LOW V2O5 - CONTENT AND V2O5 - FREE PORCELAIN ENAMELS

摘要

The present invention relates to a low-V2O5- content and even V2O5-free porcelain enamel with improved dish-washer resistance, very good acid resistance and good adherence on various substrates. The invention moreover relates to a transparent low-V2O5- content and even V2O5-free porcelain enamel frit for application of enamel coatings with infinite colour range on a substrate made of aluminium, cast aluminium, aluminium alloy, aluminium-magnesium alloy, cast aluminium alloy, copper, austenitic stainless steel and mild steel, presenting improved dish-washer resistance, good acid resistance and good adherence on the substrate. The composition of the porcelain enamel in question comprises about 30 wt- % to about 50 wt-% SiO2, about 30 wt-% to about 40 wt-% R2O, about 15 wt-% to about 25 wt-% TiO2, about 0 wt-% to about 5 wt-% RO, about 0 wt-% to about 4 wt-% V2O5, about 0.3 wt-% to about 7 wt-% Fe2O3, about 0 wt-% to about 3 wt-% Sb2O3, about 0 wt-% to about 3 wt-% SnO2, about 0wt-% to about 2wt-% B2O3, about 0 wt-% to about 3 wt-% AI2O3, about 0 wt-% to about 4 wt-% P2O5, about 0 wt-% to about 1 wt-% MoO3, about 0 wt-% to about 2 wt-% F2, about 0 wt-% to about 4 wt-% ZrO2, about 0 wt-% to about 4 wt-% ZnO, about 0 wt-% to about 6 wt-% NOx, R2O is a combination of alkaline oxides selected from the group of: Na2O 10 - 23 mol%, K2O 7 - 20 mol% and Li2O 1 - 6.5 mol%, wherein RO represent at least one earth alkali oxide and wherein the molar ratio of (Li2O + B2O3) to TiO2 amounts to 0.2 to 0.6.