Method for preparing porous ceramic green body by combining microemulsion with freeze drying

A technology of porous ceramics and microemulsions, which is applied in the field of preparation of porous ceramics by combining oil-in-water emulsions with freeze-drying, and microemulsions combined with freeze-drying to prepare porous ceramic bodies. Problems such as the mechanical properties of ceramic products, to achieve the effect of microstructure and mechanical properties regulation, inhibition of ice crystal growth, effective microstructure and mechanical properties

Active Publication Date: 2020-08-21
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, it is often difficult to control the growth of ice crystals during the freezing process, and overgrown ice crystals will leave large-sized pores after the ice crystals are removed, which destroys the uniformity of the microstructure and is not conducive to the mechanical properties of porous ceramic products.

Method used

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  • Method for preparing porous ceramic green body by combining microemulsion with freeze drying
  • Method for preparing porous ceramic green body by combining microemulsion with freeze drying
  • Method for preparing porous ceramic green body by combining microemulsion with freeze drying

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preparation example Construction

[0036] Preparation of oil-in-water emulsions. Water, cyclohexane, and Tween 80 were stirred to form an oil-in-water emulsion. Among them, cyclohexane exists as an oil phase, but it can also be selected from n-octane, diphenylmethane, cyclopentane and the like. Tween 80 exists as a surfactant, but it can also be selected from sodium dodecylbenzene sulfate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan monolaurate, and the like. Wherein, the volume ratio of water and oil phase may be 1:(0.05-0.8), more preferably 1:(0.05-0.5), more preferably 1:(0.05-0.4). If the oil phase is excessive, the ceramic green body is prone to microcracks.

[0037] The ceramic powder and the sintering aid for the ceramic powder are added into the oil-in-water emulsion, and a uniformly mixed ceramic slurry is obtained after ball milling. In the slurry, the recommended amount of the oil phase (for example, cyclohexane) can be 5-40 wt% of the ceramic powder. The amount of water added is...

Embodiment 1

[0048] (1) The water of 56.4g is stirred and mixed with the water-soluble polyvinyl alcohol of 3.6g to form an aqueous solution;

[0049] (2) Transfer the above aqueous solution to a ball mill jar, then add 170g of zirconia balls, 7.7g cyclohexane (density 0.78g / ml), 2.3g Tween 80, 1g ammonium polyacrylate and 100g yttrium oxide to the ball mill jar Stabilized zirconia powder (YSZ, yttrium oxide content is 8mol%), ball mill speed is 300r / min, after ball milling for 2.5 hours, a uniformly mixed water-based slurry is obtained;

[0050] (3) The slurry is vacuum degassed, then injected into a metal mold, and then the mold is transferred to a cold source at -18°C, and frozen for 6 hours to obtain a solidified green body;

[0051] (4) Transfer the molded ceramic body to a freeze dryer, the freeze drying conditions are vacuum degree 5Pa, condensation chamber -68°C, heating plate 60°C, and dry for 48 hours;

[0052] (5) Raise the ceramic body to 600°C at 2°C / min under air conditions,...

Embodiment 2

[0056] (1) The water of 56.4g is stirred and mixed with the water-soluble polyvinyl alcohol of 3.6g to form an aqueous solution;

[0057] (2) Transfer the above-mentioned aqueous solution to a ball mill jar, then add 180g of zirconia balls, 15.4g of cyclohexane, 4.6g of Tween 80, 1g of ammonium polyacrylate and 100g of yttria stabilized zirconia powder (YSZ) to the ball mill , the rotating speed of the ball mill is 300r / min, and the uniformly mixed water-based slurry is obtained after ball milling for 2.5 hours;

[0058] (3) The slurry is vacuum degassed, then injected into a metal mold, and then the mold is transferred to a cold source at -18°C, and frozen for 6 hours to obtain a solidified green body;

[0059] (4) Transfer the molded ceramic body to a freeze dryer, the freeze drying conditions are vacuum degree 5Pa, condensation chamber -68°C, heating plate 60°C, and dry for 48 hours;

[0060] (5) Raise the ceramic body to 600°C at 2°C / min under air conditions, keep it warm...

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Abstract

The invention relates to a method for preparing a porous ceramic green body by combining microemulsion with freeze drying. The method comprises the following steps: (1) mixing water, an oil phase anda surfactant to obtain an oil-in-water emulsion, wherein the oil phase is preferably selected from at least one of cyclohexane, n-octane, diphenylmethane and cyclopentane; (2) adding ceramic powder, asintering aid, a dispersing agent and a binder into the obtained oil-in-water emulsion, and mixing to obtain ceramic slurry; and (3) carrying out vacuum degassing on the obtained ceramic slurry, pouring the ceramic slurry into a mold, and carrying out freeze curing and freeze drying to obtain the porous ceramic green body.

Description

technical field [0001] The invention relates to a method for preparing a porous ceramic body by combining microemulsion with freeze-drying, in particular to a method for preparing porous ceramics with oil-in-water emulsion and freeze-drying, and belongs to the field of preparation of ceramic materials. Background technique [0002] Porous ceramics is a kind of ceramic material that has been fired at high temperature and has a large number of closed pores or a pore structure that communicates with each other and the surface of the material. Due to the existence of a large number of micropores and holes, small bulk density, high porosity, and large specific surface area, porous ceramics also have the unique wear resistance, high temperature resistance, and good chemical stability of ceramic materials, so that porous ceramics can be It is widely used in purification and separation, gas and liquid filtration, sound absorption and shock absorption, biological implant materials, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/06C04B35/48C04B35/632C04B35/634C04B35/64
CPCC04B35/48C04B35/632C04B35/63404C04B35/64C04B38/0645C04B2235/3225C04B2235/6562C04B2235/6567C04B2235/96C04B2235/9615C04B38/0074C04B38/0054
Inventor 曾宇平姚冬旭李雪晴左开慧夏咏锋尹金伟梁汉琴
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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