PORCELAIN GLAZE (VARIANTS) Russian patent published in 2003 - IPC

FIELD: porcelain industry. SUBSTANCE: invention relates to preparing decorative coating in making porcelain articles. Glaze comprises the following components, wt.-%: Variant 1: SiO₂, 67.1-71.86; Al₂O₃, 11.2-16.68; CaO, 6.71-7.57; MgO, 3.58-4.0; K₂O, 3.74-4.1; Na₂O, 1.1-1.26; TiO₂, 0.16-0.18; Fe₂O₃, 0.27-0.31; SO₃, 0.12-0.14; Variant 2: SiO₂, 67.07-73.45; Al₂O₃, 11.28-17.3; CaO, 7.02-8.0; MgO, 3.03-4.55; K₂O, 2.42-2.78; Na₂O, 1.07-1.23; TiO₂, 0.15-0.17; Fe₂O₃, 0.22-0.26; Variant 3: SiO₂, 68.14-69.56; Al₂O₃, 14-16; CaO, 7.05-7.95; MgO, 3.6-4.0; K₂O, 2.42-2.72; Na₂O, 1.7-1.9; TiO₂, 0.14-0.16; Fe₂O₃, 0.31-0.35; Variant 4: SiO₂, 65.4-73.0; Al₂O₃, 11.2-18.0; CaO, 7.0-7.8; MgO, 3.0-4.8; K₂O, 2.5-3.5; Na₂O, 1.0-1.8; TiO₂, 0.1-0.3; Fe₂O₃, 0.2-0.4; Variant 5: SiO₂, 58.6-65.6; Al₂O₃, 10.3-14.0; CaO, 13.0-15.0; MgO, 5.0-9.6; K₂O, 2.3-2.7; Na₂O, 1.0-2.0; TiO₂, 0.1-0.2; Fe₂O₃, 0.2-0.4 Melting range is 1100-1320 C, coefficient of heat expansion (CHE) is (4.77-5.13) x 10^-6 1/C, microhardness is (7.15-7.62) x 10³ MPa, heat resistance is above 13 heat changes. Glazes exhibit clear and good luster, uniform spread and they are melted with crock good. Invention provides enhancement of thermal and chemical resistance, elevated values of CHE and microhardness. EFFECT: improved quality and properties of glazes. 5 cl, 7 tbl