parts Micro-arc oxidation

Micro-arc oxidation, also known as plasma electrolytic oxidation, is developed on the basis of anodizing technology, and the resulting coating is superior to that of anodizing

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The micro-arc oxidation process mainly relies on the matching adjustment of electrolyte and electrical parameters.

Under the action of instantaneous high temperature and high pressure generated by arc discharge, the surface of valve metals such as aluminum, magnesium, titanium and their alloys grows mainly based on matrix metal oxides.

The modified ceramic coating supplemented with electrolyte components has significantly better anti-corrosion and wear-resistant properties than traditional anodized coatings, so its application in marine ships and aviation components has received extensive attention.
 

basic introduction

In the process of micro-arc oxidation, chemical oxidation, electrochemical oxidation, and plasma oxidation coexist, so the formation process of the ceramic layer is very complicated. So far, there is no reasonable model to fully describe the formation of the ceramic layer.

The micro-arc oxidation process introduces the working area from the Faraday area of ordinary anodization to the high-voltage discharge area, which overcomes the defects of hard anodization and greatly improves the comprehensive performance of the film. The micro-arc oxidation film layer is firmly combined with the substrate, has a compact structure, high toughness, and has good wear resistance, corrosion resistance, high temperature impact resistance and electrical insulation.

The technology has the characteristics of simple operation and controllable function of the film layer, and the process is simple and the environmental pollution is small. prospect.
 

Principle features

Micro-arc oxidation or plasma electrolytic oxidation surface ceramicization technology refers to the use of arc discharge to enhance and activate the reaction on the anode on the basis of ordinary anodic oxidation, so as to use aluminum, titanium, magnesium and other metals and their alloys as The method of forming a high-quality reinforced ceramic film on the workpiece surface of the material is to apply a voltage to the workpiece with a special micro-arc oxidation power supply, so that the metal on the surface of the workpiece interacts with the electrolyte solution, and a micro-arc discharge is formed on the surface of the workpiece. Under the action of electric field and other factors, a ceramic film is formed on the metal surface to achieve the purpose of strengthening the surface of the workpiece.
The outstanding features of micro-arc oxidation technology are:
(1) The surface hardness of the material is greatly improved. The microhardness ranges from 1000 to 2000HV and can reach up to 3000HV, which is comparable to that of cemented carbide and greatly exceeds that of high-carbon steel, high-alloy steel and high-speed tool steel after heat treatment. hardness;

(2) Good wear resistance;

(3) Good heat resistance and corrosion resistance. This fundamentally overcomes the shortcomings of aluminum, magnesium and titanium alloy materials in application, so this technology has broad application prospects;

(4) It has good insulation performance, and the insulation resistance can reach 100MΩ.
(5) The solution is environmentally friendly and meets the environmental discharge requirements.

(6) The process is stable and reliable, and the equipment is simple.

(7) The reaction is carried out at room temperature, and the operation is convenient and easy to master.

(8) The ceramic film is grown in situ on the substrate, and the bonding is firm, and the ceramic film is dense and uniform.

 

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Source: @cyanbat   Author: cyanbat

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