Development of thermal conductive adhesive for improving stability of superconducting coil

Research Summary

Low-temperature superconducting (LTS) coils for PPMS, MPMS, VSM, and accelerators are impregnated with an adhesive to increase the thermal conductivity of the LTS coil. Therefore, it is urgent to improve the thermal conductivity of functional adhesives recommended for the manufacturing of the LTS coil.

One strategy to increase the thermal conductivity of the adhesive is mixing the boron nitride. Although hydrophobic boron nitride does not mix well with adhesive, it is possible to obtain high hydrophilicity by irradiating ultrasonic energy to a mixture of boron nitride with excellent thermal conductivity and boric acid with unique chemical reactivity. The hydroxyl group present at the edge of the modified boron nitride improved the dispersibility of the particles in the adhesive by increasing the affinity. The uniform distribution of the thermal conductive particles in the adhesive leads to an increase in the thermal conductivity of the adhesive.

It shows that the LTS coil impregnated with the modified boron nitride mixed adhesive improved the normal zone propagation velocity and cooling rate by 66% and 13%, respectively, compared to the coil with the epoxy composites used.

Expected Outcomes

Cooling and maintenance costs of superconducting devices can be reduced by using an adhesive with high thermal conductivity.

Related Figures

[Fig. 1] Schematic drawing of the surface modification of boron nitride and the thermal conduction process of the composite

[Fig. 2] Test results of the normal zone propagation velocity and cooling rate