Preparation of aluminum or aluminum alloy dual-layer anodic oxide film and preparation of multi-color coloring film thereof

A technology of anodic oxidation film and aluminum alloy, applied in the direction of coating, surface reaction electrolytic coating, electrolytic coating, etc., can solve problems such as difficult technology, complicated process, and difficult to master in actual operation

Inactive Publication Date: 2012-01-25
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In short, multi-color electrolytic coloring makes up for the lack of monotonous color of ordinary electrolytic coloring. Some technologies have been appl

Method used

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  • Preparation of aluminum or aluminum alloy dual-layer anodic oxide film and preparation of multi-color coloring film thereof
  • Preparation of aluminum or aluminum alloy dual-layer anodic oxide film and preparation of multi-color coloring film thereof

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0025] Embodiment one

[0026] 1) Pretreatment: use 250g / L NaOH, 460g / L NaNO 3 , 1g / L CoSO 4 The composed chemical polishing solution is used to chemically polish the sample. The temperature is 80-95°C, and the time is 10-20s. Aluminum samples were rinsed repeatedly with deionized water after polishing.

[0027] 2) Anodizing: take 3 pretreated aluminum samples and carry out anodizing treatment respectively. The bath composition is 184g / L H 2 SO 4 and 1g / LAl 2 (SO 4 ) 3 . At room temperature (20-25°C), first use DC 1A / dm 2 Oxidize for 20min, and then use a sine wave asymmetric alternating current in the same anodizing tank (the average current density of the anode is 1.5A / dm 2 , the ratio of the average current density of the anode to the average current density of the cathode is 3:1) respectively oxidized for 10 min, 15 min or 20 min to obtain double-layer anodized films with different AC film thicknesses.

[0028] 3) Electrolytic coloring: the above three double-l...

Example Embodiment

[0030] Embodiment two

[0031] 1) Mechanical pretreatment: use sandblasting or sandpaper grinding to remove foreign matter such as burrs, firm oxides, lubricants for extrusion, cutting oil, etc., reduce surface roughness, and wash with water.

[0032] 2) Chemical polishing: use 300g / L NaOH, 500g / L NaNO 3 , 2g / L CoSO 4 The composed chemical polishing solution is used to chemically polish the sample. Temperature 80~95℃, time 10-20s, wash with water.

[0033] 3) Anodizing: take 3 pre-treated aluminum samples and carry out anodizing treatment respectively. The bath composition is 184g / L H 2 SO 4 and 8g / L H 2 C 2 o 4 . At room temperature, adopt symmetrical sine wave AC 1A / dm 2 Oxidize for 10min, 15min or 20min respectively. During the oxidation process, the voltage rises from 21V to 23V. Then use DC 1.5A / m in the same anodizing tank 2 Oxidation for 15min. A double-layer anodized film whose outer layer is a common AC film and whose inner layer is a DC film is obtained....

Example Embodiment

[0036] Embodiment Three

[0037] 1) Mechanical pretreatment: Sandblasting and sandpaper grinding are used to remove foreign matter such as burrs, firm oxides, lubricants for extrusion, cutting oil, etc., and reduce surface roughness. wash.

[0038] 2) Chemical polishing: use 300g / L NaOH, 520g / L NaNO 3 , 5g / L CoSO 4 The composed chemical polishing solution is used to chemically polish the sample. The temperature is 80-95°C, and the time is 10-20s. wash.

[0039] 3) Anodizing: take 3 pre-treated samples for anodizing treatment. The bath composition is 184g / LH 2 SO 4 and 1g / LAl 2 (SO 4 ) 3 . At room temperature, using pulsed DC 2A / dm 2 , The working ratio is 80%, respectively oxidized for 10min, 15min or 20min, and then in the same anodic oxidation tank, use a sine wave alternating current with a constant current of 1A / dm 2 Oxidize for 20 minutes to obtain a double-layer anodic oxidation film (wherein, the film layer structure and elemental analysis of No. 3 test pie...

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Abstract

The invention provides preparation of an aluminum or aluminum alloy dual-layer anodic oxide film and preparation of a multi-color coloring film thereof, and particularly provides a preparation method of a high-decoration multi-color alumina coloring film by forming a dual-layer oxide film on the surface of aluminum or aluminum alloy by adopting a twice anodic oxidation method in the same medium, and performing electrolytic coloring treatment. The preparation method comprises the following steps: oxidizing an aluminum sample which is subjected to mechanical pre-treatment, deoiling and polishing in sulfuric acid or oxalic acid containing electrolyte with current density between 0.5 and 2A/dm<2>by adopting power waveform; and keeping on oxidization for 8 to 20 minutes with current density of between 0.5 and 2A/dm<2> by adopting a second type of power waveform in the same oxidation tank. A dual-layer anodic oxide film with different structures and compositions is prepared by controlling changes of two types of power waveforms and changes of electrolytic parameter oxidation time and current density related to the power waveforms, and the dual-layer anodic oxide film is subjected to electrolytic coloring by adopting a conventional electrolytic coloring method. The structures and compositions of the dual-layer film can be regulated by the power waveform and electrolytic parameters of twice anodic oxidations, so that colors and tones of the film can be regulated and changed in a large range after the electrolytic coloring, and an alumina coloring film which is more colorful than that by conventional oxidation-electrolytic coloring can be acquired.

Description

technical field [0001] The invention belongs to the surface treatment technology of aluminum and its alloys, and relates to a method for preparing a double-layer anodic oxidation film on the surface of the aluminum and its alloys by an electrochemical method, and forming a highly decorative aluminum anodic oxidation coloring film layer after electrolytic coloring. The invention belongs to the field of protective decoration of aluminum and its alloy surface. Background technique [0002] The anodized film of aluminum obtained in sulfuric acid is colorless and porous, and is often used in electrolytic coloring to improve the decorative properties of aluminum. Electrolytic coloring is due to the scattering of incident light by metal particles deposited at the bottom of the porous layer. The more sediment in the pores, the darker the color due to multiple scattering. Generally speaking, the colors obtained from various industrial electrolytic coloring solutions are relatively ...

Claims

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Application Information

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IPC IPC(8): C25D11/12C25D11/22
Inventor 旷亚非唐胜果周海晖刘书黄鹏程
Owner HUNAN UNIV
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