Absorption of hydrogen by amorphous and crystalline 89Fe-11P powder: Deformation of the powder under pressure and relaxation on heating

Abstract

The process of hydrogen absorption by amorphous and crystalline powder of the 89Fe-11P alloy, obtained by electrolyzing an aqueous solution of the corresponding electrolytes, was studied by differential scanning calorimetry. It was shown that hydrogen absorption takes place exothermally in the temperature range 100-300 °C. The relevant kinetic and thermal parameters of the absorption process were determined: rate constants, enthalpies, activation energies and frequency factors. The process of powder deformation by pressing and its relaxation was investigated by measuring the electrical resistance during heating and cooling in the temperature range 20-610 °C. The X-ray diffractograms show that the powder obtained contains 10% crystal phase and that by heating to 500 °C complete crystallization takes place.