Provided is a surface hardening method for surface hardening a sulfuric acid-anodized aluminum alloy oxide layer, which includes: pre-treatment in which various foreign substances, including an oxide film, attached to a surface of an aluminum alloy are removed; sealing treatment in which the aluminum alloy having been subjected to the pre-treatment is immersed in a sealing solution, whereby fine pores formed in a film are sealed; and heat treatment in which the aluminum alloy having been subjected to the sealing treatment is charged to, and thermally treated in, a heat treatment furnace and then naturally cooled. By lowering the withstand voltage of an aluminum alloy oxide layer and increasing the hardness by subjecting the same to sealing treatment and subsequent post-heat treatment, the present invention has the effect of providing an environmentally-friendly and crack-free lightweight material that can replace steel products.

Provided is a surface hardening method for surface hardening a sulfuric acid-anodized aluminum alloy oxide layer, which includes: pre-treatment in which various foreign substances, including an oxide film, attached to a surface of an aluminum alloy are removed; sealing treatment in which the aluminum alloy having been subjected to the pre-treatment is immersed in a sealing solution, whereby fine pores formed in a film are sealed; and heat treatment in which the aluminum alloy having been subjected to the sealing treatment is charged to, and thermally treated in, a heat treatment furnace and then naturally cooled. By lowering the withstand voltage of an aluminum alloy oxide layer and increasing the hardness by subjecting the same to sealing treatment and subsequent post-heat treatment, the present invention has the effect of providing an environmentally-friendly and crack-free lightweight material that can replace steel products.

Development of an alternative process to conventional toxic chromic acid anodization (CAA) with equivalent corrosion resistance is a challenging task. The present invention provides a chromate free process for the manufacture of corrosion resistant sealed anodized coating for long term corrosion resistance of aerospace grade aluminum alloy. This method includes the steps of cleaning, chemical etching, anodizing in Tartaric-Sulphuric acid electrolyte followed by dipping the specimen in the sealing bath containing at least two water soluble either Mn and Mo or Mn and V oxyanions as corrosion inhibitors and a sufficient amount of alkali metal ion based nitrates at a temperature range between 60 and 80° C. for about 20 to 40 minutes at a pH range of 7 to 9. The sealed anodic coatings developed from this invention showed improved corrosion resistance in neutral 5% NaCl fog environment for greater than 2000 h of exposure. The sealed anodic coatings developed by this invention also showed self-healing protection in NaCl environment.

The present disclosure provides a surface-treated aluminum material having excellent adhesiveness to resins, on the surface of which an oxide film is formed, the oxide film comprising a surface-side porous aluminum oxide film having a thickness of 20 to 500 nm and a base-side barrier aluminum oxide film having a thickness of 3 to 30 nm, wherein small pores each having a diameter of 5 to 30 nm are formed on the porous aluminum oxide film, and the length of cracks formed in a boundary between the porous aluminum oxide film and the barrier aluminum oxide film is not more than 50% of the length of the boundary, a method for manufacturing the surface-treated aluminum material, and a surface-treated aluminum material-resin bonded body, comprising the surface-treated aluminum material and a resin that covers the surface of the oxide film formed thereon.

The present disclosure provides a surface-treated aluminum material having excellent adhesiveness to resins, on the surface of which an oxide film is formed, the oxide film comprising a surface-side porous aluminum oxide film having a thickness of 20 to 500 nm and a base-side barrier aluminum oxide film having a thickness of 3 to 30 nm, wherein small pores each having a diameter of 5 to 30 nm are formed on the porous aluminum oxide film, and the length of cracks formed in a boundary between the porous aluminum oxide film and the barrier aluminum oxide film is not more than 50% of the length of the boundary, a method for manufacturing the surface-treated aluminum material, and a surface-treated aluminum material-resin bonded body, comprising the surface-treated aluminum material and a resin that covers the surface of the oxide film formed thereon.

In a method, an aluminum body is chemically treated with at least one of an alkaline solution and an acid solution. Anode-oxidization is performed on the chemically treated aluminum body to form an aluminum oxide layer. The aluminum oxide layer is treated with hot water at a temperature more than 75° C. or steam. The aluminum oxide layer after being treated with hot water or steam includes plural columnar grains, and an average width of the columnar grains is in a range from 10 nm to 100 nm.

Anodic oxide coatings that provide corrosion resistance to parts having protruding features, such as edges, corners and convex-shaped features, are described. According to some embodiments, the anodic oxide coatings include an inner porous layer and an outer porous layer. The inner layer is adjacent to an underlying metal substrate and is formed under compressive stress anodizing conditions that allow the inner porous layer to be formed generally crack-free. In this way, the inner porous layer acts as a barrier that prevents water or other corrosion-inducing agents from reaching the underlying metal substrate. The outer porous layer can be thicker and harder than the inner porous layer, thereby increasing the overall hardness of the anodic oxide coating.

A heat transfer unit for a motor vehicle may include a metallic heat transfer block and a base plate. The heat transfer block may include channels that are configured to be flowed through. The base plate may include an outer region and a material bonding region. The base plate may be exposed towards the outside and may be materially bonded to the heat transfer block in the material bonding region. The base plate may be formed out of an aluminium, an aluminium alloy, or a wrought aluminium alloy. The outer region of the base plate may comprise a protective coating produced by anodising at least in regions, and the material bonding region of the base plate may not have a protective coating produced by anodising.

The present invention provides: a lightweight optical member which can be produced at relatively low cost and which provides low reflectance, stability upon exposure to light, and abrasion resistance; and an efficient method for producing such an optical member. An optical member according to the present invention is characterized by comprising: a metallic base material; a low-reflective treatment layer formed on the surface of the metallic base material; and a silica layer formed on the surface of the low-reflective treatment layer. It is preferable for the silica layer to have a layer thickness of 0.1-10 μM.

Disclosed are an electronic device including a housing having a matte surface and a method of manufacturing the same. An electronic device according to various embodiments of the disclosure is an electronic device including a housing. The housing may include a base material including an aluminum alloy, a plurality of pits adjacently formed on a surface of the base material, and a crystal grain boundary protrusion part formed as a crystal grain boundary of the surface of the base material portion protrudes on the surface. A method of manufacturing a housing for an electronic device may include an etching step of generating irregularities on a surface of a base material including an aluminum alloy in a way to etch the base material by dipping the base material into an etching solution containing chloride ions, and an anodizing step of forming an anodizing layer on the surface of the base material by dipping, into an anodizing solution, the base material on which the etching step has been completed and applying a current to the base material by using the base material as an anode.