The aim of this project was to synthesise via low temperature routes novel mixed metal oxide materials which are stable at high temperatures and chemically resistant. Low temperature routes include synthesis techniques such as sol-gel and coprecipitation. Zircon is used extensively as a crystal host system for chromophores in the pigment industry. Sol-gel and co-precipitation techniques for the production of zircon were investigated with a view to optimising the process to achive shorter firing times and lower firing temperatures (Chapter 4). Zircon was made by several gel methods and the structure of the gels investigated using a small angle x-ray scattering technique (Chapter 3), this method highlights the internal properties of the gel. The sol-gel and co-precipitation products were fired with, and without a mineraliser and analysed using x-ray diffraction. It was found that co-precipitation techniques proved more successful and this approach was transferred to other crystal systems related to zircon. A scheelite phase is formed when zircon is under high pressure and temperature with the silicon in a tetrahedral site and the zirconium in a dodecahedral site as in zircon. GeZrO4 and CaWO4 (Chapter 5 and Chapter 6) both minerals have a scheelite crystal structure at room temperature and pressure. Germanium and silica have the same oxidation state and are both in the tetrahedral site, but CaWO4 has Ca 2* and a We" in the dodecahedral and the tetrahedral site respectively. Both scheelite synthesis routes were optimised using a factorial experimental design experiment. Pr-GeZrO4 and Cr-CaWO4 were optimised and the resulting methodology transferred
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:398908 |
| Date | January 2004 |
| Creators | Kendrick, Emma |
| Publisher | Keele University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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