Iron—Cobalt Fe—Co

Abstract

The system is characterized by an extensive solid solution range between fcc γ(Fe) and fcc γ(Co) and a wide α-Fe solid solution region which transforms via a second order reaction into the ordered CsCl type phase FeCo. Two additional ordered phases near 28 and 74 at.% Co, found by electrical resistivity measurements only (Viting [1]), could not be detected by any other method. (He may have measured the second order A2/B2 transition which appears possible considering the phase diagram in Fig. 13). Since the publication of the Fe-Co system by Hansen [A], the more recent investigations concentrated mainly on the clarification of second order reaction (A2/B2 and magnetic transformations) as well as the low temperatures Co-rich region.