Oxychloride glasses in the ternary system Sb2O3 - PbCl2 - ZnCl2 have been prepared. The thermal properties and the crystallisation behaviour of these glasses have been investigated by differential scanning calorimetry, viscometry, x-ray diffraction, scanning electron microscopy with energy dispersive x-ray analysis and infra-red spectroscopy. Thermal stability gaps, T1 - T4 up to 149°C are observed. The predominant crystal phases formed, depending on composition, are ZnCl2, Sb2O3 and a lead antimony oxychloride Sillan phase whose stoichiometry varies with glass composition from PbSb2O2.Cl2 to PbSb1O2.Cl. Relative crystal growth rates for the glasses have also been measured and values up to 0.16 μm sec−1 are observed. These values are found to be strongly dependent on the chlorine content of the glasses as are also the viscosity characteristics. The chemical durability of the glasses has also been studied under various conditions. Initial water dissolution rates between 10−2 to 10−4 gm cm day were observed. The corrosion rates were found to be chlorine content dependent and reaction mechanisms are suggested. The introduction of a heavy metal chloride such as BlCl2 or TlCl, as a fourth component, was found to increase the chlorine content without much affecting the thermal stability. However, an excessive amount of chlorine makes the glass less durable.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:254421 |
| Date | January 1990 |
| Creators | Sahar, Md Rahim |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/106571/ |
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