Lv Pengxiang, Zhang Xiaozhou, Chen Lei, Wang Shixuan, Wang Zhen, He Rongguo, Guan Le
School of Mechanical Engineering, Dalian University, Dalian 116000, China.
Liaoning Tiansheng Engineering Technology Co., Ltd., Dalian 116001, China.
Materials (Basel). 2023 Jul 18;16(14):5065. doi: 10.3390/ma16145065.
Currently, research on the edge effect issue in the micro-arc oxidation process primarily focuses on investigating process conditions and enhancing additives. However, some scholars have utilized finite element analysis software to simulate the edge effect during the simulation process, overlooking the investigation of the morphology of the auxiliary cathode. This study analyzes the growth characteristics of the oxide film on aluminum alloy 2A12 during micro-arc oxidation. Additionally, the inter-electrode discharge electric field is simulated using the finite element analysis method. The auxiliary cathode is optimized to mitigate the influence of the edge effect on the film layer. The findings indicate that employing a cylindrical shape as the auxiliary cathode instead of a rectangular groove leads to an increased thickness of the micro-arc oxidation film. However, it also results in an augmented length of the film layer affected by the edge effect at both ends of the workpiece. Decreasing the distance between the auxiliary cathode and the workpiece surface leads to a higher thickness of the obtained micro-arc oxidation film. Decreasing the length of the auxiliary cathode results in a reduction in both the thickness of the film layer on the workpiece surface and the area affected by the edge effect. Increasing the eccentric cone ratio of the auxiliary cathode enhances the uniformity of the micro-arc oxidation film layer. In this study, we present a novel auxiliary cathode model that incorporates a smaller cylindrical shell at the center and eccentric cone shells on each side. This model has the potential to enhance the optimization rate of the micro-arc oxidation film layer on cylindrical workpieces by 17.77%.
目前，微弧氧化过程中边缘效应问题的研究主要集中在工艺条件研究和增强添加剂方面。然而，一些学者在模拟过程中利用有限元分析软件对边缘效应进行模拟，却忽略了对辅助阴极形貌的研究。本研究分析了2A12铝合金在微弧氧化过程中氧化膜的生长特性。此外，采用有限元分析方法模拟了极间放电电场。对辅助阴极进行优化，以减轻边缘效应对膜层的影响。研究结果表明，采用圆柱形作为辅助阴极而非矩形槽，会使微弧氧化膜的厚度增加。然而，这也导致工件两端受边缘效应影响的膜层长度增加。减小辅助阴极与工件表面之间的距离，会使所得微弧氧化膜的厚度更高。减小辅助阴极的长度，会导致工件表面膜层厚度和受边缘效应影响的面积均减小。增大辅助阴极的偏心锥比，可提高微弧氧化膜层的均匀性。在本研究中，我们提出了一种新型辅助阴极模型，该模型在中心处包含一个较小的圆柱形外壳，两侧各有一个偏心锥壳。该模型有可能将圆柱形工件上微弧氧化膜层的优化率提高17.77%。
