3rd-8th September, 2017: The International Conference on the Applications of the Mössbauer Effect, St.Petersburg, Russia

[Z. Klencsar]

The International Conference on the Applications of the Mössbauer Effect (ICAME-2017) was held during the days of September 03-08, 2017, in St.Petersburg, Russia. On the conference Károly Lázár presented a lecture dealing with results related to the characterization of complex particle systems obtained via the electric explosion of steel wires in water and other media.

Vaporization of iron wires by electric explosion: influence of cooling media

Lázár K. 1, Varga L.K. 2, Kovács Kis V. 3, Klencsár Z. 1, Stichleutner S. 1

1 Department of Nuclear Analysis, Centre for Energy Research, Hung. Acad. Sci.
2 Institute for Solid State Physics, Wigner Research Centre, Hung. Acad. Sci.
3 Thin Film Physics Laboratory, Centre for Energy Research, Hung. Acad. Sci.

Electric wire explosion can be used for fabrication of nanoparticles. In a typical process a few cm long piece of a thin (ca. 0.2 mm diameter) diameter wire is exposed to a current of several thousand amperes for a short time. Series of stages is taking place from vaporization to final condensation within a few microseconds window for the whole process. In case of iron various interactions may also occur with the cooling media in this short time window. Either the core structure of the formed nanoparticles or their suface can be different from bcc iron. In the present contribution the effects of cooling media on the structure and composition of the formed explosion products are compared. The first medium is commonly used water. Water molecules are decomposed and both active oxygen and hydrogen atoms can be formed during the current shock. The other tested medium, paraffin oil is a distinctly different one, as it does not contain oxygen. Conversely, its decomposition may result in formation of hydrogen and carbon atoms. Mössbauer spectra of fine fractions of explosion products are shown in Fig. 1 for the two cases. Products were also analyzed by XRD and HRTEM methods. All the three applied techniques attest that in the case of water medium high amount of wüstite is formed, presence of Fe3+ containing oxides (magnetite, hematite) is not detected. In contrast, in the case of paraffin oil medium the prevailing product is iron carbide appearing in different phases. Studies with other coolants are in progress.

Acknowledgement
The work was supported in part by the Hungarian National Research, Development and Innovation Office - NKFIH (K115784).