A surface treatment method for aluminum heat exchangers including (a) a step wherein a chemical conversion coating film is formed on the surface of an aluminum heat exchanger by subjecting the aluminum heat exchanger to chemical conversion using a chemical conversion agent; (b) a step wherein the aluminum heat exchanger, the surface of which has been provided with a chemical conversion coating film in step (a), is brought into contact with a hydrophilizing agent that contains a hydrophilic resin; and (c) a step wherein a hydrophilized coating film is formed on the surface of the aluminum heat exchanger by baking the aluminum heat exchanger, which has been subjected to a contact treatment in step (b). The chemical conversion agent used in step (a) contains zirconium and/or titanium in an amount of 5-5,000 ppm by mass in total, vanadium in an amount of 10-1,000 ppm by mass and a metal stabilizer in an amount of 5-5,000 ppm by mass. In addition, the chemical conversion agent used in step (a) has a pH of 2-6.

A surface treatment method for aluminum heat exchangers including (a) a step wherein a chemical conversion coating film is formed on the surface of an aluminum heat exchanger by subjecting the aluminum heat exchanger to chemical conversion using a chemical conversion agent; (b) a step wherein the aluminum heat exchanger, the surface of which has been provided with a chemical conversion coating film in step (a), is brought into contact with a hydrophilizing agent that contains a hydrophilic resin; and (c) a step wherein a hydrophilized coating film is formed on the surface of the aluminum heat exchanger by baking the aluminum heat exchanger, which has been subjected to a contact treatment in step (b). The chemical conversion agent used in step (a) contains zirconium and/or titanium in an amount of 5-5,000 ppm by mass in total, vanadium in an amount of 10-1,000 ppm by mass and a metal stabilizer in an amount of 5-5,000 ppm by mass. In addition, the chemical conversion agent used in step (a) has a pH of 2-6.

A trivalent-chromium chemical conversion coating from which substantially no hexavalent chromium is released. The trivalent-chromium chemical conversion coating is one formed on the surface of a zinc or zinc-alloy deposit. In a brine spray test, the chemical conversion coating has unsusceptibility to corrosion (time required for white-rust formation) of 96 hours or longer. The chemical conversion coating has a hexavalent-chromium concentration less than 0.01 μg/cm.sup.2 in terms of metal atom amount. The amount of hexavalent chromium released after 30-day standing in a thermo-hygrostatic chamber at a temperature of 80° C. and a humidity of 95% (amount of hexavalent chromium released when the coating is immersed in 100° C. water for 10 minutes) is smaller than 0.05 μg/cm.sup.2.

A magnesium alloy part is inserted into a mold, a resin composition is injected and joined to the part, and a composite is obtained. A part having, formed thereon, a surface layer of a metal oxide, a metal carbonate, or a metal phosphate in use of a usual conversion treatment or a modification method thereof can be used for the magnesium alloy plate 1. The surface that has a larger amount of crystal-like objects of a nanolevel on the surface layer composed of the metal oxide, metal carbonate, or metal phosphate has a higher level of hardness, microscopic roughness, and good injection joining force, and these parameters can be controlled by a conversion treatment method. A resin composition 4, containing PBT or PPS as the main component, is used as the resin composition part.

A magnesium alloy part is inserted into a mold, a resin composition is injected and joined to the part, and a composite is obtained. A part having, formed thereon, a surface layer of a metal oxide, a metal carbonate, or a metal phosphate in use of a usual conversion treatment or a modification method thereof can be used for the magnesium alloy plate 1. The surface that has a larger amount of crystal-like objects of a nanolevel on the surface layer composed of the metal oxide, metal carbonate, or metal phosphate has a higher level of hardness, microscopic roughness, and good injection joining force, and these parameters can be controlled by a conversion treatment method. A resin composition 4, containing PBT or PPS as the main component, is used as the resin composition part.

