Wettability and interfaces in B13O2/Al system.

The wettability of B13O2 substrate by liquid aluminium was measured by the sessile drop method under vacuum at 1073-1273 K. A non-wetting to wetting transition was noted at about 1173 K. The oxy-redox reaction initiated at the B13O2 grain boundaries was found to be responsible for two phenomena in the Al/B13O2 system, i.e. wetting and infiltration of initially dense substrate by liquid Al. This reaction results in the formation of Al2O3 precipitates as well as AlB2 and AlB12 aluminium borides. The AlB12 crystallites are heavily faulted and contain numerous small inclusions of AlxOy or AlxOyBz type.