Abdihamzehkolaei Alireza, Ahad Md Tanvir, Siddique Zahed
School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA.
Polymers (Basel). 2021 Mar 3;13(5):773. doi: 10.3390/polym13050773.
This study examines the influence of various electrical parameters on the volume resistivity of the Viton fluoroelastomer. The transient current, the temperature dependence of volume resistivity, the voltage dependence of resistivity, and the surface morphology of Viton insulators are investigated for new and aged specimens. An accelerated aging process has been employed in order to simulate the natural aging of insulators in service. A detailed comparison between the new and aged samples is presented. The transient effect, which is a challenge to the resistivity measurement of insulators, has been investigated. The first 60 s of the resistivity measurement test showed a significant influence from the transient effect and should be excluded from the data. The volume resistivity of both new and aged samples decreased when the temperature increased. However, the resistivity of the aged sample was lower than the new one at all tested temperatures. When the temperature increased from 35 to 190 °C, resistivity decreased from 4.77 × 10 to 6.99 × 10 Ω-cm for the new sample and from 2.6 × 10 to 6.68 × 10 Ω-cm for the aged sample under 500 V. Additionally, the results from this study showed that the volume resistivity is inversely proportional to the applied voltage. Finally, scanning electron microscope (SEM) micrographs/images allowed us to closely examine the surface morphology of new and aged Viton samples. The surface of aged samples has been recognized with higher surface roughness and more significant surface cracks leading to poor performance under high voltage applications.
本研究考察了各种电参数对氟橡胶体积电阻率的影响。针对新的和老化的样品，研究了瞬态电流、体积电阻率的温度依赖性、电阻率的电压依赖性以及氟橡胶绝缘体的表面形态。为了模拟绝缘子在实际使用中的自然老化，采用了加速老化过程。给出了新样品和老化样品之间的详细比较。研究了对绝缘子电阻率测量构成挑战的瞬态效应。电阻率测量测试的前60秒显示出瞬态效应的显著影响，该时间段的数据应予以排除。新样品和老化样品的体积电阻率均随温度升高而降低。然而，在所有测试温度下，老化样品的电阻率均低于新样品。在500V电压下，当温度从35℃升高到190℃时，新样品的电阻率从4.77×10Ω·cm降至6.99×10Ω·cm，老化样品的电阻率从2.6×１０Ω·cm降至6.68×10Ω·cm。此外本研究结果表明，体积电阻率与施加电压成反比。最后，扫描电子显微镜（SEM）显微照片/图像使我们能够仔细观察新的和老化的氟橡胶样品的表面形态。老化样品的表面粗糙度更高，表面裂纹更明显，导致其在高压应用下性能不佳。
