Observations of rapid freezing of salt solutions.

Crystallization patterns of binary aqueous solutions of sodium chloride, potassium chloride, and calcium chloride have been observed and photographed during rapid freezing of thin films at very low subfreezing temperatures.One to three crystallization waves were observed to come in succession, usually ice first, then solute. Time delays for nucleation, and times for complete crystallization were of the order of seconds or fractions of a second for the first two salts, and minutes for the calcium chloride solutions.