Ionic Conductivity in Li2O-Al2O3-SiO2Based Glasses and Glass Ceramics

Lunkenheimer, P.; Gerhard, G.; Drexler, Franz; Böhmer, Roland; Loidl, A.

doi:10.1515/zna-1995-1216

Cited by 8 publications

(3 citation statements)

References 17 publications

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“…This composition ensures that near room temperature the positive thermal expansion of the glassy host compensates the negative thermal expansion of the homogeneously embedded crystalline grains [12]. The Li + ion conductivity in Zerodur M and its precursor glass were studied previously [13,14]. Zerodur M is characterized by a [Al 3+ ]/[Si 4+ ] ratio of x ¼ 0.44.…”

Section: Introductionmentioning

confidence: 99%

Spin relaxation and ultra-slow Li motion in an aluminosilicate glass ceramic

Böhmer

2007

Solid State Nuclear Magnetic Resonance

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Section: Introductionmentioning

confidence: 99%

Spin relaxation and ultra-slow Li motion in an aluminosilicate glass ceramic

Böhmer

2007

Solid State Nuclear Magnetic Resonance

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“…The present investigation of -spodumene is part of an ongoing research program devoted to the study of ionic motions in lithium aluminosilicates. [18,19,20] For the present work we have used polycrystalline samples, since a study on single crystals has revealed that the conductivity of -spodumene is isotropic [21].…”

mentioning

confidence: 99%

The lithium ion conductor β-spodumene: an orientational glass

Böhmer

Lunkenheimer

Lotze

et al. 1996

Zeitschrift für Physik B Condensed Matter

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Polycrystals of -spodumene were investigated using impadence spectroscopy for frequencies 0.1 Hz ( (235 GHz and for temperatures 5 K (T(500 K. At high temperatures the Li ions are mobile and lead to dc and ac conductivity phenomena. These are analyzed in terms of the universal dielectric response and using the modulus formalism. The results obtained by both procedures are critically compared. At low temperatures or very high frequencies dielectric loss due to a dipolar freezing process is observed which bears a close resemblance to an orientational glass transition. To further confirm the glassy character of -spodumene, we report measurements of the low temperature specific heat (3 K(T(50 K) which provide evidence for the existence of excess contributions that are usually observed in amorphous materials. Introduction Spodumene, LiAlSiO , belongs to the small class of crystals that exhibit a contraction of certain crystallographic axes upon heating. The negative thermal expansion coefficient has technological relevance and is for instance used in ''zero'' expansion materials [1], it is due to the peculiar network structure which is built up from an array of corner-sharing SiO and AlO tetrahedra. This structure is similar to that of keatite which itself is a modification of quartz [2]. In -spodumene the centers of the tetrahedra are however occupied randomly by Al> or by Si> and, to keep the charge balance, the network is ''stuffed'' by Li> ions which occupy interstitial sites.The structure of -spodumene involves 5, 7, and 8 membered rings of the SiO and AlO units which are

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“…Ionic conductivity studies on Zerodur precursor glass showed increasing conductivity with increasing temperature due to the drop in activation energy (E ac ) required for electrical conduction at higher temperatures. 18 Once phase separation, nucleation or crystal growth occur, the interfaces or structural discontinuity increase which act as resistance in series and play a role in the dielectric heating. In a crystal lattice, disruption of the charge neutrality will create a net dipole moment.…”

Section: Introductionmentioning

confidence: 99%

Near‐zero thermal expansion transparent lithium aluminosilicate glass‐ceramic by microwave hybrid heat treatment

et al. 2017

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The material of choice for space applications which demand very high dimensional stability is lithium aluminosilicate (LAS) based Ultra Low thermal Expansion Glass-Ceramic (ULEGC). Generally, the controlled crystallization process recommended for the processing of transparent ULEGC involves a long soaking duration to achieve the required crystal number density. This paper brings out the process optimization procedure adopted for realizing transparent and nanocrystalline ULEGC from conventionally processed LAS glass using microwaveassisted (hybrid) crystallization. The experimental strategy involves two stages (i) identification of the optimum crystallization temperature (T c ) under a microwave field (ii) optimization of a microwave-assisted crystallization process to achieve near zero Coefficient of Thermal Expansion (CTE).. Optimum heat-treatment schedules for nucleation and crystallization under a microwave environment were found to be 720°C/24 hours and 775°C/0.3 hours, respectively. The optimized heat-treatment condition revealed the efficacy of the microwave hybrid heating, by producing nanocrystalline (35-50 nm) and transparent (>82%) ULEGC having a thermal expansion of À0.03 9 10 À6 K (0°C to 50°C).

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Ionic Conductivity in Li₂O-Al₂O₃-SiO₂Based Glasses and Glass Ceramics

Cited by 8 publications

References 17 publications

Spin relaxation and ultra-slow Li motion in an aluminosilicate glass ceramic

Spin relaxation and ultra-slow Li motion in an aluminosilicate glass ceramic

The lithium ion conductor β-spodumene: an orientational glass

Near‐zero thermal expansion transparent lithium aluminosilicate glass‐ceramic by microwave hybrid heat treatment

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