The influence of environmental conditions on the properties of housing materials for power electronics

The study correlates the microstructure of different glass-fiber reinforced thermoplastics, used as housing materials in power electronics, to their electrical behavior under the influence of humidity and temperature. The results show how microstructural defects like voids within the matrix material or gaps between glass-fillers and the polymer matrix lead to an increased water absorption resulting in an elevated ion conductivity and a decrease of the dielectric strength. In addition, a novel specimen geometry is introduced, which allows a deeper study of the long-term behavior and the aging mechanisms of engineering plastics under different environmental conditions.