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TO THE 85-th ANNIVERSARY OF ACADEMICAL SCIENCE OF THE URALS
ArticleName Electrowinning and annealing of Ir – Re – Ir material
DOI 10.17580/tsm.2017.11.10
ArticleAuthor Isakov A. V., Apisarov A. P., Nikitina A. O.
ArticleAuthorData

Institute of High Temperature Electrochemistry of Ural Branch of RAS, Ekaterinburg, Russia:

A. V. Isakov, Senior Researcher, e-mail: ihte_uran@mail.ru
A. O. Nikitina, Engineer, e-mail: info@ihte.uran.ru


1Institute of High Temperature Electrochemistry of Ural Branch of RAS, Ekaterinburg, Russia ; 2Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:

A. P. Apisarov, Researcher1, 2, e-mail: aap@ihte.uran.ru

Abstract

We investigated the electrodeposition of a multilayer material based on iridium and rhenium in the CsCl – NaCl – KCl – IrCl3 and CsCl – Cs2ReCl6 melts. The thermodynamic calculations were carried out for the exchange reaction of the rhenium and iridium chloride in a CsCl – NaCl – KCl – IrCl3 melt. The calculations of the isobaric-isothermal potential for the exchange reaction show the temperature range below 873 K for the rhenium-iridium pair, in which the reaction is unlikely; and the reverse reaction, thermodynamically probable at the temperatures below 830 K. Based on the calculations, the electrodeposition conditions were chosen and the multilayer compositions of the Ir – Re – Ir were obtained. Taking into account the exchange processes in the molten salts, it is possible to obtain the continuous coatings on substrates with a more negative conventional standard potential by electrodeposition. The Ir – Re – Ir material consisting of the homogeneous iridium and rhenium layers without the formation of diffusion layers was produced by the sequential galvanostatic electrolysis. This is confirmed by the X-ray phase analysis of the cross-section. The iridium layers were obtained in the CsCl – NaCl – KCl – IrCl3 melt at the temperature of 853 K. The rhenium layers were obtained in the CsCl – Cs2ReCl6 melt at the temperature of 1073 K. The behavior of the Ir – Re – Ir composition under vacuum annealing at 2073 K was studied. The microhardness of the Ir – Re – Ir material was measured before and after annealing. The microhardness of the iridium and rhenium layers increases after annealing. The microhardness of iridium rises from 320 HV to 520 HV. In this case, the microhardness of the rhenium layer increases less significantly, from 380 to 435 HV. The formation of the diffusion layers after annealing, consisting of rhenium and iridium, was revealed by the optical and electron microscopy, coupled with micro-X-ray spectral analysis. The microhardness of the diffusion layers exceeds the parameters of the homogeneous layers of iridium and rhenium after annealing. At the same time, the microhardness of the intermediate layer in the sample is 720 HV after annealing.
This investigation was carried out with the financial support of the Federal Target Programm “Investigations and developments on the priority ways of development of scientific and technological complex of Russia for 2014–2020”. Agreement No. 14.578.21.0238.

keywords Rhenium, iridium, salt melts, electrolysis, electroforming, hightemperature annealing, composite, structure, microhardness
References

1. Zhu L., Bai S., Zhang H., Ye Y. Effect of cathodic current density and temperature on morphology and microstructure of iridium coating prepared by electrodeposition in molten salt under the air atmosphere. Applied Surface Science. 2013. Vol. 256. pp. 537–545.
2. Nesterenko A. N., Solodova S. V. Perspective monofuel thermocatalytic engines. Vestnik BFU imeni I. Kanta. Seriya: Fiziko-matematicheskie i tekhnicheskie nauki. 2008. No. 5. pp. 80–84.
3. Grigoriev A., Polozov I., Sufiiarov V., Popovich A. In-situ synthesis of Ti2AlNb-based intermetallic alloy by selective laser melting. Journal of Alloys and Compounds. 2017. Vol. 704. pp. 434–442.
4. Antipova T. N., Labutin A. A., Lenkovets A. S. The main provisions of the technology production and quality control of high-temperature structural material Ta–Mo for rocket space technology. Informatsionno-tekhnologicheskiy vestnik. 2016. Vol. 9, No. 3. pp. 99–108.
5. Bai S., Zhu L., Zhang H., Ye Y., Gao W. High-Temperature diffusion in couple of chemical vapor deposited rhenium and electrodeposited iridium. International Journal of Refractory Metals and Hard Materials. 2013. Vol. 41. pp. 563–570.
6. Zaykov Yu. P., Isakov A. V., Apisarov A. P., Chemezov O. V. Production of silicon by electrolysis of halide and oxide-halide melts. Non-ferrous Metals. 2014. No. 1. pp. 33–36.
7. Zhu L., Bai S., Zhang H., Ye Y., Gao W. Rhenium used as interlayer between carbon-carbon composite and iridium coating: Adhesion and wettability. Surface and Coatings Technology. 2013. Vol. 235. pp. 68–747.
8. Baraboshkin A. N. Electrocrystallization of metals from salt melts. Moscow : Nauka, 1976. 280 p.

9. Saltykova N. A. Electrodeposition of Platinum metals and alloys from chloride melts. Journal of Mining and Metallurgy. 2003. Vol. 39 (1–2). pp. 201–208.
10. Molchanov A. M., Fazlutdinov K. K., Minchenko L. M., Isakov A. V., Zaykov Yu. P. Investigation of influence of oxygen in molten electrolyte CsCl – Cs2ReCl6 on texture and morphology of rhenium coatings. Vestnik Kazanskogo tekhnologicheskogo universiteta. 2012. Vol. 15, No. 16. pp. 78–81.
11. Barin I., Knacke O., Kubaschewski O. Thermochemical Properties of Inorganic Substances. Berlin : Springer-Verlag, 1977. 861 p.
12. Barin I. Thermochemical Data of Pure Substances. Weinheim : VCH Verlags Gesellschaft, 1989. 816 p.
13. Ruzinov L. P., Gulyanitskiy B. S. Equilibrium transformations of metallurgical reactions. Moscow : Metallurgiya, 1975. 416 p.
14. Mumtaz K., Echigoya J., Enoki H., Hirai T., Shindo Y. Thermal cycling of iridium coatings on isotropic graphite. Journal of Material Science. 1995. Vol. 30. pp. 465–472.
15. Yusenko K. V. Phase Diagramm of the Iridium-Rhenium system. Platinum metals Review. 2013. Vol. 57, No. 1. pp. 57–65.

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