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Barolin S.A.,National University of Rosario | Barolin S.A.,Complutense University of Madrid | De La Rubia M.A.,Kelsen Inc. | De La Rubia M.A.,Complutense University of Madrid | And 8 more authors.
Boletin de la Sociedad Espanola de Ceramica y Vidrio | Year: 2014

KNL-NTS powder with (K0.44Na0.52Li 0.04)(Nb0.86Ta0.10Sb0.04)O 3 stoichiometry was prepared following the conventional ceramic method of mixing carbonates and oxides. KNL-NTS powder synthesis is carried out in solid state at 700°C for 3h. To obtain ceramic samples with different porosity the sintering of pellets is carried out in air at different temperatures between 1088 and 1125°C for 2h. Structural and microstructural characterizations are performed by XRD and SEM and the degree and type of porosity is determined by mercury intrusion porosimetry. The influence of sintering temperature on the porosity and its consequence on both the ferroelectric hysteresis loops and the piezoelectric response was evaluated. The maximum densification is achieved at 1125°C and the best ferroelectric response is achieved in sintered pellets at 1125°C. Meanwhile, it was observed that pellets sintered in a lower temperature range (1094-1100°C) where porosity reaches values up to 15 % have good ferroelectric piezoelectric response, similar to that found in the sintered pellets to 1125°C.


Munoz-Senovilla L.,Kelsen Inc. | Munoz-Senovilla L.,Autonomous University of Madrid | Munoz F.,Kelsen Inc.
Journal of Non-Crystalline Solids | Year: 2014

The experimental viscosity data of a series of alkali, alkaline earth and zinc metaphosphate glasses have been analysed using Vogel-Fulcher-Tamman, Avramov-Milchev and Mauro-Yue-Ellison-Gupta-Allan models. The kinetic fragility and activation energy for viscous flow have been obtained and studied as a function of the composition, paying special attention to the short and intermediate range order structure as studied by Nuclear Magnetic Resonance and Raman spectroscopy. The fragility shows an increasing tendency within the alkali and alkaline earth series and presents the lowest value for the Zn(PO 3)2 composition. Meanwhile the modifiers influence on the local structure of the PO4 tetrahedra follows a direct relationship with their cationic potential; both static Nuclear Magnetic Resonance and Raman experiments showed evidence of a change in the rings versus chains configurations at the medium range order that could have an important contribution on the variation of activation energy. Furthermore, the molar volume and average bond strength of the glasses have shown to play a most important role, having a similar variation as the activation energy in the high viscosity range. However, the low viscosity range data seem to increase with the modifier's cationic potential, thus suggesting a different flow mechanism when compared with the high viscosity range. © 2013 Elsevier B.V.


Munoz-Senovilla L.,Kelsen Inc. | Venkatachalam S.,University of Augsburg | Munoz F.,Kelsen Inc. | Van Wullen L.,University of Augsburg
Journal of Non-Crystalline Solids | Year: 2015

The experimental viscosity data of a series of lithium-zinc metaphosphate glasses of composition xLi2O·(50 - x)ZnO·50P2O5 have been analyzed in order to get new insights into the compositional and structural influence on viscosity in phosphate glasses. The short and intermediate range order structures have been studied by Raman spectroscopy and Nuclear Magnetic Resonance at room temperature and at temperatures above Tg with in situ solid state high temperature Nuclear Magnetic Resonance. The substitution of ZnO by Li2O leads to changes on the short and medium range order structures that are reflected in the glass properties, such as molar volume, glass transition temperature and fragility. It was demonstrated that the fragility increases as a consequence of a weaker and more flexible glass network that makes easier the flow of the rigid structural units through the glass. © 2015 Elsevier B.V. All rights reserved.


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Kelsen Group A S and Kelsen Inc. | Date: 2010-12-21

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Kelsen Group A S and Kelsen Inc. | Date: 2012-01-17

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Kelsen Inc. | Entity website

An average lawyer generatesover 3,6 millionmega bytes of structured and unstructured dataevery year. There are over 11million legalcaseson-lineand human kind generates over2 petabytes of data every year ...


Kelsen Inc. | Entity website

ContactUnter den Linden 17,10117 Berlinservices@ask-kelsen.com Follow us

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