The press office of the Russian Ministry of Education and Science reported that scientists at the National University of Science and Technology have created an alloy that represents a step towards producing permanent magnets without the use of rare earth metals.
The statement from the office reads: "Russian scientists propose an alloy for the efficient and economical production of powerful magnets necessary for power systems, electrical engineering and transportation, with an improved composition and advanced processing method, without the use of rare earth elements."
Researchers propose a promising alternative to rare-earth metal magnets: a manganese-aluminum alloy. Its magnetic properties are attributed to a structural phase formed during heat treatment. However, this phase is unstable and degrades easily with changes in temperature or manufacturing conditions. The alloy's behavior is altered by adding a small amount of vanadium and employing various cooling methods, ranging from conventional rapid cooling to ultra-rapid cooling of the molten metal on a rotating copper disc.
“The composition and cooling pattern allow for precise control of the material’s structure,” says Mikhail Gorshenkov, associate professor in the Department of Physical Materials Science at the university. “We found that adding vanadium makes the magnetic phase less stable, as it forms within a narrower compositional range and fades at a lower temperature. However, ultrafast cooling helps to obtain this phase without the need for additional heat treatment.”
He notes that the best results were achieved with a manganese-aluminum-vanadium alloy, where the magnetic phase exceeded 90 percent in the cast sample after rapid cooling and annealing. A high proportion of this phase also formed in thin metal sheets obtained using ultra-rapid cooling, without the need for additional heat treatment. This could simplify the production of the required fine-grained ferromagnetic phase.
The study is published in the Journal of Magnetism and Magnetic Materials
