The Co-Ni-Sn (Cobalt-Nickel-Tin) System

摘要

Very little work has been done in the Co-Ni-Sn system. Only one pseudobinary has been established and reported here. The Co-Ni system [1991Nas] (Fig. 1) is a simple isomorphous system. In the fcc alpha solid solution, there are indications of formation of short range order near the CoNi_3 composition. The Co-Sn system [1983Nis, Massalski2] (Fig. 2) has three intermediate phases, Co_3Sn_2 in two allotropic forms, Co_3Sn_2(HT) and Co_3Sn_2(LT); CoSn; and CoSn_2. The Co_3Sn_2 phase melts congmently at approx 1170 deg C and the other two phases form through peritectic reactions L + Co_3Sn_2(HT) reversible CoSn at 936 deg C and L + CoSn reversible CoSn_2 at 525 deg C. Co_3Sn_2(HT) - > Co_3Sn_2(LT) transformation occurs at approx 500 deg C. Two eutectic reactions L reversible (alpha Co) + Co_3Sn_2(HT) and L reversible CoSn_2 + (beta Sn) occur at approx 1112 and approx 229 deg C, respectively. The fcc (alpha Co) —> hcp (epsilon Co) reac-tion, possibly a eutectoid type reaction, occurs at approx 420 deg C.