Silica

In ceramic glazes, silica is the primary glass-forming oxide (SiO₂). It determines glaze viscosity, surface tension, thermal expansion, hardness, gloss, and chemical durability. Higher SiO₂ content generally improves glaze hardness and chemical resistance but raises the maturing temperature.

Free silica undergoes phase transformations (α-β quartz inversion at 573°C) during firing and cooling, influencing the thermal expansion behaviour of the ceramic body. Careful control of silica particle size and content is essential to match the thermal expansion of body and glaze, preventing crazing.

Particle size depends on the application. For ceramic bodies, 300 mesh (45 microns) silica is commonly used to balance reactivity and shrinkage control. For glazes, finer silica is preferred for uniform glass formation and smooth surface. Our MICRON SILICA 300 MESH and QUARTZ grades cover these requirements.

Yes. Excess free silica can cause quartz inversion cracking during rapid cooling, and may mismatch the thermal expansion with the glaze layer, causing crazing or shivering. Balanced silica content formulated with the appropriate flux system ensures optimal fired strength and glaze integrity.

Yes. Silica is used in both wall and floor tile bodies, though the specification may differ. Floor tiles require higher mechanical strength, so silica loading and particle size may be optimised for densification. Wall tiles use silica primarily for shrinkage control and warpage reduction during firing.