An Overview of Navy Composite Developments for Thermal Management

Abstract

This paper reviews: (1) Navy sponsorship of pitch graphite fiber development, and (2) assesses the impact of the high thermal conductivity fibers on future Navy applications. Navy exploratory development programs (6.2) have revealed potential applications in advanced systems for graphite fiber reinforced composites: (1) electronic packaging, (2) satellite radiators, and (3) elevated temperature applications such as missiles. Thermal management in these applications can be improved through the development and use of high thermal conductivity graphite fibers. In electronic packaging, the thermal planes that conductively cool the Standard Electronic Module, Format E (SEM-E) printed wiring board require both high thermal conductivity and thermal expansion matching. For satellite radiators, the graphite fiber reinforced metals offer a zero coefficient of thermal expansion, with maximum specific modulus. The joints between titanium missile structures and their ceramic nose cones require thermal expansion control, but high thermal conductivity is also a distinct advantage. Pitch graphite fibers are now available with a thermal conductivity of 1000–1100 W/mK and a modulus of 130–140 msi. Significant growth toward the theoretical thermal conductivity of graphite, at 2400 W/mK, is possible. The benefits of these fiber properties are shown for applications that are either thermal expansion or thermal conductivity dependent.