Cyrogenic Properties of Advanced Composites and Their Applications

Abstract

This chapter presents the characteristics of advanced composite materials (ACMs), and discusses the special application of some ACMs. It compares the cryogenic properties of advanced composites with those of conventional glass fiber reinforced plastics (GFRP), and discusses the advantages of the advanced composites. The thermal properties such as thermal contraction and thermal conductivity of advanced composites are different from those of GFRP. The organic fiber reinforced plastics show negative thermal contraction behavior that is they show expansion with decreasing temperature in the fiber direction. The composites with organic fiber can be used as the former of the superconducting magnets to increase the stability. The pitch-carbon fiber reinforced plastics show high thermal conductivity and high electric resistivity. The composites have been applied to the thermal shield to prevent the eddy current in the magnet system. The thermal conductivity of alumina fiber reinforced plastics is found to be small all temperature range down to liquid helium temperature. The composite is used as the thermal supporting system with high performance in the magnet. The high glass content GFRP or 3 dimensionally reinforced plastics are developed to decrease the thermal contraction especially in the thickness direction. These materials are promising as the spacer in superconducting magnet.