Thermal expansion of Cu-graphite composites: effect of copper coating

Cu/graphite composites with 30 and 50 vol.% of graphite were prepared.Copper coated graphite particles enabled to prepare more homogeneous structure at 50 vol.% of graphite as simple powder mixture.In the case of 30 vol.% of graphite, composite prepared from mixture of coated graphite and copper powders is more heterogeneous as simple powder mixture.Measured CTE of coated composites was significantly smaller at both compositions.It is the result of the different area of copper-graphite interface that is established only by mechanical clamping.For coated composites the area of interface increases significantly due to avoiding graphite clustering.Simple model was proposed to predict this behaviour on the basis of anisotropy of graphite CTE.Further, the model can be used for calculation of the thermal expansion coefficient of the graphite reinforcement.K e y w o r d s :