电压对铝合金微弧氧化陶瓷层形成的影响

研究了正向和负向电压对6063铝合金微弧氧化陶瓷层形成的影响,并结合微弧氧化过程中正向电流密度的变化,对影响机理进行了探讨.结果表明,提高正负向电压均有利于提高陶瓷层的厚度与均匀性当正负向电压从420V/120V提高到480V/200V时,陶瓷层厚增加了一倍;负向电压对陶瓷层形成的影响更加显著,当保持正向电压440V不变,负向电压从120V提高到200V时,层厚增加了约60%,均匀性明显提高.正负向电压提高时,通过试样的正向电量随之增大,而且与陶瓷层厚度之间有着较好的线性关系.正向和负向电压分别通过加快物质的迁移和强化膜层的击穿从而促进陶瓷层的形成.

Effect of voltage on formation of ceramic coating prepared by micro-arc oxidation on aluminum alloy

The effect of positive and negative voltage on formation of ceramic coating prepared by micro-are oxidation in silicate electrolyte on 6063 aluminum alloy was investigated. The influencing mechanism of voltage on formation of ceramic coating was also discussed based on the variation of positive current under different voltages. The result shows that with increase of voltage, especially negative voltage, the thickness of the ceramic coating increases and its uniformity becomes better. Positive/negative voltages increase from 420V/120V to 480V/200V, the thickness is doubled. The negative voltage increases from 120V to 200V under a constant positive voltage of 440V, the thickness increases about 60%. The amount of charge passing forward sample also increases. As increasing voltages, there is linear relation between amount of charge and the thickness of the coating. The positive and negative voltages promote the formation of ceramic coating by accelerating transportation of materials and intensifying breakdown to dielectric.