不同电压下制备等厚微弧氧化膜层的能耗及膜层的耐蚀性

首先对硅酸盐体系中的AZ91D镁合金进行微弧氧化处理,然后通过调节电压制备厚度均为25 μm和厚度均为40 μm的两组微弧氧化膜层,并针对这两组等厚度膜层的制备时间、能耗、质量厚度比及耐蚀性随电压的变化规律等进行对比研究.结果表明:随着电压的增大,两组等厚度膜层的制备时间均缩短,能耗均降低.相对于厚度均为25 μm的膜层,厚度均为40 μm的膜层的制备时间更长、能耗更大,同时因40 μm膜层较低的致密性,其在氯化钠介质中的耐蚀性较差,但其较厚的厚度使得膜层在硝酸介质中显现出更为优异的耐蚀性能.

Energy consumption and corrosion resistance of MAO coatings with same thicknesses fabricated under different voltages

AZ91D magnesium alloy was treated by micro-arc oxidation (MAO) technique in the silicate-containing electrolyte, and two groups of MAO coatings that have same thickness of 25 μm and same thickness of 40 μm were prepared respectively by adjusting voltage. The time for treatment, energy consumption, mass to thickness ratio and corrosion resistance of the two groups of equal thickness coatings were investigated in the case of increase of voltage, and compared further with each other trying to find out latent regularity. The results show that with the increase of voltage, the time for treatment as well as the energy consumption of the two groups of equal thickness coatings are both shortened and reduced respectively. At the same time, in contrast to coatings with thickness of 25 μm, those with thickness of 40 μm need longer time for treatment and consume more energy. Meanwhile, due to the low density of 40 μm coating, its corrosion resistance in sodium chloride medium is poorer, but its thicker thickness makes coatings exhibiting more excellent corrosion resistance in HNO₃ corrosive medium.