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Gel-casting method of silicon nitride ceramic material containing silicon metal powders

A technology of gel injection molding and silicon nitride ceramics, which is applied in the field of gel injection molding of silicon nitride ceramic materials containing metal silicon powder, and can solve the problem of difficult gel injection molding near-net size molding and firing temperature High and unsatisfactory sintering shrinkage, etc., to achieve ideal sintering shrinkage, promote reaction sintering, and reduce energy consumption

Inactive Publication Date: 2010-06-23
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the sintering shrinkage of ordinary ceramics is generally greater than 10%, or even 15%, and it is difficult to truly realize the effect of gel injection molding near net size.
[0013] The fly in the ointment of the prior art is that the sintering temperature of the product is too high, and the sintering shrinkage rate is not ideal. For example, the Chinese patent CN03112361 adopts the gel injection molding technology of the acrylamide polymerization system to prepare the ceramic cylinder liner. Bottom firing, the sintering shrinkage rate is 9.5%

Method used

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  • Gel-casting method of silicon nitride ceramic material containing silicon metal powders
  • Gel-casting method of silicon nitride ceramic material containing silicon metal powders

Examples

Experimental program
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Effect test

Embodiment 1

[0048] (1) Pretreatment of metal silicon powder: Weigh 630g of metal silicon powder, mix 945g of agate balls and 630g of deionized water according to the ratio of material:ball:water of 1:1.5:1, and ball mill for 72h; then put the slurry in a beaker Place in the slurry for 5 days, stirring from time to time; after 5 days, add 3.15g of polysiloxane surfactant to the slurry, and stir for 2 hours; dry in an oven at 100°C to obtain metal silicon powder A, and set aside.

[0049] (2) Slurry preparation: Weigh 16 g of acrylamide, 1.6 g of methylene acrylamide, and 0.7 g of dispersant ammonium polyacrylate, dissolve in 181.7 g of water, filter to remove impurities, and obtain a clear solution, which is the premix. Take premix 50g, weigh MgO35g, weigh Y 2 o 3 35g, placed in a ball mill jar, mixed and ball milled for 24 hours to obtain a sintering aid slurry, immediately pour it into a beaker, slowly add the metal silicon powder A treated in step (1), and gradually add 150g of the rem...

Embodiment 2

[0054] (1) Pretreatment of metal silicon powder: Weigh 630g of metal silicon powder, mix 945g of agate balls and 630g of deionized water according to the ratio of material:ball:water of 1:1.5:1, and ball mill for 24h; then put the slurry in a beaker Place in the slurry for 4 days, stirring from time to time; after 4 days, add 0.25g of polysiloxane surfactant to the slurry, and stir for 2 hours; dry in an oven at 100°C to obtain metal silicon powder B, and set aside.

[0055] (2) Weigh 40 g of acrylamide, 2 g of methylene acrylamide, and 1.0 g of ammonium polyacrylate as a dispersant, dissolve them in 157 g of water, filter to remove impurities, and obtain a clear solution, which is the premix. Take premix 100g, 5g, weigh Si 3 N 4 215g, weighing Y 2 o 3 8g, weigh 7g of MgO and place it in a ball mill jar, mix and mill it for 24 hours, pour it into a beaker immediately, slowly add 250g of metal silicon powder B processed in step (1), and gradually add 100g of the remaining pr...

Embodiment 3

[0060] (1) Pretreatment of metal silicon powder: Weigh 630g of metal silicon powder, mix 375g of agate balls and 250g of deionized water according to the ratio of material:ball:water of 1:1.5:1, and ball mill for 24h; then put the slurry in a beaker Place in the slurry for 2 days, stirring from time to time; after 2 days, add 1.26g of polysiloxane surfactant to the slurry, and stir for 2 hours; dry in an oven at 100°C to obtain metal silicon powder C, and set aside.

[0061] (2) Weigh 20g of acrylamide, 1.5g of methylene acrylamide, and 1.4g of ammonium polyacrylate as a dispersant, dissolve them in 178.5g of water, filter to remove impurities, and obtain a clear solution, which is the premix. Take 50g of the premixed solution, weigh Si 3 N 4 50g, weighed Al 2 O10g, weighing Y 2 o 3 10g, placed in a ball mill jar, mixed and ball milled for 24 hours to obtain a sintering aid slurry, immediately pour it into a beaker, slowly add 630g of the metal silicon powder C processed i...

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Abstract

The invention discloses a gel-casting method of a silicon nitride ceramic material containing silicon metal powders, which can be used for preparing silicon nitride ceramics through pressureless sintering and reaction sintering and comprises the following steps: (1) pretreatment of silicon metal powders, (2) slurry preparation, (3) casting molding, (4) drying, and (5) rubber removal and sintering. A gel system adopted is a polyacrylamide system, the solid content in the slurry is 65-77.7% by mass percent, the shrinkage rate of the sintering line of the obtained silicon nitride ceramic sintered body is 0.8-3.3%, the apparent density is 2.03-2.85g / cm<3>, and the intensity range is 136-378MPa. The gel-casting method is applicable to molding components with large dimension and complex shape and reaction sintering and preparing silicon nitride ceramics with low sintering shrinkage rate and low sintering temperature.

Description

technical field [0001] The invention relates to a molding method of silicon nitride ceramics, in particular to a gel injection molding method of silicon nitride ceramic materials containing metallic silicon powder. The method can be used for pressureless sintering and reaction sintering to prepare silicon nitride ceramics. Background technique [0002] Gelcasting is a colloidal molding process pioneered by Oak Ridge National Laboratory in the late 1980s. The main principle is to use the organic monomer aqueous solution as the medium to prepare ceramic slurry with high solid phase content and low viscosity. After injection molding of the slurry, under the action of initiator and catalyst, the organic monomer aqueous solution in the slurry is cross-linked and polymerized into a three-dimensional network polymer gel, so that the slurry is solidified in situ into a blank with complex shape and uniform microstructure body. [0003] Gel injection molding technology is a perfect ...

Claims

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Application Information

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IPC IPC(8): C04B35/622C04B35/64C04B35/584
Inventor 梁辉李晓雷季会明庞学满李强
Owner TIANJIN UNIV
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