materials discussed can be chemically doped to control their expansion properties. Thus, one can envisage a single material that could be adjusted to have zero overall expansion. Such materials are of use where repeated thermal shock might lead to mechanical failure (an everyday example is oven‐to‐table cookware) or in optical devices such as high precision mirrors where any thermal expansion might distort optical properties. Materials that have strong intrinsic thermal contraction are most likely to be used as compensators for the positive expansion of other phases. In “negative thermal expansion” materials considered in the remainder of this article, there will always be an underlying expansive component caused by vibrational modes that tend to increase bond distances. In certain circumstances, however, these modes may be dominated by other more exotic effects.

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Phase transformation in Na1+xSixZr2P3−xO12 compounds

Cited by 200 publications

References 3 publications

Structure, Conductivity, and Ionic Motion in Na₁₊_xZr₂Si_xP₃_-_xO₁₂: A Simulation Study

Structure, Conductivity, and Ionic Motion in Na₁₊_xZr₂Si_xP₃_-_xO₁₂: A Simulation Study

Gas Sensors for Monitoring Air Pollution

Thermoresponsive Inorganic Materials

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Phase transformation in Na1+xSixZr2P3−xO12 compounds

Cited by 200 publications

References 3 publications

Structure, Conductivity, and Ionic Motion in Na1+xZr2SixP3-xO12: A Simulation Study

Structure, Conductivity, and Ionic Motion in Na1+xZr2SixP3-xO12: A Simulation Study

Gas Sensors for Monitoring Air Pollution

Thermoresponsive Inorganic Materials

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Structure, Conductivity, and Ionic Motion in Na₁₊_xZr₂Si_xP₃_-_xO₁₂: A Simulation Study

Structure, Conductivity, and Ionic Motion in Na₁₊_xZr₂Si_xP₃_-_xO₁₂: A Simulation Study