TiN颗粒对镁合金微弧氧化过程及膜层性能的影响

目的分析Ti N颗粒在镁合金微弧氧化过程中的作用,并研究其在膜层中对镁合金硬度、耐磨和耐蚀等性能的影响。方法通过在微弧氧化电解液中添加2.7μm Ti N颗粒,并使其充分分散于电解液中,使电解液中Ti N颗粒的质量浓度分别为0、2、4、6 g/L,并控制其他实验参数(如电流密度、频率、占空比和氧化时间)一样的情况下进行实验,通过电子显微镜、涂层厚度测厚仪、显微维氏硬度计、X射线衍射和电化学工作站,分别从膜层的表面形貌、厚度、硬度、相组成及耐蚀性等方面,研究了Ti N颗粒对镁合金微弧氧化膜层性能的影响。结果在微弧氧化电解液中添加Ti N颗粒后,相同电化学参数下制得的微弧氧化膜层变得致密,厚度、硬度有所增加,氧化膜层主要由Mg、MgO、Mg2Zr5O12、Ti N组成。极化曲线显示,加入Ti N颗粒,制备的微弧氧化膜层比未加入Ti N颗粒制得的膜层的腐蚀电流下降了2个数量级。阻抗图谱表明,电阻值增加了1个数量级。结论 Ti N颗粒能够随镁合金的微弧氧化过程进入制得的氧化膜层中,并且能够增加膜层厚度和硬度,使膜层的耐磨、耐蚀性得到提高。

Effect of TiN Particles on Micro-arc Oxidation Process and Film Properties of Magnesium Alloy

The work aims to analyze the effect of TiN particles during micro-arc oxidation of magnesium alloy, and study the effect of TiN particles on hardness, wear resistance and corrosion resistance of magnesium alloy in the film. The experiment was completed by adding 2.7 μm TiN particles to the micro-arc oxidation electrolyte and fully dispersing it in the electrolyte, the concentration of TiN particles in electrolyte was set to 0 g/L, 2 g/L, 4 g/L, 6 g/L, respectively, and other experimental parameters (such as current density, frequency, duty cycle and oxidation time) were controlled identical to the same experiment. The effect of TiN particles on properties of micro-arc oxidation coatings on magnesium alloys was studied by measuring surface morphology, film thickness, film hardness, phase composition and corrosion resistance using electron microscope, coating thickness gauge, micro-Vickers hardness tester, X-ray diffractometer and electrochemical workstation. After TiN particles were added to the micro-arc oxidation electrolyte, the micro-arc oxidation film obtained under the identical electrochemical parameters became denser, thicker and harder. The oxide film was mainly composed of Mg, MgO, Mg2Zr5O12and TiN. Polarization curves showed that compared with TiN particle-free micro-arc oxidation film, corrosion current of the film containing TiN particles decreased by two orders of magnitude. Impedance graph showed that the resistance value increased by one order of magnitude. TiN particles can enter the prepared oxide film along with micro-arc oxidation process of magnesium alloy, and can increase the film thickness and hardness, and thereby improving wear and corrosion resistance of the film.