Recently, composite materials with nonlinear dielectric or resistive properties performed well in electric field homogenization and space charge suppression in a high voltage transmission and distribution system. For the purpose of obtaining insulation materials with desirable dielectric and electrical resistance properties, we investigated several fillers with nonlinear electrical properties doped in silicon rubber composites, and their dependency on the temperature and field. The samples of silicone rubber composites with different components were prepared using barium strontium titanate (BST) and zinc oxide (ZnO) as the filler, and high temperature vulcanized silicone rubber (SiR) as the matrix. The investigations revealed that the BST-doped samples showed different dielectric properties compared to ZnO-doped composites, with an increase in the electric field, which was nonlinear. The resistivity of both doped samples was similar. Results demonstrated that it was possible to achieve higher values of permittivity, and lower values of tanδ and resistivity, with respect to unfilled silicone rubber composites over a wide electrical field and temperature range. Discussion of the results attributes these important functional behaviours to the spontaneous polarization of nonlinear nanoparticles and the interaction between the SiR chains and the nonlinear nanoparticles at the interfacial area.

Rubber sealing materials’ aging behavior under challenging circumstances, such as high temperatures, oxygen exposure, or oil immersion, significantly effects how well they seal and how long they last. In order to systematically examine nitrile rubber’s aging behavior and the evolution of mechanical properties under thermo–oxidative and thermo-oil conditions, this study used accelerated high-temperature aging tests. Test results indicate that in a hot-oil environment, the rubber exhibits significant swelling, with mass increasing by up to 9.96%. Hardness undergoes a non-monotonic change, first decreasing and then increasing. In contrast, under thermal-oxidative conditions, hardness increases continuously, exhibiting a marked rise after 7 days of aging at 125 °C. Mechanical property tests revealed a substantial increase in elastic modulus after thermal–oxygen aging. At 125 °C, the modulus rose from an initial 0.4128 MPa to 0.9626 MPa, representing an approximate 133% increase. The compression set reached 83.23% after 7 days of thermal–oxygen aging at 125 °C, compared to 66.89% under thermal-oil conditions. Infrared spectroscopy analysis further indicates enhanced nitro groups and alterations in other functional groups during aging, confirming oxidative chain scission and crosslinking reactions. This study provides quantitative experimental evidence for predicting the service life and optimizing the performance of nitrile rubber under severe environmental conditions.

Traditional neutral salt spray tests fail to accurately simulate the accelerated corrosion that occurs under actual energized conditions. We have developed a salt spray test chamber capable of reducing the relative humidity (RH) in the testing environment to prevent short circuits, insulation failures, and other faults that lead to premature damage during testing. Initially, the effect of salt spray concentration on corrosion at 85 % RH was examined, and it was found that the corrosion rate does not increase when the concentration surpasses 50 mg/m ³ . The humidity-controllable salt spray test demonstrated a closer match to real environmental corrosion, judging by both the appearance of corrosion and the acceleration ratios across different metals, where the acceleration ratio difference between maximum and minimum values was reduced from 18.6 times to 1.4 times. The influence of RH on the corrosion rate was revealed, with the highest rate observed at 75 % RH. Lastly, we proposed optimal parameters for energized salt spray tests, evaluated the failure modes of several products under these tests, preliminarily confirmed the consistency and acceleration effects of this method for electrical products in real marine atmospheric conditions.

Metal cabinets such as switch cabinets and ring network cabinets have the advantages of small footprints and good protection for equipment and offer neat and orderly protection. They are widely used in power systems. In a hot and humid environment, condensation can easily cause equipment to age and even cause insulation failure. Therefore, research on reliable anticondensation methods is of great significance for the safe operation of power equipment. In this study, phase change capsules with phase transition temperatures of 22 and 32 °C were used as fillers and liquid silicone rubber was used as a matrix to prepare liquid silicone rubber composites filled with phase change capsules for a temperature-control coating. Studies have shown that liquid silicone rubber coatings containing phase change capsules can significantly enhance the anticondensation performance of metal cabinets. By using a temperature-control coating on the surface where the cabinet experiences condensation, the temperature difference between the surface and the dew point is reduced, thereby slowing down the condensation rate and even preventing condensation.

In this study, low-alloy structural steels with different La and Ce contents were prepared via vacuum smelting and controlled rolling and controlled cooling technologies, and their microstructures were characterized. The influence of La and Ce on the corrosion resistance of low-alloy steels was compared through indoor cyclic-immersion accelerated tests simulating tropical marine atmospheres. The corrosion mechanism of low-alloy steels with different La and Ce contents in simulated tropical marine atmospheres was investigated using electrochemical measurements and corrosion product analysis. The results show that La and Ce improve the uniform corrosion resistance of low-alloy steels. With increasing La/Ce content, the corrosion current density decreased from 1.8936 × 10⁻⁶ A cm⁻² for 0LaCe to 1.29 × 10⁻⁶ A cm⁻² for 0.3LaCe, corresponding to a reduction of approximately 31.9%. This is attributed to the fact that La/Ce addition promotes rust layer stabilization and densification, as suggested by the evolution of major rust phases and the presence of La/Ce-related oxidized species. Meanwhile, alloying with La and Ce improves the cracking of the rust layer, reduces the number of pores, and stabilizes the rust layer structure.