摘要
应用在核电站、宇宙航天器等辐射环境中的环氧树脂绝缘材料因表面电荷积聚而易于引发沿面放电事故,研究高能辐射对材料表面电荷动态特性的影响对保障电气设备的绝缘安全具有重要意义。为此,选取厚1.5mm的环氧树脂薄板为试样,采用60 Co伽玛射线源以10kGy/h的辐射率辐射试样,总辐射量为100和1 000kGy。通过直流电晕向试样表面注入电荷,采用静电电位计测量不同时刻的表面电荷分布,分析伽玛线辐射对电荷消散特性的影响。结果表明:表面电荷呈双指数规律消散;随着总辐射量从0增大至1 000kGy,表面电荷的消散速度加快。伽玛线辐射引发的化学反应使试样表层的羰基和羟基数量增加,表面陷阱能级变浅,因而提高了电荷的消散速度。
Epoxy resin used as insulating material in radioactive environment is subjected to a great risk of surface discharge that is originated from surface charge accumulation.For the safe use of the material,it is essential to gain a firm understanding of surface charge dynamics in response to high energetic irradiation.To investigate the effect of gamma-ray irradiation on surface charge decay of epoxy resin,by employing laminate epoxy resin with thickness of 1.5 mm as test sample,we experimentally investigated charge decay.Prior to the test,the sample was irradiated by 60Co gamma source with dosage rate of 10 kGy/h up to total dose of 100 kGy then to 1 000 kGy.The sample surface was corona charged through a pair of needle-plane electrode.The charge distribution was measured by an electrostatic voltmeter,and thereby the decay behavior was obtained.The experimental results show that the decay process is bi-exponential.With the growth of the total dose of irradiation from 0 to 1 000 kGy,surface charge decay is accelerated.The acceleration of negative charge decay is more remarkable than that of positive charge decay.It is proposed that the charge decay is mainly due to lateral charge spreading.Charge decay behavior is dependent upon the characteristics of surface trap that are varied by gamma-ray irradiation induced chemical reactions.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2012年第4期824-830,共7页
High Voltage Engineering
基金
教育部博士点基金新教师类(20100032120082)~~
