Net Shape Processing of Graphite Components via Powder Injection Moulding (PIM)

摘要

Carbonaceous mesophase is a promising precursor to produce high strength micro grain graphite. Unfortunately, compacting mesophase powders with automated die shaping processes is difficult, since these fine powders have a strong tendency to agglomerate and thus exhibit a bad pourability. Another major disadvantage of this method is the inhomogeneous density distribution in the specimens, arising from the production technique. Furthermore, the complexity of the final product is limited to simple shapes. For more complex parts, expensive mechanical post-processing is inevitable. To overcome these disadvantages powder injection moulding (PIM) is applied to carbon mesophase powders. The difficulty in this PIM process lies in the selection of an appropriate binder system. If conventional binders are used, problems arise because the sintering temperature of carbon mesophase is below the thermal degradation temperature of most organic binders. In this work, properties of specimens produced with (a) a partially water-soluble system and (b) a water-based system are compared to conventional produced graphite. Yet PIM-graphite exhibits inferior properties, but further improvements are to be expected, since the applied mesophase itself has not yet been optimised for PIM processing.