A kind of preparation method of single-layer micro-arc oxidation ceramic film on aluminum alloy surface

A technology of micro-arc oxidation on the surface of aluminum alloy, applied in the direction of anodic oxidation, etc., can solve the problems of increasing the process, increasing the production cost, increasing the difficulty of process operation and production cost, etc., and achieving the effect of inhibiting excessive growth

Inactive Publication Date: 2016-04-13
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Removing the outer loose layer not only increases the process and increases the production cost, but also has a certain impact on the structure and performance of the oxide film itself during the removal operation (in order to avoid the impact of the removal process on the inner dense layer of the oxide film, Need to increase many auxiliary measures), which undoubtedly increases the difficulty of process operation and production cost
Therefore, the existence of the surface loose layer of the conventional double-layer micro-arc oxidation film seriously hinders the actual engineering application process of the micro-arc oxidation technology.

Method used

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  • A kind of preparation method of single-layer micro-arc oxidation ceramic film on aluminum alloy surface
  • A kind of preparation method of single-layer micro-arc oxidation ceramic film on aluminum alloy surface

Examples

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Embodiment 1

[0017] Specimen material: D7, size 100×100mm. The aluminum alloy workpiece is placed in a stainless steel tank containing an electrolyte, and the stainless steel tank and the surface of the workpiece form an electrolytic circuit; the surface of the aluminum alloy workpiece is placed in the electrolyte as an anode, and the stainless steel as a cathode. Electrolyte ratio: sodium hydroxide 3~5g / L, sodium silicate 2~5g / L, sodium borate 5~7g / L, benzotriazole 0.5~1g / L, yttrium nitrate 0.2~3g / L , and the rest is water. The pH value of the electrolyte is 5-8 (the pH value is adjusted with diluted NaOH or dilute nitric acid solution, the following examples are the same as examples). The double-pulse square-wave voltage with high-frequency carrier is applied to the electrolysis circuit by using Durcott Ⅳ high-power pulse power supply. 0.6ms, negative voltage amplitude 500~550V, pulse width 0.4ms; high frequency carrier voltage amplitude 70~100V, high frequency carrier frequency 2200Hz...

Embodiment 2

[0020] Specimen material: LY12, size 100×100mm, the surface of the aluminum alloy workpiece is placed in the electrolyte as the anode, and the stainless steel as the cathode. Electrolyte ratio: sodium hydroxide 3~5g / L, sodium silicate 2~5g / L, sodium borate 5~7g / L, sodium vanadate 3~4g / L, sodium malate 0.7~1.2g / L, Yttrium nitrate is 0.2~3g / L, cerium nitrate is 0.8~2.1g / l, and the pH value of the electrolyte is 5~8. The double-pulse square-wave voltage with high-frequency carrier is applied to the electrolysis circuit by using Durcott Ⅳ high-power pulse power supply. 0.6ms, negative voltage amplitude 500~550V, pulse width 0.4ms; high frequency carrier voltage amplitude 80~100V, high frequency carrier frequency 2000Hz; current density 1.5~16A / dm 2 , oxidation time 140 ~ 150min, the treatment temperature is not higher than 40 ℃. The micro-arc oxidation ceramic film has a thickness of 35-40μm, a hardness of 1600Hv, a salt spray time of 3000h, and a surface roughness of Ra0.15μm. ...

Embodiment 3

[0022] Specimen material: LC4, size 100×100mm, the surface of the aluminum alloy workpiece is placed in the electrolyte as the anode, and the stainless steel as the cathode. Electrolyte ratio: sodium hydroxide 3~5g / L, sodium silicate 2~5g / L, sodium vanadate 3~4g / L, sodium molybdate 0.2~0.8g / l, benzotriazole 0.5~1g / L, sodium malate 0.7~1.2g / L, cerium nitrate 0.8~2.1g / L, electrolyte pH value 5~8. The double-pulse square-wave voltage with high-frequency carrier is applied to the electrolysis circuit by using Durcott Ⅳ high-power pulse power supply. 0.6ms, negative voltage amplitude is 590~620V, pulse width is 0.4ms; high frequency carrier voltage amplitude is 120~150V, high frequency carrier frequency is 2500Hz; current density is controlled at 2.5~17A / dm 2 , oxidation time 170 ~ 200min, the treatment temperature is not higher than 40 ℃. The thickness of the micro-arc oxidation ceramic film is 40~50μm, the hardness is 1400Hv, the salt spray time is 2500h, and the surface rough...

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Abstract

The invention discloses a preparation method of a single-layer micro-arc oxidation ceramic film on the surface of an aluminum alloy, and belongs to the technical field of aluminum alloy surface treatment. The method comprises the following steps: placing an aluminum alloy workpiece in an electrolyte, and allowing the surface of the aluminum alloy workpiece in the electrolyte and a stainless steel conductor to form an electrolysis loop respectively as a work electrode and a counter electrode; and applying a double-pulse square wave voltage with a high-frequency carrier wave to the electrolysis loop under a controlled current density of 0.2-20A / dm<2> at an electrolyte temperature of 50DEG C or less for 30-200min to form the micro-arc oxidation ceramic film on the surface of the aluminum alloy. The single-layer micro-arc oxidation ceramic film prepared in the invention can effectively solve a technical problem brought by the loose layer of routine two-layer films, and also effectively improves the performances of a micro-arc oxidation ceramic film.

Description

technical field [0001] The invention relates to the technical field of aluminum alloy surface treatment, in particular to a method for preparing a single-layer micro-arc oxidation ceramic film on the surface of an aluminum alloy. Background technique [0002] Micro-arc oxidation (Plasma Electrolytic Oxidation or Micro-arcOxidation) is a preparation technology for in-situ growth of ceramic oxide film on the metal surface. It is a special anodic oxidation and is the most effective way to improve the corrosion resistance of non-ferrous metals such as aluminum alloy one of the means. Due to the use of higher voltage, in addition to electrochemical reactions, the oxidation process also includes plasma chemical and thermal chemical reactions, accompanied by plasma micro-arc discharge. It is due to the local high temperature and high pressure sintering effect caused by plasma discharge that the formed oxide film has a crystalline ceramic structure. The oxide film has excellent bo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25D11/04C25D11/06
Inventor 杜克勤郭兴华郭泉忠王勇王福会
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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