The effects of carbon substitution on the behavior of hydrogen in Nd–Fe–B-type magnetic alloys

Abstract In the present study, the hydrogen absorption and desorption behavior of Nd–Fe–B-type alloys with the substitution of carbon for boron was investigated focusing on the disproportionation and recombination reaction of the hydrogenation, disproportionation, desorption and recombination (HDDR) process. Furthermore, the HDDR treatment of carbon-substituted Nd–Fe–B alloy was carried out. It was found that the most distinct effect of carbon substitution for boron in Nd–Fe–B-type alloy is the lowering of the starting temperature of disproportionation reaction in the HDDR process. The HDDR-treated Nd 12.6 Fe bal. Co 11.6 Ga 1.0 Zr 0.1 B 4.0 C 2.0 powder shows better magnetic properties than the Nd 12.6 Fe bal. Co 11.6 Ga 1.0 Zr 0.1 B 6.0 powder at short disproportionation reaction time. This may be due to the rapid disproportionation of Nd 2 Fe 14 (B,C) phase at the disproportionation reaction temperature.