Spark plasma sintering of B4C ceramics: The effects of milling medium and TiB2 addition

► B4C ceramics can be fully densified at a relatively low temperature of 1850C. ► Different milling medium is found to have quite different effect on the sintering densification. ► The B2O3 impurity may promote the densification of B4C ceramics at the early stage of sintering. ► The B2O3 impurity can be eliminated at the final stage of sintering by a TiB2 addition. ► This process further promotes the final densification of B4C ceramics.