Rate of Growth of Ice at an Aluminium-Water Interface

Abstract

As part of an investigation of the way in which water freezes on solid surfaces, we have measured the dependence on temperature of the velocity of a freezing front advancing across an aluminium–water interface. We find that at least two distinct modes of growth occur and that the appearance of one or the other or both depends on the amount of super-cooling and on the manner of nucleation. For one of these, the orientation of the c-axis is nearly perpendicular to the interface and the structure is multiply branched (Fig. 1B). For the other, the c-axis makes a much smaller angle with the interface and the structure is that of tightly bound feathers (Fig. 1A). The branched structure dominates at lower temperatures, choking off whatever feathered structure may start. At temperatures close to 0° C, the converse is true and the growth becomes predominantly feathered. Fig. 1 is a photograph of a sample in which both types of growth were nucleated at a temperature such that their growth rates were nearly equal.