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EP-4741540-A1 - SURFACE-TREATED ALUMINUM MATERIAL, METHOD FOR PRODUCING SAME, METAL HOUSING, AND KITCHEN DEVICE

EP4741540A1EP 4741540 A1EP4741540 A1EP 4741540A1EP-4741540-A1

Abstract

A surface-treated aluminum material (1) comprises: a base material (2), which is composed of aluminum or an aluminum alloy; and a protective film (3), which is formed on the base material. The protective film (3) comprises: an oxide layer (31), which is composed of an oxide or oxides of aluminum and covers the base material (2); and a hydrated oxide layer (32), which covers the oxide layer (31). The hydrated oxide layer (32) contains a hydrated oxide or hydrated oxides of aluminum and an oxide or oxides and/or a hydroxide or hydroxides of a prescribed metal element or metal elements. In the situation in which cathodic polarization measurements have been performed, using a prescribed measurement solution, on the base material (2) and on the surface-treated aluminum material (1) after it had been heated for 4 hours at a temperature of 200°C, the ratio J1/J2 of the current density J1 of the surface-treated aluminum material (1) to the current density J2 of the base material (2) at a prescribed potential is 90 × 10 -5 or less.

Inventors

  • NAKAJIMA DAIKI
  • MURATA TAKUYA

Assignees

  • UACJ Corporation

Dates

Publication Date
20260513
Application Date
20240730

Claims (10)

  1. A surface-treated aluminum material comprising: a base material, which is composed of aluminum or an aluminum alloy; and a protective film, which is formed on the base material, wherein: the protective film is composed of an oxide or oxides of aluminum, and has: an oxide layer, which covers the base material; and a hydrated oxide layer, which covers the oxide layer; the hydrated oxide layer contains: a hydrated oxide or hydrated oxides of aluminum; and a metal oxide or metal oxides and/or a metal hydroxide or metal hydroxides containing one or two or more metal elements selected from the group consisting of Ni, Cr, Zr, Si, Ti, Au, Ag, Co, Mo, Mn, Nb, Ta, W, Zn, Fe, Ir, and Sc; and in the situation in which cathodic polarization measurements are performed-using a measurement solution obtained by mixing a solution of NaCl having a concentration of 5 mass% and acetic acid having a concentration of 99.7% such that the volumetric ratio of the NaCl solution:acetic acid = 1000:1-on the base material and on the surface-treated aluminum material after it had been heated for 4 hours at a temperature of 200°C, and the current density at the electric potential at the center of an electric-potential region of the base material that exhibits the diffusion-limited current of hydrogen ions was measured, the ratio J1/J2 of the current density J1 of the surface-treated aluminum material to the current density J2 of the base material is 90 × 10 -5 or less.
  2. A surface-treated aluminum material comprising: a base material, which is composed of aluminum or an aluminum alloy; and a protective film, which is formed on the base material, wherein: the protective film is composed of an oxide or oxides of aluminum, and has: an oxide layer, which covers the base material; and a hydrated oxide layer, which covers the oxide layer; the hydrated oxide layer contains: a hydrated oxide or hydrated oxides of aluminum; and a metal oxide or metal oxides and/or a metal hydroxide or metal hydroxides containing one or two or more metal elements selected from the group consisting of Ni, Cr, Zr, Si, Ti, Au, Ag, Co, Mo, Mn, Nb, Ta, W, Zn, Fe, Ir, and Sc; and a sample having the protective film on one surface of the base material was prepared from the surface-treated aluminum material and measured in a state in which a strain gauge has been mounted on the sample on a rear surface of the protective film, the difference ε1 - ε2 between the amount ε1 of strain of the sample at a temperature of 200°C and the amount ε2 of strain of the base material at a temperature of 200°C is 100 × 10 -6 or less.
  3. The surface-treated aluminum material according to claim 1 or 2, wherein a mass loss per unit of area is 0.3 g/dm 2 or less in the situation in which a sealing test has been performed using a method stipulated in JIS H8683-2:2013.
  4. The surface-treated aluminum material according to any one of claims 1-3, wherein a ratio A M /A H of the integrated value A M of light-emission intensities of the metal element(s) to the integrated value A H of the light-emission intensities of hydrogen measured in a range from a surface of the aluminum material to a depth of 500 nm by glow-discharge optical emission spectroscopy is 0.1 or more and 5.0 or less.
  5. A metal casing composed of the surface-treated aluminum material according to any one of claims 1-4.
  6. A kitchen appliance comprising the metal casing according to claim 5.
  7. A method of manufacturing the surface-treated aluminum material according to any one of claims 1-4, comprising: forming the oxide layer, which has pores, on the base material by performing an anodizing treatment on the base material; thereafter, heating the base material and the oxide layer at a temperature of 200°C or higher and 400°C or lower; and thereafter, contacting the oxide layer with a sealing agent that contains the metal element(s), thereby forming the hydrated oxide layer on the oxide layer and sealing the pores.
  8. The method of manufacturing the surface-treated aluminum material according to claim 7, wherein, during the heating, the heating time from the start of heating the oxide layer up until the end of the heating is 3 minutes or more and less than 12 hours.
  9. The method of manufacturing the surface-treated aluminum material according to claim 7 or 8, wherein the electrolyte solution employed in the anodizing treatment contains an inorganic electrolyte composed of an inorganic cation and one or two or more anions selected from the group consisting of a sulfate ion, a phosphate ion, and a borate ion.
  10. The method of manufacturing the surface-treated aluminum material according to any one of claims 7-9, wherein the sealing agent is an aqueous solution that contains ions of the metal element(s).

