Structural and magnetic properties of Sm-2(Fe1-xTix)(17) (x=0-0.1) alloys prepared by hydrogenation processes and their nitrides

Sm-2(Fe1-xTix)(17) alloys (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1) were prepare d by are-melting, subsequently annealing, hydrogenation and nitrogenation p rocesses. The phase components, structures and magnetic properties involved in the processes have been investigated systematically. The Sm-2(Fe1-xTix) (17) alloys have different main phases including Sm-2(Fe,Ti)(17) with Th2Zn 17-type for x = 0-0.04, Sm-3(Fe, Ti)(29) with Nd-3(Fe,Ti)(29)-type for x = 0.06, and Sm(Fe,Ti)(12) with ThMn12-type for x = 0.08-0.1. Curie temperatur e T-c of the main phase of the alloys increases from 125 degrees C for x = 0 to 318 degrees C for x = 0.1. The corresponding hydride phases similar to the main phase structures of the parent alloys were formed after a hydroge n decrepitation (HD) process at 300 degrees C. The hydrogenation at 800 deg rees C mainly shows a hydrogenation-disproportionation-desorption-recombina tion (HDDR) process. The HD and nitrogenation resulted in the Curie tempera ture increments of alloys by 30-150 degrees C and by 140-350 degrees C due to lattice expansions, respectively. The magnetic properties achieved for t he Ti-containing alloys and their nitrides are lower than those of Sm-2 Fe1 7Ndelta prepared by the same processes of HD and HDDR. (C) 2000 Elsevier Sc ience B.V. All rights reserved.