Preparation process for nano zirconia powder

A nano-zirconia, preparation technology, applied in the direction of zirconia, nanotechnology, nanotechnology, etc., can solve the problem of inapplicable preparation of multi-component oxide powder, affecting the sintering temperature and mechanical properties of the product, and poor component controllability and other problems, to achieve the effect of easy large-scale industrial production, easy control of process parameters, and less agglomeration

Inactive Publication Date: 2014-02-19
NANNING DINGFA POWDER METALLURGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The disadvantage is that the prepared powder often has more hard aggregates, which affects the sintering temperature and mechanical properties of the product
The disadvantage of the hydrothermal method is that the preparation conditions are relatively harsh, the

Method used

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  • Preparation process for nano zirconia powder
  • Preparation process for nano zirconia powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment l

[0033] Take 30 kg of crystalline zirconium oxychloride and dissolve in water so that the concentration of zirconium ions in the aqueous solution is 0.2 mol / liter, add 0.1 mol / liter of solution, and control the doping amount of oxidized zirconia powder to 3 mol. Add a certain amount of alcohol, and add 50% ammonia water (volume ratio) dropwise under vigorous stirring until the pH value of the solution is greater than 9. The hydroxide precipitate was separated by pressure filtration, and the precipitate was washed with distilled water until no chloride ions were detected (silver nitrate test).

[0034] Mix the precipitated hydroxide with 2 times of butanol (weight ratio), and process it with a colloid mill or vigorously stir. Place in a distillation dehydration drying device, dehydrate at 150°C until the powder is completely dry, and calcinate the powder in a high-temperature furnace at 400°C for 4 hours. The specific surface area of ​​the powder was measured by the BET method...

Embodiment 2

[0038] Take 1,000 grams of zircon sand concentrate powder and mix it with 1,400 grams of sodium hydroxide, and decompose it in a corundum vessel at 700°C for 1.5 hours in a high-temperature furnace. The decomposition products were washed with water, dissolved in hydrochloric acid, and silicon, iron, aluminum, sodium, etc. were removed to prepare a 4-liter solution. The concentration of zirconia in the zirconium precursor solution was determined by mandelic acid gravimetric method to be 0.915 mol / liter, and the recovery rate of zirconia in zircon sand was 69.4%. A certain amount of alcohol was added to the zirconium precursor solution, and 50% ammonia water (volume ratio) was added dropwise under vigorous stirring until the pH value of the solution was greater than 9. The hydroxide precipitate was separated by centrifugation, and the precipitate was washed with distilled water until chloride ions were no longer detectable (silver nitrate test).

[0039] The hydroxide precipita...

Embodiment 3

[0043] Hydroxide colloid precipitation was prepared according to the process in Example 2 (the doping amount of the oxide in the zirconia powder was 6 mol%). The hydroxide precipitate was mixed with 2 times ethanol (by weight) and stirred vigorously. Centrifuge, wash again with the same amount of ethanol, and centrifuge again. Place in a distillation drying dehydration device, dehydrate at 100°C until the powder is completely dry, and calcinate the powder in a high-temperature furnace at 500°C for 3 hours. The specific surface area of ​​the powder was measured by the BET method, the particle size, particle size distribution and crystal morphology of the powder were measured by transmission electron microscopy, and the crystal structure of the powder and the average particle size of the primary particles were measured by X-ray powder crystal diffraction.

[0044] The results are shown in Table 3, transmission electron microscopy see figure 2 .

[0045] Table 3 Example 3 ob...

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Abstract

The invention relates to a preparation process for nano zirconia powder. The preparation process comprises the steps of adding an alkaline precipitating agent in a zircon salt-containing aqueous solution to obtain a hydroxide precipitate; and then filtering, washing, dehydrating, drying and sintering to obtain zirconia powder. A colloidal solution obtained by dehydration with an azeotropic distillation method is dried in a distillation apparatus; and the colloidal solution is continuously stirred during dehydration and drying. The preparation process has the advantages of short reaction time, few procedures, large production capacity and high security, is suitable for large-scale production and can greatly reduce production cost.

Description

technical field [0001] The invention relates to a preparation process of highly dispersed nano zirconia powder, in particular to a preparation process of nano zirconia powder. Background technique [0002] Due to its inherent chemical composition and basic properties such as crystal structure, zirconia has the advantages of good chemical stability, small thermal conductivity, and high hardness. It is an important structural and functional ceramic material. Ordinary zirconia exists in a monoclinic phase at room temperature to 1170°C, and transforms into a tetragonal phase when heated to 1170°C-2370°C, and transforms from a tetragonal phase to a cubic phase (melting at about 2700°C) above 2370°C. Since the high-temperature phase (cubic phase or tetragonal phase) of pure zirconia will transform into a low-temperature phase (monoclinic phase) as the temperature decreases, to obtain a stable high-temperature phase zirconia at room temperature, it is necessary to dope a certain am...

Claims

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Application Information

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IPC IPC(8): C01G25/02B82Y30/00
Inventor 钟孝贤韦年江覃家源闭俊东韦鞾胡小兵黄建
Owner NANNING DINGFA POWDER METALLURGY
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