Dielectric AlN/epoxy and SiC/epoxy composites with enhanced thermal and dynamic mechanical properties at low temperatures

In a superconducting magnet, the thermal properties of the insulating material at low temperatures is an important technical index to ensure the normal operation of a superconducting coil. Herein, a low-temperature thermal conductivity testing device with a tiny uncertainty was developed to measure the composites. Furthermore, SiC/epoxy and AlN/epoxy composites were prepared and their properties were tested at low temperatures. The results showed that the composites have a better thermal conductivity at low temperatures than pure epoxy. In addition, the AlN/epoxy and SiC/epoxy composites have excellent dynamic mechanical properties and low coefficient of thermal expansion. Due to the fair thermal and dynamic mechanical properties, the composites will have potential application in the superconducting magnet. [Display omitted] •An experimental system with a tiny uncertainty that measures the thermal conductivity of composites form 60 ​K–300 ​K was built.•SiC/Epoxy and AlN/Epoxy composites were successfully prepared and the composites maintained an enhanced thermal conductivity at low temperatures.•The composites also show enhanced dynamic mechanical properties, dielectric properties, a small thermal expansion coefficient.