Growth mechanism and thermal behavior of electroless Cu plating on short carbon fibers

Short carbon fibers (Csf), when used at 550–650 °C, often suffer from oxidization and mass loss during the preparation of Csf reinforced magnesium matrix composites (Csf/Mg composites). Here, a Cu coating is deposited on the Csf by using electroless plating to address this long-standing issue. The growth mechanism of the Cu coating, as well as its protection capability, is investigated. FT-IR suggests a proper pretreatment on the Csf provides favorable nucleation sites for subsequent electroless plating. SEM images show that, initially, a thin Cu coating with a thickness of 0.30 μm is grown on nucleation sites during electroless plating, and the Cu nanoparticles appear to be deposited on such Cu coating afterwards. With the electroless plating time increasing, the Cu particles are accumulated and become massive and flaky, then some holes and cracks appear. More importantly, TG conducted at 600 °C reveals that the mass loss of the Cu-coated Csf (4 min) is 8%, which is 4 times lower than that of the Csf without Cu coating. The optimal electroless plating time is 3–4 min for the Cu coating, which can effectively protect the Csf at high temperature for preparing Csf/Mg composites. More importantly, TG conducted at 600 °C reveals that the mass loss of the Cu-coated Csf (4 min) is 8%, which is 4 times lower than that of the Csf without Cu coating.