Metallic substrates with a vitreous or glass-ceramic pigmented protective layer are obtainable by applying an alkali metal silicate-containing coating sol to the substrate or a surface thereof and thermally densifying the layer thus obtained, said alkali metal silicate-containing coating sol comprising an oxidic pigment of at least one element selected from the third and fourth main or subgroups of the Periodic Table of the chemical elements and the transition metals Fe, Co, Ni, Cu, Zn, Nb and Ta.

Methods of manufacture of an optical diffuser. In one embodiment, an optical diffuser is formed by providing a wafer including a silicon slice of which an upper face is covered with a first layer made of a first material itself covered with a second layer made of a second selectively etchable material with respect to the first material. The method further includes forming openings in the second layer extending up to the first layer and filling the openings in the second layer with a third material. The method yet further includes bonding a glass substrate to the wafer on the side of its upper face and removing the silicon slice.

The present invention relates to aqueous solutions, methods of manufacturing the same and uses thereof. The aqueous solution comprises an alkaline earth metal added in the form of a water-soluble salt, manganese at least mainly present as a citrate complex of manganese having an oxidation state of +3 or +4, and optionally a lanthanide present in the form of a water soluble complex. The aqueous precursor solutions contain metals at appropriate stoichiometric ratios for producing films of complex inorganic metal oxides by Chemical Solution Deposition (CSD). The complex inorganic metal oxides can be used as memristor materials, and generally in microelectronic, magnetic, and spintronic devices, in solid oxide fuel cells, in magnetic refrigeration, and in the fields of biomedicine, and as catalysts.

A method for coating a substrate with a CoPi modified BiVO.sub.4/WO.sub.3 heterostructure film includes direct current reactive sputtering tungsten (W) onto a substrate in a gaseous mixture containing oxygen to form a tungsten trioxide (WO.sub.3) film, direct current reactive sputtering bismuth (Bi) onto the tungsten trioxide (WO.sub.3) film in a gaseous mixture containing oxygen to form a dibismuth trioxide (Bi.sub.2O.sub.3) film, drop-casting a vanadyl acetylacetonate solution onto the Bi.sub.2O.sub.3 film and heating at a temperature of at least 450 C. in ambient air to convert the Bi.sub.2O.sub.3 film to a BiVO.sub.4 film, and photoelectrochemically coating the BiVO.sub.4 film with a cobalt-phosphate (CoPi) to form a modified film on the surface of the substrate. A photoanode containing the CoPi modified BiVO.sub.4/WO.sub.3 heterostructure film prepared by the method, and its application in water splitting.

Disclosed herein is a method of pre-treating a metallic substrate, the method including one or more cleaning steps, where at least part of the surface of the metallic substrate is contacted with one or more aqueous cleaning compositions, to obtain a cleaned metallic substrate; and/or one or more chemical pre-treatment steps selected from the group consisting of conversion treating steps, passivation treating steps and thin-layer forming steps, where at least part of the surface of a metallic substrate is contacted with one or more chemical pre-treatment compositions selected from the group consisting of conversion treatment compositions, passivation treatment compositions and thin-layer forming compositions to obtain a chemically pre-treated substrate. Also disclosed herein is a method of coating a metallic substrate, where the first step consists of the method of pre-treating a substrate, where after a last rinsing step one or more coating compositions are applied and cured.