Sintering behavior and mechanical properties of B4C ceramics fabricated by spark plasma sintering

The sintering behavior, microstructure and mechanical properties of boron carbide ceramics, which were fabricated by a spark plasma sintering process, were investigated. The relative density of B4C ceramics using a spark plasma sintering method reached as high as 99% theoretical at a lower temperature than a conventional sintering method, and in addition, without any sintering additives. The mechanical properties of B4C ceramics could be improved by soaking at 1,300 degrees C during the sintering process which removed the B2O3 phase from the B4C powder surface. A remarkable improvement of mechanical properties could be achieved by the introduction of a soaking process during the spark plasma sintering process. In particular, the fracture toughness values of the specimens which experienced the B2O3 removal process improved by over 30% compared with the specimens without this process. These achievements resulted from the formation of a fine and homogeneous microstructure because the grain coarsening was suppressed by the elimination of the B2O3 phase.