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Projects / Programmes source: ARIS

Transport snovi in naboja v trdnih snoveh (Slovene)

Periods
Research activity

Code Science Field Subfield
2.04.00  Engineering sciences and technologies  Materials science and technology   

Code Science Field
P320  Natural sciences and mathematics  Nucleic acids, protein synthesis 
T150  Technological sciences  Material technology 
Evaluation (rules)
source: COBISS
Researchers (5)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  11517  PhD Marjan Bele  Materials science and technology  Researcher  2001 - 2003  542 
2.  19277  PhD Robert Dominko  Materials science and technology  Researcher  2001 - 2003  739 
3.  19090  PhD Jernej Drofenik  Chemistry  Researcher  2001 - 2003  51 
4.  00582  PhD Miran Gaberšček  Materials science and technology  Researcher  2001 - 2003  896 
5.  10180  PhD Janko Jamnik  Materials science and technology  Head  2001 - 2003  337 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0104  National Institute of Chemistry  Ljubljana  5051592000  21,470 
Abstract
Transport along and across grain boundaries in solid materials has been subject of investigation in electrochemistry of solid state materials, materials science and photographic sciences. Our group has been involved in these studies for more than a decade. In cooperation with other research groups, we have built the so-called core/space charge model to describe the interfacial properties in ceramic materials. The model explains the correlation between the structure of a solid/solid interface and the mobile defect density at and near the interface and represents a starting point for derivation of various transport coefficients. Verification of this model through carefully designed experiments is a central point of our programme. At present, only overall transport coefficients of a ceramic material can be measured. However, there exist several models which correlate individual (interfacial, bulk) properties with overall propreties. A common message of these models is that, for a given microstructure and for given local boundary properties, one can straightforwardly predict the ceramics conductivity while the inverse is not true. This is an inherent problem of conventional studies of boundaries. Based on these facts, the goals of the present programme can be defined as follows: 1) Development of a technique which allows for precise measurements of transport properties of a single grain and grain boundary in a polycrystal, 2) Based on the experimental results, development of a general model explaining the correlation between local and macroscopic properties of ceramic materials. A significant step towards the single grain boundary characterisation in ceramics was achieved by AFM. However, using this technique it is still not possible to measure grain boundary conductivities. Recently, development of alternative techniques has started. One is microimpedance spectroscopy which, at present, is mainly used to study the contacts in semiconductors. The technique which is going to be developed within the programme is based on the conventional impedance spectroscopy where, instead of conventional planar electrodes, microelectrodes acting as point electrodes are used. By measuring impedance at various positions on the surface of a polycrystalline material, it will be possible to separately determine the bulk grain and the the grain-boundary conductivity. As model materials AgCl and AgBr single- and polycrystals will be used. After that the application of the technique to various ceramic materials of interest will be carried out. Once the technique has been developed, various materials of practical importance such as anodes and cathodes in Li ion batteries, fuel cell materials, and other (electro)ceramic materials will be investigated.
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