Magnesium alloy anodizing electrolyte and method for preparing anodic oxide film by electrolyte

An anodizing and electrolyte technology, applied in anodizing and other directions, can solve the problems of film morphology, color uneven, affecting the practical value of magnesium alloys, different electrical parameters, etc., to achieve excellent corrosion resistance, low cost, and economical energy effect

Active Publication Date: 2015-11-18
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, most of the environmentally friendly electrolyte systems for magnesium alloys are concentrated in the anodic oxidation spark discharge area, where the energy consumption is large, the equipment is complicated, and it is difficult to be widely used.
Since the non-spark discharge process is different from the spark discharge anodic oxidation process, the influence of electrical parameters is also different, and the influence of electrical parameters on the non-spark discharge process needs to be further studied
There are few studies on low-voltage anodic oxidation, and most of the film morphology and color are uneven, which affects the practical value of magnesium alloys.

Method used

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  • Magnesium alloy anodizing electrolyte and method for preparing anodic oxide film by electrolyte
  • Magnesium alloy anodizing electrolyte and method for preparing anodic oxide film by electrolyte
  • Magnesium alloy anodizing electrolyte and method for preparing anodic oxide film by electrolyte

Examples

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Embodiment 1

[0025] A magnesium alloy anodic oxidation electrolyte consists of: sodium tetraborate 20g / L, boric acid 10g / L, sodium hydroxide 5g / L, sodium carbonate 5g / L, sodium citrate 6g / L; adopt 20wt% sodium hydroxide The solution adjusts the pH of the electrolyte to 8.5.

[0026] The method for preparing a black anodized film by utilizing the above-mentioned magnesium alloy anodic oxidation electrolyte comprises the following steps:

[0027] 1) Pre-treatment: sand paper to 1500#, then put the magnesium alloy into the alkaline washing solution at 55°C for 15 minutes; the alkaline washing solution consists of 50g / L sodium hydroxide and 20g / L trisodium phosphate , anhydrous sodium carbonate 5g / L;

[0028] 2) Anodizing: Put the magnesium alloy that has been pretreated in step 1) into the above-mentioned anodizing electrolyte for AC anodizing; when AC anodizing, set the waveform as a sinusoidal waveform, the voltage is 8V, and the current density is 4A / dm 2 , the frequency is 50Hz, the tem...

Embodiment 2

[0032] A magnesium alloy anodic oxidation electrolyte consists of: sodium tetraborate 30g / L, boric acid 20g / L, sodium hydroxide 5g / L, sodium molybdate 5g / L, sodium citrate 8g / L; The sodium solution adjusted the pH of the electrolyte to 8.8.

[0033] The method for preparing a black anodic oxidation film by adopting magnesium alloy anodic oxidation electrolyte comprises the following steps:

[0034] 1) Pre-treatment: sand paper to 1500#, then put the magnesium alloy into the alkali washing solution at 60°C for 10 minutes; the alkaline washing solution consists of 50g / L sodium hydroxide and 20g / L trisodium phosphate , anhydrous sodium carbonate 5g / L;

[0035] 2) Anodizing: Put the magnesium alloy that has been pretreated in step 1) into the above-mentioned anodizing electrolyte for AC anodizing; when AC anodizing, set the waveform as a sinusoidal waveform, the voltage is 10V, and the current density is 6A / dm 2 , the frequency is 50Hz, the temperature of the anodic oxidation el...

Embodiment 3

[0039] A magnesium alloy anodic oxidation electrolyte consists of: sodium tetraborate 40g / L, boric acid 15g / L, sodium hydroxide 10g / L, sodium molybdate 6g / L, sodium citrate 10g / L; The sodium solution adjusts the pH of the electrolyte to 9.0.

[0040] The method for preparing a black anodized film by using the above-mentioned magnesium alloy anodic oxidation electrolyte comprises the following steps:

[0041] 1) Pre-treatment: sand paper to 1500#, then put the magnesium alloy into the alkali washing solution at 50°C for 30 minutes; the alkaline washing solution consists of 50g / L sodium hydroxide and 20g / L trisodium phosphate , anhydrous sodium carbonate 5g / L.

[0042] 2) Anodizing: Put the magnesium alloy that has been pretreated in step 1) into the above-mentioned anodizing electrolyte for AC anodizing; when AC anodizing, set the waveform as a sinusoidal waveform, the voltage is 12V, and the current density is 8A / dm 2 , the frequency is 50Hz, the temperature of the anodic ox...

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Abstract

The invention belongs to the technical field of magnesium alloy surface treatment, and discloses magnesium alloy anodizing electrolyte and a method for preparing an anodic oxide film by the electrolyte. The electrolyte consists of 10-50 g / L of sodium tetraborate, 10-30 g / L of boric acid, 5-30 g / L of sodium hydroxide, 4-15 g / L of film forming accelerant and 5-10 g / L of buffer agent; and the pH value of the electrolyte is adjusted within 8.5-9.5. The electrolyte is used for performing the anodic oxidation treatment to obtain the anodic oxide film. The prepared anodic oxide film is a black film layer excellent in corrosion resistance. The electrolyte is stable in system, environment-friendly, free of poison, low in cost and easy to realize the industrialization; the anodic oxidation process temperature is low, so that the energy saving is facilitated; and the anodic oxidization voltage is lower, no spark discharge phenomenon is generated, and large cooling equipment is not needed, so that the process is simple, and the energy consumption is lower.

Description

technical field [0001] The invention belongs to the technical field of magnesium alloy surface treatment, and in particular relates to a magnesium alloy anodic oxidation electrolyte and a method for preparing an anodic oxidation film from the electrolyte. Background technique [0002] Magnesium alloy anodic oxidation technology refers to the process of forming a layer of anodic oxidation film on the surface of magnesium alloy in a specific electrolyte system with magnesium alloy as the anode and an external current. The anodic oxidation film formed on the surface of magnesium alloy can improve its corrosion resistance and protect the metal surface. At present, this processing method is widely used in auto parts, electronic communication fields, biological materials and so on. [0003] Most of the commercialized magnesium alloy anodizing electrolyte systems contain Cr, F and P and other substances that pollute the environment, and it is urgent to develop an economically and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D11/30
Inventor 李文芳张明康张果戈
Owner SOUTH CHINA UNIV OF TECH
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