阴阳极放置模式对圆筒工件微弧氧化膜厚的影响

Effect of Place Mode of Cathode and Anode on Thickness of Inner-Wall Micro-Arc Oxidation Coating of Cylinder

目前针对微弧氧化中工件形状以及阴阳极放置模式的影响研究得不多。为此,利用自制的微弧氧化设备考察了阴阳极不同放置模式对具有内表面的圆筒铝合金工件微弧氧化膜层的影响。结果表明:阳极垂直竖向放置的膜层不均匀程度要高于卧式放置,随着圆筒长度的增加这种不均匀性越来越严重;圆筒内增加辅助阴极使圆筒内壁电场分布均匀,内壁陶瓷层均匀程度提高,膜层较为致密;圆筒长度增加,圆筒内的陶瓷层仍然非常均匀;内壁陶瓷层中除Al基体外,主要由α-Al2O3和少量的γ-Al2O3组成。

Micro-arc oxidation coating was prepared on the inner wall of Al alloy cylinder.The effect of the place modes of anode and cathode on the thickness of the micro-arc oxidation coating was investigated.Results show that the coating obtained with the vertically placed anode is more non-uniform than that obtained with horizontally placed anode,and the non-uniformity is enhanced with increasing length of the cylinder.Moreover,introducing auxiliary cathode on the inner wall of the cylinder resulted in more uniformly distributed electric field and hence contributed to increased compactness and thickness of the ceramic coating.The uniformity of the ceramic coating kept almost unchanged with increasing length of the cylinder.The inner-wall ceramic coating was mainly composed of Al,α-Al2O3 and a small amount of γ-Al2O3.