环氧树脂真空沿面闪络后表面形貌的AFM分析及分形特征提取

AFM Analysis and Fractal Characteristics Extraction of the Surface Morphology of Epoxy Resin After Vacuum Flashover

系统而准确地描述绝缘材料表面形貌特征有利于进一步掌握材料表面形貌的放电损伤规律,对建立表面形貌与闪络特性之间的关联具有重要意义。在不同电场下对环氧树脂进行真空沿面闪络,通过原子力显微镜(AFM)研究不同闪络次数、不同放电位置的试样表面形貌特征,并引入分形理论对形貌特征进行定量分析。结果表明,随着闪络损伤增强,试样表面形貌依次经历了毛刺状、颗粒状、山峰状和连续山峦状的演变过程,表面粗糙度不断增大,且极不均匀电场下闪络对表面形貌的影响更为显著。此外,环氧树脂表面形貌具有分形特性,利用分形维数与多重分形参数能定量表征表面形貌的复杂程度及高度分布状况。研究发现,闪络后环氧树脂的沿面耐压性能总体呈下降趋势,且介质的沿面绝缘特性与表面粗糙度及分形参数间均存在一定关系。

A systematic and accurate description to the surface morphology of insulating materials helps to obtain a better understand of the damage effects of discharge on the material surface.It is essential to explore the relationship between the surface morphology and flashover characteristics.In this paper,vacuum flashover experiments were conducted on epoxy resin under different electric fields.Then,the surface morphology of the samples under different damage degrees and discharge regions was investigated by atomic force microscopy(AFM),and fractal theory was utilized to quantitatively analyze the morphological features.The results show that the sample surfaces sequentially experience the shape of sting,granule,peak,and continuous mountain during the four stages of damage process,and the surface roughness increases constantly in the process.In addition,the impact of flashover driven by highly non-uniform field on the surface morphology is more significant.Furthermore,the surface morphology of samples has fractal characteristics.The fractal dimension and multifractal parameters can be used to quantitatively characterize the complexity of the surface morphology as well as the height distribution of the surface.It is also found that the surface insulating strength decreases after flashover treatment,and the insulating performance is related to the surface roughness as well as the fractal parameters of the dielectric surface.