电解液体系对石墨烯镁基复合材料微弧氧化膜层组织及耐蚀性能的影响

Effect of electrolyte system on microstructure and corrosion resistance of micro-arc oxidation coatings on graphene reinforced magnesium matrix composite

分别在3种不同电解液体系（硅酸盐体系、铝酸盐体系、磷酸盐体系）对石墨烯镁基复合材料表面进行微弧氧化,并对微弧氧化后膜层的微观组织形貌和物相组成进行分析,通过电化学和浸泡实验对其耐蚀性进行测试。结果表明：硅酸盐体系微弧氧化膜层表面光滑平整,微孔分布均匀;铝酸盐微弧氧化膜层较薄,孔隙尺寸最小;磷酸盐体系膜层微孔分布不均匀,表面存在较多裂纹;硅酸盐体系微弧氧化膜层物相组成主要为SiO2和MgO,磷酸盐和铝酸盐体系膜层物相组成主要为MgO。3种电解液体系微弧氧化膜层耐蚀性能较基体复合材料提高一个数量级左右,其中硅酸盐体系微弧氧化膜层耐蚀性最好。

Micro-arc oxidation （MAO） surface modification was carried out on the graphene magnesium matrix composite surface in three electrolyte systems of silicate, aluminate and phosphate, and the microstructure and phase composition of the MAO coatings were investigated and the corrosion resistance was tested by the electrochemistry and immersion test. The results show that the coating prepared in silicate system possesses a smooth surface with homogeneous pore distribution. The thickness of the coating prepared in aluminate system is thin with the smallest pore size. The pore distribution of the coating prepared in phosphate system is heterogeneous with many micro-cracks on the surface. The coating prepared in silicate system is mainly composed of SiO2 and MgO phases, while there is only MgO phase for the coatings prepared in the aluminate and the phosphate system. The corrosion resistance of the coatings prepared in three systems is about an order of magnitude higher than that of the uncoated graphene reinforced magnesium matrix composite, and the coating prepared in silicate system exhibits the best corrosion resistance.