Mechanical, Electrical, and Thermal Characterization of G-10Cr and G-11Cr Glass-Cloth/Epoxy Laminates Between Room Temperature and 4 K

The United States magnetic fusion energy program will require large-scale use of industrial high-pressure glass-reinforced epoxy laminates for structural supports and for electrical and thermal insulation in superconducting magnets. This choice is based on such factors as availability, cost, machinability, high strength-to-weight ratio, and low electrical and thermal conductivities. There is an immediate need for a commercial supply of these materials having predictable cryogenic performance. Therefore, the National Bureau of Standards (NBS) has cooperated with the laminating industry and the National Electrical Manufacturers’ Association (NEMA) to establish specifications for cryogenic grades of NEMA G-10 and G-11 glass-cloth-reinforced epoxy laminates. These materials, designated G-10CR and G-11CR, meet existing NEMA, as well as federal and military specifications for G-10 and G-11 products. The component and manufacturing specifications have been distributed to all U. S. manufacturers through the NEMA organization. The products are currently available from one manufacturer, and others have shown an interest in their production.