Surface self-diffusion of ice under high hydrostatic pressure

Abstract

The temporal evolution of the width of a scratch on the basal plane (0001) of a pure ice single crystal was analyzed under hydrostatic pressures of 0.1 MPa and 10 MPa. The sample was immersed in ultrapure silicone oil at −5 °C to suppress sublimation. A custom-designed pressurized cell enabled the application of controlled hydrostatic pressure, while time-lapse imaging was conducted using an optical microscope equipped with a digital camera. Images of the scratch were acquired at 30-min intervals over a 24-h period. Quantitative analysis of the scratch profiles was performed using image processing software, allowing for the extraction of the timedependent broadening of the scratch under the specified hydrostatic pressures. From this, the surface selfdiffusion coefficient was determined, providing insight into pressure-dependent surface mass transport mechanisms in ice.