Abstract
Alloy powders containing rare earth metals are prepared by the gas atomization method and their structure, surface, technological, and electrochemical properties are studied. Powders of the alloys LaNi4.5Al0.5, LaNi2.5Co2.4Al0.1, and (Mm, La)Ni3.5Co0.7Al0.35Mn0.4Zr0.05 are prepared with different particle sizes. The morphology, oxygen content and crystal structure of powders in relation to particle size are studied by x-ray analysis, electron microscopy, and surface dispersion spectroscopy. The hydrogen capacity and electrochemical properties of different fractions are determined. It is established that all of the fractions have similar morphology and alloy lattice parameters. The surface of gas atomized powders with less particle size is less contaminated with oxygen compared with larger fractions. At the same time fractions with a particle size <50 μm have poor activity during gas and electrochemical hydrogenation. DTA curves for fractions of fine particles have an additional exothermic peak that may be caused by thermally induced transformation of the amorphous component into crystalline. The coarse fraction of gas atomized powder has the same hydrogen and electrochemical capacity as for fuzzed alloys.
Published Version
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