Densification of graphite/copper compound powders

For graphite/copper composite, poor wettability between carbon and copper restricts its improvement of density and property. Intrinsic characteristics of sintering expansion for its sintering billets, the process of powder compacting followed by vacuum hot pressed sintering and hot extrusion had been utilized to densitify the compound powders. Relation curves of pressed compacts prepared by mechanical milling graphite/copper compound powders about relative density vs. compacting pressure had been achieved at room temperature. Cold compactability of these powders had been investigated. Effects of processing parameters on sintering pre-densification of milling graphite/copper powder pressed compacts and hot extrusion of sintering billets had also been studied. Sintering billets or microstructures of graphite/copper composite had been analyzed with scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM). The results show that pressed compacts with better quality can be obtained when compacting pressure and dwell time is 700MPa and 30s respectively. Sintering at 48MPa-hot-pressure, 600 °C holding for lh, and extrusion at 750°C is the rational processing parameters for vacuum hot pressed sintering and hot extrusion respectively. The problem of difficult to densification for mechanical milling compound powders had been overcome by this technical process, and composites with near full densification had been obtained.