Evaluation of Cu-coated graphite compacts prepared by pulsed current activated sintering process

Cu-coated graphite powder for weight reduction and a high thermal conductivity was fabricated using a chemical reaction process. First, 4 g of graphite powders, which was treated using an activation and wetting process, was added to an aqueous solution of copper (Cu) sulfate; also, zinc (Zn) powders (such as 35, 40, 45, and 50 wt.%) was added as a transposition solvent to the aqueous solution and stirred for 1 hr for a transposition reaction. After the addition of the fabricated powders mixture to a 75 wt.% DI water: 10 wt.% H₃PO₄: 10 wt.% H₂SO₄: 5 wt.% mixture, tartaric acid was added to the aqueous solution to produce a passivating oxide film, followed by a drying for 24 hrs. The particle size of the fabricated powder, which is coarser than the initial graphite powder, is approximately 3 µm to 4 µm, and the low-intensity oxide peak of the XRD pattern of the fabricated powders is due to the low Zn powder content. With the use of the Cu-coated graphite powder, Cu-coated graphite sintered bodies were fabricated using a pulse current activated sintering (PCAS) process. The Cu-graphite sintered bodies were sintered with heating rate of 60, 100 and 150 °C/min, respectively. The Cu-coated graphite powders and compacts were evaluated using FE-SEM, EDS, XRD, a particle analysis, and the Archimedes method.