KR-20260064630-A - MANUFACTURING METHOD OF ANODIZED ALUMINIUM OXIDE MEMBRANE WITH MACRO PORE BY ANODIZING APPLIED HIGH VOLTAGE

KR20260064630AKR 20260064630 AKR20260064630 AKR 20260064630AKR-20260064630-A

Abstract

The present invention relates to a method for phosphoric acid anodic oxidation by applying high voltage and a method for manufacturing a large-pore anodic oxidation membrane using the same. More specifically, the invention relates to a method for anodic oxidation by applying high voltage that can manufacture an anodic oxidation membrane having large pores of 200 nm or more by anodic oxidation in a phosphoric acid solution while sequentially increasing the voltage by applying a high voltage of 190 V or more, a method for manufacturing a large-pore anodic oxidation membrane using the same, and a large-area, large-pore anodic oxidation membrane manufactured by the same.

Inventors

김태선
남호철
임현홍

Assignees

주식회사 헥사프로

Dates

Publication Date: 20260507
Application Date: 20251030
Priority Date: 20241030

Claims (14)

i) a step of preparing an aluminum substrate, for preparing an aluminum substrate; ii) a first anodizing step of immersing the aluminum substrate in a solution containing phosphoric acid, maintaining the temperature of the solution containing phosphoric acid at -5°C to -2°C, and performing anodic oxidation while increasing the applied voltage from 10V to 195V to 200V to form a first anodic oxidation layer on the aluminum substrate; iii) a first etching step for removing a first anodic oxide layer formed on the surface of the aluminum substrate; and iv) a second anodizing step comprising immersing the aluminum substrate from which the first anodic oxide layer has been removed in a solution containing phosphoric acid, maintaining the temperature of the solution containing phosphoric acid at -5°C to -2°C, and performing anodic oxidation while increasing the applied voltage from 10V to 195V to 200V to form a second anodic oxide layer on the aluminum substrate; Method for manufacturing an anodic oxidation membrane by high voltage application anodic oxidation.
In Article 1, The above first anodizing step A 1-1 step-up step of performing anodizing while stepping up the applied voltage from 10V to 170V; A first-second step-up stage for performing anodizing while increasing the applied voltage from 170V to 175V; A first-third step-up step of performing anodizing while increasing the applied voltage from 175V to 195V to 200V; and A first-to-fourth step-up step of performing anodizing while maintaining the applied voltage at 195V to 200V; comprising, In the above 1-1 boosting step Anodizing is performed by maintaining an applied voltage of 10V and a current limit of 0.5A for 60 seconds, and then the applied voltage is gradually increased at a rate of 10V/1 time, and anodizing is performed by maintaining the increased voltage for 60 seconds, thereby sequentially increasing the applied voltage up to 170V. In the above 1st-2nd boosting stage After performing anodizing at a boosted voltage of 170V while maintaining a current limit of 0.5A for 30 seconds, the applied voltage is then boosted by 5V to 175V, and anodizing is performed while maintaining the boosted voltage for 3 hours. In the above 1st-3rd boosting stages Set the current limit to 0.5A, increase the applied voltage from 170V to 195V or 200V at a rate of 1V/1 cycle, and perform anodizing while maintaining the increased voltage for 6 seconds. In the above 1st-4th boosting steps Performing anodizing for 15 hours while maintaining an applied voltage of 195V to 200V and a current limit of 0.5A. Method for manufacturing an anodic oxidation membrane by high voltage application anodic oxidation.
In Article 1, The above second anodizing step 2-1 step-up, which performs anodizing while stepping up the applied voltage from 10V to 190V; A 2-2 step-up step of performing anodizing while increasing the applied voltage from 190V to 195 to 200V; and A second-third step-up step of performing anodizing while maintaining an applied voltage of 195 to 200V; comprising, In the above 2-1 boosting step Anodizing is performed by maintaining the voltage for 60 seconds at an applied voltage of 10V and a current limit of 0.5A, and then anodizing is performed by increasing the voltage at a rate of 10V/1 time and maintaining the increased voltage for 60 seconds, thereby performing anodizing while sequentially increasing the applied voltage up to 190V. In the above 2-2 boosting step Perform anodizing while maintaining the voltage at an applied voltage of 190V and a current limit of 0.5A for 30 seconds, and thereafter, increase the applied voltage by 5V in one step with a current limit of 0.5A to 195V to 200V, and perform anodizing while maintaining the increased voltage for 30 seconds. In the above 2nd-3rd boosting stage Performing anodizing while maintaining a final applied voltage of 195V to 200V and a current limit of 0.5A for 15 hours Method for manufacturing an anodic oxidation membrane by high voltage application anodic oxidation.
In Article 1, The above solution containing phosphoric acid is prepared by mixing distilled water and ethanol in a volume ratio of 4:1 to 5:5 in a solvent, and maintaining the concentration of phosphoric acid at 0.05 to 2 wt%. Method for manufacturing an anodic oxidation membrane by high voltage application anodic oxidation.
In Article 1, v) a third anodizing step of forming a third anodic oxide layer by immersing the aluminum substrate having the second anodic oxide layer formed thereon in a sulfuric acid solution, and then performing anodic oxidation while maintaining the temperature of the sulfuric acid solution at -5°C to -2°C and sequentially increasing the applied voltage from 10V to 195V to 200V; and vi) a second etching step for removing the third anodic oxide layer generated in the third anodizing step to separate the second anodic oxide layer from the aluminum substrate; further comprising Method for manufacturing an anodic oxidation membrane by high-voltage application anodic oxidation
In Article 5, v) In the third anodizing step above, the current limit is 0.2 to 1 A, and the anodizing is performed. Method for manufacturing an anodic oxidation membrane by high-voltage application anodic oxidation
In Article 5, The concentration of the sulfuric acid solution in the above v) third anodizing step is 60 wt% to 98 wt%. Method for manufacturing an anodic oxidation membrane by high-voltage application anodic oxidation
In Article 5, In the above vi) second etching step, The aluminum substrate having the second anodic oxide layer and the third anodic oxide layer formed thereon is immersed in a phosphoric acid solution having a concentration of 4 wt% to 8 wt% at 30°C to 50°C for 2 minutes to 2 hours. Method for manufacturing an anodic oxidation membrane by high-voltage application anodic oxidation
In Article 5, vii) a step of expanding the pores of the anodic oxidation membrane; further comprising Method for manufacturing an anodic oxidation membrane by high-voltage application anodic oxidation
In Article 9, In the step of expanding the pores of the anodic oxidation membrane vii) above, Immersing the anodic oxidation membrane in a 4 wt% to 8 wt% phosphoric acid solution at 30°C to 50°C for 2 minutes to 2 hours Method for manufacturing an anodic oxidation membrane by high-voltage application anodic oxidation
An anodic oxidation membrane manufactured by the manufacturing method of claims 1 to 10
In Article 11, The above anodic oxidation membrane has a pore size of 150 nm or more and an interpore distance of 400 nm or more. anodic oxidation membrane
In Article 11, The above anodic oxidation membrane has a pore size of 300 nm or more and an interpore distance of 400 nm or more. anodic oxidation membrane
In Article 11, The above anodic oxidation membrane is 100 mm * 100 mm or larger and has a thickness of 10 μm or larger. anodic oxidation membrane

