A Diffusion Solution for the Melting/Dissolution of a Solid at Constant Temperature and Its Use for Measuring the Diffusion Coefficient in Liquids

摘要

A general solution to the diffusion equation isobtained for the composition in two phases when one phasedissolves and the other grows at constant temperature. Therelevance of the derivation to melting is discussed. The exactsolution is used to examine the condition when diffusion may beconsidered to occur in only one phase. Experiments have beencarried out using the analysis to obtain solute diffusioncoefficients in liquid succinonitrile-water alloys. The methodrelies on an interface displacement measurement and does notrequire the composition to be measured as function of positionas is usually necessary with a diffusion couple.