A new experimental approach for accelerated investigations of carbothermal reactions

The carbothermal process has been investigated with an experimental approach based on a modern commercial carrier gas hot extraction analyser which allows kinetic studies of reduction reactions as a function of temperature and time with in situ CO(2) analysis. The influences of various parameters such as different solid starting materials - mainly fine grained TiO2 and ZrO2 powders and types of carbon (active carbon, carbon black, graphite) - in stoichiometric mixtures, or different gas flow conditions can be studied by this method, The concept includes a combination of dynamic measurements over a temperature range of 1000-2000 degrees C and isothermal experiments at temperatures selected from certain temperature ranges. Solid reaction products were characterised ex situ by chemical and phase analysis. The interpretation of the qualitative and quantitative results is in agreement with lab-scale and thermoanalytical investigations. The method should be applicable for further experiments to find faster and more information about new syntheses of hard materials based on carbothermal reduction. (C) 1999 Elsevier Science Ltd. All rights reserved.