Description

Manufacturing Method of Anodic Oxidized Aluminum Oxide Membrane with Macro Pore by Anodic Oxidation with High Voltage Application The present invention relates to a method for phosphoric acid anodic oxidation by applying high voltage and a method for manufacturing a large-pore anodic oxidation membrane using the same. More specifically, the invention relates to an anodic oxidation method capable of manufacturing an anodic oxidation membrane having large pores of 200 nm or more by using a phosphoric acid solution as an electrolyte and stably applying a high voltage of 190 V to 200 V or more to anodic oxidation, and to a large-area, large-pore anodic oxidation membrane manufactured by the same. When aluminum is electrochemically anodic oxidized in an aqueous solution containing an electrolyte such as sulfuric acid, oxalic acid, or phosphoric acid, a thick anodic oxide film is formed on the surface. Anodic oxide films exhibit minimal thermal deformation in high-temperature environments and possess electrical insulating properties. Research is underway to utilize these physical and/or electrical characteristics in various fields. It is known that the structure of the porous layer and the boundary layer, such as the pore spacing, pore size, and boundary layer thickness, of such anodized films, which have regular spacing pores that grow from the outer surface toward the inner metal, is generally independent of the type or temperature of the electrolyte and is predominantly determined by the applied voltage. It is known that well-aligned porous alumina oxide membranes are synthesized under specific anodic oxidation conditions depending on the electrolyte solution. Previously, there were many anodized aluminum membranes using sulfuric acid, phosphoric acid, or oxalic acid as electrolytes, but in each electrolyte, well-aligned anodic oxidation membranes were produced only under appropriate voltage conditions, and the controllable pore size was limited. In particular, it was known that in order to produce a large-pore anodic oxidation membrane of 100 nm or more, phosphoric acid must be used as the electrolyte and a voltage of 190 V or higher must be applied. However, when such high voltage of 190 V or higher is applied, a burning phenomenon occurs in which the aluminum metal burns during the anodizing process, so it is not known that large-pore anodic oxidation membranes can be produced over a large area. Therefore, there were limitations in synthesizing anodic alumina films having large nanopores with a pore size of 150 nm or more using the conventional anodizing method with an electrolytic solution. Accordingly, while conducting research in consideration of the technical limitations mentioned above, the inventors confirmed that even when anodizing with a voltage of 190V or higher is performed using a phosphoric acid solution as an electrolytic solution, a well-aligned anodic oxidized alumina membrane with large nanopores of 150 nm or more can be stably synthesized without surface burning by improving the voltage boosting process, and thus completed the present invention. FIG. 1 shows an aluminum substrate on which a first anodizing process has been performed, manufactured according to an embodiment of the present invention. FIG. 2 shows an aluminum substrate that has undergone a second anodizing process manufactured according to an embodiment of the present invention. FIG. 3 shows an aluminum substrate that has been processed up to the first anodizing step according to a comparative example of the present invention. FIG. 4 shows an aluminum substrate that has been subjected to a second anodizing step according to a comparative example of the present invention. Figure 5 shows an anodic oxidation membrane manufactured according to an example of the present invention. Figures 6 and 7 show the SEM measurement results of an anodic oxidation membrane manufactured according to an embodiment of the present invention. Figure 8 shows the SEM measurement results of an anodic oxidation membrane prepared according to a comparative example of the present invention. FIG. 9 shows an aluminum substrate that has been subjected to the second anodizing step in an embodiment of the present invention. FIG. 10 shows an anodic oxidation membrane manufactured according to an example of the present invention. Figures 11 and 12 show the SEM measurement results of an anodic oxidation membrane manufactured according to an embodiment of the present invention. The present invention will be explained in more detail below through examples. However, the present invention is not limited by the following examples. <Example 1> <Example 1-1> Pretreatment of an aluminum substrate by electrolytic polishing Electropolishing was performed on a 99.999% pure aluminum plate with dimensions of 100mm * 100mm and a thickness of 1mm. A titanium mesh coated with platinum was used as the counter electrode of an aluminum plate and immersed in a perchloric acid + eth