石墨烯对7050高强铝合金微弧氧化陶瓷膜层组织性能的影响

Effect of Graphene Additive on Microstructure and Properties of MAO Ceramic Coatings Formed on 7050 Aluminum Alloy

为解决7050高强铝合金在海洋环境中的腐蚀、磨损问题,设计了涂层结构以延长其使用寿命。采用微弧氧化(MAO)技术,以硅酸盐为主要电解液成分,通过加入不同浓度的石墨烯添加剂,在7050高强铝合金表面制备含石墨烯的陶瓷膜层。利用扫描电镜(SEM)、体视显微镜、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、涂层附着力自动划痕仪以及电化学工作站,研究含石墨烯的MAO陶瓷膜层形貌、粗糙度、相组成和元素分布、结合力以及耐蚀性。结果表明:石墨烯添加剂的加入使得陶瓷膜层表面微孔尺寸降低、结构致密,且主要是由α-Al2O3、γ-Al2O3组成;当石墨烯添加剂浓度为10 g/L时,MAO陶瓷膜层粗糙度最低,为857.835 nm,且结合力最好,达到46 N;膜层的腐蚀电位最大,腐蚀电流最小,耐腐蚀性最好。

For the corrosion and wear of 7050 high strength aluminum alloy in the marine environment,an excellent coating structure is designed to prolong its service life.The graphene-containing ceramic coating was prepared on the surface of 7050 high strength aluminum alloy by micro-arc oxidation(MAO)in a silicate electrolyte added with different concentrations of graphene.The surface morphology,roughness,phase composition,distribution of elements,bonding force and corrosion resistance of micro-arc oxidation ceramic coating are analyzed by using the scanning electron microscopy(SEM),stereomicroscope,X-ray diffractometer(XRD),X-ray photoelectron spectrometer(XPS),automatic scratch instrument for coating adhesion,electrochemical workstation,respectively.It is shown that the micro-pore size of ceramic coating which mainly consists ofα-Al2O3,γ-Al2O3 decreases and its compactness is obviously improved with the addition of graphene.In addition,the roughness of ceramic coating is the lowest(857.835 nm),its adhesion is the best(46 N),and its corrosion resistance is significantly improved when the concentration of graphene is 10 g/L.The coating has maximum corrosion potential,minimum corrosion current.