The solubility of carbon in high purity α iron measured by electrical resistivity at 4.2 K

The solubility of carbon in iron was studied using high purity (RRR approximate to 3000) alpha iron samples carbon-doped by levitation melting. Various methods of analysis were used and the results were compared to the target values. After quenching from 1000 K the obtained results show that the variation of residual resistivity at 4.2 K as a function of the carbon concentration in solid solution is nor monotonous. For carbon addition up to 50 mass ppm, the resistivity increment is 46.6 n Omega m/mol%, and for higher carbon addition the resistivity increment 31.4 n Omega m/mol%. The obtained results show that, for pure iron. carbon contents are low, at about one tenth of a ppm. The variations of carbon solubility in alpha iron, as determined in this study, are close to those obtained by diffusion methods, but lower than those derermined by internal friction.