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Method for preparing dense fluoride ceramic films on magnesium surface and magnesium alloy surface

A technology of magnesium alloy and fluoride, which is applied in the direction of surface reaction electrolytic coating, anodic oxidation, metal material coating technology, etc., can solve the problem of high content of MgO in the oxide film, and achieve the effect of good bonding, low equipment and uniform thickness

Inactive Publication Date: 2010-09-29
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, there is a large amount of OH in the solution - It is inevitable to transport a large amount of oxygen atoms to the oxide film, resulting in a higher MgO content in the oxide film

Method used

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  • Method for preparing dense fluoride ceramic films on magnesium surface and magnesium alloy surface
  • Method for preparing dense fluoride ceramic films on magnesium surface and magnesium alloy surface

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1. Material preparation: Pure magnesium is cleaned and degreased by ultrasonic cleaning in acetone solution after cutting and grinding.

[0023] 2. Chemical passivation: in the passivation solution, 85% (volume concentration) H 3 PO 4 5ml / L, NH 4 HF 2 100g / L, the rest is water. The temperature is 10-35°C, and the treatment is for 20-30 seconds. Immediately after taking it out, wash it with tap water for 1-2 minutes, and then wash it with deionized water for 1-2 minutes. The thickness of the passivation film is 1nm.

[0024] 3. Preparation of single-pulse micro-arc oxidation film: NaF 20g / L, HF 5ml / L, C 6 h 5 o 7 Na 3 2g / L, NaH 2 PO 4 5g / L, the rest is water. pH=3.5~4.0, temperature 30°C, treatment for 10 minutes, power supply mode: single forward, final oxidation voltage 320V, current density 3A / dm 2 , frequency 500Hz, duty cycle 10 -3 ms, the thickness of the oxide film in this embodiment is about 10um.

[0025] 4. Double-pulse micro-arc oxidation film pre...

Embodiment 2

[0029] 1. Material preparation: After AZ31B magnesium alloy is cut and polished, use ultrasonic cleaning in acetone solution to remove oil.

[0030] 2. Chemical passivation: in the passivation solution, 85% H 3 PO 4 2~5ml / L, the rest is water. The temperature is 40-70°C, and it is treated for 0.5-5 minutes. Immediately after taking it out, it is washed with tap water for 1-2 minutes, and then with deionized water for 1-2 minutes. The thickness of the passivation film is 2nm.

[0031] 3. Preparation of single-pulse micro-arc oxidation film: NaF 15g / L, H 3 PO 4 5ml / L, C 4 h 4 o 6 Na 2 2H 2 O 2g / L, Na 2 HPO 45g / L, the rest is water. pH=3.5~4.0, temperature 20°C, treatment for 10 minutes, power supply mode: single forward, final oxidation voltage 300V, current density 3A / dm 2 , frequency 800Hz, duty cycle 10 -3 ms, the thickness of the oxide film in this embodiment is about 10um.

[0032] 4. Double-pulse micro-arc oxidation film preparation: NaF 15g / L, H 3 PO 4 5ml...

Embodiment 3

[0036] 1. Material preparation: After AZ91D magnesium alloy is cut and polished, use ultrasonic cleaning in acetone solution to degrease.

[0037] 2. Chemical passivation: In the passivation solution, HF is 30ml / L, and the rest is water. The temperature is room temperature, and the treatment time is 30 seconds. Immediately after taking it out, wash it with tap water for 1-2 minutes, and then wash it with deionized water for 1-2 minutes. The thickness of the passivation film is 1mm.

[0038] 3. Preparation of single-pulse micro-arc oxidation film: KF 30g / L, HF 3ml / L, C 6 h 5 o 7 K 3 2H 2 O 3g / L, K 5 P 3 O106g / L, the rest is water. pH=3.5~4.0, temperature 40℃, treatment for 10 minutes, power supply mode: single forward, final oxidation voltage 350V, current density 2A / dm 2 , frequency 1000Hz, duty cycle 10 -3 ms, the thickness of the oxide film in this embodiment is about 10um.

[0039] 4. Preparation of double-pulse micro-arc oxidation film: KF 30g / L, HF 3ml / L, C 6 h...

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Abstract

The invention relates to a method for preparing dense fluoride ceramic films on a magnesium surface and a magnesium alloy surface and belongs to the technical field of metal surface treatment. The method comprises the following steps of: chemically passivating a magnesium alloy; preparing a single-pulse ceramic film; and preparing a double-pulse ceramic film. In a chemically passivating process, solution such as hydrofluoric acid, phosphoric acid, hydrogen fluoride amine and the like are used; the preparations of the single-pulse ceramic film and the double-pulse ceramic film are mainly performed in a fluoride electrolyte-containing system, wherein potassium fluoride (sodium) is taken as a main salt; phosphate is taken as an additive; and citrate or tartrate is taken as a main stabilizing agent. The fluoride ceramic film obtained by the method is complete and dense, has high hardness, is firmly combined with a substrate, can be separately used as a protective layer and can be prepared into a composite surface functional layer which has higher corrosion resistance, higher wearing resistance and high hardness after subsequent processing treatment. The overall process of the method has the advantages of simple flow, low equipment cost, environment friendliness and the like.

Description

Technical field: [0001] The invention relates to a method for preparing a dense fluoride ceramic film on the surface of magnesium and magnesium alloys, belonging to the technical field of metal surface treatment. Background technique: [0002] Due to its high specific strength, specific stiffness, and good damping properties, magnesium alloy is the most potential metal structural material to meet the development of lightweight and environmental protection. It has wide application value in automobile industry, aerospace industry and electronic industry. However, the thermodynamic stability of magnesium is poor, and the oxide (film) structure is loose (PBR<1), resulting in poor corrosion resistance of magnesium alloys, which have a serious corrosion tendency under normal service conditions. Moreover, due to the high activity of magnesium, the requirements for the integrity of the coating / plating layer and the ability to resist mechanical damage are high, and the binding fo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F17/00C23C22/00C23C22/36C25D11/06C25D11/08C25D11/10C25D11/30
Inventor 张伟杜克勤严川伟王福会
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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