33C - Carbon Enhanced Copper Thermal Strap

Mainstream is proposing a hybrid multi-strand braided thermal strap to enable flexible thermal connections that reduce cooldown time of SRF facilities. We will use our previously developed, scalable method for encapsulating single or small groups of carbon nanotubes (CNT) or graphene in copper to improve the metal-CNT interface in a composite, leading to improved mechanical and thermal properties of the metal-CNT composite. The thermal strap comprises many individual wires. Inclusion of CNTs into the copper wires, allows for a substantial improvement in the thermal conductance of the thermal strap. Our encapsulation and wire fabrication methods allows for good CNT distribution and alignment. Both of which are critical to enhanced thermal conductance. We will identify the ideal CNT loading in bulk material that results in peak thermal conductivity improvements without degrading mechanical properties. Next, we will extrude and draw the composite ingot with the optimum CNT loading down to a fine wire for braiding. We will fabricate and experimentally demonstrate a complete braid that is mechanically fitted with end connections. Thermal and mechanical performance will be compared to available literature of commercial thermal straps and pre-extrusion ingot results to quantify net improvement. The proposed solution has many benefits in commercial and military applications by enabling the scalable manufacturing of CNT modified materials. Enhanced thermal conductance thermal straps enable improved conductors for other deep cryogenic applications, such as quantum computing. Additionally, CNT modified materials enable low loss electrical conductors and tailored material properties for a range of applications.