Anisotropic thermal conductivity and enhanced hardness of copper matrix composite reinforced with carbonized polydopamine

For thermal management applications, copper (Cu) metal matrixes reinforced by carbon are undoubtedly one of the most promising composites for heat spreaders In the frame of this work, hard Cu matrix composites having anisotropic thermal conductivity were fabricated by using Cu flakes coated with carbonized polydopamine. The flakes were coated by simply immersing them into a dopamine aqueous solution, then they were submitted to a thermal treatment under dihydrogen. This easy synthesis method results in a asymptotic to 10 nm thick N-doped graphenelike film surrounding the Cu flakes. The subsequently densified composites that contains about 0.23 wt % of C show an increase of hardness up 44% and 172% as compared to pure Cu in the parallel and perpendicular sintering direction, respectively. In addition an anisotropic thermal conductivity is obtained with an anisotropy ratio of 2.75.