The impact and freezing processes of a saltwater droplet on an ice surface

In this study, the new findings of a low-concentration saltwater droplet impacting and freezing on an ice surface were presented for the first time. A detailed parameter study regarding the concentration of the saltwater and the temperature of the ice surface was carefully performed. Besides, the experiments with de-ionized water droplets were also carried out to make a comparison. The findings revealed that the maximum spreading factors of saltwater droplets decreased as the concentration of saltwater increased or the temperature of the ice surface decreased. When the saltwater droplets were freezing on the ice surface, some small protrusions might appear, which were different from the single pointy tip formed by the freezing de-ionized water droplet. Furthermore, as the concentration of the saltwater or the temperature of the ice surface decreased, the number of the protrusions increased, while the size of the protrusions decreased. In addition, the saltwater droplets were found to have a shorter freezing time and a lower freezing height than those of the de-ionized water droplets.