Dense ceramic gelcasting method based on low-concentration agarose and low-solid-content slurry

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 in particular relates to a dense ceramic gel injection molding method based on low-concentration agarose and low-solid-content slurry. Background technique

[0002] In the early 1990s, Oak Ridge National Laboratory in the United States invented a ceramic net size molding technology—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 attracted attention. Agarose is a natural polysaccharide that can be dissolved in water heated above 90°C, and forms a good semi-solid hydrogel 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-toxic, th...

Examples

Embodiment 1

[0016] Measure 16.8ml of distilled water and add it to the ball mill jar, and add a total of 26g of zirconia powder (theoretical density is 6.1g / cm 3 , particle diameter is 1um), 0.221g agarose powder and mass fraction are 0.6% ammonium citrate (about 0.156g) one-time join in the ball mill jar and stir evenly, make solid phase volume fraction be 20.2%, agarose concentration It is 1.3wt% mixed suspension slurry. The pH of the obtained mixed slurry was adjusted to 10 with ammonia water, and after ball milling for 20 hours, it was shaken in vacuum at room temperature for 30 minutes to defoam. After the vacuum defoaming is completed, the mixed slurry is injected into a non-porous glass mold at room temperature, and then the mold is placed in an environment of 110°C and fully heated 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 is dried in multiple steps to obtain a zirconia green body wi...

Embodiment 2

[0018] Measure 16.8ml of distilled water and add it to the ball mill jar, and add a total of 43.9g of zirconia powder (theoretical density is 6.1g / cm 3 , particle diameter is 1um), 0.431g agarose powder and mass fraction are 1% ammonium citrate (about 0.439g) one-time join in the ball mill jar and stir evenly, make solid phase volume fraction be 30%, agarose concentration It is 2.5wt% mixed suspension slurry. The pH of the obtained mixed slurry was adjusted to 10 with urea, and after ball milling for 32 hours, vacuum shaking was performed at room temperature for 30 minutes to defoam. After the vacuum defoaming is completed, the mixed slurry is injected into a non-porous metal mold at room temperature, and then the mold is fully heated at 110°C for 3 hours, and the mixed slurry does not need to be stirred during this process. After it is cooled to room temperature and fully shaped, it is dried in multiple steps to obtain a zirconia green body with high strength, and finally si...

Embodiment 3

[0020] Measure 34.3ml of distilled water and add it to the ball mill jar, and add a total of 35.2g of alumina powder (theoretical density is 3.97g / cm 3 ), 0.5g of agarose powder and 1% ammonium citrate (about 0.352g) by mass fraction were added to the ball mill and stirred evenly to make a solid phase volume fraction of 20.5% and agarose solubility of 1.4wt%. alumina ceramic slurry. The pH of the obtained mixed slurry was adjusted to 10 with urea, and after ball milling for 24 hours, vacuum shaking was performed at room temperature for 30 minutes to defoam. 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 placed in an environment of 110°C and fully heated 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 is dried in multiple steps to obtain a high-strength alumina green body, a...

technical field

[0001] The invention belongs to the technical field of ceramic materials, and in particular relates to a dense ceramic gel injection molding method based on low-concentration agarose and low-solid-content slurry. Background technique

[0002] In the early 1990s, Oak Ridge National Laboratory in the United States invented a ceramic net size molding technology—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 attracted attention. Agarose is a natural polysaccharide that can be dissolved in water heated above 90°C, and forms a good semi-solid hydrogel 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-toxic, th...

Examples

Embodiment 1

[0016] Measure 16.8ml of distilled water and add it to the ball mill jar, and add a total of 26g of zirconia powder (theoretical density is 6.1g / cm 3 , particle diameter is 1um), 0.221g agarose powder and mass fraction are 0.6% ammonium citrate (about 0.156g) one-time join in the ball mill jar and stir evenly, make solid phase volume fraction be 20.2%, agarose concentration It is 1.3wt% mixed suspension slurry. The pH of the obtained mixed slurry was adjusted to 10 with ammonia water, and after ball milling for 20 hours, it was shaken in vacuum at room temperature for 30 minutes to defoam. After the vacuum defoaming is completed, the mixed slurry is injected into a non-porous glass mold at room temperature, and then the mold is placed in an environment of 110°C and fully heated 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 is dried in multiple steps to obtain a zirconia green body wi...

Embodiment 2

[0018] Measure 16.8ml of distilled water and add it to the ball mill jar, and add a total of 43.9g of zirconia powder (theoretical density is 6.1g / cm 3 , particle diameter is 1um), 0.431g agarose powder and mass fraction are 1% ammonium citrate (about 0.439g) one-time join in the ball mill jar and stir evenly, make solid phase volume fraction be 30%, agarose concentration It is 2.5wt% mixed suspension slurry. The pH of the obtained mixed slurry was adjusted to 10 with urea, and after ball milling for 32 hours, vacuum shaking was performed at room temperature for 30 minutes to defoam. After the vacuum defoaming is completed, the mixed slurry is injected into a non-porous metal mold at room temperature, and then the mold is fully heated at 110°C for 3 hours, and the mixed slurry does not need to be stirred during this process. After it is cooled to room temperature and fully shaped, it is dried in multiple steps to obtain a zirconia green body with high strength, and finally si...

Embodiment 3

[0020] Measure 34.3ml of distilled water and add it to the ball mill jar, and add a total of 35.2g of alumina powder (theoretical density is 3.97g / cm 3 ), 0.5g of agarose powder and 1% ammonium citrate (about 0.352g) by mass fraction were added to the ball mill and stirred evenly to make a solid phase volume fraction of 20.5% and agarose solubility of 1.4wt%. alumina ceramic slurry. The pH of the obtained mixed slurry was adjusted to 10 with urea, and after ball milling for 24 hours, vacuum shaking was performed at room temperature for 30 minutes to defoam. 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 placed in an environment of 110°C and fully heated 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 is dried in multiple steps to obtain a high-strength alumina green body, a...