Abstract: The present invention provides an aqueous cleaning solution for aluminum-based metals which comprises an inorganic acid in an amount to provide a pH value of 2 or less, an oxidized form metal ion and a surfactant represented by the following formula (I)R--O--(EO).sub.n H (I)wherein R represents an alkyl group having on average 10 to 18 carbon atoms per molecule, n represents an integer of 8 or greater, and EO represents an ethyleneoxy group which may contain a small proportion of a propyleneoxy group. The degradation of cleaning properties due to the accumulation of lubricating oil or decomposition of surfactants is lessened even when the cleaning operation is carried out for a long period of time.

Abstract: A zinc phosphate coating film suitable for cationic electrodeposition coating and superior in both of coating film adhesion and corrosion resistance (especially, warm brine resistance and scab resistance) is formed by a conversion treatment of a metal surface using an acidic zinc-phosphating solution which does not contain a nickel ion as an essential component. The conversion treatment is carried out by bringing a metal surface into contact with a zinc-phosphating solution containing a zinc ion of 0.1 to 2.0 g/l, a phosphate ion of 5 to 40 g/l, a lanthanum compound of 0.001 to 3 g/l in terms of a lanthanum metal, and a phosphating accelerator, thereby the zinc phosphate coating film is formed on the metal surface.

Abstract: A copolymer for a protective coating is formed from a mixture of .alpha., .beta.-ethylenically unsaturated monomer, .alpha., .beta.-ethylenically unsaturated carboxylic acid monomer, and amphiphilic monomer. The protective coating has an average molecular weight of 7000 to 25000 to provide the desired properties of rapid drying, substantial film strength, and easy removal with an alkaline aqueous solution.

Abstract: A zinc phosphate film on a metal surface is used as a surface-protecting film and an under coating film for coating and so on. The zinc phosphate film is formed by treating a metal surface with an aqueous zinc phosphate solution. The aqueous zinc phosphate solution includes solutions containing a zinc ion in a concentration of more than 2 g/l to 20 g/l, a phosphate ion in a concentration of 5 g/l to 40 g/l, and at least one of silicotungstic acid and a silicotungstate in a concentration of 0.005 g/l to 20 g/l measured in terms of tungsten content.

Abstract: A process for phosphating the surfaces of iron-based metals, zinc-based metals or combination of such surfaces by treating the metal surfaces with an aqueous acidic zinc-phosphating solution comprising from about 0.1 to about 200 g/l of zinc ion, from about 5 to about 40 g/l of phosphate ion, from about 0.01 to 20.0 g/l as tungsten of soluble tungsten compound and a conversion coating accelerator. The metal surfaces thus phosphated with the solution are suitable for electrocoating.

Abstract: A method of phosphating the surfaces of iron-based metals, zinc-based metals, or combinations of such surfaces by contacting the metal surfaces with an acidic aqueous phosphating solution containing from about 0.1 to about 2.0 g/l of zinc ion, from about 5 to about 30 g/l of phosphate ion, from about 0.2 to about 3 g/l of manganese ion, and a conversion coating accelerator. The phosphated metal surfaces are then suitable for electrocoating.

Abstract: A method for replenishing a nitrite accelerated zinc phosphate treating liquid for forming zinc phosphate coatings on metal surfaces, wherein the metal surface is treated at the rate of 3 to 15 m.sup.2 per hour per cubic meter of treating liquid and the treating liquid is replenished with free phosphoric acid at the rate of 0.10 to 0.31 moles per 10 m.sup.2 of treated surface area.