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Gel-casting method for dense ceramics based on low-concentration agarose and low-solid slurry

A technology of gel injection molding and low solid content, which is applied in the field of ceramic materials, can solve the problems of high viscosity of ceramic slurry, the inability to discharge air bubbles, and reduced density of ceramic products, achieving low solid content, low cost, Excellent effect

Inactive Publication Date: 2019-05-03
WUHAN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high concentration of agarose and the high viscosity of the ceramic slurry with high solid phase content, the air bubbles generated during the stirring process cannot be discharged by themselves, resulting in a decrease in the density of the final ceramic product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Measure 16.8ml of distilled water and add it to the ball mill tank, and add a total of 26g of zirconia powder (theoretical density of 6.1g / cm 3 , The particle size is 1um), 0.221g agarose powder and 0.6% ammonium citrate (about 0.156g) are added into the ball milling tank at one time and stirred evenly, the solid phase volume fraction is 20.2%, the agarose concentration It is 1.3wt% of the mixed suspension slurry. The pH of the resulting mixed slurry was adjusted to 10 with ammonia water, and then ball milled for 20 hours and then shaken and defoamed under vacuum at room temperature for 30 minutes. After the vacuum defoaming is completed, the mixed slurry is injected into the non-porous glass mold at room temperature, and then the mold is fully heated at 110°C for 2 hours. During this process, the mixed slurry does not need to be stirred. After it is cooled to room temperature and completely formed, it undergoes multiple drying steps to obtain a high-strength zirconia gr...

Embodiment 2

[0018] Measure 16.8ml of distilled water and add it to the ball mill tank, and add a total of 43.9g of zirconia powder (theoretical density is 6.1g / cm 3 , The particle size is 1um), 0.431g agarose powder and 1% ammonium citrate (about 0.439g) are added to the ball milling tank at one time and stirred evenly, and the solid phase volume fraction is 30%, the agarose concentration It is 2.5wt% of mixed suspension slurry. The pH of the resulting mixed slurry was adjusted to 10 with urea, and after 32 hours of ball milling, it was shaken and defoamed under vacuum at room temperature for 30 minutes. After the vacuum defoaming is completed, the mixed slurry is injected into the non-porous metal mold at room temperature, and then the mold is fully heated at 110°C for 3 hours. During this process, the mixed slurry does not need to be stirred. After it is cooled to room temperature and fully formed, it undergoes multiple drying steps to obtain a high-strength zirconia green body, and fina...

Embodiment 3

[0020] Measure 34.3ml of distilled water and add it to the ball milling tank, add a total of 35.2g of alumina powder (theoretical density of 3.97g / cm 3 ), 0.5g agarose powder and 1% ammonium citrate (about 0.352g) were added to the ball milling tank at one time and stirred uniformly, the volume fraction of the solid phase was 20.5%, and the solubility of agarose was 1.4wt% Alumina ceramic slurry. The pH of the resulting mixed slurry was adjusted to 10 with urea, and after ball milling for 24 hours, it was shaken and defoamed under vacuum at room temperature for 30 minutes. After the vacuum defoaming is completed, the mixed slurry is injected into the non-porous polytetrafluoroethylene mold at room temperature, and then the mold is fully heated at 110°C for 2 hours. During this process, the mixed slurry does not need to be stirred. After it is cooled to room temperature and fully formed, it undergoes multiple drying steps to obtain a high-strength alumina green body, and finally...

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PUM

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Abstract

The invention belongs to the technical field of ceramic materials, and particularly discloses a dense ceramic gelcasting method based on low-concentration agarose and low-solid-content slurry. The method includes the steps that ceramic powder, dispersant and agarose are added into water at a time to be prepared into mixed suspension slurry with the solid phase volume fraction of 20-30% and the agarose concentration of 1.3-2.5wt%; then, after the pH of the mixed suspension slurry is regulated to be 10, the mixed suspension slurry is subjected to ball milling, defoamed and injected into a mould for heating treatment in sequence, after the mould is cooled naturally, drying is carried out in multiple steps, and a green body is obtained; finally, sintering is carried out, and ceramic with the density of 95-99% is obtained. According to the method, all the raw materials are prepared into the mixed suspension slurry with a low solid content and a low agarose concentration at a time, ball milling and vacuum defoaming are directly carried out, the mixed suspension slurry does not need to be stirred after being poured into the mould, it can be avoided that foam is carried in and influences the density of the ceramic, and a good defoaming effect and high defoaming efficiency can be achieved; besides, due to the ultralow agarose concentration, the extremely small agarose use amount and the low solid content of the ceramic slurry, the sintering cost of the high-density ceramic is low.

Description

Technical field [0001] The invention belongs to the technical field of ceramic materials, and specifically relates to a compact ceramic gel injection molding method based on low-concentration agarose and low-solid content slurry. Background technique [0002] The American Oak Ridge National Laboratory invented a ceramic net size molding technology in the early 1990s—gel injection molding. Its AM-MBAM system is a gel system widely used in industrial production, but AM and MBAM have Neurotoxins are easily absorbed by the skin after contact and affect human health. [0003] In recent years, the use of natural polysaccharides for gel injection molding has begun to attract attention. Agarose is a natural polysaccharide, which can be dissolved when heated to above 90°C in water, and a good semi-solid hydrogel is formed when the temperature drops to 35-40°C. Agarose has many advantages as a gel medium: the preparation process is simple and controllable, environmentally friendly, non-tox...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B28B1/26C04B35/636C04B35/626C04B35/634C04B35/632C04B35/48C04B35/10
CPCC04B35/10C04B35/48C04B35/62605C04B35/6261C04B35/632C04B35/63444C04B35/636C04B2235/6023
Inventor 陈常连王璀璨黄小雨
Owner WUHAN INSTITUTE OF TECHNOLOGY
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