Title :
High pressure gas-solid interstitial modification with H and N atoms and HDDR processing of Nd(Fe,M)12 (M=Ti,V,Mo)
Author :
Oleinek, Ph ; Gutfleisch, O. ; Handstein, A. ; Müller, K.H. ; Schultz, L. ; Harris, I.R.
Author_Institution :
Inst. fur Metallische Werkstoffe, IFW Dresden, Germany
fDate :
9/1/1999 12:00:00 AM
Abstract :
The pressure dependency of hydrogenation and nitrogenation in the range of 1-30 bar and the hydrogenation disproportionation desorption recombination (HDDR) process in NdFe11Ti, NdFe10.75V1.25 and NdFe10.5Mo1.5 were studied by differential scanning calorimetry, differential thermal analysis, temperature-pressure analysis, X-ray diffraction, and high resolution scanning electron microscopy. With increasing gas pressure from 1 bar to 30 bar the temperatures of interstitial absorption and decomposition reactions decrease by typically 30 K. During the decomposition reaction with nitrogen the phase NdFe10.5 Mo1.5, like the other two phases, transforms into α-Fe and an amorphous phase. At a pressure of 1 bar the hydrogen disproportionation reaction occurs at 713°C, 670°C and 815°C for NdFe11Ti, NdFe10.75V1.25 and NdFe 10.5Mo1.5, respectively. The HDDR process was successfully performed for all compounds
Keywords :
X-ray diffraction; amorphisation; desorption; differential scanning calorimetry; differential thermal analysis; dissociation; ferromagnetic materials; high-pressure effects; hydrogenation; interstitials; iron alloys; molybdenum alloys; neodymium alloys; permanent magnets; scanning electron microscopy; sorption; titanium alloys; vanadium alloys; α-Fe; HDDR processing; Nd(Fe,Mo)12; Nd(Fe,Ti)12; Nd(Fe,V)12; NdFe10.5Mo1.5; NdFe10.75V1.25; NdFe11Ti; ThMn12-type structure; X-ray diffraction; amorphization; amorphous phase; differential scanning calorimetry; differential thermal analysis; gas pressure; high pressure gas-solid interstitial modification; high resolution scanning electron microscopy; hydrogenation; hydrogenation disproportionation desorption recombination process; nitrogenation; pressure dependency; temperature-pressure analysis; Atmosphere; Electromagnetic wave absorption; Hydrogen; Magnetic properties; Nitrogen; Powders; Scanning electron microscopy; Temperature; X-ray diffraction; X-ray scattering;
Journal_Title :
Magnetics, IEEE Transactions on
