Hot-pressing and characterization of TiB2–SiC composites with different amounts of BN additive

Abstract This research aimed to study the influence of different amounts of hBN additive on the mechanical properties and microstructure of TiB2-15 vol% SiC samples. All ceramics, containing 0, 3.5, and 7 vol% hBN, were sintered at 2000 oC using a hot-pressing route and reached their near full densities. Thanks to two different chemical reactions among the SiC reinforcement and the TiB2 surface oxides (B2O3 and TiO2), the in-situ phases of SiO2 and TiC were generated over the sintering process. The intergranular mode was identified as the predominant fracture type in all three composite samples. The hBN additive could contribute to grain refining of composites so that the sample containing 7 vol% hBN reached the finest microstructure. Finally, the highest Vickers hardness of 25.4 HV0.5 kg and flexural strength of 776 MPa were attained for the TiB2-SiC and TiB2-SiC-7 vol% hBN samples, respectively.