The Ga-Ni-Si (Gallium-Nickel-Silicon) System

Abstract

The Ga-Ni system [1991Nas] (Fig. 1) has eight intermediate phases, GaNi3 ( b1), Ga3Ni5 ( d 0), Ga2Ni3 (HT) ( e), Ga2Ni3 (LT) ( c0), GaNi ( m), Ga4Ni3 ( h), Ga3Ni2ðb2Þ, and Ga4Ni (q), of which the m phase melts congruently at 1220 C. The b1, b 0 2, q, and (Ga) phases form through peritectic reactions: Lþ c $ b1 at 1212 C, Lþ m $ b2 at 895 C, Lþ b2 $ q at 363 C, and Lþ q $ (Ga) at 30.2 C. The c phase is the terminal solid solution (Ni). The e, d0, and h phases form through peritectoid reactions: b1 þ m $ e at 949 C, b1 þ e $ d0 at 741 C, and m þ b2 $ h at 542 C. The e $ c0 phase transformation occurs at 680 C. A eutectic reaction L $ b1 þ m occurs at 1207 C. The Ga-Si system [Massalski2] (Fig. 2) is possibly a simple eutectic system with eutectic temperature close to Ga. There is practically no solid solubility of Ga in Si or Si in Ga. The Ni-Si system [1991Nas] (Fig. 3) has eight intermediate phases, Ni3Si (b1), Ni3Si (b2 and b3), Ni31Si12ðc1Þ, Ni2Si ( d), Ni2Si ( h1), Ni3Si2 (e0 and e00), NiSi (g), and NiSi2 (f and f 0), of which several phases b2 and b3, e 0, and e00, and f and f0 are polymorphic forms of Ni3Si, Ni3Si2, and NiSi2 phases, respectively. The b1, b3, d, e 00, and f0 phases form through peritectic or peritectoid reactions: Lþ c1 $ b3 at 1178 C, Lþ h $ d at 1255 C, Lþ ðSiÞ $ f0 at 993 C, c þ b2 $ b1 at 1035 C, and h þ g $ e00 at 845 C. There are eight eutectic or eutectoid reactions in the Ni-Si system: L $ c þ b3 at 1143 C, L $ c1 þ d at 1215 C, L $ h1 þ g at 964 C, L $ g þ f at 966 C, b2 $ b1 þ c1 at 990 C, h1 $ d þ e00 at 825 C, e00 $ d þ e0 at 820 C, and e00 $ e0 þ g at 800 C. The c1, d, g, and f phases are single-composition phases.