Description

[TECHNICAL FIELD] The present invention relates to a surface-treated aluminum material, a method of manufacturing the same, a metal casing, and a kitchen appliance. [BACKGROUND ART] Aluminum materials composed of aluminum or an aluminum alloy are utilized in various applications. An anodic oxide film can be provided on the surface(s) of these aluminum materials for purposes such as surface protection. In addition, a sealing treatment is sometimes performed for the purpose of closing up the pores formed in the anodic oxide film and increasing the corrosion resistance of the aluminum material. For example, a method of surface-treating aluminum or an aluminum alloy is described in Patent Document 1, characterized by having: a step of forming an anodic oxide film on a surface of aluminum or an aluminum alloy; a first sealing treatment step of immersion in an aqueous solution, which contains nickel fluoride, at 20-35°C; and a second sealing treatment step of immersion in an aqueous solution, which contains nickel acetate, at 80-93°C. [PRIOR ART LITERATURE] [Patent Documents] [Patent Document 1] Japanese Laid-open Patent Publication 2021-70847 [SUMMARY OF THE INVENTION] [PROBLEMS TO BE SOLVED BY THE INVENTION] However, with regard to aluminum materials obtained by the manufacturing method of Patent Document 1, cracks are more likely to form in the anodic oxide film when the temperature has risen, and there is a risk that debris composed of small pieces of the anodic oxide film might be formed. To curtail the formation of such debris, there is a demand to further increase the heat resistance of aluminum materials having anodic oxide films on their surfaces. The present invention was conceived in view of this background, and it is an object to provide: a surface-treated aluminum material that is capable of curtailing the formation of cracks even when the temperature has risen; a method of manufacturing the same; a metal casing; and a kitchen appliance. [MEANS FOR SOLVING THE PROBLEMS] One aspect of the present invention is a surface-treated aluminum material comprising: a base material, which is composed of aluminum or an aluminum alloy; and a protective film, which is formed on the base material; wherein: the protective film is composed of an oxide or oxides of aluminum, and has: an oxide layer, which covers the base material; anda hydrated oxide layer, which covers the oxide layer;the hydrated oxide layer contains: a hydrated oxide or hydrated oxides of aluminum; anda metal oxide or metal oxides and/or a metal hydroxide or metal hydroxides containing one or two or more metal elements selected from the group consisting of Ni (nickel), Cr (chromium), Zr (zirconium), Si (silicon), Ti (titanium), Au (gold), Ag (solver), Co (cobalt), Mo (molybdenum), Mn (manganese), Nb (niobium), Ta (tantalum), W (tungsten), Zn (zinc), Fe (iron), Ir (iridium), and Sc (scandium); andin the situation in which cathode polarization measurements are performed-using a measurement solution obtained by mixing a solution of NaCl having a concentration of 5 mass% and acetic acid having a concentration of 99.7% such that the volumetric ratio of the NaCl solution to the acetic acid = 1000:1-on the base material and on the surface-treated aluminum material after it had been heated for 4 hours at a temperature of 200°C, and the current density at the electric potential at the center of an electric-potential region of the base material that exhibits the diffusion-limited current of hydrogen ions was measured, the ratio J1/J2 of the current density J1 of the surface-treated aluminum material to the current density J2 of the base material is 90 × 10-5 or less. A second aspect of the present invention is a surface-treated aluminum material having a base material, which is composed of aluminum or an aluminum alloy, and a protective film, which is formed on the base material, wherein: the protective film is composed of an oxide or oxides of aluminum, and has: an oxide layer, which covers the base material; anda hydrated oxide layer, which covers the oxide layer;the hydrated oxide layer contains: a hydrated oxide or hydrated oxides of aluminum; anda metal oxide or metal oxides and/or a metal hydroxide or metal hydroxides containing one or two or more metal elements selected from the group consisting of Ni, Cr, Zr, Si, Ti, Au, Ag, Co, Mo, Mn, Nb, Ta, W, Zn, Fe, Ir, and Sc; anda sample having the protective film on one surface of the base material was prepared from the surface-treated aluminum material and measured in a state in which a strain gauge is mounted on the sample on a rear surface of the surface having the protective film, the difference ε1 - ε2 between the amount ε1 of strain of the sample at a temperature of 200°C and the amount ε2 of strain of the base material at a temperature of 200°C is 100 × 10-6 or less. A third aspect of the present invention is a metal casing composed of the surface-treated aluminum material according to the above-menti