Investigation of the Tracking and Erosion Resistance of a Ceramifiable Filler System for Silicone Rubber Composites

Improving the tracking and erosion resistance of silicone rubber (SiR) is of great significance to outdoor SiR insulators. In this work, a feasible method to enhance the antitracking performance of SiR by a ceramifiable system is investigated. Through scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and other characterization methods, the mechanism that aluminum hydroxide (ATH) and low-melting glass (LMG) powder synergistically improve the tracking resistance of SiR is proposed. In this ceramifiable system, ATH plays a role in absorbing heat and serves as a precursor under the synergy with LMG, which promotes the formulation of dense mullite ceramic layer on the surface of SiR at the high temperature generated by dry band arc discharges, thereby the internal SiR is protected from degradation. Hydrophobicity and mechanical properties of ATH/LMG/SiR composites are also investigated, revealing that ATH/LMG improves the mechanical properties and hydrophobicity compared with one filler filled with the same amount. The ceramifiable system exhibits a good effect that the antitracking performance, mechanical properties, and hydrophobicity of SiR composites are improved at the same time. This system provides a new method for the research of antitracking SiR materials applied in outdoor SiR insulators.