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Preparation method of porous alpha-alumina membrane

A technology of aluminum oxide film and anodized aluminum, which is applied in the field of nano-synthesis and micro-nano, can solve the problems of periodic hexagonal close-packed structure damage, membrane curling, cracking, etc., and achieve orderly arrangement, smooth membrane and wide application foreground effect

Inactive Publication Date: 2015-03-11
常毅
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, since the composition of the porous alumina membrane prepared by anodic oxidation is mainly composed of amorphous alumina and alumina hydrate: alumina trihydrate (namely aluminum hydroxide), this composition characteristic determines the porous anode The aluminum oxide film will lose a lot of water at high temperature, which will cause the film to curl or crack macroscopically, and the ordered periodic hexagonal close-packed structure on the microscopic level will be destroyed.

Method used

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  • Preparation method of porous alpha-alumina membrane
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  • Preparation method of porous alpha-alumina membrane

Examples

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Effect test

Embodiment 1

[0031] A method for preparing a porous α-alumina membrane, comprising the steps of:

[0032] (1) Use conventional techniques to anneal and electropolish pretreatment of high-purity aluminum foil with a purity of more than 99.99%; put it in a muffle furnace for annealing to eliminate the internal stress of the aluminum foil; Ultrasonic cleaning in medium to remove surface grease; then put the cleaned aluminum foil into perchloric acid absolute ethanol mixture for electropolishing at a constant voltage of 21V;

[0033] (2) Use the aluminum foil pretreated in step (1) as the anode, and graphite as the cathode, and perform two-step anodization in a mixed solution of phosphoric acid and aluminum oxalate to obtain an aluminum-based porous anodized aluminum film; two-step anodization The mass ratio of phosphoric acid in the electrolyte used is 0.01-5%, the concentration of aluminum oxalate is 0.005-0.05 mol / liter, the anodic oxidation voltage is 180V-250V, the electrolyte temperature...

Embodiment 2

[0040] A method for preparing a porous α-alumina membrane, comprising the steps of:

[0041] (1) Put high-purity aluminum foil (above 99.99% purity) into a muffle furnace for annealing at 450°C for 6 hours to eliminate the internal stress of the aluminum foil, and ultrasonically clean the annealed aluminum foil for 15 minutes in acetone and absolute ethanol solutions respectively, To remove surface grease; then put the cleaned aluminum foil into a perchloric acid absolute ethanol mixture with a volume ratio of 1:4 for electropolishing at a constant voltage of 21V;

[0042] (2) Use the aluminum foil pretreated in step (1) as the anode, and graphite as the cathode, and perform two-step anodization in a mixed solution of 1% phosphoric acid and 0.01 mol / liter aluminum oxalate by mass ratio; the anodic oxidation voltage is 210V , the electrolyte temperature is 5°C, and the anodic oxidation time is 8 hours;

[0043] (3) The aluminum-based porous anodic aluminum oxide membrane prepare...

Embodiment 3

[0049] This embodiment is implemented under the following technical requirement conditions:

[0050] Other conditions are the same as in Example 2 in this example. The aluminum foil pretreated in step (1) was used as the anode, graphite was used as the cathode, and two-step anodic oxidation was carried out in a mixed solution with a mass ratio of 0.03% phosphoric acid and 0.005 mol / L aluminum oxalate. The anodizing voltage was 185V, the electrolyte temperature was 0°C, and the anodizing time was 10 hours. By implementing the above method, a porous α-alumina inorganic membrane with a periodic hexagonal close-packed through-hole structure is finally prepared.

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Abstract

A preparation method of a porous alpha-alumina membrane comprises the following steps: carrying out an annealing and electric polishing pretreatment on a high purity aluminum foil; taking the processed aluminum foil as the positive electrode, and graphite as the negative electrode, then carrying out two-step positive electrode oxidation in a mixed solution of phosphoric acid and aluminum oxalate to obtain an aluminum-base-containing porous anodic alumina membrane; subjecting the obtained aluminum-base-containing porous anodic aluminum membrane to a pore enlarging treatment; then subjecting the pore-enlarged aluminum-base-containing porous anodic alumina membrane to a water boiling treatment or a hydrothermal treatment; then removing the aluminum base from the aluminum-base-containing porous anodic alumina membrane, which has been treated by water boiling or a hydrothermal treatment; using a sodium citrate solution to remove the baffle layer and alumina hydrate on the external layer of the porous alumina membrane from the aluminum-base-free porous anodic alumina membrane so as to form a periodical hexahedral densely-arranged alumina through hole structure finally; and sintering the prepared alumina membrane with a periodical hexahedral densely-arranged alumina through hole structure in a muffle furnace at a high temperature so as to obtain porous alpha-alumina membrane.

Description

technical field [0001] The invention relates to the fields of nano-synthesis and micro-nano technology, in particular to a method for preparing an α-alumina inorganic film with a periodic hexagonal close-packed through-hole structure. Background technique [0002] Since α-alumina is the most stable phase among all aluminas, it has the characteristics of high melting point and excellent chemical stability, so α-alumina inorganic membranes are widely used in many fields including assembly of nanomaterials, filtration and separation. In the process of preparing the α-alumina inorganic membrane, different methods can be used to prepare it according to the different factors such as membrane pore size and material. Common methods include solid particle sintering method (suspended particle method), anodic oxidation method, epitaxial molecular sieve, molecular self-assembly, laser etching and other methods. [0003] The porous anodic aluminum oxide membrane prepared by anodic oxida...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D11/08C25D11/10C25D11/24C25D11/18C25D11/16
CPCC25D11/08C25D11/10C25D11/12C25D11/16C25D11/18C25D11/24
Inventor 常毅
Owner 常毅
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