管状铝质材料的等离子体电解沉积行为研究

对管状铝质材料的等离子体电解沉积行为进行了研究.测试了不同工作电压和不同电极放置模式条件下铝管内部不同位置的电位分布，并通过显微分析观察，对比了不同电极放置模式对铝管内外壁陶瓷沉积层生长情况的影响.结果表明，不同的电极放置模式下，铝管内外壁陶瓷沉积层生长情况有很大差异.这是因为不同的电极放置模式对铝管内的电场分布具有很大影响，进而影响到铝管内外壁陶瓷层的沉积过程.只有外电极时，由于电场屏蔽作用，不能在铝管内壁形成均匀陶瓷层；在铝管内部加入辅助中心电极后，铝管内部产生均匀电场，这有利于在其内壁形成均匀的陶瓷层. 关键词： 等离子体电解沉积 铝管 表面改性 陶瓷层

Plasma electrolytic deposition on aluminum tubes

Plasma electrolytic oxidation (PEO), also called micro-arc oxidation or anode spark deposition, is a novel technique to produce hard ceramic coatings on metals, such as aluminum, titanium, magnesium and their alloys (called by a joint name of valve metals). Up to now, almost all the researchers focused attention on the PEO process for samples of regular shapes such as cubes, discs or rods, and no one paid attention to the irregular samples such as tubes. In this work, the PEO behavior of aluminum tubes was investigated. The potential difference, which had a liner relation with the coating thickness inside the tube, was measured. A central axial accessorial electrode was used to eliminate the effect of potential decay inside tubes, which was effective for obtaining axially uniform coating on the inner surface of the tube.