Engobe (also called slip coating) is a thin ceramic layer applied between the tile body and the glaze to improve whiteness, smooth the surface, control moisture absorption from the glaze, and improve glaze adhesion.
Application Overview
For digital printing tile production, the engobe is critical — it provides the white, smooth substrate that enables high-resolution digital ink printing with accurate color reproduction. Nepheline syenite in engobe formulations provides: controlled fluxing (the engobe must mature enough to bond to the body and accept the glaze, but not vitrify completely — partial vitrification at the body-engobe interface provides adhesion while maintaining some porosity at the engobe-glaze interface for glaze anchoring); whiteness (K200 with Fe2O3 0.08% ensures the bright white engobe surface needed for accurate digital printing); and alumina (improving the mechanical integrity of the thin engobe layer). Typical engobe: 20-25% kaolin, 15-20% nepheline K200, 10-15% frit, 10-15% zirconium silicate, 15-20% quartz, 5-10% ball clay, plus deflocculant..
Technical Details & Formulation
