This thesis describes a theoretical and experimental investigation into the sintering of ice. When two ice spheres are brought together to touch at a point, the area of contact is found to increase with time. This phenomenon is well known in the field of powder metallurgy where it is termed sintering. The motivating force for the material . transfer is provided by the surface tension forces existing in the sharply concave region of the neck between two particles. The current theory of sintering considers four possible mechanisms for the material transfer: viscous or plastic flow, evaporation—condensation, volume diffusion, and surface diffusion. A new theory has been developed for sintering involving the transfer of material by diffusion through the environment. Measurements made on the rates of growth of the neck between spheres of polycrystalline ice and single crystals of ice are found to be in quantitative agreement with the new theory. The effect of adding impurities to the ice and changing the environmental conditions has also been investigated and the results interpreted in terms of the proposed theory. Two previous claims have been made that the sintering of ice occurs by volume diffusion and surface diffusion. These two mechanisms are analysed but the results predicted by each are shown to be at least three orders of magnitude smaller than those observed experimentally. It is concluded that surface diffusion and volume diffusion make negligible contributions to the sintering of ice and that the predominant mechanism for the growth of the neck is provided by the diffusion of water vapour through the environment.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:602211 |
| Date | January 1963 |
| Creators | Hobbs, Peter Victor |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/13297 |
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