Disclosed are an environment-friendly heat shielding film using a non-radioactive stable isotope and a manufacturing method therefor and, more specifically, an environment-friendly heat shielding film using a non-radioactive stable isotope and a manufacturing method therefor, wherein a heat shielding layer is formed on one surface of a substrate layer; the heat shielding layer is composed of stable isotopes as elements constituting a precursor and contains a non-radioactive stable isotope tungsten bronze compound having an oxygen-deficient .sup.(Y)A.sub.x.sup.(182,183,184,186)W.sub.1O.sub.(3-n) type hexagonal structure, thereby preventing the generation of radioactive materials, fundamentally blocking haze, and improving the visible light transmittance and the infrared light blocking rate; and the heat resistance and durability problems that may occur when the heat shielding layer is formed of the non-radioactive stable isotope tungsten bronze compound are solved by a passivation film.

Disclosed are an environment-friendly heat shielding film using a non-radioactive stable isotope and a manufacturing method therefor and, more specifically, an environment-friendly heat shielding film using a non-radioactive stable isotope and a manufacturing method therefor, wherein a heat shielding layer is formed on one surface of a substrate layer; the heat shielding layer is composed of stable isotopes as elements constituting a precursor and contains a non-radioactive stable isotope tungsten bronze compound having an oxygen-deficient .sup.(Y)A.sub.x.sup.(182,183,184,186)W.sub.1O.sub.(3-n) type hexagonal structure, thereby preventing the generation of radioactive materials, fundamentally blocking haze, and improving the visible light transmittance and the infrared light blocking rate; and the heat resistance and durability problems that may occur when the heat shielding layer is formed of the non-radioactive stable isotope tungsten bronze compound are solved by a passivation film.

The invention relates to the use of an acidic aqueous composition for pretreating cans, wherein an inorganic-organic conversion layer is formed in the course of the pretreatment, said conversion layer, as such, offering an excellent adhesive base for wax which improves sliding of the formed can and for the subsequent coating. The invention relates to a wet-chemical pretreatment method in which a can cylinder is first contacted with an acidic aqueous composition that contains water-soluble inorganic compounds of Zr, Ti, Si, Hf or Ce, and water-soluble polymers comprising carboxyl groups or hydroxyl groups; and subsequently is contacted with an aqueous wax dispersion. The invention further relates to an acidic aqueous composition suitable for the pretreatment method comprising water-soluble polymers selected from condensation products of glycoluril and aldehydes. The invention further relates to a method for producing can cylinders, said method including the pretreatment according to the invention.

The invention relates to the use of an acidic aqueous composition for pretreating cans, wherein an inorganic-organic conversion layer is formed in the course of the pretreatment, said conversion layer, as such, offering an excellent adhesive base for wax which improves sliding of the formed can and for the subsequent coating. The invention relates to a wet-chemical pretreatment method in which a can cylinder is first contacted with an acidic aqueous composition that contains water-soluble inorganic compounds of Zr, Ti, Si, Hf or Ce, and water-soluble polymers comprising carboxyl groups or hydroxyl groups; and subsequently is contacted with an aqueous wax dispersion. The invention further relates to an acidic aqueous composition suitable for the pretreatment method comprising water-soluble polymers selected from condensation products of glycoluril and aldehydes. The invention further relates to a method for producing can cylinders, said method including the pretreatment according to the invention.

Disclosed is a combined treatment method for improving corrosion resistance of metal component in chlorine-containing solution. First, the metal component is placed in the chlorine-containing solution. Large-area overlapping laser shock peening without an absorbing layer is used, when laser pulses are irradiated on the target metal component, the metal matrix surface absorbs the laser energy, vaporizes and expands to form a high-temperature and high-pressure plasma, a chlorine-containing passivation film is formed, to improve the surface corrosion resistance of the metal component. After that, the surface layer of the metal component is subjected to surface polishing, followed by large-area overlapping laser shock peening with an absorbing layer at room temperature, to further improve the corrosion resistance of the metal component. The combined treatment method of the present invention can be applied to improve the corrosion resistance of metal components in highly corrosive chlorine-containing environments of seawater and the like.