Ferrite Synthesis Simulation via Carbon Combustion using Slip, Temperature, and Concentration Gas Species Jump at Pore Surface
The Carbon Combustion of Solid Oxides (CCSO) is a promising method to fabricate nanosized complex oxides. Although successfully utilized for many systems, there is lack of complete theoretical model to predict the combustion parameters for CCSO systems. For a typical CCSO synthesis for cylindrical samples we measured the ignition temperature, estimated the combustion wave axial temperature distribution, activation energy, combustion heat and thermal losses experimentally. We developed a two level model of chemically active nanodispersed mixture combustion using the experimentally measured ignition temperature and combustion parameter values, using the slip-jump method for high Knudsen numbers. The theoretical calculations for highly porous samples, when the flow resistivity is small and the gas can easily flow through the cylindrical sample, are in good agreement with the experiment (differences less than 15%). Using the developed theoretical model, we predict the combustion characteristics for the lower porosity values, where the surface combustion takes place due to high flow resistivity of the sample. We observed finger combustion features at this regime. Look at the picture below as an example.