Abstract: The present invention provides an inexpensive, non-chromium anticorrosive coating composition and anticorrosion treatment method, which are superior in anticorrosion to conventional chromium-containing anticorrosive compositions.The anticorrosive coating composition of the invention comprises 0.2 to 50 g of thiocarbonyl group-containing compound, 0.1 to 5 g of phosphate ions, and aqueous resins in water. The amount of the thiocarbonyl group-containing compound and phosphate ions is based on one liter of the total amount of the aqueous resin and water. The above anticorrosive coating composition can further comprise 10 to 500 g of water-dispersible silica. The anticorrosion treatment method of the invention comprises coating zinc-type coated steel or non-coated steel with the anticorrosive coating composition.

Abstract: The invention provides a rust inhibiting technology for zinc-coated and uncoated steel which insures at least the equivalent of results obtainable by the technology using a Cr-containing coating composition.This method comprises coating a zinc-coated or uncoated steel substrate with a water-based resin composition comprising a carboxylated polyolefin resin and 70-0 part by weight of solid matter of at least one member selected from the group consisting of polyurethane resin, polyester resin, acrylic resin, epoxy resin, and alkyd resin as supplemented with 0.01-0.5 part by weight of phosphate ion based on 100 parts by weight of total solid matter of said water-based resin composition and adjusted to a pH value of not less than 7, either followed by heating the coated substrate at 50.degree.-250.degree. C. to dry the coat or preceded by heating said steel substrate at 50.degree.-250.degree. C. to let the then-applied coat dry spontaneously.

Abstract: Disclosed is an acidic cleaning aqueous solution for aluminum and aluminum alloy and a process for cleaning the same, intended to execute acidic cleaning without using harmful fluoride and chloride ions.The oxidation-reduction potential of a cleaning bath is controlled to be at 0.5 to 0.8 V (vs. Ag-AgCl). The cleaning bath is obtained by diluting an acidic cleaning aqueous solution for aluminum and aluminum alloy to a predetermined volume. The acidic cleaning aqueous solution contains specified amounts of at least one of inorganic acids, Br.sup.- ions and oxidized metal ions, with the addition of a surfactant and oxidizing agent if necessary.It is thus possible to present a uniform etching effect irrespective of low temperature (below 60.degree. C.) without containing fluoride ions and chromic ions within the acidic cleaning aqueous solution. Br.sup.

Abstract: The method for forming a chemical conversion film on a substrate made of aluminum or its alloy which comprises the steps of: (a) etching a surface of the substrate with an aqueous solution of acid or alkali; (b) immersing the etched substrate in an aqueous, phosphate-based chemical conversion solution which is substantially free from fluoride ions; and (c) applying a negative voltage to the substrate during at least a part of the immersion step so that a potential of the substrate reaches a predetermined minimum potential which is lower than a natural electrode potential of the substrate in the aqueous chemical conversion solution.