Abstract

The HDDR(hydrogenation-disproportionation-desorption-recombination) process can be used as an effective way of converting no coercivity Nd-Fe-B material, with a coarse Nd_2Fe_14B grain structure to a highly coercive one with a fine grain. Careful control of the HDDR process can lead to an anisotropic Nd_2Fe_14B without any post aligning process. In this study, the effect of hydrogen gas input at various temperature in range of 200sim500°C of hydrogenation stage (named Modified-solid HDDR, MS-HDDR) on the magnetic properties has been investigated. The powder from the modified-solid HDDR process exhibits Br of 11.7 kG and iHc of 10.7 kOe, which are superior to those of the powder prepared using the normal HDDR process.

• Keywords: HDDR;Nd-Fe-B magnets;Magnetic properties;