Tungsten oxide, which may be applied for producing thermal insulation paper, may be prepared by hydrothermal/solvent method (high pressure solution method). This production method is a common method of crystal growth.
Preparation of Tungsten Oxide by Hydrothermal/Solvothermal Method
A tungsten trioxide nanowire array can be synthesized by hydrothermal method. Compared to the sintering process, the process has a lower synthesis temperature, so that fewer defects are generated in the crystal during growth. Compared to the atmospheric pressure heating method, a higher synthesis pressure causes the crystal to have a higher crystallinity during growth. At the same time, strong convection in the hydrothermal/solvent heat process will make the mass transfer more uniform and rapid, and the temperature gradient is small, so that the crystal growth has characteristics of higher growth rate and uniformity.
The hydrothermal/solvothermal method is a process in which a high-pressure environment is generated by heating in a closed vessel, and a substance which is insoluble or poorly soluble under normal temperature and pressure is dissolved and recrystallized under the action of high temperature and high pressure. Due to the high temperature and high pressure environment, the nature of the reactants also changes to produce a product different from normal temperature and pressure.
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