电压增幅对镁合金微弧氧化膜层性能的影响

研究了硅酸盐体系微弧氧化过程中，电源电压增幅对放电火花形态及AZ91D镁合金膜层的厚度、表面形貌和耐蚀性有影响。结果表明，随着脉冲电压增加，电弧的弧斑亮度增强、尺寸变大，但数目减少，大弧倾向增加；微弧氧化膜层的厚度增厚，但成膜速率降低；膜层表面熔融物颗粒增大，表面孔径增加，粗糙度增加；腐蚀率呈现出先减小后增加的趋势。当电压增幅为100~150 V时，其过程稳定性、成膜速率、膜层外观质量和耐蚀性等方面的综合性能相对最优。

Effects of Voltage Increment on Performances of Micro-Arc Oxidation Coatings of Magnesium Alloys

The source voltage increment can influence the shape of arc spark and the thickness, surface morphology and corrosion rate of MAO coatings treated with silicate aqueous solution on AZ91D magnesium alloys. The results reveal that with the voltage increment of supply pulse increasing, the brightness and size of the arc sparks is increased but the amount is decreased accordingly, and the tendency of large arc discharge is intensified; the coating thickness is increased but the film growth rate is decreased; the surface melt grain, microspore size and surface roughness are increased; corrosion rate is first decreased and then increased. The comprehensive performances such as the process stability, film growth rate, coating appearance quality and corrosion resistance are relatively optimum when the voltage increment is within 100-150 V.