There is disclosed the coating of a metallic substrate with a cross-linked polymeric film by contacting the substrate with an aqueous composition containing: at least an acrylic or metacrylic compound which can be defined by the general formula: ##STR1## wherein: R is a straight-line or branched aliphatic hydrocarbon radical, either saturated or unsaturated containing from 2 to 10 carbon atoms, or a cycloaliphatic or an aromatic group; R.sub.1 and R.sub.2, equal to or different from one another, are straight-line or branched alkyl groups, either saturated or unsaturated and containing from 1 to 8 carbon atoms, or cycloaliphatic or aromatic groups; at least one unsaturated organic acid capable of being copolymerized with the compound (I), in an amount of from 5 to 40 parts by weight per 100 parts of the compound (I) or an organic or a mineral acid which cannot be copolymerized with the compound (I) in an amount of from 1 to 10 parts by weight per 100 parts of the compound (I), and a polymerization catalyst preferably selected from among the persulphates, the hydroperoxides, the peracids H.sub.2 O.sub.2 and the peroxides. A metallic substrate coated by the composition of polymeric nature as described above is then heated to a temperature equal to, or lower than 180.degree. C. approximately and for the time which is necessary to originate a polymeric film cross-linked upon said substrate. A film so deposited exhibits optimum properties as to adherence, resistance to bending and shocks and resistance to the saline mist.
A corrosion-resistant protective coating for an apparatus and method of processing a substrate in a chamber containing a plasma of a processing gas. The protective coating or sealant is used to line or coat inside surfaces of a reactor chamber that are exposed to corrosive processing gas that forms the plasma. The protective coating comprises at least one polymer resulting from a monomeric anaerobic chemical mixture having been cured in a vacuum in the absence of oxygen. The protective coating includes a major proportion of at least one methacrylate compound and a minor proportion of an activator compound which initiates the curing process of the monomeric anaerobic mixture in the absence of oxygen or air.
A hydrophilic corrosion-resistant coat is formed on the surface of a metallic material, e.g., aluminum and its alloys, by a method which comprises preparatorily cleaning the surface of the metallic material, applying on the cleaned surface of the metallic material an aqueous treating liquid produced by adding a water-soluble acrylic acid polymer and colloidal silica and effective amounts of a polyhydric alcohol and/or saccharide to an aqueous solution containing hexavalent chromium compound or trivalent and hexavalent chromium compounds, phosphoric acid, and a fluorine compound. The applied layer of the treating liquids is dried and baked, the baking being at a temperature in the range of 100.degree. to 250.degree. C.
A process is provided for coating an electrically conductive substrate with an aqueous coating composition containing a cationic binder wherein the binder is obtained by polymerization of 100 parts by weight of a specified monomer mixture in the presence of 0.5 to 25 parts by weight of a polyurethane having 2-5 acryloyl groups or methacryloyl groups, a molecular weight of 400-7000 and a molecular weight per (meth)acryloyl group of at least 200. The invention also pertains to the aqueous composition as such.
