Diffusion of copper ions into kaolinite layers

Kaolinite transforms to mullite at 1200 °C temperature. The additive copper oxide decreases this temperature by approximately 200 °C. The aim of present paper is to analyze how copper oxide, as additive, influences the high-temperature processes of kaoline. In this article we present the investigations for diffusion of copper ions into the kaolinite matrix. At the work pressed tablets of kaolinite were weighted into powders of crystal copper oxide during heating at 900, 950 and 1000 °C temperatures for 6.5 and 13 h, respectively. Influence of temperature and exposition time at the maximum temperature on the thickness of diffusive layer, formed structures, and dependence of these formed structures from the depth of penetration of copper ions into the kaolinite matrix has been reported using a combination of optical microscopy, SEM, X-ray diffraction and microanalysis.