Microstructure and humidity-sensitive properties of ZnCr2O4-LiZnVO4 ceramic sensors

Yokomizo, Yuji; Uno, Shigeki; Harata, Mitsuo; Hiraki, Hideaki; Yuki, Keiji

doi:10.1016/0250-6874(83)85073-2

Cited by 68 publications

(22 citation statements)

References 4 publications

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“…Such a behavior has not been found in the case of LiCuVO 4 where no water absorption has been observed [18]. The effect of humidity on the conductivity of LiFeVO 4 is of particular interest, as it could help us clarify the actual origin and nature of its electrical properties, which might lead to its use as a humidity sensor as in the case of LiZnVO 4 [19][20][21].…”

Section: Introductionmentioning

confidence: 98%

Impedance spectroscopy study on the ionic conductivity processes of the novel LiFeVO4 phase

Kazakopoulos

Kalogirou

2010

Ionics

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The recently discovered compound LiFeVO 4 was prepared by solid-state reaction at 570°C during a 7-h period. The X-ray diffraction pattern revealed an orthorhombic crystal structure. Thermogravimetric measurements revealed a reversible mechanism which was attributed to absorption-desorption of humidity. Impedance spectroscopy measurements were carried out at 25°C steps in the temperature range from 25 to 500°C and equivalent circuits were drawn to fit the impedance measurement results at each temperature level. The elements of the equivalent circuits were assigned to bulk, grain boundary, and along grain boundary conductivity. All three conduction mechanisms were found to be humidity sensitive. Arrhenius plots were plotted for the bulk and grain boundary conductivity processes. The activation energy for the bulk conductivity process was calculated to be 0.25 eV over the temperature range from 175 to 500°C and the activation energy for the grain boundary conductivity process was calculated to be 0.41 eV from 300 to 500°C and 0.20 eV from 175 to 275°C. An explanation for the existence of these two grain boundary activation energies is attempted. The dependence of the material conductivity mechanisms on humidity suggests that LiFeVO4 could be used as a humidity sensor.

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Section: Introductionmentioning

confidence: 98%

Impedance spectroscopy study on the ionic conductivity processes of the novel LiFeVO4 phase

Kazakopoulos

Kalogirou

2010

Ionics

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“…The electrical properties of LiMgVO 4 have not yet been reported as far as we know. As it is discussed below, the study of the electrical properties of LiMgVO 4 and especially the effect of humidity on its conductivity is of particular interest, since it may lead to the possibility of its use as a humidity sensor like LiZnVO 4 [13][14][15]. As a matter of fact, it is the dramatic change in conductivity due to the humidity of the surrounding atmosphere (up to seven orders of magnitude as shown below), which could be exploited in humidity sensor applications.…”

Section: Introductionmentioning

confidence: 99%

Study of LiMgVO4 electrical conductivity mechanism

Paraskeva

Kazakopoulos

Chrissafis

et al. 2010

Journal of Alloys and Compounds

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“…It was expected that a well-defined microstructure should be formed in order to improve the humidity sensitive properties [2,[6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…The structure of spinel oxide is responsible for a variety of interesting properties [2][3][4][5][6]. Determination of cation distribution is of considerable relevance because the theoretical interpretation of the chemical and physical properties of these compounds depends on this distribution [5].…”

Section: Introductionmentioning

confidence: 99%

“…Amongst the various types of solid-state humidity sensors that have been proposed in the literature the simplest are sensors which use solid electrolytes or semiconductors as the active elements [1,2]. A ceramic material seems to be more appropriate as active elements, given that they are thermally and chemically stable, reliable and selective [3].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Morphology, Structure and Nonstoichiometry of ZnCr2O4 Nanophased Powder

Mančić

Marinković

Vulić

et al. 2003

Sensors

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It is well established that gas/humidity-sensing properties of spinels are markedly influenced by their stoichiometry and microstructure. In this work nucleation and spinel phase development in the Zn-Cr-O system were investigated from the viewpoint of structural and morphological phenomena occurred during nanophased particle synthesis through aerosol reaction. The aerosol was generated from nitrates precursor solution using ultrasonic atomizer operated at 1.7 MHz. The influence of different decomposition schedules on the particle chemical content and morphology was determined by adjusting the processing parameters (aerosol droplet density 3.9x10 6 droplets/cm 3 , droplet velocity 0.035m/s, max. temperature 900 o C and residence times 3, 6 and 9s). A composite particle structure comprised of primary crystallites sized from 22 to 44nm is revealed by SEM and TEM analysis. XRD structural analysis (crystallite size, microstrains, unit cell and ionic occupancies) is performed in accordance with procedure based on Koalariet-Xfit program. A certain degree of non-stochiometry is characteristic for all powders. Homogenous distribution of the constituting elements and Zn/Cr ratio of about 0.68 are proved by EDAX

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Microstructure and humidity-sensitive properties of ZnCr2O4-LiZnVO4 ceramic sensors

Cited by 68 publications

References 4 publications

Impedance spectroscopy study on the ionic conductivity processes of the novel LiFeVO4 phase

Impedance spectroscopy study on the ionic conductivity processes of the novel LiFeVO4 phase

Study of LiMgVO4 electrical conductivity mechanism

Morphology, Structure and Nonstoichiometry of ZnCr2O4 Nanophased Powder

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