On the Specific Heat of α Phase Alloys of Iron and Cobalt

The specific heat of 17 alloys in the range of α solid solution of iron and cobalt system has been measured. It has been found that there are 3 maximum portions on the curve of the maximum temperature of specific heat against concentration, beside the one corresponding to the transformation of FeCo superlattice; the 3 portions extend over the concentration ranges of 20 to 29, 34.6 to 66 and 66 to 78 percent of cobalt, respectively. The maximum portion in the range of 34.6 to 66 percent of cobalt has been already found by S. Kaya and H. Sato and is considered by the present investigators to be due to a lattice transformation of FeCo superlattice. The other maximum portions, in the ranges of 20 to 29 and 66 to 78 percent of cobalt, are considered to be due to the existence of superlattices of Fe3Co and FeCo3, respectively.