Thermal diffusivity of graphite paper and its joint with alumina substrate

Though graphite paper exhibits unique thermal conduction characteristics, a backing layer is needed to provide its structural rigidity. In the present study, the graphite paper is bonded to alumina substrate using an active brazing technique. The thermal diffusivity of graphite paper and of alumina/braze/graphite joint is measured. The thermal diffusivity of the alumina/braze/graphite joint is slightly higher than that of alumina substrate alone, and much higher than that of the graphite paper perpendicular to the planar direction. The high thermal diffusivity of joint can be related to the structure distortion of graphite paper.