低温等离子体表面处理抑制绝缘材料表面电荷的研究

发布时间：2018-12-16 18:30

【摘要】：环氧树脂材料凭借其优异的机械性能和电学性能,被大范围的应用在高压电气设备中。但是环氧树脂材料在直流高压电场下,其金属导体/绝缘材料/气体的三接触面处容易积聚表面电荷,削弱其绝缘性能,甚至引发沿面闪络事故,严重影响了电气设备的安全运行。因此,本文研究利用低温等离子体在环氧树脂材料表面沉积类Si O_2薄膜,在不影响绝缘材料本体性能的前提下改善其表面电学性能,达到抑制表面电荷积聚的目的。本文基于大气压等离子体增强型化学气相沉积技术,搭建了一套绝缘材料表面沉积处理实验系统,采用介质阻挡放电、大气压等离子体射流与滑动放电作为等离子体源,选用正硅酸四乙酯作为反应前驱物,使其在等离子体中发生反应,在环氧树脂样品表面沉积得到类SiO_2薄膜。通过一系列的物理化学和电学特性测试,对比分析沉积处理前后环氧树脂材料表面绝缘性能的变化;然后利用自主搭建的表面电位测试系统,研究了沉积处理对环氧树脂材料表面电荷积聚、分布及消散特性的影响;最后,结合多种测量手段得到的实验结果对沉积处理抑制表面电荷积聚的机理进行了探讨。沉积处理后,在环氧树脂表面生成了一层厚达200 nm以上的致密均匀的类SiO_2薄膜,其主要组成为Si-O-Si与Si-OH基团,呈现珊瑚状颗粒排布并完全覆盖了原有表面上的瑕疵,使表面润湿性提升、粗糙度下降;而且环氧树脂表面与体积电导率均大幅度提升,沿面闪络电压的提升幅度也达到25%以上,其绝缘耐压能力得到了改善。实验中分别采用正负极性直流电晕和脉冲电晕充电后,相对于未处理的环氧树脂,经过等离子体沉积处理后的环氧树脂样品表面电位初始积聚减少、电位衰减速率加快,电位分布更加均匀,表面电荷陷阱能级的深度更浅、密度更小,有利于提升环氧树脂的绝缘耐压水平;而且随着沉积处理时间的延长,对表面积聚电荷的抑制效果也在不断提升。总之,采用等离子体沉积处理可以抑制环氧树脂表面电荷积聚,这对提升绝缘支撑中环氧树脂的绝缘性能具有重要参考意义和实用价值。
[Abstract]:Epoxy resin is widely used in high voltage electrical equipment due to its excellent mechanical and electrical properties. However, when epoxy resin is in DC high voltage electric field, it is easy to accumulate surface charge at the three contact surfaces of metal conductor / insulating material / gas, which weakens its insulation performance, and even causes flashover accident along the surface. It seriously affects the safe operation of electrical equipment. Therefore, Si O _ 2 thin films deposited on the surface of epoxy resin by low-temperature plasma are studied in this paper. The surface electrical properties of the insulating materials are improved without affecting the bulk properties of the insulating materials, and the surface charge accumulation is restrained. Based on the atmospheric pressure plasma enhanced chemical vapor deposition technology, a set of experimental system for surface deposition of insulating materials has been set up. Dielectric barrier discharge, atmospheric pressure plasma jet and sliding discharge are used as plasma sources. Tetraethyl orthosilicate was used as the precursor of the reaction, which was reacted in plasma and deposited on the surface of epoxy resin to obtain SiO_2 like film. Through a series of physical, chemical and electrical tests, the changes of surface insulation properties of epoxy resin before and after deposition were compared and analyzed. Then, the effect of deposition on the surface charge accumulation, distribution and dissipation characteristics of epoxy resin was studied by using the self-built surface potential measurement system. Finally, the mechanism of inhibition of surface charge accumulation by deposition is discussed in combination with the experimental results obtained by various measurement methods. After deposition, a dense and uniform SiO_2 like film was formed on the surface of epoxy resin with a thickness of more than 200 nm. Its main composition was Si-O-Si and Si-OH groups. The coral-like particles are arranged and completely covered with defects on the original surface, which improves the wettability of the surface and decreases the roughness. Moreover, the surface and volume conductivity of epoxy resin were greatly improved, and the flashover voltage along the surface was increased by more than 25%, and the insulation voltage resistance was improved. After charged by positive and negative DC corona and pulse corona respectively, compared with the untreated epoxy resin, the initial potential accumulation of the epoxy resin sample after plasma deposition decreases and the potential decay rate is accelerated. The potential distribution is more uniform, the depth of surface charge trap energy level is lighter and the density is smaller, which is helpful to improve the insulation voltage level of epoxy resin. Moreover, with the increase of deposition time, the inhibition effect of surface charge accumulation is also increasing. In a word, plasma deposition can inhibit the surface charge accumulation of epoxy resin, which has important reference significance and practical value to improve the insulation performance of epoxy resin in insulation support.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM215.1

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