A glass flux material for applying an opaque coating is provided. The glass flux material includes at least one pigment and a glass component with the following composition: SiO.sub.2 55-70 mol %, Al.sub.2O.sub.3 2.5-8 mol %, Bi.sub.2O.sub.3 0.5-<4 mol %, B.sub.2O.sub.3 14-27 mol %, with at least 2.5 mol % of at least one oxide of the group Li.sub.2O, Na.sub.2O, and K.sub.2O, wherein the ratio of alkali oxides to aluminum oxide ?R.sub.2O/Al.sub.2O.sub.3 is less than 6.

The invention is in the field of vitreous enamel coatings, more particularly vitreous enamel coatings for steels. The invention provides a process for obtaining adhering light-coloured coatings in a single layer system, hereinafter referred to as Pyro Light coatings, that can be applied to the steel by powder electrostatic spraying.

A multi-layer glass enamel is disclosed. The various layers of the enamel are included to provide certain performance characteristics to the enamel. The components of each layer can be individually adjusted to tailor the performance characteristics influenced by that layer without changing the influence of the remaining layers.

The amorphous, or at least partially crystalline, glass-based joining material is suitable for high-temperature applications, particularly in fuel cells and/or sensors. In addition to SiO.sub.2 and B.sub.2O.sub.3 as glass formers, the joining material similarly contains BaO and CaO, whereby the amount of Al.sub.2O.sub.3 is limited. The joining material has a coefficient of linear thermal expansion of at least 7.0.Math.10.sup.6 K.sup.1 in a range of 20 C. to 300 C. The joining material can be used for joining ferritic high-grade steels and/or chromium-containing alloys and/or ceramics, such as stabilized zirconium oxide and/or aluminium oxide.

The present invention relates to a process for manufacturing a one-way vision glass pane comprising one or more separate enamel patterns composed of a number of exactly aligned layers, characterized in that:

a) at least one protective layer based on oxides, having a thickness greater than or equal to 10 nm, is deposited on the glass substrate,
b) at least two layers of different compositions are deposited on the protective layer, the composition of one containing at least one mineral pigment and being free of glass frit, the composition of the other being an enamel containing at least one glass frit and at least one mineral pigment having a color different from that of the layer free of glass frit, the layer free of glass frit being deposited over all or some of the surface of the pane and the layer of enamel being deposited by screen printing in the shape of the desired pattern(s),
c) the pane coated with said layers is heated at a temperature sufficient to fire the enamel, and
d) the pigments not fixed by the enamel that are located outside of the pattern(s) are removed, the particles of pigment(s) and the particles of glass frit(s) having a similar size, in particular a particle size distribution such that 50% of the particles have a size of less than 7 m.