Physical properties and microstructure of traditional kaolin-based ceramics with additive fly–ash (FA)

Abstract

In this research, the kaolin–based ceramic with 10-50 wt.% FA additive was fabricated by solid-state reaction. All powders were weighed, mixed and further milled by ball-milling for 4 h. All compositions of powders were uniaxial pressed in pellets and sintered at 1100 °C for 4 h. The XRD pattern of kaolin with FA additive showed that the kaolin phase was decreased with increasing FA and the single peak and the right shift resulted from the mix phase between quart phase and mullite phase of 40 to 50 wt.% FA. The SEM image of 10 to 30 wt.% FA addition illustrated melting grain and high roughness surface area. However, at the concentration of 40 to 50 wt.% FA addition provided the flat surface area and increased a porosity of the ceramics. The optimization of physical properties of ceramics included density, average linear shrinkage and hardness are 2.63 g/cm3, 24.62% and 135.32 kgf, respectively. The physical properties and microstructure of kaolin-based ceramics with FA additive are as the results of a structure properties relation.