In vacuo production of α-AlB12, C4AlB24, AlB12C2 and Al3B48C2 powders

The production of pure powder samples of boron-rich ternary Al-B-C phases was investigated in vacuum at temperatures between 1400 °C and 1600 °C, using a range of different starting powders. Compacted powder mixes of B-AlB2-B4C, Al-B-C, Al-B-B4C, B-C-AlB2, B-AlB2 and Al-B were heated for 1-2 h under vacuum in a carbon resistance furnace and the products characterised by X-ray diffraction. It was found impossible to produce significant quantities of C4AlB24 under these conditions, but >95% pure samples of α-AlB12, AlB12C2 and Al3B48C2 were obtained. This study is a precursor to further research aimed at producing dense B4C-type materials which might offer the advantages of easier densification and fabrication as compared with B4C itself.