Preparation and properties of B6O/TiB2-composites

Abstract: B6O/TiB2 composites with varying compositions were produced by FAST/SPS at temperatures between 1850 and 1900°C following a non-reactive or a reactive sintering route. The densification, phase and microstructure formation and the mechanical and thermal properties were investigated. The comparison to an also investigated pure B6O material showed that the addition of TiB2 in a non-reactive sintering route promotes the B6O densification. Further improvement was obtained by sintering reactive B–TiO2 mixtures which also results in materials with a finer grain size and thus in enhanced mechanical properties. The fracture toughness was significantly improved in all composites and is up to 4.0MPam1/2 (SEVNB) and 2.6–5.0MPam1/2 (IF method) while simultaneously a high hardness of up to 36GPa (HV0.4) and 28GPa (HV5) could be preserved. The high temperature properties at 1000°C of hardness, thermal conductivity and CTE were up to 20GPa, 18W/mK and 6.63×10−6/K, respectively. [Copyright &y& Elsevier]