(1. 四川理工学院 材料科学与工程学院，自贡 643000；
2. 四川理工大学 材料腐蚀与防护四川省重点实验室，自贡 643000)
摘 要: 通过微弧氧化和多弧离子镀两种等离子体技术，在AZ31B镁合金表面制备MAO/Ti复合涂层。采用SEM、EDS、XRD、电化学等手段表征涂层的形貌、元素组成、物相结构及其在3.5% NaCl(质量分数)溶液中的腐蚀行为。结果表明：随着磁场电流从0 A增加到20 A， 30 min沉积的MAO/Ti涂层表面大尺寸熔滴粒子数量逐渐减少，真空室温度由128 ℃增加到192 ℃；10 A磁场电流作用下，当沉积时间由30 min延长到120 min时，真空室温度迅速增加，MAO/Ti涂层表面呈现微裂纹，表面液体熔滴粒子的数量增加；无外加磁场时，随着沉积时间从30 min延长到120 min，MAO/Ti涂层表面呈现大量球形熔滴颗粒，Ti镀层厚度逐渐增加并完全覆盖MAO膜；多弧离子镀过程未改变MAO镁合金的主要物相结构；MAO/Ti涂层φcorr正移，Jcorr降低。外加轴向磁场，过滤带电以及中性大颗粒粒子，有利于致密化镀层，但提高弧斑运动速度，升高阴极靶温度，增加靶材的液滴数量，必须加以控制；Ti镀层提高了MAO膜对镁合金基体的腐蚀防护能力，但仍有待于通过工艺调整致密化镀层，进一步强化MAO/Ti涂层的综合性能。
关键字: 镁合金；涂层；微弧氧化；物理气相沉积；钛；耐蚀性
（1. School of Materials and Chemical Engineering, Sichuan University of Science and Engineering, Zigong 643000, China;
2. Material Corrosion and Protection Key Laboratory of Sichuan Province,
Sichuan University of Science and Engineering, Zigong 643000, China）
Abstract:The MAO/Ti composite coating was fabricated on AZ31B Mg alloy through a combined process of micro-arc oxidation (MAO) with multi-arc ion plating. The morphology, composition, phase structure and corrosion resistance of the coatings were evaluated using SEM, EDS, XRD and electrochemical methods. The results show that, with the magnetic current increasing from 0 A to 20 A, the temperature of vacuum chamber increases to 192 ℃ from 128 ℃, and the number of the droplet with large size on MAO/Ti coating decreases. When the deposition time increases from 30 min to 120 min at magnetic current of 10 A, the temperature of vacuum chamber increases sharply, the droplet number increases gradually, and the surface of MAO/Ti coating appears micro-cracks. However, under condition without magnetic field, the surface of the MAO/Ti coating presents plenty of droplets with the deposition time increases from 30 min to 120 min, and the surface of MAO coating is coated gradually by the Ti coating. The phase structures of MAO coating don’t change during this multi ion plating, while the φcorr of the MAO/Ti coating shifts to a positive potential, and the Jcorr decreases slightly. It can be concluded that the neutral or charged particles with large size may be filtered or decreased by controlling the magnetic current. Meanwhile, the magnetic increases movement velocity of the arc spot and rises the temperature of the cathode target, which could result in an increasing of droplets on the MAO/Ti coating. Although all results prove that the Ti coating further enhances the corrosion protection ability of the MAO coating on AZ31 Mg alloy, the compact Ti coating is required to be fabricated to provide a better properties through process optimization.
Key words: magnesium alloy; coating; plasma electrolytic oxidation; physical vapour deposition; titanium; corrosion resistance
