X-ray diffraction was employed to examine the phase composition and determine the amount of a specific phase (quantitative phase composition) in the ZrNi1.2Mn0.5Cr0.3 (1), ZrNi1.2Mn0.5Cr0.2V0.1 (2), ZrNi1.2Mn0.45Cr0.2V0.15 (3), ZrNi1.2Mn0.4Cr0.2V0.2 (4), and ZrNiMn0.5Cr0.2V0.5 (5) alloys. The dependence of the quantitative phase composition on the chemical composition of the alloys, on the vanadium amount in our case, was established. Alloys 1–4 with a lower vanadium content (~2.5–5 wt.%) consisted of four phases: C15, C14, Zr7Ni10, and Zr9Ni11. Alloy 5, with the highest vanadium content (~12 wt.%), consisted of the same phases, except for Zr7Ni10. With growing vanadium amount in the alloy, the total content of the main phases, C15 and C14, increased (from ~70 to 95 vol.%) and the amount of the Zr7Ni10 phase decreased (from ~28 to 0 vol.%) until it disappeared in alloy 5. The microstructure of two alloys (1 and 5) was analyzed in detail. According to X-ray diffraction, these alloys were characterized, respectively, by the largest and smallest content of secondary phases (Zr7Ni10 + Zr9Ni11). To determine the elemental composition of typical (three) structural sections, integral and point analyses were carried out by energy-dispersive X-ray spectroscopy (EDX), whose results agreed well with X-ray diffraction. The elemental content of the alloys, calculated using local EDX for different points in the structure, was presented as formulas of all phases identified by metallographic analysis. To assess the ratio between the number of Laves phases and secondary phases and their mutual arrangement, contrast structural images were obtained by computer processing of metallographic data for alloys 1 and 5, which allowed the ratio of the specified phases to be analyzed automatically. The contrast images clearly showed that the layers of the dark phase (Laves phase) penetrated the areas (white) of the secondary phases, thus creating a large interfacial surface and facilitating the diffusion of hydrogen into the inner layers. The hydrogen sorption properties of electrodes produced from alloys 1–5 were studied. With a higher total amount of Laves phases with C15 and C14 structures at a temperature of 25°C and a discharge current of 50 mA/g, the maximum discharge capacity did not increase for all alloys. The minimum discharge capacity, 210 mA · h/g, was shown by the electrode from alloy 1 with the minimum amount of the C15 and C14 phases (~70 vol.%), and the maximum discharge capacity, 255 and 265 mA · h/g, was exhibited by the electrodes from alloys 2–3 (81–82 vol.%, respectively). When this phase reached 84 vol.%, the discharge capacity decreased, and the electrode from alloy 5 (95 vol.%) achieved a discharge capacity of only 100 mA · h/g after 40 cycles. This was associated with a decrease in the Zr7Ni10 phase, until it disappeared in alloy 5. The activation of the alloys also depended on the amount of this phase. The electrodes from alloys 1, 2, and 3–4 with ~28, ~17, and ~7–3 vol.% Zr7Ni10 phase activated in 3, ~8, and ~18 cycles, respectively, and those from alloy 5, without the Zr7Ni10 phase, did not activate within the 40 cycles. The best cyclic stability was demonstrated by the electrodes from alloys containing ~3.7–5 wt.% vanadium.

Multicomponent Alloys of the ZrNiMnCr(V) System for Chemical Current Sources I. Influence of Vanadium on the Phase Composition, Structure, and Electrochemical Activity

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发表日期：

2026年7月21日

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Yu. M. Solonin,
O. Z. Galiy,
K. O. Graivoronska,
A. V. Samelyuk

摘要

X-ray diffraction was employed to examine the phase composition and determine the amount of a specific phase (quantitative phase composition) in the ZrNi_1.2Mn_0.5Cr_0.3 (1), ZrNi_1.2Mn_0.5Cr_0.2V_0.1 (2), ZrNi_1.2Mn_0.45Cr_0.2V_0.15 (3), ZrNi_1.2Mn_0.4Cr_0.2V_0.2 (4), and ZrNiMn_0.5Cr_0.2V_0.5 (5) alloys. The dependence of the quantitative phase composition on the chemical composition of the alloys, on the vanadium amount in our case, was established. Alloys 1–4 with a lower vanadium content (~2.5–5 wt.%) consisted of four phases: C15, C14, Zr₇Ni₁₀, and Zr₉Ni₁₁. Alloy 5, with the highest vanadium content (~12 wt.%), consisted of the same phases, except for Zr₇Ni₁₀. With growing vanadium amount in the alloy, the total content of the main phases, C15 and C14, increased (from ~70 to 95 vol.%) and the amount of the Zr₇Ni₁₀ phase decreased (from ~28 to 0 vol.%) until it disappeared in alloy 5. The microstructure of two alloys (1 and 5) was analyzed in detail. According to X-ray diffraction, these alloys were characterized, respectively, by the largest and smallest content of secondary phases (Zr₇Ni₁₀ + Zr₉Ni₁₁). To determine the elemental composition of typical (three) structural sections, integral and point analyses were carried out by energy-dispersive X-ray spectroscopy (EDX), whose results agreed well with X-ray diffraction. The elemental content of the alloys, calculated using local EDX for different points in the structure, was presented as formulas of all phases identified by metallographic analysis. To assess the ratio between the number of Laves phases and secondary phases and their mutual arrangement, contrast structural images were obtained by computer processing of metallographic data for alloys 1 and 5, which allowed the ratio of the specified phases to be analyzed automatically. The contrast images clearly showed that the layers of the dark phase (Laves phase) penetrated the areas (white) of the secondary phases, thus creating a large interfacial surface and facilitating the diffusion of hydrogen into the inner layers. The hydrogen sorption properties of electrodes produced from alloys 1–5 were studied. With a higher total amount of Laves phases with C15 and C14 structures at a temperature of 25°C and a discharge current of 50 mA/g, the maximum discharge capacity did not increase for all alloys. The minimum discharge capacity, 210 mA · h/g, was shown by the electrode from alloy 1 with the minimum amount of the C15 and C14 phases (~70 vol.%), and the maximum discharge capacity, 255 and 265 mA · h/g, was exhibited by the electrodes from alloys 2–3 (81–82 vol.%, respectively). When this phase reached 84 vol.%, the discharge capacity decreased, and the electrode from alloy 5 (95 vol.%) achieved a discharge capacity of only 100 mA · h/g after 40 cycles. This was associated with a decrease in the Zr7Ni10 phase, until it disappeared in alloy 5. The activation of the alloys also depended on the amount of this phase. The electrodes from alloys 1, 2, and 3–4 with ~28, ~17, and ~7–3 vol.% Zr₇Ni₁₀ phase activated in 3, ~8, and ~18 cycles, respectively, and those from alloy 5, without the Zr₇Ni₁₀ phase, did not activate within the 40 cycles. The best cyclic stability was demonstrated by the electrodes from alloys containing ~3.7–5 wt.% vanadium.