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High pressure gas-solid interstitial modification with H and N atoms and HDDR processing of Nd(Fe,M)/sub 12/ (M=Ti,V,Mo)

1999; IEEE Magnetics Society; Volume: 35; Issue: 5 Linguagem: Inglês

10.1109/20.800487

1941-0069

Ph. Oleinek, Oliver Gutfleisch, A. Handstein, K.‐H. Müller, L. Schultz, I.R. Harris,

Rare-earth and actinide compounds

The pressure dependency of hydrogenation and nitrogenation in the range of 1-30 bar and the hydrogenation disproportionation desorption recombination (HDDR) process in NdFe/sub 11/Ti, NdFe/sub 10.75/V/sub 1.25/ and NdFe/sub 10.5/Mo/sub 1.5/ 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 NdFe/sub 10.5/Mo/sub 1.5/, like the other two phases, transforms into /spl alpha/-Fe and an amorphous phase. At a pressure of 1 bar the hydrogen disproportionation reaction occurs at 713/spl deg/C, 670/spl deg/C and 815/spl deg/C for NdFe/sub 11/Ti, NdFe/sub 10.75/V/sub 1.25/ and NdFe/sub 10.5/Mo/sub 1.5/, respectively. The HDDR process was successfully performed for all compounds.