Archive / Том LVI 2019

Khrystyna KHRUSHCHYK, Lidiya BOICHYSHYN

Ivan Franko National University of Lviv Kyryla and Mefodia Str. 6, 79005 Lviv, Ukraine

DOI: https://doi.org/10.37827/ntsh.chem.2019.56.169

MODIFICATION OF MICROHARDNESS OF TEMPERATURY MODIFICATE AT DIFFERENT STAGE OF NANOCRYSTALLIZATION OF THE AMORPHOUS ALLOYS OF SYSTEM Al–Ni–(RE ≡ Y, Gd) AND THEIR CATALIC ACTIVITY IN HYDROGEN RELEASE PROCESS

The properties of the amorphous metallic alloys (AMA) are determined by the nature of the base metal, as well as the composition of alloying additions. Therefore, changing the elemental composition of the AMA it could be expanded the field of their applicability. The amorphous metallic alloys based on aluminum and alloyed with transition and rare-earth metals (RE) can demostrate catalytic action in various oxidation-reduction processes, including the hydrogen evolution reactions, while maintaining a high level of corrosion. The purpose of the research work was to investige electrochemical hydrogen evolution reactions from alkaline solutions by the Al-based amorphous alloys doped with Y and Gd.
Investigated the processes of hydrogen release on aluminum amorphous and nanostructured electrodes Al₈₇Y₅Ni₈, Al₈₇Y₄Gd₁Ni₈, Al₈₇Gd₅Ni₈ in alkaline solution of 1 M KOH. By energy-dispersive X-ray spectroscopy method it was investigated that the surface of electrodes and established that elemental composition before and after the reaction of hydrogen release in alkaline environment. Shown change of microhardness of electrodes after the reaction of hydrogen release.
Analyzing the research results, it can be seen that the Al₈₇Y₅Ni₈ alloy during heat treatment at the temperature T3 (stable nanocrystallization) produces a sufficiently large amount of hydrogen - 1.02 mL/cm²·min and has the highest microhardness of 3.6 GPa. The Al₈₇Y₄Gd₁Ni₈ alloy at the T1 temperature (nanocrystals origin) produces the largest amount of hydrogen – 1.17 mL/cm²·min among the investigated samples, however, its microhardness is 1.58 GPa much less than in case of the Al₈₇Y₅Ni₈ alloy. By the method of electron microscopy it was shown that due to the electrochemical hydrogen evolution reaction from the 1 M KOH solution, an overstress of the surface of aluminum amorphous alloys is observed. It was established that on the surface of the electrodes the amount of Y, Gd and Ni increases as a result of dissolving Al in an alkaline solution. The volume of released hydrogen increases with an increase of Ni content during aluminum dissolution from the surface of AMA electrodes.

Keywords: amorphous metal alloys (AMA), nanocrystals, microhardness, hydrogen release reactions.

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How to Cite

Khrushchyk K., Boichyshyn L. MODIFICATION OF MICROHARDNESS OF TEMPERATURY MODIFICATE AT DIFFERENT STAGE OF NANOCRYSTALLIZATION OF THE AMORPHOUS ALLOYS OF SYSTEM Al–Ni–(RE ≡ Y, Gd) AND THEIR CATALIC ACTIVITY IN HYDROGEN RELEASE PROCESS Proc. Shevchenko Sci.bSoc. Chem. Sci. 2019 Vol. LVI. P. 169-177.