Yellow tungsten oxide powder applying for thermal insulation dispersion may be prepared by low temperature hydrothermal method.
Preparation of Yellow Tungsten Oxide Powder by Low Temperature Hydrothermal Method
Step one: Weigh 3.000g sodium tungstate and 0.0050g PVP, and dissolve them in 30mL distilled water, then stir well.
Step two: Add 3mL of the above solution dropwise into 5mL HCl with a concentration of 3mol•L-1, and stir for 0.5h.
3. Transfer the yellow solution obtained in the step two into the stainless steel reaction vessel with polytetrafluoroethylene inner pot, and heat it at 100°C for 24 hours.
4. After cooling, centrifugal settling, and wash with distilled water and acetone 3 ~ 4 times repeatedly.
5. Dry in the forced air oven at 80°C for 6-7 hours, burn in muffle furnace at 300°C for 3 hours to obtain yellow powder.
The yellow powders before and after photochromism was dispersed in absolute ethanol. And the ultraviolet spectrum of the two samples were measured by using UV-visible spectrophotometer in a wavelength range of 200~800nm.
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