Aluminum anodizing electrolyte for improving oxide film adhesion density of electrode foil

By optimizing the formulation and process conditions of the aluminum anodizing electrolyte, the problem of insufficient oxide film adhesion density and uniformity in the existing technology has been solved, and the high uniformity and reliability requirements of high-performance aluminum electrolytic capacitors have been achieved.

CN121023607BActive Publication Date: 2026-07-10GUANGDONG HENGYANG ELECTRONIC TECHNOLOGY CO LTD
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Patent Information

Application Number
CN202511141124.6
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2025-08-15
Publication Date
2026-07-10
Estimated Expiration
2045-08-15

AI Technical Summary

Technical Problem

Existing aluminum anodizing electrolyte systems have shortcomings in reaction rate, film structure, and adhesion density, making it difficult to meet the requirements of high uniformity and high reliability of film layers for high-performance aluminum electrolytic capacitors.

Method used

An electrolyte formulation containing ammonium dihydrogen phosphate, sulfuric acid, nano-titanium dioxide or nano-alumina, and organic buffers is used. By controlling the pH value within the range of 4.5 to 6.0, nanoparticles are used as nucleation centers to promote the directional crystallization of γ′-Al2O3, thereby improving the adhesion density and uniformity of the oxide film. The dispersibility of nanoparticles is improved by using surfactants.

Benefits of technology

It significantly improves the adhesion density and crystallinity of the oxide film, enhances film uniformity, strengthens waterproofing, improves specific volume stability and formation efficiency, and reduces production costs.

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Abstract

The application discloses an aluminum anodic oxidation electrolyte for improving the oxide film adhesion density of an electrode foil, and relates to the technical field of anodic oxidation. The electrolyte comprises 3-10% of ammonium dihydrogen phosphate, 0.5-3% of sulfuric acid, 0.01-0.2% of nano titanium dioxide or nano aluminum oxide, 0.05-0.5% of an organic buffer, and the rest is deionized water. The organic buffer is used for stabilizing the pH value in the range of 4.5-6.0. The nano titanium dioxide or nano aluminum oxide serves as an oxide film nucleation center and promotes the directional crystallization of gamma'-Al2O3. The sulfuric acid component improves the electrolyte conductivity. The ammonium dihydrogen phosphate generates an aluminum phosphate barrier layer on the surface of the oxide film, thereby enhancing the waterproof performance of the film layer. The electrolyte can significantly improve the adhesion density and crystallinity of the oxide film, improve the uniformity and waterproof performance of the film layer, improve the specific capacity stability and formation efficiency, and is suitable for the continuous production of high-performance aluminum electrolytic capacitors.
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