Study of Hydrogen Interactions with Nd2Fe17 and Nd2Fe14B by Means of Calorimetric Method

Abstract

Hydrogen interactions with Nd2Fe17 and Nd2Fe14B was investigated by means of the calorimetric method with application of differential heat-conducting calorimeters that were of the Tean-Calvet type. The reaction of hydrogen absorption and desorption was carried out at 250 and 300 °C for Nd2Fe17, while the pressure-composition-isotherms (P-C-T) and enthalpy change with hydrogen concentration in the intermetallic compound (IMC) were obtained. The Nd2Fe14B-H2 system was studied at 50 °C and the dependence of the enthalpy change with hydrogen concentration in the intermetallic compound was also obtained. Based on the measured data, the assumption about the order of filling the interstitial sites by hydrogen atoms was made.

Keywords

• Nd2Fe17-H2
• Nd2Fe14B-H2
• calorimetry
• thermodynamics
• enthalpy