ELECTROLYTIC TREATMENT OF METAL SURFACES TO ELECTRODEPOSIT ALUMINA

1412126 Deposition of aluminium oxide or hydroxide NATIONAL RESEARCH DEVELOPMENT CORP 27 Feb 1973 [ 14 March 1972] 11853/72 HeadingC7B Aluminium oxide and/or hydroxide is electrodeposited from a bath containing an aluminate solution stabilized by at least one aliphatic monocarboxylic acid containing at least 6 carbon atoms and at least 4 hydroxyl groups or a salt, boro derivative or lactone thereof. The boro derivative may be produced by reacting boric acid with the acid or salt. The stabilizer may be sodium gluconate, sodium glucoheptonate, 1, 5-gluconolactone or sodium borogluconate. The bath may contain a corrosion inhibiter e.g. benzotriazole, rubeanic acid, trisodium orthophosphate or disodium hydrogen phosphate. The article may be coloured during or after electrolysis then rinsed in water, dried in acetone, and sealed and/or lacquered. It may be treated with a corrosion inhibitor before electrolysis. The article may be stainless steel, Fe, Pb, Sn, Al, Zn, Cu or Mg. The cathode may be Pt or stainless steel.