Title :
Metastable borides and the inducement of texture in Pr2Fe14B-type magnets produced by HDDR
Author :
Gutfleisch, O. ; Teresiak, A. ; Gebel, B. ; Müller, K.H. ; Cannesan, N.B. ; Brown, D. ; Harris, I.R.
Author_Institution :
Inst. of Metallic Mater., IFW Dresden, Dresden, Germany
fDate :
7/1/2001 12:00:00 AM
Abstract :
A modified hydrogenation-disproportionation-desorption-recombination (HDDR) process has been applied to Pr2(Fe,Co,Zr)14B-type alloys. XRD and Rietveld analysis show that a Fe3B phase observed in a Pr13.7Fe80.3B6 alloy solid-disproportionated at 875°C is transformed to Fe2B and bcc Fe on further hydrogen annealing and that the formation of Fe 3B is partly suppressed when the alloy is processed at 800°C. No residual 2-14-1-type phases are observed after disproportionation of Pr13.7Fe63.5Co16.7Zr0.1B 6 alloy but here a new intermediate boride phase, Pr(Fe,Co) 12B6 (rhombohedral R¯3m), is found. Pr(Fe,Co) 12B6 transforms to (Fe,Co)2B and α-(Fe,Co) on further hydrogen annealing or conventional disproportionation. For both alloys it is found that processing at higher temperature leads to a better texture on recombination. The role of the Co and Zr additives is not primarily the stabilization of the 2-14-1 matrix phase against hydrogen disproportionation but more importantly the stabilization of intermediate boride phases
Keywords :
X-ray diffraction; annealing; boron alloys; ferromagnetic materials; hydrogenation; iron alloys; magnetic anisotropy; permanent magnets; praseodymium alloys; texture; 800 to 875 C; HDDR processing; Pr2(FeCoZr)14B; Pr2Fe14B; Pr2Fe14B magnet; Rietveld analysis; X-ray diffraction; hydrogen annealing; hydrogenation-disproportionation-desorption-recombination; magnetic anisotropy; metastable boride phase; solid disproportionation; texture; Cobalt alloys; High definition video; Hydrogen; Iron alloys; Magnetic properties; Magnets; Metastasis; Powders; Temperature; Zirconium;
Journal_Title :
Magnetics, IEEE Transactions on
