Abstract: A method for applying a porous coating incorporating a tricomponent powder mixture deposited on a hard substrate (i.e. metallic or ceramic) by plasma spraying. The coating has high adhesion strength to the substrate, with outstanding thermo-mechanical characteristics and with good resistane to thermal or mechanical action. The mixure includes aluminum oxide and/or titanium oxide powder and glass powder as the coating's microstructure forming materials; aluminum and/or titanium power metal binder and aluminum hyroxide and/or titanium hydroxide powder as a material assuring the formation of coating's microstructure. Plasma spraying includes passing the powder through the plasma beam, simultaneously melting of the metal oxide, partially alloying components into separate plasma beam zones—the hydroxide to the colder zone, and the metal to the hotter zone. The aluminum particles reach the substrate first and develop the adhesion of the sprayed layer to the substrate.