Fabrication and Characterization of Chromium-Coated Graphite Fibers Reinforced Copper Matrix Composites

Abstract

Milled form of mesophase pitch-based graphite fibers were coated with a chromium layer using chemical vapor deposition technique, and Cr-coated graphite fiber/Cu composite with 50 vol.% fibers was fabricated by hot-pressing. The composite was characterized with scanning/transmission electron microscopies and by measuring thermal properties, including thermal conductivity and coefficient of thermal expansion (CTE). The results showed that the milled fibers were preferentially oriented in a plane perpendicular to the pressing direction, leading to anisotropic thermal properties of the composite. The Cr coating reacted with graphite fiber and formed to a continuous and uniform Cr 3 C 2 layer. This carbide layer established a good metallurgical interfacial bonding in the composite, which can improve the thermal properties effectively. The in-plane thermal conductivity and CTE of the composite reached to 392 W/mK and 6.5 ppm/K respectively, making the composite suitable for being electronic packaging materials.