Universal curve of ionic conductivities in binary alkali germanate glasses
| Autor: | Nascimento, Marcio Luis Ferreira, Nascimento, Eduardo do, Watanabe, Shigueo |
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| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: | |
| Zdroj: | Repositório Institucional da UFBA Universidade Federal da Bahia (UFBA) instacron:UFBA |
| Popis: | Submitted by Marcio Luis Ferreira Nascimento (mlfn@ufba.br) on 2010-11-18T14:52:21Z No. of bitstreams: 1 UniversalGermanate-MCP96-Nascimento.pdf: 312785 bytes, checksum: 06f0dbe7732aa25762038739b6e881cb (MD5) Made available in DSpace on 2010-11-18T14:52:21Z (GMT). No. of bitstreams: 1 UniversalGermanate-MCP96-Nascimento.pdf: 312785 bytes, checksum: 06f0dbe7732aa25762038739b6e881cb (MD5) Previous issue date: 2006-01-01 An analysis and brief discussion of experimental ionic conductivity a in the binary alkali germanate system is presented, exemplified on 31 binary GeO2 glasses that span ionic conductivity by more than 17 orders of magnitude in a wide composition range. An 'universal' finding using modified Arrhenius plots log sigma or log sigma T versus E-A/k(B)T is obtained, where E-A is the activation enthalpy for conduction, k(B) the Boltzmann constant and T is the absolute temperature. For a given value of E-A/k(B)T, the difference between large to small values of or is only about one order of magnitude in 87% of the glass systems considered. The fact that a lies on these single 'universal' curves for so many ion-conducting binary germanate glasses means that or is governed mainly by EA while the pre-exponential factor sigma(0) varies around an average value approximate to 50 S cm(-1). The activation enthalpy composition dependence is explained concerning the Anderson-Stuart theory. |
| Databáze: | OpenAIRE |
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