INVESTIGATION OF THE INFLUENCE OF THE THERMAL PREHISTORY OF ZINC AND CADMIUM MELTS ON THEIR CRYSTALLIZATION

Methods of thermal analysis were used to study how the temperature and hold time of zinc and cadmium melts and their rate of cooling influen ce their crystallization. It was established that zinc and cadmium mel ts exhibit no precrystallization supercooling. It was confirmed that n either cooling at a rate between 0.001 and 8 K/s, nor heating Zn and C d melts to temperatures 200 K above the appropriate melting point, nor isothermal ''annealing'' for up to 4 h, nor using a mass between 50 m g and 50 g resulted in supercooling during crystallization. The result s are analyzed using a cluster model of the crystallization of Zn and Cd melts based on the similarity between the crystal-chemical paramete rs of the solid and liquid phases of these substances. (C) 1998 Americ an Institute of Physics.