Change in partial discharge resistance of epoxy/Al2O3 nanocomposites irradiated with high energy electron beam

Epoxy-based nanocomposites working in the irradiation environment could be exposed to a great risk of degradation induced by partial discharge. It is then of necessity to investigate the effect of irradiation on the resistance to partial discharge of epoxy nanocomposites. In this paper, epoxy/Al2O3 nanocomposites have been prepared to estimate the influence of electron beam on the erosion of partial discharge. The content of the Al2O3 nano-particle was set at 1wt%, 4wt% and 7wt%, respectively, and the total irradiation dose was 0 kGy, 100 kGy and 500 kGy. Partial discharge erosion of the nanocomposites was attained by employing the needle-to-plate electrode system, the erosion profile was measured and the maximum erosion depth was obtained and compared. The test results showed that the maximum erosion depth increased with the total dose varying from 0 kGy to 100 kGy, but decreased with the total dose changing from 100 kGy to 500 kGy. It is suggested that the chemical structure of the material is altered by means of radiation-induced chemical reactions, which in turn influences the electrical properties of the nanocomposites.

I. Introduction

Owing to its excellent electrical and mechanical properties, epoxy resin has been widely used as insulating material in electrical devices operating in aerospace [1]–[3]. It has been found that the material has to work in radiation environment, where high energy electron beam is often included [4]. The electron beam irradiation could introduce deep charging of the dielectrics that initiates electrical discharge, or change the chemical structure of the material which leads to the deterioration and thereby threatening its safe use. Accordingly, it is of great importance to investigate the effect of electron beam irradiation on the electrical performance of epoxy.