EXAFS determination of Hf localization in HDDR-Nd-Fe-B-Hf alloys

C.E. RODRÍGUEZ TORRES, M. B. FERNÁNDEZ VAN RAAP, F. H SÁNCHEZ. AND A. F. PASQUEVICH

PHYSICA B - CONDENSED MATTER

Elsevier

Año: 2005 vol. 362 p. 145 - 152

0921-4526

The local structure around Hf in Nd15.78Fe76.3xHfxB7.8 (x ¼ 0:1 and 0.2) submitted to conventional and solid hydrogenation?disproportionation?desorption?recombination (HDDR) sequence was studied by extended X-ray absorption fine structure (EXAFS) in order to understand the relation between the presence of Hf and magnetic anisotropy found only in solid-HDDR samples. EXAFS results show that Hf is not in the Nd2Fe14B structure but incorporated into a local atomic arrangement (HfB ClNa-type) which is the same for as-cast, solid and conventional HDDR samples. It is concluded that the magnetic anisotropy induced by Hf addition to NdFeB alloys must be related to microstructural features.15.78Fe76.3xHfxB7.8 (x ¼ 0:1 and 0.2) submitted to conventional and solid hydrogenation?disproportionation?desorption?recombination (HDDR) sequence was studied by extended X-ray absorption fine structure (EXAFS) in order to understand the relation between the presence of Hf and magnetic anisotropy found only in solid-HDDR samples. EXAFS results show that Hf is not in the Nd2Fe14B structure but incorporated into a local atomic arrangement (HfB ClNa-type) which is the same for as-cast, solid and conventional HDDR samples. It is concluded that the magnetic anisotropy induced by Hf addition to NdFeB alloys must be related to microstructural features.