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Method for preparing overlarge crystal-cell porous pellumina

A porous alumina, unit cell technology, applied in electrolytic coatings, surface reaction electrolytic coatings, coatings, etc., can solve problems such as low environmental temperature requirements, high preparation conditions, and complex preparation processes, and achieve high flash voltage. Effect

Inactive Publication Date: 2011-07-20
QINGDAO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

To sum up, in the prior art, the preparation process is relatively complicated, the preparation conditions are high, the ambient temperature is low, the cost of the prepared alumina film material is high, the quality is not easy to guarantee, and the application range is small.

Method used

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  • Method for preparing overlarge crystal-cell porous pellumina
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  • Method for preparing overlarge crystal-cell porous pellumina

Examples

Experimental program
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Effect test

Embodiment 1

[0013] The electrolyte composition is selected as a volume ratio of citric acid aqueous solution to ethylene glycol of 2:1, wherein the weight percentage concentration of the citric acid aqueous solution is 2%, the temperature is 20°C, the primary anodic oxidation voltage is 390V, and the time is 20 hours; figure 1 The scanning electron micrograph of the porous alumina film prepared in this example shows that the unit cell pores of the porous alumina are about 900 nm.

Embodiment 2

[0015] The electrolytic solution is selected to be composed of citric acid aqueous solution and ethylene glycol volume ratio of 2:1, wherein the weight percent concentration of citric acid aqueous solution is 2%, the temperature is 10°C, the primary anodic oxidation voltage is 600V, and the time is 11.5 hours; in the mixed acid solution After removing the aluminum oxide produced in the first anodization, the conditions of the second anodization are the same as the first time, and the time is 2 hours; figure 2 The scanning electron micrograph of the porous alumina membrane prepared for this example shows that the unit cell of the porous alumina is about 1.5 μm.

Embodiment 3

[0017] The electrolytic solution is selected to be composed of citric acid aqueous solution and ethylene glycol volume ratio of 1:2, wherein the weight percent concentration of citric acid aqueous solution is 1%, the temperature is 13°C, the primary anodic oxidation voltage is 700V, and the time is 15.5 hours; the mixed acid solution removes After anodizing the alumina generated in the first anodization, the conditions of the second anodization are the same as the first time, and the time is 2 hours; image 3 The scanning electron micrograph of the porous aluminum oxide membrane prepared for the present embodiment, image 3 a The unit cell of porous alumina is about 1.8 μm, and the pore diameter is about 300nm; in order to obtain a porous membrane with a larger pore size, it can be chemically etched in a phosphoric acid solution with a concentration of 5% by weight at 53°C for 20 minutes, and the pore size is expanded to about 800nm ,like image 3 As shown in a and b, the por...

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Abstract

The invention belongs to the technical field of nanometer physical material preparation, in particular to a method for preparing an overlarge crystal-cell porous pellumina. The method comprises the following steps of: firstly, preparing a mixed solution of citric acid, ethylene glycol and deionized water for an electrolyte, preparing citric acid and deionized water into 1-2% by weight of aqueous citric acid solution; then, compounding the aqueous solution and the ethylene glycol into the electrolyte; selecting an annealed and electrochemically polished aluminum flake as a raw material and controlling the temperature and the anodizing voltage of the electrolyte for primary anodizing to prepare a sample; soaking the sample in the mixed acid solution of chromic acid and phosphoric acid at a controlled temperature and removing alumina generated in the primary anodizing process; and then, carrying out secondary anodizing to make an alumina film with the crystal cell of 2.0 micros and the hole of 800 micros under the condition of primary anodizing parameters. The invention has simple preparation process, reliable principle, high flash voltage, large product crystal-cell size and loose oxidization condition.

Description

Technical field: [0001] The invention belongs to the technical field of nanoscale physical material preparation, and relates to a preparation method of a super large unit cell porous aluminum oxide film. Background technique: [0002] Porous alumina film is a nanostructured alumina material with ordered pores that self-organizes and grows during the anodic oxidation process. An anodic oxidation voltage of 15-27V is usually used in sulfuric acid solution, 40V in oxalic acid, and 40V in phosphoric acid. Usually 60-150V, the pore diameter of the porous alumina membrane is 5-220nm, and the unit cell is 50-350nm. Studies have shown that the unit cell size is directly proportional to the anodizing voltage. In the prior art, in order to obtain a porous membrane with a larger unit cell, a higher anodizing voltage is required. The unit cell of the porous alumina film can reach 500nm under the electrolytic condition of 195V in the phosphoric acid solution, but the experimental condi...

Claims

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Application Information

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IPC IPC(8): C25D11/10C25D11/12
Inventor 王清涛龙云泽孙彬
Owner QINGDAO UNIV
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