摘要
为增强间位芳纶绝缘纸的电绝缘及导热性能,该文选取了球形氮化铝(AlN)和片形氮化硼(BN)两种填料,采用聚多巴胺和硅烷偶联剂对填料表面进行化学修饰后,将填料掺入间位芳纶基体中。利用湿法抄造技术,制备了AlN/BN复配改性的间位芳纶绝缘纸试样,对其微观形貌、击穿场强、体积电导率以及面外热导率进行表征测试。结果表明,在复配改性体系中,当AlN和BN的复配质量比为3:7时,样品出现最优的击穿场强为186 kV/mm,较纯芳纶纸提升66.07%;而当复配质量比为7:3时,其面外热导率高达0.671 W/(m·K),较纯芳纶纸提升213.6%。基于密度泛函理论对基体和填料的能带结构进行计算分析发现,AlN和BN的引入在基体和填料界面形成了“阶梯陷阱”,进一步提高了电子跃迁势垒,抑制了击穿时漏电流的形成和发展。此外,借助相场法分析了不同复配比例下填料对基体电流密度和电场畸变的影响,发现AlN/BN的复配结合有助于均化电场分布,提高复合体系的绝缘强度。
Meta-aramid(PMIA)is a unique fiber that possesses exceptional insulation strength and thermodynamic stability.It is widely regarded as an ideal material for the development of the next generation of insulation paper.However,its intrinsic thermal conductivity of 0.21 W/(m·K)is relatively low and may not meet the long-term service requirements in high-temperature environments.To enhance the thermal conductivity and insulation of the PMIA paper,AlN and BN fillers are selected for composite doping modification of PMIA paper.The surfaces of the two fillers are coated with polydopamine(PDA)and modified with a KH550 silane coupling agent to improve the dispersibility of the two fillers.By adjusting the doping ratio,AlN-BN/PMIA composite insulation paper with different concentrations was prepared.The microstructure was characterized and the breakdown strength,conductivity,and thermal conductivity were tested.The effect of two different filler ratios on the insulation and thermal conductivity of the material was studied.Firstly,the surfaces of the two fillers are coated with polydopamine(PDA)and modified with a KH550 silane coupling agent to enhance their dispersibility.By adjusting the doping ratio,AlN-BN/PMIA composite insulation paper with different concentrations is prepared.Secondly,the microstructure of samples is characterized and the breakdown voltage,conductivity,and thermal conductivity are tested.The influence of the ratio of two fillers on the insulation and thermal conductivity of the material was studied.Thirdly,based on density functional theory,band structure calculation and analysis are conducted,and a design concept of a“stepped charge trap”is proposed.In addition,the composite breakdown model is constructed using the phase field method,explaining the inherent mechanism of performance improvement.According to the test results,adding BN to the AlN filler can further improve the matrix structure and fix the damage caused by the high concentration aggregation of AlN.The surface of the composite material appears relatively dense when the AlN/BN ratio is 3:7,with only a small amount of PMIA fibers and fillers precipitated.At a mass fraction of 40%,the breakdown strength of the composite gradually increases as the BN doping ratio increases.At a ratio of AlN/BN of 3:7,the composite paper exhibits its maximum breakdown strength of 186 kV/mm,which is 66.07%higher than that of the pure PMIA sample.Additionally,the conductivity of the composite is at its lowest value during this ratio.On the other hand,at an AlN/BN ratio of 7:3,the thermal conductivity of the composite is optimal,increasing by 213.6%compared to pure PMIA samples.The high aspect ratio structure of BN links it with AlN fillers to form an“thermal conductivity network”,which increases the thermal conductivity.Energy band structure analysis based on density functional theory suggests that the wide bandgap properties of AlN and BN result in the formation of“stepped traps”at the PMIA interface.This leads to an increased energy barrier for charge transitions and limits the migration of charge carriers.In addition,a phase field simulation model indicates that the introduction of BN can further homogenize the electric field distribution,reduce the degree of local polarization,and thus enhance the insulation performance of the composite system.
作者
王齐斌
范晓舟
高宇轩
庾翔
刘云鹏
Wang Qibin;Fan Xiaozhou;Gao Yuxuan;Yu Xiang;Liu Yunpeng(College of Electrical and Electronic Engineering,North China Electric Power University,Beijing 102206,China;Hebei Key Laboratory of Power Transmission Equipment Security Defense,North China Electric Power University,Baoding 071003,China;College of Electrical and Control Engineering,North China University of Technology,Beijing 100144,China)
出处
《电工技术学报》
北大核心
2025年第11期3618-3629,共12页
Transactions of China Electrotechnical Society
基金
中央高校基本科研业务费专项资金资助项目(2023MS106,2023MS002)。
关键词
间位芳纶
氮化硼
氮化铝
击穿场强
面外热导率
Meta-aramid
boron nitride
aluminum nitride
breakdown strength
thermal conductivity
