Study On Accelerating Surface Charge Dissipation Of Epoxy Treated By Atmospheric Pressure Low Temperature Plasma

Epoxy is widely used in electrical and electronic equipment for its excellent electrical and mechanical properties. However, with the increase of the transmission level of DC power, surface charge accumulated on the dielectric material becomes one of the key factors which restricts its further development. By using low temperature plasma to modify material surface, the physical and chemical properties of the material surface will be changed without affecting the bulk material. This can accelerate the dissipation of surface charge.Firstly, based on home-made dielectric barrier discharge (DBD) experiment platform, surface potential measurement system and surface flashover experiment device, we carried out the research of voltage-current characteristics, spectral properties and charge transporting properties under different home-made pulse power supply. Secondly, low-temperature plasma generated by dielectric barrier discharge was used to modify epoxy for surface treatment. Thirdly, surface potential decay was studied before and after treatment under different factors. At the same time, the flashover tests were carried out before and after the plasma treatment. Finally, this phenomenon that surface charge decay was obviously influenced by plasma treatment was discussed by means of a series of measurement and characterization methods.The voltage-current characteristics of microsecond and nanosecond excitation were studied for comparison. Under the same conditions, nanosecond excitation had a higher du/dt and instantaneous power. From the point of charge transporting properties, the energy of microsecond excitation of single pulse discharge was higher than that under nanosecond excitation. The gap distance affected mode conversion of discharge. The discharge energy increased first and then decreased with the increase of the gap distance.We built a set of device of surface potential measurement system for the needle-plate electrode. By using the measurement system, the surface potential of epoxy material was studied for several factors. The results showed that plasma treatment could significantly accelerate the decay of surface potential and this conclusion was verified under both the needle-plate electrode and the planar electrode. In addition, the decay rate first increased and then decreased with the increase of processing time, maximum at 180 s. The aging had an important influence on the decay of surface potential. The experimental results showed that plasma treatment could improve the surface flashover ability at a certain extent. This could be attributed to the uniform distribution of surface electric field induced by plasma treatment. The way of surface charge dissipation showed that surface conduction was the dominant way of charge dissipation. The results showed that plasma treatment in the air could improve surface conductivity and trap energy levels, which was the main reason for the acceleration of decay of surface charge. In short, DBD generated by repetition frequency pulse can effectively accelerate the surface charge dissipation of epoxy. This can expand the application of low temperature plasma and provide a reference for industry application.