Magnetocaloric particles of the Laves phase compound HoAl2 prepared by electrode induction melting gas atomization

TL;DR

This paper reports a new method to produce high-quality magnetocaloric particles of HoAl2 with desirable properties for magnetic refrigeration, using electrode induction melting gas atomization, suitable for practical applications.

Contribution

A novel electrode induction melting gas atomization process for producing magnetocaloric particles of HoAl2 with improved morphology and magnetic properties.

Findings

Particles are submillimeter and spherical with few pores.

Magnetocaloric effect comparable to bulk HoAl2.

Method applicable to other high-melting-point magnetocaloric materials.

Abstract

Processing magnetocaloric materials into magnetic refrigerant particles is an essential issue in developing high-performance magnetic refrigerators. Here, we succeed in stably producing magnetocaloric particles of the promising material HoAl2 by a newly devised method based on electrode induction melting gas atomization process. The particle size range is on the order of submillimeter, which is suitable for practical refrigeration systems. The resulting particles with less contamination have good morphological, magnetic, and magnetocaloric properties: (i) almost spherical shapes with few internal pores, (ii) a sharp ferromagnetic transition around 30 K, and (iii) a large magnetocaloric effect comparable to the bulk counterpart. These features suggest the HoAl$_{2}$ gas-atomized particles have the potential of use as a magnetic refrigerant. The presented method can be applied not only to HoAl2 but also to other brittle magnetocaloric materials with high melting points, facilitating the production of various magnetic refrigerants needed to develop magnetic refrigerators for hydrogen liquefaction.