Influence of calcite on the microstructure and mechanical properties of pottery ceramics obtained from a kaolinite-rich clay from Burkina Faso

Addition of calcite to clay powders for the elaboration of ceramics lies in the fact that upon firing this mineral acts as a fluxing agent and a mineral promoter (formation of new mineral phases). In the case of a kaolinite-rich clay from Burkina Faso, a correlation of the mechanical properties and the microstructure characteristics determined by image analysis is proposed. The main influence of calcite on the material strength is a broader distribution of the flexural strengths. The key parameter relating the fracture toughness and the amount of calcite is the free mean path in the solid phase.