Investigation of temperature measurements of silicon-containing nonlinear composite varistors

The study investigates the electrical and dielectric properties of polar and non-polar polymer-based composites and Si-based composite varistors across a range of temperatures. Current-voltage characteristics (CVC) were measured, and the real (ε′) and imaginary (ε″) components of the dielectric constant were calculated at different frequencies. The results show that the CVC exhibits non-linearity over the entire measured temperature range, with the breakdown voltage shifting to lower electric fields as temperature increases. The polar polymer-based composites exhibit a current flow approximately five times higher than non-polar composites under the same applied voltage. For polar polymer composites, the dielectric constant (ε) increases monotonically with rising temperature, whereas non-polar polymer composites show a sharp decline in ε with temperature. A decrease in ε″ and loss tangent (tgδ) was observed with increasing temperature. The electrical conductivity (σ) of polar polymer composites decreases monotonically as temperature increases. In contrast, for non-polar polymer composites, σ decreases sharply at low voltages (<50 V) with increasing temperature, while at higher temperatures, σ increases. These findings highlight the contrasting behaviors of polar and non-polar polymer composites under varying thermal and electrical conditions, offering insights into optimizing materials for advanced dielectric and varistor applications.

Graphical Abstract