Measurement of atomic kinetics of solidification using peltier heating and cooling—I. theory

Abstract

Periodic Pettier heating and cooling may be generated at a solid/liquid interface by the passage of an alternating electric current. Melting and freezing will then occur at rates which will be influenced by the kinetic law of molecular attachment relating solidification velocity to interface temperature. We describe here the theory of an experiment in which the equation describing the interface attachment kinetics is to be determined by measuring the response of a solid/liquid interface to square-wave Peltier heating and cooling. The mathematical methods required for extracting the kinetic equation by analysis of the waveform of interface motion are given and it is shown that with this technique, linear, parabolic and exponential kinetics should give distinguishably different waveforms. The advantages of the method are discussed, along with the precautions necessary to eliminate possible confusing effects.