Phase transformation and magnetic properties of Nd8Fe84Ti8 alloy during HDDR process

The effects of the hydrogenation-disproportionation-desorption-recombinatio n (HDDR) process on the structure and the magnetic properties of the Nd8Fe8 4Ti8 alloy prepared by mechanical alloying (MA) and its nitride counterpart have been studied in detail. It has been found that Nd(Fe,Ti)(12)H-x is fo rmed from. 300 degrees C to 550 degrees C. The disproportionation starts at 550 degrees C and is completed at 960 degrees C. The desorption and the re combination are almost synchronized. Nd(Fe,Ti)(7) is formed at 750 degrees C during the HDDR treatment. With increasing temperature of HDDR process, t he metastable structure of TbCu7 type is gradually transformed into the str ucture of ThMn12 type. The intrinsic coercivity increases with increasing t he temperature of HDDR process. (C) 1999 Elsevier Science S.A. All rights r eserved.