Coating precursor and method for coating a substrate with a refractory layer

Method for coating a surface of a substrate with at least one refractory layer containing silicon, comprising the steps of:

• coating the surface with a coating precursor to form a green layer, the coating precursor comprising a silicone resin selected from the group consisting of polymethylsiloxanes, polymethylsilsesquioxanes, and mixtures thereof, the silicone resin comprising a proportion of OH groups substituted for methyl groups between about 0.5% and about 2%, a mineral filler, and an organic solvent in which the resin is soluble and the mineral filler is suspendable,
• the silicone resin and the mineral filler producing a solid layer on a substrate after the organic solvent has evaporated, and being chemically reactive so as to produce a cohesive refractory layer on the substrate after calcining;
• heat treating the coated surface to eliminate volatile materials from the green layer and calcining the green layer to form a cohesive refractory layer, said cohesive refractory layer containing, by weight, about 5 to 25% silica from decomposition of the silicone resin and about 75 to 95% of said mineral filler.