Preparation and study of ceramics based on kaolin DD3 with the addition of tri-calcium phosphate

In this work, samples based on local kaolin DD3 were prepared with and without the addition of tricalcium phosphate (TCP) in varying weight percentages (5%, 10%, and 15%). These samples were sintered at different temperatures, ranging from 900°C to 1300°C, for two hours to assess their behavior and properties. The results of the analysis demonstrated that the incorporation of TCP significantly enhanced the sintering process. Specifically, TCP reacted with cristobalite and alumina, forming anorthite, while simultaneously promoting the formation of mullite from the kaolin component. Additionally, TCP contributed to a reduction in porosity, leading to denser samples. This improvement in the sintering process positively influenced the mechanical properties of the samples, particularly microhardness, which showed noticeable enhancement. In samples with a lower percentage of TCP, the thermal expansion was almost linear between room temperature and 1000°C, further indicating the beneficial effects of TCP on the material's performance. These findings highlight the potential of TCP as an additive to optimize the sintering behavior and properties of kaolin-based materials.