A Calorimetric Study of Iron–Cobalt Alloys

Abstract

AbstractAn adiabatic calorimeter has been used to measure heat capacities and heats of transformation for iron–eobalt alloys over the temperature range 700–1500 K. Estimates of the entropy associated with magnetic and configurational disorder suggest that ∼75% of the magnetic order is lost by the Curie temperature and that although the Bragg–Williams theory correctly predicts the entropy of disordering FeCo, it overestimates the entropy of disordering alloys away from the ideal ordering compositions. Phase-diagram information for the α→γ transformation, the ordering reaction, and the Curie temperature are given.