Microstructure and thermal properties of Cr7C3 coated graphite flakes/Al composites

Graphite flakes (Gf) were coated with Cr7C3 by salt bathing coating, and the Cr7C3 coated Gf reinforced Al matrix composites were prepared by gas pressure infiltration. Surface morphology of uncoated and Cr7C3 coated Gf, the interfacial characteristics of Cr7C3 coated Gf/Al composites were observed by SEM. Surface of Cr7C3 coated Gf is smooth without defects, the Cr7C3 coating effectively improved the wettability. When volume fraction of Gf is below 50%, the experimental value of thermal conductivity (TC) is basically consistent with the calculated value of the EMA model. When volume fraction of Gf is over 50%, the growth of deviates from the EMA model curve. Coefficient of thermal expansion (CTE) of composite was predicted by Kerner model and Orientation Disc model, because Kerner model does not consider the anisotropy of Gf and inaccurately predict the change of CTE. However, the Orientation Disc model can predict the change of CTE better, but there is certainly deviation.