Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/12—Anodising more than once, e.g. in different baths
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
  • C25D11/08—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing inorganic acids
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D21/00—Processes for servicing or operating cells for electrolytic coating
  • C25D21/02—Heating or cooling

Definitions

• the present invention relates to a corrosion resistance treatment method for aluminum or an aluminum alloy.
• Patent Document 1 Conventionally, as a method of applying corrosion resistance to aluminum or an aluminum alloy, for example, in Patent Document 1, a surface of an aluminum alloy is treated with a noble anodic acid soot and heated to be degassed. A method is disclosed.
• each of A1050 alloy, A5052 alloy and A6061 alloy is degreased with a weak alkaline degreasing solution and then desmutted in an aqueous nitric acid solution to obtain adipine.
• a barrier type anodizing treatment with acid ammonium was carried out, and when the form of the formed barrier type anodizing film was observed with a scanning electron microscope, a relatively continuous film was formed on the A1050 alloy.
• the films formed on the A5052 alloy and the A6061 alloy have a problem in the corrosion resistance with many defects and the gas release characteristics in a vacuum atmosphere.
• Patent Document 1 Japanese Patent No. 3506827
• the present invention provides a dense anodized anodized film for imparting corrosion resistance to aluminum or aluminum alloy. Accordingly, it is an object of the present invention to provide a corrosion resistance treatment method for aluminum or an aluminum alloy so as to have excellent gas release characteristics.
• a dense acid having a thickness of 5 to 20 nm is formed on the surface of aluminum or aluminum alloy. And forming a barrier layer and thereafter performing a barrier type anodizing treatment.
• the present invention according to claim 2 is characterized in that, in the method according to claim 1, the oxide layer is subjected to an acid solution treatment with an acidic solution.
• the acidic solution contains 50 to 80% by weight of phosphoric acid and 1 to 5% by weight of nitric acid.
• the aluminum or aluminum alloy is immersed in 1 to 10 minutes by heating to ⁇ 100 ° C.
• the present invention according to claim 4 is the method according to any one of claims 1 to 3, wherein the aluminum or aluminum alloy on which the oxide layer is formed is subjected to a vacuum, air or nitrogen atmosphere in the aluminum Alternatively, the barrier type anodizing treatment is performed after heat-treating the aluminum alloy at 150 to 300 ° C.
• the barrier type anodized film is formed by forming a dense oxide layer before forming the barrier type anodized film for imparting corrosion resistance to aluminum or an aluminum alloy. It is possible to obtain a barrier type anodized film that can be made dense and has excellent corrosion resistance and gas release characteristics.
• Aluminum or aluminum alloy that can be used in the present invention is not particularly limited.
• the present invention is effective for 2000 series, 30000 series, 5000 series, and 6000 series aluminum alloys.
• the dense oxide layer formed on the aluminum or aluminum alloy has a thickness of 5 to 20 nm.
• a dense acid-oxide film is a continuous film having no pores of nanometer order or more except for defects due to the presence of non-metallic inclusions.
• this acid layer is less than 5 nm, it becomes a non-uniform oxide film that is difficult to grow continuously in layers, and if it exceeds 20 nm, a dense oxide layer cannot be formed and a porous structure is formed. This is because if a noria-type anodic acid film is grown thereafter, the amount of outgassing increases.
• the method for forming the acid layer is not particularly limited, but it is preferably carried out with an acidic solution.
• the acidic solution contains 50 to 80% by weight of phosphoric acid and 1 to 5% by weight of nitric acid. It is preferable to heat the acidic solution to 80-100 ° C and soak aluminum or aluminum alloy for 1-10 minutes.
• the oxide layer after forming the oxide layer, it is preferable to heat-treat the aluminum or aluminum alloy at 150 to 300 ° C in a vacuum, air or nitrogen atmosphere. This is because acidity can be promoted.
• the noble anodic acid treatment of aluminum or aluminum alloy on which the acid oxide layer is formed is performed by electrolysis with an electrolyte solution.
• aqueous electrolyte solution examples include adipates such as ammonium adipate, borate such as a mixture of boric acid and ammonium borate, and phosphates such as ammonium dihydrogen phosphate. , Tartrate, caate, phthalates such as potassium hydrogen phthalate, carbonates such as sodium carbonate, forces using solutions such as citrate, sodium chromate, etc., or a mixed solution thereof Can be used.
• electrolysis is performed by connecting to a power source so that aluminum or an aluminum alloy material serves as an anode, and an insoluble conductive material is used for the cathode.
• the electrolysis current is not particularly limited, but in the case of a direct current, the direct current density can be about 0.2 to 5 A / cm 2 , and the electrolysis time is an electrolysis such as the thickness of the film to be formed. It can be selected appropriately according to the conditions.
• the applied voltage is not particularly limited, but can be 20 to 500V.
• a surface-cut A5052 alloy disc with a diameter of 45 mm and a thickness of 3 mm was prepared as the workpiece.
• the object to be treated was immersed in an 85 ° C. solution containing 80% by weight phosphoric acid and 3% by weight nitric acid, and then subjected to an acid treatment for 2 minutes while stirring. Next, the object to be treated was immersed in pure water and again immersed in pure water for cleaning.
• the object to be treated was immersed in a 10 wt% ammonium adipate solution at 40 ° C., and a barrier type anodic oxide film was formed at a direct voltage of 200 V for 1 hour.
• This object to be treated was immersed in a solution at 85 ° C. containing 80% by weight phosphoric acid and 3% by weight nitric acid, and then subjected to an acid soaking treatment for 2 minutes while stirring.
• the object to be treated was immersed in pure water, immersed in 50 ° C. pure water, and again immersed in pure water for cleaning.
• Example 1 The same workpiece used in Example 1 was prepared.
• This object to be treated is immersed in a solution at room temperature containing 15% by weight nitric acid and 1% by weight hydrofluoric acid solution for 3 minutes, immersed in pure water, immersed in pure water at 50 ° C, and purified again. It was immersed in water and washed. The washed object was immersed in a 35 wt% nitric acid solution for 1 minute and washed with pure water.
• a barrier type anodic oxide film was formed under the same conditions as in Example 1.
• Example 1 The same workpiece used in Example 1 was prepared.
• This object to be treated was degreased and washed with acetone.
• a barrier-type anodic oxide film was formed on the cleaned object under the same conditions as in Example 1.
• FIG. 1A is a surface SEM image of Example 1
• FIG. 1B is a surface SEM image of Comparative Example 1.
• Example 1 and 2 and Comparative Examples 1 and 2 with an adipate ammonium before forming a noria-type anodic acid husk film were analyzed in the depth direction by Auger electron spectroscopy, and the surface oxide layer was analyzed. Extract 8 points of thickness (nm) so that the measurement positions of each sample correspond to each other. Table 2 shows the results.
• the surface oxide layer thickness is half the value of the oxygen peak.
• the power of the present invention is effective for pure aluminum, 2000 series, 3000 series, 5000 series, and 6000 series anoroleum alloys using an A5052 series aluminum alloy.
• ammonium borate, ammonium phosphate, etc., using ammonium adipate can be used for the barrier type anodizing treatment.
• the corrosion resistance treatment method for aluminum or aluminum alloy of the present invention can be used for imparting corrosion resistance to a member placed in a vacuum atmosphere such as a semiconductor manufacturing apparatus or a thin film forming apparatus.

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• Chemical Kinetics & Catalysis (AREA)
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• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Treatment Of Metals (AREA)
• Inorganic Chemistry (AREA)
• Other Surface Treatments For Metallic Materials (AREA)

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• 2005
  • 2005-05-18 JP JP2005146043A patent/JP4716779B2/ja active Active
• 2006
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  • 2006-05-18 KR KR20077006012A patent/KR100935964B1/ko active IP Right Grant
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