Aluminum-magnesium alloy rubbed with alcohol after heating the surface turns black what is the reason?

Magnesium alloy micro-arc oxidation refers to the use of arc discharge to enhance and activate the reaction that occurs on the anode on the basis of ordinary anodic oxidation, so as to form a high-quality strengthened ceramic film on the surface of the magnesium metal as the material of the workpiece method, is through the use of special micro-arc oxidation power supply to apply voltage on the workpiece, so that the metal on the surface of the workpiece interacts with the electrolyte solution, the formation of a micro-arc discharge on the surface of the workpiece at a high temperature, under the action of electric field and other factors, to achieve the purpose of strengthening the surface of the workpiece.

Micro-arc oxidation is a process in which a ceramic film is formed on the surface of magnesium metal under the action of factors such as high temperature, electric field, etc. to achieve the purpose of strengthening the surface of the workpiece.

The outstanding features of the micro-arc oxidation technology are: (1) significantly improve the surface hardness of the material, micro-hardness in 1000 to 2000 HV, up to 3000 HV, comparable to cemented carbide, greatly exceeding the hardness of heat-treated high-carbon steel, high-alloy steel and high-speed tool steel;

(2) good wear resistance;

() (3) good heat resistance and corrosion resistance.

This fundamentally overcomes the shortcomings of magnesium alloy materials in the application, so the technology has a broad application prospect;

(4) good insulation properties, insulation resistance up to 100MΩ.

(5) the solution is environmentally friendly, in line with the requirements of environmental protection emissions.

(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) In-situ growth of ceramic membrane on the substrate, strong bonding, dense and uniform ceramic membrane.

Process: degreasing and de-oiling - water washing - micro arc oxidation ---- water washing - closed - drying.