Disclosed are methods for coating aluminum alloy heat exchangers that include the use of a waterborne top coating. By using a waterborne top coating, relative to a solvent borne, useful advantages can be achieved, such as improved penetration depth of the top coating. An example method includes cleaning a surface of a heat exchanger; contacting the surface of the heat exchanger with a first mixture to provide a passivation layer on the surface of the heat exchanger; contacting the passivation layer with a second mixture in a bath and applying a positive charge to the bath to provide an electro-coating on a surface of the passivation layer; and contacting the electro-coating with a third mixture, the third mixture including water and a polymer resin having anti-corrosion and ultraviolet protection properties, to provide a top coating including the polymer resin on a surface of the electro-coating.

Disclosed are methods for coating aluminum alloy heat exchangers that include the use of a waterborne top coating. By using a waterborne top coating, relative to a solvent borne, useful advantages can be achieved, such as improved penetration depth of the top coating. An example method includes cleaning a surface of a heat exchanger; contacting the surface of the heat exchanger with a first mixture to provide a passivation layer on the surface of the heat exchanger; contacting the passivation layer with a second mixture in a bath and applying a positive charge to the bath to provide an electro-coating on a surface of the passivation layer; and contacting the electro-coating with a third mixture, the third mixture including water and a polymer resin having anti-corrosion and ultraviolet protection properties, to provide a top coating including the polymer resin on a surface of the electro-coating.

A piston has a piston main body including an aluminum alloy, and a covering layer formed on the outer surface of the piston main body, and the covering layer has a first plating layer including an iron-phosphorous alloy, and a second plating layer including a nickel-phosphorous alloy formed on the first plating layer.

A piston has a piston main body including an aluminum alloy, and a covering layer formed on the outer surface of the piston main body, and the covering layer has a first plating layer including an iron-phosphorous alloy, and a second plating layer including a nickel-phosphorous alloy formed on the first plating layer.

A surface-treated material (10) according to the present invention comprises an electroconductive substrate (1) and a surface treatment film (2) formed of at least one or more layers of metal layers (3 and 4) which are formed on the electroconductive substrate (1), wherein among the at least one or more layers of metal layers (3 and 4), the lowermost metal layer (3) which is directly formed on the electroconductive substrate (1) comprises a plurality of metal-buried portions (3a) that are scattered in the electroconductive substrate (1), branch from a surface of the electroconductive substrate (1) and widely extend toward the inside thereof, and as a vertical cross section of the surface-treated material (10) is viewed, in which at least one of the metal-buried portions (3a) exists in the electroconductive substrate (1), an average value of an area ratio of the metal-buried portion (3a) occupying the predetermined observation region of the electroconductive substrate (1) is in a range of 5% or more and 50% or less.

A surface-treated material (10) according to the present invention comprises an electroconductive substrate (1) and a surface treatment film (2) formed of at least one or more layers of metal layers (3 and 4) which are formed on the electroconductive substrate (1), wherein among the at least one or more layers of metal layers (3 and 4), the lowermost metal layer (3) which is directly formed on the electroconductive substrate (1) comprises a plurality of metal-buried portions (3a) that are scattered in the electroconductive substrate (1), branch from a surface of the electroconductive substrate (1) and widely extend toward the inside thereof, and as a vertical cross section of the surface-treated material (10) is viewed, in which at least one of the metal-buried portions (3a) exists in the electroconductive substrate (1), an average value of an area ratio of the metal-buried portion (3a) occupying the predetermined observation region of the electroconductive substrate (1) is in a range of 5% or more and 50% or less.

A copper plating solution includes: water-soluble copper salt; ethylenediamine; at least one of EDTA, a substituted derivative of EDTA, an ethylenediamine derivative, or glycine; and at least one of hydantoin or a substituted derivative thereof. The copper plating solution allows an aluminum or aluminum alloy base to be displacement-plated with copper.

A copper plating solution includes: water-soluble copper salt; ethylenediamine; at least one of EDTA, a substituted derivative of EDTA, an ethylenediamine derivative, or glycine; and at least one of hydantoin or a substituted derivative thereof. The copper plating solution allows an aluminum or aluminum alloy base to be displacement-plated with copper.

The present invention provides a method for ceramization of an aluminum alloy surface, comprising the steps of: (1) providing a clean aluminum alloy surface; (2) pre-polishing; (3) etching; (4) polishing; and (5) performing ceramic oxidation. The advantages of the method are as follows: (1) good corrosion resistance, good elasticity and insulation; (2) the coating being similar to plastic, with enamel-like luster and attractive appearance; and (3) good adsorption capacity, capability of being dyed with different colors, and good decorative effect etc.

The present invention provides a method for ceramization of an aluminum alloy surface, comprising the steps of: (1) providing a clean aluminum alloy surface; (2) pre-polishing; (3) etching; (4) polishing; and (5) performing ceramic oxidation. The advantages of the method are as follows: (1) good corrosion resistance, good elasticity and insulation; (2) the coating being similar to plastic, with enamel-like luster and attractive appearance; and (3) good adsorption capacity, capability of being dyed with different colors, and good decorative effect etc.