PREPARATION AND STUDY OF RED-COLORED COPPER-CONTAINING CERAMIC GLAZE FIRED IN AN OXIDIZING ENVIRONMENT

Abstract

Red copper glazes, also known as Chinese red glazes, owe their coloration to the dispersion of colloid copper particles in the glaze and firing in a highly reducing atmosphere. The addition of some substances can be used for the reduction of copper oxide to metal nanoparticles and the glazed ceramics can be fired in an oxidation atmosphere. The colloidal copper red colouring of ceramic glazes was applied in this study. It was investigated the influence of copper oxide type (CuO or Cu₂O) added as colouring agent to a ceramic glaze and the firing temperature of the glazed for obtaining red colouring of the glaze. The samples were fired in an oxidizing atmosphere and SiC and SnO₂ were added as  reductants. A structural and phase characterization of the obtained samples was done by using the XRD, DTA, FT-IR and SEM analyses. The reduction with silicon carbide when fired in an oxidizing atmosphere is more complete and the red glaze coloration is more intensive when copper is introduced as Cu₂O rather than CuO into the glaze. The best red coloration has been obtained for the composition containing 0.5 mass % Cu₂ O + 1 mass % SiC added to the glaze and fired at 1200oC.