TbCu7-type Sm-X-Fe compounds (X = Zr, Hf, Y, Dy, La, Ce and Nd) synthesized by low-temperature reduction-diffusion (LTRD) process using molten salt

Abstract

TbCu7-type Sm-Fe-N anisotropic powder with a high Fe content has the potential to surpass the Nd-Fe-B magnet. In this study, elemental substitution of Sm in a Sm-Fe system was investigated for the purpose of synthesizing Fe-rich TbCu7-type Sm-Fe compounds using a low-temperature reduction-diffusion (LTRD) process, which is a synthesis method capable of producing TbCu7-type Sm-Fe-N anisotropic powder. Sm-X-Fe powders have been synthesized by mixing ɑ-Fe, SmCl3, one chloride of additives (X = Zr, Hf, Y, Dy, La, Ce and Nd), Ca, and LiCl, and performing the reduction-diffusion reaction at 600 °C. The results of an EDX analysis and the variation of a-axis lengths of the TbCu7-type Sm-X-Fe phase suggested that all additional elements could be substituted for Sm. Although the synthesis of Fe-rich TbCu7-type phase was not achieved in this study, substitution of Zr and Hf showed a potential to increase Fe content.