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Method for controlling medium-temperature strength of gel-cast ceramic parts

A technology for ceramic parts and gel injection molding, applied in the field of ceramic parts preparation, can solve the problems of low strength and body damage, and achieve the effects of good high temperature resistance, improved strength and excellent heat resistance

Active Publication Date: 2014-08-27
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the degreasing process, the ceramic green body has not yet started the sintering reaction, the strength is low, and the local excessive thermal stress will cause serious damage to the green body

Method used

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  • Method for controlling medium-temperature strength of gel-cast ceramic parts

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Example 1: Al 2 o 3 Fabrication of base ceramic parts

[0028] 1) Dilute the silica sol to SiO with deionized water 2 The mass fraction is 30%, and organic monomer acrylamide (AM), crosslinking agent N, N'-methylenebisacrylamide (MBAM) and dispersant sodium polyacrylate (PAANa) are added to the diluted silica sol , stirring and dissolving to obtain a premix; then polysiloxane is added to the premix, and the polysiloxane is uniformly dispersed in the premix by ultrasonic dispersion, and at the same time, a surfactant is added during the ultrasonic dispersion process to promote the dissolution of the polysiloxane. Disperse, then add ceramic powder (including 40 μm alumina, 5 μm alumina and sintering aid magnesium oxide) and polyimide, stir evenly to obtain a mixture, adjust the pH value of the mixture to 9 with ammonia water, and then ball mill the mixture, When ball milling, first add the mixture after adjusting the pH value to the ball milling jar, and then add corun...

Embodiment 2

[0034] Example 2: Preparation of SiC-based ceramic parts

[0035] 1) Dilute the silica sol to SiO with deionized water 2 The mass fraction is 10%, add organic monomer methacrylic acid, crosslinking agent N, N'-methylenebisacrylamide (MBAM) and dispersant sodium polyacrylate (PAANa) to the diluted silica sol, stir Dissolve to obtain a premix; then add polysiloxane to the premix, disperse the polysiloxane evenly in the premix by ultrasonic dispersion, and add a surfactant during the ultrasonic dispersion process to promote the dispersion of polysiloxane, Then add ceramic powder (including SiC powder of 45 μm and 5 μm) and polyimide, stir evenly to obtain a mixture, adjust the pH value of the mixture to 11 with ammonia water, and then ball mill the mixture. During ball milling, first add After adjusting the pH value of the mixture, add corundum balls to the ball mill jar according to the ratio of the mass ratio of the mixture to the balls of 2.5:1, and ball mill and disperse for...

Embodiment 3

[0040] Example 3: SiO 2 Fabrication of base ceramic parts

[0041] 1) Dilute the silica sol to SiO with deionized water 2 The mass fraction is 20%, add organic monomer methacrylamide, crosslinking agent acryl methyl acrylate and dispersant polyacrylic acid sodium (PAANa) in the silica sol after the dilution, stir and dissolve, obtain premix; Then Polysiloxane is added to the premix, and the polysiloxane is uniformly dispersed in the premix by ultrasonic dispersion. 2The ceramic powder raw materials and polyimide of the system are stirred evenly to obtain a mixture, and the pH value of the mixture is adjusted to 10 with ammonia water, and then the mixture is ball-milled. When ball-milling, the mixture after adjusting the pH value is first added to the ball mill tank, Then add corundum balls to the ball mill tank according to the mass ratio of the mixture to the balls at a ratio of 1.5:1, and ball mill and disperse for 30 minutes in a planetary ball mill with a rotating speed ...

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Abstract

The invention discloses a method for controlling the medium-temperature strength of gel-cast ceramic parts. The method comprises the steps of firstly, adding organic monomers, a cross-linking agent and a dispersant sodium polyacrylate into diluted silica sol, so as to obtain a premix, then, adding polysiloxane, ceramic powder and polyimide, and carrying out ball milling, so as to obtain ceramic slurry, carrying out in-situ curing, then, carrying out freeze drying, and carrying out degreased pre-sintering, impregnation aftertreatment and final-sintering, thereby obtaining the ceramic parts. According to the method, polyimide has adhesion property due to the high-temperature resistance of polyimide, a reticular structure is formed due to the low-temperature cross-linking of polysiloxane, a role in adhering ceramic granules is played, after freeze drying, silica sol is dehydrated, so as to form a silicon-oxygen bond three-dimensional reticular structure, and the medium-temperature strength of ceramic blanks at a degreasing stage can be remarkably improved due to the synergism of polyimide, polysiloxane and silica sol; the method can be applied to the preparation of the gel-cast ceramic parts, and the medium-temperature strength of the ceramic blanks at the degreasing stage is effectively controlled, so that the integrity of the ceramic parts can be guaranteed.

Description

technical field [0001] The invention belongs to the field of preparation of ceramic parts, in particular to a method for controlling the medium-temperature strength of gel injection molded ceramic parts. Background technique [0002] Gelcasting is a new ceramic molding technology invented by Oak Ridge National Laboratory (ORNL) in the early 1990s. The method firstly prepares a low-viscosity high-solid-phase ceramic slurry containing a gel system, and under the induction of an initiator and a catalyst, the gel system undergoes a gelation reaction to solidify the ceramic slurry and form a ceramic green body with a near-net size. After drying, debinding and sintering, ceramic parts with certain functions are obtained. Acrylamide / N,N'-methylenebisacrylamide (AM / MBAM) is one of the most widely used gel systems. [0003] During the debinding process of the ceramic body formed by gel injection molding technology, the organic matter in the original gel system is pyrolyzed and burn...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/622C04B35/634
Inventor 鲁中良李涤尘荆慧
Owner XI AN JIAOTONG UNIV
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