Sintering effects on the development of mechanical properties of fired clay ceramics

This paper addresses the effects of processing techniques on the development of mechanical properties of fired clay ceramics. The influence of thermal treatment, both the rate of heating and firing temperature, were investigated in order to optimize the fabrication process and to obtain the enhanced mechanical properties. Single clay raw material was used for this study. Samples were hand pressed in a rectangular mould and sintered to temperature ranging from 900 to 1200 °C at various heating rates. The variation of flexural strength and elastic modulus starting from 200 to 1200 °C was also presented with heating rate 10 °C/min. In addition, the density, apparent porosity and shrinkage of the fired samples have been determined. Analysis of the firing transformation and microstructure was carried by X-ray diffraction and SEM. Mechanical properties characterization was performed by means of three-point bending tests as well as microindentation tests. In this study, the results revealed that fast heating rate in the early stage of firing has profound influence on densification and the resulting mechanical properties.