Zero Thermal Expansion Material / Thermal expansion (CTE) of Carbon Fiber
Graphite is composed of layers of carbon atoms in hexagonal ring.Specification of Graphite is different in axis and thickness direction.
In axis direction, graphite has high elastic modulus, high thermal conductivity and negative thermal expansion. In thickness direction, graphite has positive thermal expansion. Thermal expansion (CTE) of high modulus carbon fiber is negative in fiber direction and positive in thickness direction.
Thermal expansion (CTE) of laminate with pitch based high modulus fiber and matrix resin has can be controlled. Zero thermal expansion (CTE) can be designed.
Zero CTE composite has been widely used for satellite and machinery toll needing high dimensional accuracy in deferent temperature.