Cesium Doped Tungsten Oxide Powder

Infrared light, especially near-infrared, has a significant thermal effect, which tends to cause temperature rise, which causes an increase in temperature, such as indoors or in a car. Infrared barrier materials generally refer to a class of functional materials that have a strong absorption or reflection of infrared light without affecting the transmission of visible light. 

Inorganic materials that have been reported to have strong infrared absorption or reflection properties are mainly concentrated in several oxides such as antimony tin oxide (ATO), indium tin oxide (ITO), and zinc aluminum oxide (AZO), but such oxides The material generally can only block the mid-range infrared light with a wavelength greater than 1400 nm, which cannot meet the performance requirements of high transparency and high heat insulation at the same time.

The cesium doped tungsten oxide powder (Cs0.3WO3) has near-infrared blocking properties, and can block near-infrared light having a wavelength greater than 900 nm. Therefore, it has excellent near-infrared blocking properties. However, the current preparation of strontium tungsten powder has the problems of complicated process and high cost, and the prepared powder has insufficient performance for near-infrared barrier properties.

Some scholars have improved the traditional preparation method, introduced hydrolysis inhibitor and two-component complexing agent, and strictly controlled the reaction time, temperature and atmosphere while relieving the hydrolysis of raw materials. The prepared tungsten oxide niobium nanopowder has better dispersion effect and significant improvement. The phenomenon of agglomeration of nano-powders. The operation process includes:

300 ml of ethanol and 30 ml of water were premixed to form a mixed solvent according to a volume ratio of 1:0.1, and then 9 ml of hydrochloric acid was added as a hydrolysis inhibitor for the subsequent reaction; the compound of ruthenium and tungsten was subjected to a molar ratio of Cs:W=0.32:1. Ingredients, weighed 6.24g of cesium  nitrate, 39.66g of tungsten chloride, added to the previous mixture of alcoholic acid, stirred by magnetic heating stirrer until all dissolved; then 19.29g of ethylenediaminetetraacetic acid and 25.36 g citric acid and water premixed, mix well, add ammonia water until the complexing agent is dissolved, then add to the above mixed solution, and continue to add ammonia water to adjust the pH to 8, continue to stir; wait until the above mixture is stirred into a sol Thereafter, the mixture was further heated and stirred at 80 ° C for 2 hours to a gel state, and then dried in a blast oven at 200 ° C for 5 hours to obtain a black sintered precursor; the sintered precursor was calcined in an air atmosphere at 800 ° C for 8 hours, and the temperature was raised. The rate is controlled to 6 ° C / min; then converted to a nitrogen atmosphere to cool, and then converted to a hydrogen argon mixture, calcined in a reducing atmosphere of 500 ° C for 6 hours, finally to obtain yttria stabilized tungsten oxide nano powder Cs0.32 WO3; using a nano-grinding technique to achieve a high dispersion and high stability on a microscopic scale of a mixed slurry of 200 g of yttria-stabilized tungsten oxide, 20 g of sodium hexadecyl sulfate dispersant and 780 g of deionized water. 20% solids content of cesium  oxide nano-dispersion.

The use of two-component complexing agent, hydrolysis inhibitor and basic synthesis conditions can significantly improve the uniformity of reactant mixing, can significantly improve the particle agglomeration of nanomaterials, and increase the uniformity of particle size. The prepared cesium  oxide nanometer nano powder can be applied to the field of heat insulation film such as building or window, and has good infrared blocking effect.

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