Effect of firing atmosphere on precipitation of micro crystallite of iron oxide at surface of fired clay bodies

Abstract

Clay bodies containing 2 mass% Fe2O3 were fired at 1250°C in air, CO2 and CO2-H2. The relationship between color and chemical states of iron in fired bodies was studied by ESR, reflectance spectra and XPS. Color of the sample fired in air was dark yellow. Brown surface of fired body was obtained by heating in reducing atmosphere followed by cooling in oxidizing one.