INVESTIGATION OF THE PROCESS OF HYDROGEN DISPERSION OF (Nd,Pr,Dy)(Fe,Co)2.6 ALLOY IN THE SET TEMPERATURE AND PRESSURE RANGE

10.25712/ASTU.1811-1416.2022.02.012

Abstract

The paper presents studies of hydrogen dispersion of the alloy (Nd,Pr,Dy)(Fe,Co)_2.6 in a wide range of temperatures and pressures. The substantiation of the chemical composition of the investigated alloy (Nd,Pr,Dy)(Fe,Co)_2.6, the choice of the method of production of the initial alloy based on out-of-furnace calcium-thermal reduction is given. The introduction of dysprosium into the composition of the alloy contributes to an increase in the coercive force. Additional doping with cobalt is associated with the need to increase the Curie temperature for this class of magnetic materials. The studies were carried out on two groups of alloys. The first group of alloys is the initial one. The second was loaded into a steel reactor and subjected to isothermal annealing (heat treatment) in vacuum at 833 К for an hour, followed by the supply of argon and quenching of the samples by immersing the reactor with them in water. Using the method of scanning electron microscopy, it was found that heat treatment led to the formation of microcracks and an increase in relief on the surface of the samples. The initial and heat-treated samples were subjected to hydrogenation at different temperatures and pressures, which contributed to their transfer to a powdered state. High-purity hydrogen was used for hydrogenation, obtained by its desorption from the LaNi₅ alloy. The hydrogenation process was carried out in the temperature range from 298 to 473 °C, and pressures from 100 to 200 kPa. It was established that the degree of hydrogenation had the highest values of the main indicator of the process at low pressures and temperatures. It was also found that for an alloy that has undergone heat treatment, the induction period is 432 seconds, in contrast to the alloy that has not been heat treated, the induction period for which was 3200 seconds.