Abstract
In order to determine the liquidus surfaces, the ternary system Ni-B(<30 at %)-Si(<30 at %) was studied by thermal analysis, X-ray diffraction and the observation of microstructures. The results obtained are summarized as follows:
(1) The phases appeared in this region were Ni(solid solution), Ni3B, Ni2B, Ni3Si, Ni5Si2 and Ni6Si2B.
(2) Quasi-binary eutectic reactions took place at the boundaries of liquidus surfaces of Ni(solid solution) and Ni3B; Ni3B and Ni2B; Ni(solid solution) and Ni3Si; Ni3Si and Ni3B; Ni3B and Ni6Si2B; and Ni2B and Ni6Si2B. Monovariant-peritectie reactions took place at the boundaries of liquidus surfaces of Ni5Si2 and Ni3Si, and Ni5Si2 and Ni6Si2B.
(3) Following four invariant reactions with melt were observed at the intersections of the above i monovariant reaction lines;
L(11 at %B, 13 at %Si)+Ni5Si2=Ni6Si2B+Ni3Si at 1012°C
L(12.3 at %B, 12.0 at %Si)+Ni6Si2B = Ni3B+Ni3Si at 1002°C
L(9.8 at %B, 12.9 at %Si)=(Ni)+Ni3B+Ni3Si at 993°C
L(20.3 at %B, 9.8 at %Si)=Ni3B+Ni2B+Ni6Si2B at 991°C
Thus, the liquidus surfaces have been experimentally determined.
