B - Hf (Boron - Hafnium)

H. Bittermann and P. Rogl

The phase diagram of the B-Hf binary systems from [Mas2] basically is consistent with the versions presented by [1966Rud] except for small changes, in order to correspond to the accepted (αHf)/(βHf) transition temperature ([1966Rud] at ~1800°C, [Mas2] at 1743°C) and melting temperature of zirconium-free hafnium ([1966Rud] at 2218±6°C, [Mas2] at 2231°C). A thermodynamic calculation of the B-Hf phase diagram is from [1988Rog]. A refinement of this modeling is due to [1997Bit] (Fig. 1). With respect to these critical assessment and calculation of the B-Hf, it should be noted that the phase boundary data for the liquidus l/l+HfB₂, as reported by [1966Rud] widely scatter owing to the lack of suitable crucible materials for the aggressive B-containing melts at elevated temperatures. For ...