本文采用无机盐溶剂中高温循环过热和真空下单辊快淬两种方法获得Ｎｉ－Ｓｎ合金的深过冷，从而测得了Ｎｉ－Ｓｎ合金的伪共生区，分析表明：深过冷条件下共晶两相的形核是彼此独立的异质形核；尽管Ｎｉ３Ｓｎ是易于形核的相，但合金中的固有杂质有利于Ｎｉ（α）相形核． In this paper, inorganic salt solvent in the high temperature cycle overheating and single-roll rapid quenching under vacuum two methods were obtained Ni-Sn alloy deep undercooled Ni-Sn alloy pseudo-symbiotic area was measured, the analysis showed that: The nucleation of the two phases of the crystal is a heterogeneous nucleation independent of each other. Although Ni3Sn is an easily nucleable phase, the inherent impurities in the alloy favor the Ni (α) phase nucleation.