Method for non-pressure spark plasma sintering of ceramics

A technology of discharge plasma and sintered ceramics, which is applied in the field of preparation of inorganic non-metallic ceramics. It can solve the problems of single shape, axial/radial tissue composition and microstructure differences, etc., and achieve high density, uniform tissue composition, and improved tissue composition. and the effect of microstructural inhomogeneity

Inactive Publication Date: 2018-12-25
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, traditional spark plasma sintering often uses powder as raw material and is used with high pressure. Th...

Method used

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  • Method for non-pressure spark plasma sintering of ceramics
  • Method for non-pressure spark plasma sintering of ceramics
  • Method for non-pressure spark plasma sintering of ceramics

Examples

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Embodiment example 1

[0042] 45vol.% solid phase volume fraction, 1.2wt.% ammonium polyacrylate as dispersant, 5wt.% yttrium oxide and 2wt.% alumina as sintering aid, 5wt.% diacetate as curing agent for direct solidification injection molding ceramics The green body was sintered with pressureless discharge plasma at a heating rate of 100°C / min to 1700°C for 30 minutes to obtain silicon nitride ceramics.

[0043] Fully mix 93g of silicon nitride powder, 5g of yttrium oxide powder, 2g of alumina powder, 1.2g of ammonium polyacrylate and 35.95ml of deionized water, and ball mill for 120min at a ball milling speed of 300r / min to make it fully mixed evenly. 5:1, the grinding beads are made of silicon nitride ceramic balls to make a negatively charged ceramic slurry on the surface, then add 5g of diacetate, stir evenly, and place in a vacuum degasser for 15 minutes to remove the gas in the suspension , and then inject the ceramic slurry into a non-porous mold, and place it in a water bath at 70°C for 50 ...

Embodiment example 2

[0045] 65vol.% solid phase volume fraction, 0.1wt.% tetramethylammonium hydroxide as a dispersant, 2.0wt.% diacetate as a curing agent to directly solidify and inject molded ceramic green bodies at a heating rate of 300°C / min to Alumina ceramics were obtained by pressureless discharge plasma sintering at 1400°C for 5 minutes.

[0046] Fully mix 100g of alumina powder, 0.1g of tetramethylammonium hydroxide and 13.46ml of deionized water, and ball mill for 240min at a ball milling speed of 150r / min to fully mix them evenly. The ball-to-material ratio is 2:1. Zirconia ceramic balls, made of negatively charged ceramic slurry on the surface, then added 2g of diacetate, stirred evenly, placed in a vacuum degasser for 20min to remove the gas in the suspension, and then injected the ceramic slurry into the non-porous placed in the mold, and placed in a 60°C water bath for 120 minutes to solidify and form, and after the cured and formed ceramic wet blank was dried at 60°C for 48 hours,...

Embodiment example 3

[0048] 50vol.% solid phase volume fraction, 3.0wt.% ammonium citrate as a dispersant, 0.5wt.% agar powder as a curing agent, direct solidification and injection molding of ceramic green bodies, with a heating rate of 50°C / min to 1000°C without pressure Spark plasma sintering for 60min to obtain silicon dioxide ceramics.

[0049] Fully mix 100g of silica powder, 3.0g of ammonium citrate and 37.74ml of deionized water, and grind for 30 minutes at a ball milling speed of 450r / min to make them fully mixed. The ball-to-material ratio is 3:1, and the grinding beads are made of zirconia Ceramic balls, made of negatively charged ceramic slurry on the surface, then add 0.5g agar powder, stir evenly, place in a vacuum degasser for 30min to remove the gas in the suspension, and then inject the ceramic slurry into a non-porous mold , and put it in a water bath at 85°C for 10 minutes to solidify and form it, and dry the cured and formed ceramic wet blank at 70°C for 24 hours, and then plac...

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Abstract

The invention belongs to the field of inorganic nonmetal ceramic preparation and discloses a method for non-pressure spark plasma sintering of ceramics. The method includes: according to a shape of arequired ceramic sample, adopting a direct coagulation casting method for forming a ceramic biscuit; placing the ceramic biscuit in a graphite mould, and sintering by means of non-pressure spark plasma sintering to obtain the required ceramic sample. The graphite mould comprises upper and lower pressure heads and a hollow forming cavity, the upper and lower pressure heads are matched with the forming cavity, the forming cavity is internally in a non-pressure state when axial pressure is applied to the pressure heads in a sintering process, spark plasma sintering is not only available for powder forming but also available for forming of the ceramic biscuit, obtained ceramic samples are diversified in shape, and aeolotropism of the required ceramic samples is improved. By the method, problems of long sintering period, high sintering temperature, abnormal grain growth, pressure unloading and the like of a traditional sintering process are solved, and high-performance ceramic samples can be obtained.

Description

technical field [0001] The invention belongs to the field of preparation of inorganic non-metallic ceramics, and more specifically relates to a method for sintering ceramics with pressureless discharge plasma. Background technique [0002] Ceramic materials are widely used in electronic communications, aerospace, biomedical and other fields due to their advantages such as high temperature resistance, corrosion resistance, high strength, and good chemical stability. With the development of science and technology, various industries put forward higher requirements on the shape structure, preparation efficiency and performance stability of ceramic materials. However, the traditional ceramic preparation process and the ceramic molding process with a short preparation cycle have simple structure and organizational structure. Inhomogeneity, coarse grains destroy structural continuity and other problems; although the ceramic molding process with a long preparation cycle can meet th...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/10C04B35/14C04B35/622C04B35/626C04B35/64
CPCC04B35/10C04B35/14C04B35/584C04B35/622C04B35/62605C04B35/64C04B2235/3217C04B2235/3225C04B2235/6022C04B2235/6562C04B2235/6567
Inventor 吴甲民马伊欣程立金陈安南刘荣臻陈双文世峰史玉升李晨辉
Owner HUAZHONG UNIV OF SCI & TECH
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