[magnesium summit] integral micro-arc oxidation treatment technology for joints of magnesium-aluminum dissimilar alloy materials

At the 2021 China magnesium Industry chain Summit Forum, Dr. GE Yanfeng, School of Materials Science and Engineering of Xi'an University of Technology and Shaanxi magnesium Alloy Engineering Research Center, explained the design and application of magnesium alloy micro-arc composite protective film.

Difficulties in surface protection of magnesium alloy

In the harsh environment, the protection performance of the existing surface treatment process is limited; the complex shape is difficult to completely clean and peel, leaving the hidden danger of "paint film bubbling"; although the clean water is still unaffordable, the waste water can not afford to be discharged than in the past.

Principle of micro-arc compound treatment technology

The porous structure of the micro-arc oxidation ceramic layer is easy to combine with a variety of materials to form a composite film, providing diversified functions, showing the superiority of the ceramic layer as a "transition treatment layer". To meet the product in different environmental treatment selected for subsequent coating composite to form a short process and low pollution emission environment-friendly surface treatment technology.

By adjusting the structure and penetration of micro-arc blind holes, a gradient composite coating with electrophoretic coating not only firmly embedded micro-arc blind holes, but also tightly wrapped spray modified particles was developed.

Performance evaluation of micro-arc composite film

Neutral salt spray test: through the calculation of hydrogen collection test results (soaking for 120h, 25 ℃, 5 wt.% NaCl), static corrosion test conditions, there is no significant difference.

Scratch corrosion: salt spray test 168 hrs GB10125-1997, the corrosion resistance of MCC film is still excellent after local damage.

Joint corrosion: the surface morphology of magnesium alloy and aluminum alloy with different surface treatment after salt spray test; the corrosion morphology of magnesium alloy with different surface treatment and copper interference fit after salt spray test.

Binding state: the adhesion grade of direct electrophoretic film is 4, that of chemical conversion / electrophoretic film is 2, and that of chemical conversion / electrophoretic film is 2.

The adhesion grade of micro-arc oxidation / electrophoresis composite film is grade 1.

Performance evaluation of protective film on magnesium alloy wheels for vehicles: adhesion, wear, corrosion, flying stone impact, thermal shock.

Application of Micro-arc compound treatment Technology

Defense, military and aerospace, auto parts, consumer electronics, magnesium alloy templates for construction.

Development of Micro-arc compound processing equipment

Development of low energy consumption micro-arc oxidation power supply:

Pilot base: