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

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 NdFe10.5Mo1.5, like the other two phases, transforms into alpha-Fe;and an amorphous phase. At a pressure of 1 bar the hydrogen disproportionation reaction occurs at 713 degrees C, 670 degrees C and 815 degrees C for NdFe11Ti, NdFe10.75V1.25 and NdFe10.5Mo1.5, respectively, The HDDR process was successfully performed for all compounds.