Magnetic properties of electrolytic alloys of refractory metals at cryogenic and near-Curie temperatures

DOI: 10.62564/M4-YY1416

Yuliya Yapontseva¹, Oksana Gorobets², Tetyana Maltseva¹, Valeriy Kublanovsky<sup>1

1</sup>V. I. Vernadsky Institute of General and Inorganic Chemistry of the NAS of Ukraine
²National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


Alloys of refractory metals (W, Mo and Re) with iron group metals have valuable properties, such as heat and corrosion resistance, hardness and magnetic properties, which ensures their use in the aerospace, nuclear and electrical industries. Only by electrodeposition from aqueous solutions is it possible to obtain thin alloys coatings with the ability to accurately control the chemical composition, structure and thickness of the resulting deposits [1]. This paper presents a study of the influence of the nature of the refractory metal (W, Mo, Re) on the magnetic properties of electrolytic alloys with cobalt at cryogenic temperatures and temperatures close to the Curie point. The CoW, CoMo and CoRe alloys were deposited from citrate-pyrophosphate electrolytes and contained 80 at.% cobalt. The magnetic characteristics of the alloys were studied using a “Vibrating Magnetometer 7404 VSM” Lake Shore Cryotronics Inc., USA in magnetic fields of up to 5 kOe. At room temperature, saturation magnetization differs significantly for alloys of different refractory metals [2]. Ms for the CoW alloy increases more than threefold upon cooling, and for the CoMo and CoRe alloys the increase is less than 20%. With increasing temperature, the saturation magnetization should constantly and monotonically decrease, which is what take place with the CoRe alloy, for which Ms decreases to almost zero. For CoMo and CoW alloys, magnetization does not reach zero and begins to increase at a temperature of ~600K. It is known that cobalt exists in two allotropic modifications with transition temperature is 700K. Both cobalt modifications have different magnetic properties and can be present simultaneously in electrochemical coatings. Possible reasons for changes in the magnetic properties of alloys are: phase transition; enlargement of crystallites when heated; formation of an electrolytic alloy, including the formation of phases of solid solutions and intermetallic compounds.

Keywords
Electrolytic alloy, magnetic properties, refractory metals, cobalt, low and high temperature

Acknowledgments
Not provided

References
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