抄録
A series of titanium carbide (TiC)-graphite (C) composites was sintered by hot-pressing with condition of 2000℃ for 2h in Ar gas atmosphere under a pressure of 40 MPa. Monolithic TiC exhibited a grain growth with an average size of 15 times larger than that of the starting particles, whereas dispersed graphites well prohibited the grain growth of TiC grains in the composites. The graphites lay in the boundaries or their triple points of the TiC grains, and the graphites delaminated occasionally to overlay the TiC grains, which implied a good sliding properties due to solid lubricant action of the graphite. Although the relative density of the composites increased at 5 wt% graphite addition, it gradually decreased with the increase in graphite addition due to low sinterability of graphite. Room temperature flexural strength was improved by adding graphite, which would have been resulted by the inhibiting effect of grain growth by graphite dispersion. Fracture toughness was also improved mainly through the crack deflection caused by the dispersed graphite phase. Addition of graphite resulted significant improvement in sliding properties of TiC against copper in dry air. The wear of Cu occurred by adhesion, wheres that of the TiC-C composites was minimized by delamination of graphite phase.
