Effects of some processing factors on technical properties of a clay-based ceramic material

The effects of firing temperature, flux content and soaking time on shrinkage, bending strength, water absorption and density of a clay-based ceramic material were evaluated using response surface methodology (RSM) and were investigated by X-ray diffraction and scanning electron microscopy. The results of the regression models showed that the weights of the factors increased in the following order: temperature > flux content > soaking time. The interactions between the factors were relatively less important, and they had different (antagonistic/synergetic) influences on the properties. An increase of these factors resulted in the formation of mullite and melt and had positive effects on the properties. However, their vigorous increase had adverse effects, most likely because of the melt abundance and/or coalescence of pores. The RSM results showed that white floor and wall tiles could be manufactured by the use of a body consisting of 38 wt.% feldspar and selected firing temperatures and soaking times. The ceramic suitability of the body was discussed in relation to some ceramic diagrams.