Preparation of 10B Enriched B4C Ceramics by Pressureless Sintering

Boron carbide is an attractive neutron absorbing material used both in Fast Breeder Reactors (FBR) and in Pressurised Water Reactors (PWR) owing to its very high absorption cross section for thermal neutrons, chemical stability and refractory character. In the present paper, B-10 enriched B4C ceramics are prepared by pressureless sintering at 1960-2160 degrees C, under argon, using B-10 boron carbide powder as raw material, 18 wt% phenolic resin as sintering aid. In the sintering temperature range, with the increasing of sintering temperature, both the relative density and flexural strength increase linearly, the average particle sizes increase from about 3 mu m at 1960 degrees C to more than 30 mu m at 2160 degrees C. The sample sintered at 1960 degrees C has a 91.7% of relative density and 192 MPa of flexural strength and a homogeneous texture with 3-4 mu m particle size, which are enough for pellet application of reactors.