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magnetic materials

hydrogenation and nitration at elevated temperatures

The aim of these investigations is a better understanding of the way in which materials based on NdFeB and SmFe react with hydrogen and nitrogen at elevated temperatures. Hydrogen is the basis of both the hydrogen-decrepitation (HD) and hydrogenation-disproportionation-desorption-recombination (HDDR) processes, however, the reactions between the NdFeB-based materials and hydrogen are far from being thoroughly understood. The HDDR process is also used with SmFe-based materials, where it is able to reduce the grain size and homogenise the material and make it suitable for subsequent nitriding.

Our studies have concentrated on the effects of substitutions such as Zr, Dy, and Pr (for NdFeB materials) and Ta (for SmFe materials) on the HDDR reaction. We have made use of the fact that disproportionation produces iron as a reaction product to develop a magnetic monitoring system based on a vibrating-sample magnetometer (VSM). The system can operate in the temperature range from 12 K to 1300 K, and in any atmosphere from a 10
-2 mbar vacuum to 1.2 bar overpressure.

comments & suggestions to:  sanja fidler