Effects of additive elements on the behavior of hydrogen in Pr-Fe-B magnetic alloys

Abstract

In this study, the hydrogen absorption and desorption behavior of Pr-Fe-B magnetic alloys with different additive elements, such as Ti, Zr, Hf, V, Nb, Al, Ga, Cu, Ge, and Co, was investigated focusing on the disproportionation and the recombination reactions in the hydrogenation, disproportionation, desorption, and recombination (HDDR) process. Furthermore, a Pr-Fe-B anisotropic magnetic powder was fabricated by employing the HDDR process. Except Ga and Co, no other elements caused the recombination reaction in Pr-Fe-B alloys under a hydrogen atmosphere. The addition of Co and Ga enhanced the recombination by reducing the recombination reaction temperature below 1000 degrees C. On the contrary, Zr and Rf addition may not cause the recombination reaction in Pr-Fe-B alloys but do change the disproportionation reaction rate. A Pr-Fe-B-M (M=Co, Ga, Zr) magnetic powder, which had a remanence of 10.3 kG and a coercivity of 7.9 kOe, was obtained by using the HDDR process.