Method for preparing ceramic material by process steps of powder green body dipping and precursor cracking

A technology of ceramic precursors and ceramic materials, which is applied in the field of ceramic material powder green body impregnation-precursor cracking preparation, which can solve the problems of high cost of inorganic fibers and weaving, difficult selection of composition, and high cost of material manufacturing, etc., to achieve uniformity of products Excellent performance, lower sintering temperature, and lower manufacturing cost

Inactive Publication Date: 2011-09-07
NAT UNIV OF DEFENSE TECH
View PDF2 Cites 27 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The advantages of this method are relatively simple molding, high efficiency, and low cost; but there are also the following obvious disadvantages: First, the sintering temperature is very high, for example, the sintering temperature of silicon carbide ceramics is as high as 2000 ° C, and the sintering temperature of silicon nitride ceramics is as high as 1800 ° C. ℃, which brings problems to the sintering equipment and cost, and high energy consumption; second, the shrinkage during the sintering process is large, which obviously affects the molding accuracy, and is easy to deform or crack
This method overcomes the shortcomings of high temperature, large shrinkage, easy deformation, and easy cracking in the traditional sintering method to a certain extent, but this method also has the following disadvantages: First, due to the high cost of inorganic fibers and weaving, the material manufacturing cost Significantly improved; second, the production efficiency is low, because the types of fibers that can be selected are very limited, such as the current domestic commercialization is mainly carbon fiber, which makes it difficult to choose the composition of this type of material, and also significantly affects the oxidation resistance of ceramics, etc.; Yes, microscopically, the material prepared by this method is a heterogeneous material, which is not suitable for the preparation of ceramic components that require high precision or homogeneity

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for preparing ceramic material by process steps of powder green body dipping and precursor cracking

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] (1) Mix α-type silicon nitride ceramic powder and paraffin in a weight ratio of 85:15, and then press it (the traditional method of powder molding such as isostatic pressing, gel injection molding or grouting molding can also be used) Molding) method to prepare a blank with a size of 100mm×100mm×10mm, and the molding pressure is 20MPa;

[0032] (2) Put the α-type silicon nitride ceramic powder body obtained in step (1) in a high-temperature oven, and bake at 500°C for 2 hours to remove paraffin wax and make the body form pores required for impregnation;

[0033] (3) Place the green body treated in step (2) in a closed container containing the precursor borazane, and immerse it in a vacuum for 1 hour to allow the borazane to enter the pores of the green body;

[0034] (4) Put the body containing the precursor borazane in the pores in a closed autoclave, fill it with nitrogen, increase the pressure to 5MPa, heat to 70°C, and hold for 50 hours to solidify the precursor borazane a...

Embodiment 2

[0040] (1) The silicon carbide powder and paraffin are mixed in a weight ratio of 80:20, and then molded by molding (the traditional methods of powder molding such as isostatic pressing, gel injection molding or grouting molding can also be used). A blank with a size of 100mm×100mm×10mm is formed, and the molding pressure is 20MPa;

[0041] (2) Put the green body prepared in step (1) in an oven and bake it at 400°C for 3 hours to remove paraffin and make the green body form pores required for impregnation;

[0042] (3) Place the green body treated in step (2) in a closed container containing the precursor borazane, and immerse it in a vacuum for 1 hour to allow the borazane to enter the pores of the green body;

[0043] (4) Place the green body containing the precursor borazane in the pores in a closed autoclave, fill it with nitrogen, increase the pressure to 5MPa, heat to 70°C, and hold for 50 hours to solidify the borazane and cool it out;

[0044] (5) Put the solidified body of th...

Embodiment 3

[0049] (1) The silicon carbide ceramic powder and paraffin wax are mixed in a weight ratio of 80:20, and then molded by molding (the traditional method of powder molding such as isostatic pressing, gel injection molding or grouting molding can also be used) method Prepared into a blank with a size of 70mm×30mm×10mm, and the molding pressure is 25MPa;

[0050] (2) Put the body prepared in step (1) in an oven and bake at 500°C for 2 hours to remove paraffin and make the body form pores required for impregnation;

[0051] (3) Dissolve polycarbosilane in toluene, prepare a solution with a concentration of 50wt%, and add it to a sealable container; place the body treated in step (2) in a container containing polycarbosilane solution, Close the container, vacuum, and immerse for 1 hour to make the polycarbosilane solution enter the pores of the green body;

[0052] (4) Place the green body containing the precursor polycarbosilane solution in the pores in an open container, slowly heat it ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
sintering temperatureaaaaaaaaaa
sintering temperatureaaaaaaaaaa
densityaaaaaaaaaa
Login to view more

Abstract

The invention provides a method for preparing a ceramic material by process steps of powder green body dipping and precursor cracking. The method comprises the following steps: (1) preparing ceramic powder into a required green body by using a conventional method; (2) drying the green body for 1-30 hours at the drying temperature of 80-150 DEG C to obtain a porous green body; (3) dipping the porous green body into a liquid ceramic precursor for 1 hour or more in vacuum or at a certain pressure; (4) placing the porous green body with the ceramic precursor in an airtight high-pressure kettle, introducing inert gas, raising the temperature to 60-300 DEG C at the pressure of 0.1-30 MPa, and then performing heat insulation for 10-55 hours so that the precursors in the holes of the powder green body are crosslinked and cured; and (5) placing the green body with the cured ceramic precursor in a high temperature furnace, protecting with nitrogen, heating to 1200-1400 DEG C, and then performing heat insulation for 50-70 minutes, so that the cured precursor is cracked and converted into ceramic. The method has the advantages of high production efficiency, high yield and low production cost, and can be used for preparing various ceramic materials such as silicon carbide, silicon nitride, silicon oxide, boron nitride, boron carbide, alumina, aluminium nitride, zirconia and the like.

Description

Technical field [0001] The invention relates to a preparation method of ceramic materials, in particular to a preparation method of ceramic material powder body impregnation-precursor pyrolysis. Background technique [0002] Ceramic materials and ceramic composite materials have the advantages of high temperature resistance, high strength, high modulus, high hardness, corrosion resistance, friction resistance and certain special functions. Therefore, they are used in aviation, aerospace, metallurgy, petroleum, chemical industry, machinery, energy, etc. The field is widely used, and it plays an irreplaceable role in many aspects such as high temperature resistance. For example, high-temperature ceramic nozzles used in metallurgy and chemical industry, various high-temperature supports used in high-temperature kilns, various high-temperature resistant dry pots used in industry, etc. As a result, a variety of preparation methods for ceramics and their composite materials have emerg...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/583C04B35/565C04B35/622
Inventor 曹峰张长瑞王思青刘坤
Owner NAT UNIV OF DEFENSE TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap