The diffusion of chromium in iron and low carbon steels

An experimental study of the diffusion of chromium into iron and iron-carbon alloys containing up to 0.75% carbon has been carried out over a temperature range 950–1265°C. In this region two different crystal phases can exist depending on the chromium composition of the alloy. A model is outlined to account for the diffusion mechanism accompanied by a phase change. The results have revealed a dual mechanism; at low carbon concentrations a lattice vacancy mechanism can account for the diffusion of chromium but for carbon concentrations above 0.16% the effect of interstitial carbon atoms becomes predominant.