Hot pressed sintering method of ceramic products with high density and complex shapes

A technology of ceramic products and hot pressing sintering, which is applied in the direction of ceramic forming machines and manufacturing tools, and can solve the problems of reducing the mechanical properties of ceramic parts, slow temperature control technology, and grain growth.

Active Publication Date: 2014-07-02
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, as we all know, the hot pressing sintering process also has obvious shortcomings. Due to the influence of the process method, it can only sinter products with simple shapes, such as plate-shaped, square block-shaped, and cylindrical ceramic products, so its application range is also severely restricted. restrict
With the rapid development of science and technology, there are more and more demands for high-density and complex-shaped ceramic products in various industries. Although cold isostatic pressing + machining or gel injection molding and other molding technologies and pressureless sintering processes can Ceramic parts with complex shapes can be obtained, but in many cases it cannot meet the high density requirements of ceramic parts, and the pressureless sinter

Method used

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  • Hot pressed sintering method of ceramic products with high density and complex shapes
  • Hot pressed sintering method of ceramic products with high density and complex shapes
  • Hot pressed sintering method of ceramic products with high density and complex shapes

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] The preparation process of gel cast SiC and BN is as follows figure 2 Shown:

[0037] The process steps for preparing gel-cast SiC ceramics and BN ceramics are as follows:

[0038] (1) Configure the monomer solution:

[0039] Acrylamide (AM) monomer and cross-linking agent methylenebisacrylamide (MBAM) were prepared in a certain proportion and dissolved in deionized water to prepare a monomer solution; the monomer solution contained 11.4wt% AM and MBAM It is 1wt% and contains 87.6wt% purified water. Fully dissolve the prepared monomer solution, filter it with filter paper and seal it in a glass container for later use.

[0040] (2) Prepare dispersant solution:

[0041] Mix ammonium citrate (DAC) and water according to the ratio of 10g ammonium citrate (DAC) + 90g water. After fully dissolving the prepared dispersant solution, filter it with filter paper and seal it in a glass container for later use.

[0042] (3) Mixture:

[0043] a. Weigh 5 kg of zirconia grinding...

Embodiment 2

[0071] Hot-pressed target ceramic Si 3 N 4 , with C powder and BN as the mold material:

[0072] (1) First, configure Si according to the process steps of Example 1 3 N 4 slurry, and gel-form the Si 3 N 4 slurry;

[0073] (2) The mixture of C powder and BN is used as the mold material, wherein the mass fraction of C powder is 80%, and the mass fraction of BN is 20%. Using cold isostatic pressing, a block is formed under a pressure of 200MPa, and a CNC milling machine is used. Processed out with Si 3 N 4 The shape and size of the upper and lower sides of the gel;

[0074] (3) Combine the processed C powder and BN mixture mold material with Si 3 N 4 The gel body is well assembled and coordinated, and the Si with complex structure can be completed according to the hot pressing process and post-treatment process of Example 1. 3 N 4 Manufacture of ceramic products.

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Abstract

The invention belongs to the technical field of preparation and forming methods of ceramic materials and in particular relates to a hot pressed sintering method of ceramic products with high density and complex shapes. In the method, a process for forming ceramic bodies with steel molds, which belongs to traditional hot pressed sintering processes, is abandoned. The method is characterized by firstly preparing a mold material into a required mold with a complex shape through a gel forming process, or firstly preparing a body of the mold material by adopting cold isostatic pressing, secondly machining the body into a required mold with a complex shape by adopting a numerically-controlled machine tool, thirdly preparing the target ceramic powder into slurry with high solid content by adopting the advanced gel forming technology, and injecting the slurry into the mold to form the composite hot-pressed body; or firstly preparing the target ceramic powder into a part body through a gel casting process, secondly injecting the mold material slurry through the gel casting technology to form the composite hot-pressed body, and removing the hot-pressed mold material after sintering, thus finally obtaining the ceramic products with complex structures and high density and properties.

Description

technical field [0001] The invention belongs to the technical field of preparation and molding methods of ceramic materials, and in particular relates to a hot-pressing sintering method for high-density and complex-shaped ceramic products. Background technique [0002] The hot pressing sintering process is one of the commonly used sintering processes in the ceramic or powder metallurgy industry. The basic process is to first pour the ceramic powder to be sintered into a steel mold, and use a certain pressure to form a 35%~40 % theoretical density of the ceramic green body, and then put the green body into the high-strength graphite mold prepared in advance, and put it into the hot-press sintering furnace, pass through the high-strength graphite pressure head, pressurize while heating, at high temperature , High-density sintering of ceramic powder is achieved under high pressure. In actual production, ceramic powder is often directly loaded into graphite molds for sintering. ...

Claims

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Application Information

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IPC IPC(8): C04B35/645C04B35/565C04B35/584C04B35/624B28B1/14B28B7/00
Inventor 齐龙浩叶志强潘伟
Owner TSINGHUA UNIV
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