The effects of rare-earth oxide additives on the densification of pressureless sintering B4C ceramics

Boron carbide ceramics used as neutron absorbing materials in fast breeder reactor were fabricated with boron carbide powders and different rare-earth oxide additives by pressureless sintering. The effects of rare-earth oxide as well as phenolic resin on densities and mechanical properties of the composites were studied. The addition of Dy₂O₃, Eu₂O₃, and Sm₂O₃ was found to be beneficial in the densification of B₄C ceramics. B₄C with 4 wt% rare-earth oxide and 18 wt% phenolic resin, exhibiting bulk density of 90–96% T.D., flexural strength of 276–358 MPa, could be prepared by pressureless sintering at 1960–2080 °C, which are capable of meeting the requirement of fast breeder reactor.