电解液中添加钛纳米颗粒对AZ91D镁合金表面微弧氧化膜性能的影响研究

Effect of Titanium Nanoparticles in Electrolyte on the Properties of Micro-Arc Oxidation Coatings on AZ91D Magnesium Alloy Surface

在磷酸盐电解液中,通过添加钛纳米颗粒在AZ91D表面制备了含钛的微弧氧化膜,研究了电解液中钛纳米颗粒浓度对膜层形貌、组成及性能的影响。利用扫描电子显微镜、能量色散谱仪、X射线衍射仪、X射线光电子能谱表征微弧氧化膜层的形貌及组成;利用电化学工作站评价了膜层的耐腐蚀性,利用分光光度计测试了膜层的光吸收性能。结果表明:加入到电解液中的钛纳米颗粒对微弧氧化电压变化影响不大。但加入的钛纳米颗粒可以在微弧氧化膜中生成Mg2TiO4,随着钛纳米颗粒浓度增加,膜层表面较小的微孔先减少后增加,耐腐蚀性先提高后降低。随着钛纳米颗粒浓度的增加,膜层颜色由淡灰色变为浅蓝色再变为深蓝色,对模拟太阳光的反射率逐渐降低。

MAO coatings were prepared on AZ91D magnesium alloy surface in the phosphate electrolyte containing different concentrations of titanium nanoparticles.The effects of titanium nanoparticle concentration on the morphology,composition and properties of the as-prepared coatings were studied.Scanning electron microscope,energy dispersive spectrometer,X-ray diffractometer and X-ray photoelectron spectroscopy were employed to characterize the morphology and composition of such coatings.The corrosion resistance of coatings was tested by an electrochemical workstation,and the light absorption performance of the coatings was evaluated by a spectrophotometer.Results showed that the added titanium nanoparticles in electrolyte had little influence on voltage variation.However,the titanium nanoparticles in electrolyte could form Mg_(2)TiO_(4)in the micro-arc oxidation coatings.With the increase of the concentration of titanium nanoparticles,the small micropores on the surface of the coatings decreased first and then increased,so the corrosion resistance increased first and then decreased;furthermore,the coating's color changed from gray to light blue and then dark blue,leading to a gradual decrease of the reflectivity to simulated sunlight.