AZ91D镁合金微弧氧化过程中熄弧的初步探讨

Research on Arc Extinguishing during Micro Arc Oxidation of AZ91D Magnesium Alloy

镁合金的比重比铝合金还小,但是它的能量衰减系数大,而且具有优秀的电磁屏蔽等优点,作为21世纪理想的电子产品外壳材料而广为人知。采用AZ91D型镁合金作为试验材料,比较了镁合金在2种熄弧方式下微弧氧化的现象及其表面性能。结果表明:自然熄弧和强制熄弧状态下电弧的形态有明显的区别。发展方向主要表现为自然湮灭圆弧向周围发展,强制熄灭弧主要向纵深发展;2种熄弧方式对膜厚影响不大;自然熄灭电弧获得的陶瓷膜粗糙,表面有白色斑点、孔,有时会导致工件报废,而强制熄弧状态下形成的膜层表面相对光滑,陶瓷膜与基板紧密结合,性能良好。

The specific gravity of magnesium alloy was smaller than that of aluminum alloy,but its energy attenuation coefficient was large,and it had the advantages of excellent electromagnetic shielding and so on.So it was widely known as the ideal shell material of electronic products in the 21st century.AZ91D magnesium alloy was used as experimental material to compare the phenomenon of micro arc oxidation and surface properties of magnesium alloy under two arc extinguishing modes.The results showed that there were obvious differences of arc forms between natural arc extinguishing and forced arc extinguishing.The development direction mainly showed that the natural annihilation arc developed around,and the forced extinction arc mainly developed in depth.The two arc extinguishing methods had little effect on the film thickness.The ceramic film obtained by naturally extinguishing the arc was rough,and it was with white spots and holes on the surface,which sometimes led to the scrap of the workpiece.But the surface of the film formed in the forced arc rest state was relatively smooth,and the ceramic film was closely combined with the substrate,so it had good performance.