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Method for preparing porous aluminum oxide by thinning barrier layer

A technology of porous alumina and barrier layer, applied in the direction of anodic oxidation, coating, surface reaction electrolytic coating, etc., can solve the problems of affecting the quality of the film, the inconvenience of metal and metal alloy nanowires, etc., and achieve the orderly arrangement of nanopores, The effect of quality improvement and uniform pore size

Inactive Publication Date: 2008-08-13
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the removal of the barrier layer by chemical methods will seriously affect the quality of the film, which will bring inconvenience to the subsequent preparation of metal and metal alloy nanowires.

Method used

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  • Method for preparing porous aluminum oxide by thinning barrier layer
  • Method for preparing porous aluminum oxide by thinning barrier layer
  • Method for preparing porous aluminum oxide by thinning barrier layer

Examples

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Embodiment 1

[0020] High-aluminum aluminum sheet (purity 99.999%, thickness 0.5mm), annealed in 400 ° C nitrogen environment for 4 hours, then use acetone to remove surface oil, use NaOH dilute solution (0.5M) to remove surface oxide film; and then use a volume ratio of 1: 4H 4 ClO 4 The mixed solution with absolute ethanol was used as a polishing solution, and it was electropolished for 2 minutes in an ice bath under the condition of a DC voltage of 16V. Then the aluminum sheet is anodized once in 1.2M sulfuric acid electrolyte, ice bath, and 20V oxidation voltage. The oxidation time is 4h. Soak in the mixed solution for 1 hour to remove the primary oxide film; then carry out secondary oxidation according to the conditions of the first anodic oxidation, and the oxidation time is 4 hours to obtain a porous alumina template with a pore size of about 18nm to 20nm; after the secondary oxidation, then Apply a voltage of 18V to the porous alumina film for 10 minutes to oxidize, and then drop ...

Embodiment 2

[0022] High-aluminum aluminum sheet (purity 99.999%, thickness 0.5mm), after annealing, degreasing, polishing pretreatment identical with embodiment 1, aluminum sheet is under the conditions of 1.2M sulfuric acid electrolyte, ice bath, 20V oxidation voltage, carry out Primary anodic oxidation, oxidation time 4h, then rinse the surface of the aluminum sheet with distilled water and soak in a mixed solution of 0.6M phosphoric acid and 0.18M chromic acid at 50°C for 1h to remove the primary oxide film. Then carry out secondary oxidation according to the conditions of the first anodic oxidation, and the oxidation time is 4 hours, and the porous alumina template with a pore diameter of about 18nm-20nm can be obtained. After the secondary oxidation, the porous alumina membrane was oxidized by applying a voltage of 17V for 10 minutes, and then the voltage was lowered by 3V every 10 minutes until the voltage dropped to 8V. A porous aluminum oxide membrane template with a pore diameter...

Embodiment 3

[0024] High-purity aluminum sheet (purity 99.999%, thickness 0.5mm), after the same annealing, degreasing, polishing pretreatment as in Example 1, the aluminum sheet is anodized once under the conditions of 1.2M sulfuric acid electrolyte and 20V oxidation voltage , Oxidation time 4h, then rinse the surface of the aluminum sheet with distilled water and soak it in a mixed solution of 0.6M phosphoric acid and 0.18M chromic acid at 50°C for 1h to remove the primary oxide film. Then carry out secondary oxidation according to the conditions of the first anodic oxidation, and the oxidation time is 4 hours, and the porous alumina template with a pore diameter of about 18nm-20nm can be obtained. After the secondary oxidation, the porous alumina membrane was oxidized by applying a voltage of 18V for 15 minutes, and then the voltage was lowered by 2V every 10 minutes until the voltage dropped to 8V. The preparation of the porous alumina template is similar to Example 2.

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Abstract

The invention relates to a method for preparing porous alumina by thinning oxidizing barrier layer. Pretreated aluminum sheet is reoxidized in vitriolic ice-bath electrolyte to get a porous alumina film, the porous alumina film is applied with a voltage, 2 to 3 volts smaller than the oxidization voltage, the voltage is reduced every 10 to 15 minutes, 2 to 5 volts for each time, until the voltage is reduced to 7 to 8 volts, then a porous alumina with thinned oxidizing barrier layer is prepared. The invention removes the oxidizing barrier layer by local current limiting method, which reduces damage caused by removing barrier layer with chemical method to the film quality, results in more ordered nanometer pore canal arrangement, even aperture and great improvement of template quality. Meanwhile, the remained aluminum base can be used as a working electrode, in no need of sputtering or vapor plating conductive metal layer, thus bringing convenience for application to the field of metal and metal alloy nanometer wire preparation.

Description

technical field [0001] The invention belongs to the field of porous alumina preparation, in particular to a method for preparing porous alumina by thinning the oxidation barrier layer. Background technique [0002] The preparation of metal nanostructures by electrochemical deposition using porous alumina as a template has a history of more than ten years. This method can be used to prepare orderly arranged metal nano-arrays, whose special physical and chemical properties can be applied in the fields of optics, electricity, and magnetism. When the porous alumina template is prepared under constant voltage conditions, there is a dense oxide layer called a barrier layer between the aluminum substrate and the porous membrane. Because the thick barrier layer is insulating, the thickness of the barrier layer increases by 1-1.2nm for each volt of voltage increase. Therefore, when using electrochemical methods to prepare nanowires, the barrier layer will hinder the passage of cath...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D11/04C25D11/12
Inventor 李晓天左妍李楠
Owner JILIN UNIV
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