A kinetic study on carburization of Fe by using ¹³CO isotope gas

The current investigations were undertaken to clarify the kinetics of dissociation of CO gas into the molten iron and the effects of impurities in Fe. The interfacial reaction rate of CO on liquid iron at 1 823 K was measured by means of ¹³CO isotope exchange technique. Isotope exchange technique has been widely employed to evaluate the interfacial chemical reaction quantitatively. The experiments were carried out for the compositions of (0.002-3.31 mass% of carbon, (0.002-0.11 mass% of oxygen, (0.0026-0.1 mass%) of sulfur and (0.0002-0.08 mass% of nitrogen employing quadruple mass spectrometry for product gas analysis. In the carburization of molten iron containing oxygen, sulfur, carbon and nitrogen by CO, the interfacial reaction at gas-metal surface can be converted from adsorption limited control to dissociation limited reaction as the impurity concentrations of oxygen and sulfur increase. In particular, it was found that sulfur has greater influence on the conversion of rate limiting step of carburization reaction of molten iron.