The conditions for the preparation and properties of a composite coating consisting of a cured alumino-phosphate binder and a nanoporous self-structured matrix composed of aluminum oxide have been studied. The coating can be used as an electrical insulation, thermally stable. The parameters of the production process, the wetting of the nanoporous film by an alumo-phosphate binder, the filling of the porous coating, and the thermal characteristics of curing of the aluminum-phosphate binder in a nanoporous matrix are studied.