Influence of lithium oxide as auxiliary flux on the properties of triaxial porcelain bodies

The influence of Li2O-content on the properties of standard triaxial porcelains was investigated. Two series of porcelain formulations were produced. The first one comprised seven model formulations with increasing amount of Li2CO3 (1–7 wt.%), with respect to the standard triaxial porcelain formulation. The experimental results showed that desirable properties for tableware porcelains can be attained if the Li2O-content does not exceed ∼1.5 wt.%. In the light of this conclusion, the second series of formulations aimed at producing new porcelains using Li-bearing natural rocks. Under an industrial perspective, the most important finding is that these compositions matured at temperatures 100–120 °C lower than the standard triaxial porcelain formulation and exhibited remarkable resistance at over-firing conditions. The role of increasing Li2O-content at the different stages of firing is interpreted in the light of its influence on densification, the evolution of crystalline phases and microstructure.