The Effects of Nano-ZrO₂ on the Mechanical and Electrical Properties of Silicone Rubber and a Corresponding Mechanism Analysis

Improving the performance of silicone rubber (SiR) for cable accessories is the key to the safety and reliability of high-voltage direct-current (HVDC) transmission. In this article, the effects of zirconia nanoparticles (nano-ZrO2) on the electrical and mechanical properties of SiR were investigated. Nano-ZrO2 at different mass fractions was doped into SiR matrices. Then, a series of experiments was carried out to evaluate the performance of the modified SiR in terms of tensile strength, breakdown strength, and space charge characteristics. The results showed that both the mechanical and electrical properties of the modified SiR improved. The tensile strength and the breakdown strength increased significantly with the mass fraction of nano-ZrO2, maximally increasing by 21.3% and 15.4%, respectively. In addition, the incorporation of nano-ZrO2 into SiR inhibited space charge accumulation and accelerated the dissipation of the charges. Nano-ZrO2 also improved the degree of cross-linking of the modified SiR, resulting in a more compact interior structure. The synthetic effect of the improved structure and interfaces facilitated by the nanoparticles may be the origin of the improved properties of the SiR nanocomposites.