NH_(4)VO_(3)添加量对铝合金微弧氧化陶瓷膜颜色及耐蚀性的影响

Influence of NH_(4)VO_(3) Addition on Color and Corrosion Resistance of Micro-arc Oxidation Ceramic Film on Aluminum Alloy

采用微弧氧化(MAO)技术,在硅酸盐体系电解液中加入NH_(4)VO_(3),在2A12铝合金表面制备出黑色陶瓷膜。利用SEM和EDS分析了陶瓷膜的微观形貌和元素组成;使用涂层测厚仪测量膜层的厚度;采用Tafel极化曲线和电化学阻抗谱(EIS)研究膜层在质量分数为3.5%NaCl溶液中的电化学腐蚀行为。结果表明:随NH_(4)VO_(3)浓度的增加,陶瓷膜层黑度增加、厚度增加,而膜层耐腐蚀能力下降、表面粗糙度提高。发现NH_(4)VO_(3)浓度不宜过高,否则黑色陶瓷膜层易夹杂少许细微的灰白色斑纹。当NH_(4)VO_(3)浓度为7.5 g/L时,陶瓷膜的黑色纯度最高。当NH 4VO 3浓度为5 g/L时,陶瓷膜的耐蚀性最好。

Using micro-arc oxidation(MAO)technology,the black ceramic film was prepared on the surface of 2A12 aluminum alloy by adding NH_(4)VO_(3) to the silicate system electrolyte.The microscopic morphology and element composition of the ceramic film were analyzed by SEM and EDS.The thickness of the film was measured with the coating thickness gauge.The Tafel polarization curve and electrochemical impedance spectroscopy(EIS)were used to study the electrochemical corrosion behavior of film in the mass fraction of 3.5%NaCl solution.The results show that with the increase of NH_(4)VO_(3) mass concentration,the blackness and thickness of the ceramic coating increase,while the corrosion resistance of the coating decreases and the surface roughness increases.The mass concentration of NH_(4)VO_(3) should not be too high,otherwise the black ceramic film is easily mixed with a few fine gray-white markings.When the mass concentration of NH_(4)VO_(3) is 7.5 g/L,the black purity of the ceramic membrane is highest.When the mass concentration of NH_(4)VO_(3) is 5 g/L,the corrosion resistance of the ceramic membrane is best.