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Anodic oxidation method for raising rigidity and corrosion resistance of plated aluminum on surface of metal base

An anodizing and metal-based technology, applied in anodizing and other directions, can solve the problems of difficulty in improving the surface properties of electroplated aluminum layers, difficult anodizing treatment of electroplated aluminum layers, and low density of electroplated aluminum layers, and achieves significant economic benefits and benefits. Social benefits, improved properties such as hardness and corrosion resistance, and low-cost effects

Inactive Publication Date: 2010-01-06
DALIAN JIAOTONG UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the electroplated aluminum layer obtained on the surface of the metal base is composed of many aluminum crystal particles, and there are many gaps between the aluminum particles, so the obtained electroplated aluminum layer has low compactness.
This surface morphology of the electroplated aluminum layer will make it difficult to anodize the electroplated aluminum layer, which ultimately makes it difficult to improve the surface properties of the electroplated aluminum layer

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Example 1: Low temperature KCl+NaCl+AlCl at a temperature of 150°C 3 In the mixed molten salt, the current density on the surface of Q235 steel is 7.9A / dm 2 Electroplating treatment to obtain a layer of electroplated aluminum on the surface. After the electroplated aluminum layer is heated at a high temperature of 500°C, alkali-etched in a 6g / L NaOH solution for 3 minutes, and polished in a mixed solution of nitric acid, phosphoric acid and sulfuric acid for 3 minutes, the electroplated aluminum layer is placed in a 200g / L Conducted in sulfuric acid solution for 40min with a current density of 1.5A / dm 2 Anodizing treatment under the conditions. The hardness of the electroplated aluminum layer after anodic oxidation treatment and the passive current density of the corrosion resistance in 3.5% NaCl solution are respectively determined by the 59HV of the original electroplated aluminum layer 0.01 and 1.45 (1gI, mA / cm 2 ) reaches the processed 567HV 0.01 and -0.98 (1gI...

Embodiment 2

[0019] Example 2: First, an electroplated aluminum layer of a certain thickness is obtained on the surface of Q235 steel by molten salt electroplating, and the molten salt system is KCl+NaCl+AlCl 3 , the temperature is 150°C, the current is the current density is 7.9A / dm 2 . It was subjected to a high-temperature heat treatment at 300°C, an alkali etching treatment for 3 minutes, and a polishing treatment for 3 minutes. The alkali etching solution and polishing solution used are 6g / L NaOH solution and a mixed solution composed of nitric acid, phosphoric acid and acetic acid, respectively. After that, place the electroplated aluminum layer in 130g / L sulfuric acid solution for anodic oxidation treatment, the oxidation time is 60min, and the current density is 1.5A / dm 2 , after the electroplated aluminum layer is treated by the above process, its hardness is changed from the original 73HV 0.01 Increased to 606HV 0.01 .

Embodiment 3

[0020] Example 3: First, an electroplated aluminum layer of a certain thickness is obtained on the copper surface by molten salt electroplating, and the molten salt system is KCl+NaCl+AlCl 3 , the temperature is 150°C, the current is the current density is 4A / dm 2 . The obtained electroplated aluminum layer was subjected to high-temperature heating treatment at 500°C, alkaline etching treatment in 6g / L NaOH alkaline etching solution for 3 minutes, and polishing in a mixed polishing solution composed of nitric acid, phosphoric acid and sulfuric acid for 3 minutes. deal with. Afterwards, the electroplated aluminum layer was placed in 8% chromic acid solution for anodic oxidation treatment, the oxidation time was 40min, the corrosion resistance of the oxide film was significantly improved, and the passivation current density in 3.5% NaCl solution was reduced from the original 1.05 (1gI, mA / cm 2 ) to -2.13 (1gI, mA / cm 2 ).

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Abstract

This invention relates to an anodic oxidation method for improving hardness and corrosion resistance of aluminum-electroplating coating on metal matrix. The method comprises: electroplating aluminum on the surface of metal material by high-temperature or low-temperature molten salt electroplating method to obtain aluminum-electroplating coating, heating at 200-750 deg.C, treating with alkali, polishing, placing in an electroplating solution, and performing anodic oxidation to obtain an aluminum oxide film with a certain thickness on the surface of the metal material. The obtained aluminum-electroplating coating containing aluminum oxide film has such advantages as high hardness and high corrosion resistance. The method has such advantages as low cost and simple process.

Description

technical field [0001] The invention relates to a metal material surface modification process, in particular to an anodic oxidation method for improving the hardness and corrosion resistance of an electroplated aluminum layer on the surface of a metal base. Background technique [0002] Metal materials are the most widely used important engineering materials in modern times, especially steel materials occupy an extremely important position in production, construction and daily life. However, due to the reasons of the metal material itself and the influence of the environmental medium when it is in service, it is inevitable that corrosion, wear and other forms of damage will occur on its surface, which will reduce the service life of the metal material and cause huge economic losses to humans. . During the service of many metal materials, most of the damage occurs on the surface of the material. Therefore, improving the surface properties of materials has become an effectiv...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25D11/04C25D11/18C25D3/66C25D5/48
Inventor 丁志敏张浩沈长斌阎颖高宏
Owner DALIAN JIAOTONG UNIVERSITY