Solidification of Undercooled Sn-Sb Peritectic Alloys. Part 2. HeterogeneousNucleation. (Reannouncement with New Availability Information)

摘要

The undercooling behavior of fine droplet samples of Sn-rich, Sn- Sb alloys wasinvestigated using differential thermal analysis (DTA). Undercooling levels measured during cooling from the liquid state follow the trend of the intermetallic phase liquids, suggesting that solidification of all droplet samples (even those which solidify to yield a supersaturated BETA-tin product) was probably initiated with formation of primary intermetallic phase. Heterogeneous nucleation thermal cycling treatments were then used to measure the relative catalytic protency of primary intermetallic phases in this system for nucleation of BETA-tin during cooling. Crystallization reactions below the equilibrium peritectic temperature of 250 C, at 187 C and 230 C, have been interpreted as corresponding to nucleation of BETA on Sn3Sb2 and SnSb substrates, respectively.