Improved electrical resistivity-temperature characteristics of oriented hBN composites for inhibiting temperature-dependence DC surface breakdown

In this paper, oriented hBN composites with anisotropic thermal conductivity are employed to improve electrical resistivity-temperature characteristics, thus inhibiting the occurrence of DC surface flashover under the temperature gradient by directionally manipulating heat flow. The DC surface flashover performance, electrical resistivity, carrier mobility, and electric field distribution of composites depending on the hBN orientation are studied at different temperatures. When the angle between the hBN basal plane and the axis of the electrodes is 90 degrees, the out-of-plane oriented hBN composite shows the best electrical resistivity-temperature characteristics than that of the polymer filled with ceramic particles of positive temperature coefficient, whose surface flashover voltage is 28% higher than that of the out-of-plane oriented hBN composite with the angle of 0 degrees between the hBN basal plane and the axis of the electrodes under the high-voltage electrode heated at 160 degrees C. The least rise in carrier mobility and electric field intensity near the GND electrode is the main factor in inhibiting the occurrence of DC surface flashover of the oriented hBN composites at high temperatures. The work presented in this paper will notably influence future research directions and modification solutions for DC dielectric materials.