Patent ID: 9534297
Date: 2017-01-03
CPC Classifications: C23C,Y02T,Y10T

Claim:
1. A metallic substrate with a vitreous or glass-ceramic pigmented protective layer, wherein the substrate is obtainable by applying a first alkali metal silicate-containing coating sol to the substrate or a surface thereof to form a first layer and either (i) thermally densifying the first layer, applying a second alkali metal silicate-containing coating sol to the densified first layer to form a second layer, and thermally densifying the second layer, or (ii) applying a second alkali metal silicate-containing coating sol to the first layer to form a second layer and thermally densifying the first layer and the second layer together, the first alkali metal silicate-containing coating sol comprising at least one oxidic pigment that comprises at least one element selected from Fe, Co, Ni, Cu, Zn, Nb, Ta, and elements from the third and fourth main and subgroups of the Periodic Table of Elements, and the second alkali metal silicate-containing coating sol differing from the first alkali metal silicate-containing coating sol in that it does not comprise the at least one oxidic pigment.