Feasibility study for the development of FeNbC 114: effect of composition/carbon content

Nowadays cermets and cemented carbides use Ni and Co as the main constituent of the metallic matrix. Nevertheless, these elements are scarce and are considered harzardous for health, hence the current trend is to replace them totally or partially with iron. There are some studies and even commercial materials using TiC and Ti(C,N) particles bonded by a ferrous matrix, but studies using NbC are less common due to its higher price. The interest on cermets reinforced with NbC comes from the characteristics of NbC and the known beneficial effects of NbC on cemented carbides. In this study, the raw material is a composite powder obtained by treatment extraction of the ore with Al and C. Every particle of the powder contains NbC precipitates bonded by Fe, as well as other intermediate phases, whose composition is influenced by the elements present in the raw material, such as Al or Ti. Al content is particularly important and novel in this type of materials and its influence on processing and properties will be studied. A thermodynamic simulation by ThermoCalc was made to predict the phases present on the microstructure and to adjust the composition. Samples were produced by conventional powder metallurgy and by Field Assisted Hot Pressing (FAHP) to study the microstructure and properties of sintered materials. The raw material and the samples obtained were characterized using thermal analysis, particle size, density, hardness, XRD and SEM.