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The rhenium electrodeposition from the KF-KBF 4 -B 2 O 3 -KReO 4 melts at 773 K was studied by the cyclic voltammetry. Two waves were found on the E(i) dependences in the cathode region corresponding to the reduction of Re (VII) to metallic Re: Re 7+ +3e→Re 4+ , and Re 4+ +4e→Re 0 . The galvanostatic electrolysis in the KF-KBF 4 -B 2 O 3 -KReO 4 melt in an atmosphere of an ambient air was performed. It was revealed that the use of the KF-KBF 4 -B 2 O 3 -KReO 4 electrolyte (with 5.4 wt% Re) provides the Re electrowinning on the Re substrate during 20 h at 773 K without a decrease in the rhenium ions concentration. The electrolytic deposits were analyzed by the XRD, SEM-EDS and ICP-AES spectroscopy. It was demonstrated that the electrolytic deposits were the metallic Re with a purity of 99.98 wt%. The operating conditions for producing the Re deposit with a current efficiency of 98% were determined.

Bend‐contour pattern analysis is used to study processes occurring in initially dislocation‐free selenium crystals during the formation of subgrain boundaries in the course of crystal growth. Using the data obtained on the magnitude and character of lattice disorientations in various types of emerging boundaries, a block‐formation model is proposed. The model is based on the possible modes of relaxation of the crystal lattice elastic bending, inherent in crystals growing in an amorphous film.

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BaCeO 3 -based materials represent a well-known family of proton-conducting electrolytes, which can be used in different solid oxide electrochemical devices. An effective operation of the latter across an intermediate-temperature range requires improved transport of PCEs, including their grain (G) and grain boundary (GB) components. In the present work, some 3d-elements in a small amount were used as sintering additives to verify the possibility of improving the GB conductivity of BaCe 0.9 Gd 0.1 O 3-δ . It is shown that copper oxide (CuO) can be considered as one of the most effective sintering agents, since its use enables decreasing the GB density of the BCG ceramic material at the reduced sintering temperatures. The obtained results form a new tactic for designing new protonic electrolytes, whose conductivity might be prevail over ones containing Ni-based modifiers.

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