Experimental Studies on Densification and Pressure-Sintering of Ice

Abstract

Pressure-sintering experiments of ice particles were carried out at pressures between 0.1 and 2.0 MPa and temperatures between -25 and -9°C. At each experiment, logarithm of the strain rate of densification was proportional to the density, and the slope of proportionality changed at a critical density implying the alternation of predominant densification mechanisms. The critical density varied with applied pressure and temperature, but its variation was restricted between 700 and 750 kg/m3. At densities below the critical density, two-dimensional coordination numbers of constituent particles increased though specific areas of internal free surface were almost constant. The result was explained by the predominant contribution of the process of particle rearrangement in this density range. On the other hand, the contribution of dislocation creep was concluded to be dominant at densities above the critical density; the creep caused by boundary diffusion also contributes especially at higher densities.