Copper coating on graphite particles (for dispersion in cast aluminum alloys)

Experiments were carried out to determine the optimal coating conditions for obtaining 2-5 micron thick continuous coatings of copper on 2-200 micron diam graphite particles using aqueous and supersaturated copper sulfate solutions by cementation processes. Both methods required activation of the graphite particles through heating at 380 C for 1 h in conjunction with addition of 0.2 vol % glacial acetic acid to improve graphite wettability. For the aqueous solution method, best results were attained with 0.2 M CuSO4.5H2O at 25 C. For the supersaturated solution method, best coatings were obtained with a CuSO4.5H2O/water ratio of 7 at the beginning of the reaction. Copper-coated graphite particles were successfully dispersed in Al-base alloys to obtain cast graphite aluminum alloys