Carbon has a strong influence on oxide stability. It assists the sintering process by the reduction of oxides on the surface of the powder. Carbon as a small interstitial atom has also a high mobility and can easily diffuse in the material already at relatively low temperature. Due to its high mobility and its influence on oxide reduction it is of interest to predict how carbon is distributed in the sintered body. The carbon distribution in the microstructure will also determine the mechanical properties of the sintered product. Sintering trials have been made for water atomised powder pre-Alloyed with 3wt% chromium and 0.5wt% Mo. These experimental simulations have been made in different N2/H2 atmospheres. The surface reactions during sintering are monitored using photoacoustic spectroscopy, measuring the outgoing gases from the furnace. Computational methods using Thermo-Calc are used to verify the gas reactions taking place in the furnace. By applying kinetic simulations with the Dictra software the carbon diffusion can be modelled for the sintering trials. The computational methods describe the experimentally observed reactions, and contribute to a better understanding of the reduction process.