Characteristics of corona aged Nano-composite RTV and HTV silicone rubber

Silicone rubber is the first choice for composite insulators´ external insulation to improve the pollution flashover performance. It has many merits such as high hydrophobicity and transfer and recovery of the hydrophobicity, as well as the weakness such as poor aging performance because it is a kind of organic materials. Corona is one of the main factors that lead to the aging of silicone rubber. In this paper, corona aging tests of Nano-composite Room Temperature Vulcanized (RTV) and High Temperature Vulcanized (HTV) silicone rubber have been carried out. The effects of corona discharge on silicone rubber are shown with micro-analysis such as the morphology, X-ray Photoelectron Spectroscopy (XPS), and elemental components, which can help make clear what indeed happens to the silicone materials during corona aging. The results show that morphology and XPS can provide the qualitative analysis of the structural change of the silicone rubber materials caused by corona discharge, and the quantitative analysis of the elemental components before and after corona aging can indicate the chemical changes in the silicone rubber materials caused by corona discharge. The results also show that Nano-composite RTV is superior to HTV to suppress the damage from corona in the depth direction. This might be due to the contribution of Nano-composite materials.