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.

Provided is a surface treatment solution composition comprising: 30 to 51 wt % of a trivalent chromium compound comprising chromium phosphate (A) and chromium nitrate (B) and having a content ratio of A/(A+B) that satisfies 0.3 to 0.6; 5 to 15 wt % of silane coupling agent; 0.2 to 3 wt % of vanadium-based anti-corrosive rust inhibitor; 3 to 12 wt % of colloidal silica; 0.5 to 5 wt % of polysiloxane copolymer; and 14 to 61.3 wt % of water, a hot dip galvanized steel sheet surface-treated using same, and a manufacturing method thereof. The hot dip galvanized steel sheet treated with the surface treatment solution composition containing trivalent chromium has an excellent corrosion resistance, blackening resistance, pipe-forming oil reactivity, and alkali resistance.

A preparation method for adhesive bonding of magnesium-containing aluminum alloy products includes a magnesium-containing aluminum alloy product including a matrix and a surface oxide layer overlying the matrix. The magnesium-containing aluminum alloy product also includes intermetallic particles at least proximal the surface oxide layer. The method also includes ablating at least some of the intermetallic particles via an energy source, and in the absence of melting of the matrix of the magnesium-containing aluminum alloy product.

A preparation method for adhesive bonding of magnesium-containing aluminum alloy products includes a magnesium-containing aluminum alloy product including a matrix and a surface oxide layer overlying the matrix. The magnesium-containing aluminum alloy product also includes intermetallic particles at least proximal the surface oxide layer. The method also includes ablating at least some of the intermetallic particles via an energy source, and in the absence of melting of the matrix of the magnesium-containing aluminum alloy product.

Metallic substrate treatment methods and articles comprising a phosphonate functionalized layer are provided. The method comprises contacting a metallic substrate comprising at least one of aluminum and an aluminum alloy with a fluid to form a phosphonate functionalized layer on at least a region of the metallic substrate. The fluid comprises at least one of a phosphonate containing acid and a derivative thereof. At least one of the phosphonate containing acid and the derivative thereof comprises a pKa of a first acidic proton. The fluid comprises a pH at least 0.5 pH value greater than the pKa of the first acidic proton. The article comprises a metallic substrate comprising aluminum or an aluminum alloy and a phosphonate functionalized layer on at least a region of the metallic substrate.

A sealing process includes impregnating an oxide layer of an anodized metal with a corrosion inhibitor by contacting the oxide layer with a first corrosion inhibitor solution at a first temperature and sealing the impregnated oxide layer of an anodized metal by contacting the impregnated oxide layer with a second corrosion inhibitor solution at a second temperature, wherein the first corrosion inhibitor solution has a corrosion inhibitor concentration greater than the second corrosion inhibitor solution and the first temperature is less than the second temperature.

A sealing process includes impregnating an oxide layer of an anodized metal with a corrosion inhibitor by contacting the oxide layer with a first corrosion inhibitor solution at a first temperature and sealing the impregnated oxide layer of an anodized metal by contacting the impregnated oxide layer with a second corrosion inhibitor solution at a second temperature, wherein the first corrosion inhibitor solution has a corrosion inhibitor concentration greater than the second corrosion inhibitor solution and the first temperature is less than the second temperature.

An aqueous solution for metal surface treatment includes an alkyl silicate or an oligomer thereof in a concentration of 0.005 mass % or more and less than 1 mass %, and an organic silane compound in a concentration of 0.005 mass % or more and less than 1 mass %. The aqueous solution has a pH of 2 or more and 7 or less.

An aqueous solution for metal surface treatment includes an alkyl silicate or an oligomer thereof in a concentration of 0.005 mass % or more and less than 1 mass %, and an organic silane compound in a concentration of 0.005 mass % or more and less than 1 mass %. The aqueous solution has a pH of 2 or more and 7 or less.

Provided is an aluminum alloy fastening member having a novel chemical conversion coating as a colored coating, a fastener chain, and a method for producing the aluminum alloy fastening member. The aluminum alloy fastening member includes a chemical conversion coating containing manganese as a component element, and the chemical conversion coating satisfies hue ranges of −3≤a*≤12, −5≤b*≤35, and 45≤L*≤80 in a CIELAB color space as defined by JIS Z 8781-4 (2013).