Effect of hydrogen pressure on growth kinetics of Nd2Fe14B phase during hydrogen-induced reverse phase transformation in Nd2Fe14B type hard magnetic alloy

The effect of initial hydrogen pressure on the growth kinetics of Nd2Fe14B phase during hydrogen-induced reverse phase transformation in the industrial Nd2Fe14B hard magnetic alloy has been studied. It has been determined that, as the temperature and initial hydrogen pressure increase, the reverse phase transformation is significantly accelerated. It has been shown that the kinetics of growth of Nd2Fe14B phase is controlled by the diffusion of Fe atoms and that the growth rate of new Nd2Fe14B phase increases with an increase of the initial hydrogen pressure. On the base of the KolmogorovHillert-Smirnov kinetic models the kinetic equation for describing the influence of initial hydrogen pressure on the isothermal kinetic diagram for this transformation has been proposed.