Preparation method of graphene toughened silicon carbide ceramic

A technology of tough silicon carbide and graphene, which is applied in the field of preparation of graphene toughened silicon carbide ceramics, can solve the problems of high sintering temperature, slow densification speed, and low density, and achieve low sintering temperature and fast densification speed , high density effect

Active Publication Date: 2020-01-17
NUCLEAR POWER INSTITUTE OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a preparation method of graphene-toughened silicon carbide ceramics, which redesigns the sintering step and utilizes high temperature pressurization-low temperature pressureless vacuum cyc

Method used

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  • Preparation method of graphene toughened silicon carbide ceramic
  • Preparation method of graphene toughened silicon carbide ceramic
  • Preparation method of graphene toughened silicon carbide ceramic

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0056] Such as figure 1 A kind of preparation method of shown graphene toughened silicon carbide ceramics, comprises the following steps:

[0057] (A) mixing silicon carbide powder, graphene powder, sintering aid and solvent and pulverizing to prepare silicon carbide slurry;

[0058] (B) drying and pulverizing the silicon carbide slurry and sieving to prepare a uniformly mixed composite powder;

[0059] (C) packing the composite powder into a mould, applying unidirectional pressure to obtain a composite powder compact;

[0060] (D) Put the mold equipped with the composite powder compact into the sintering furnace, after the furnace temperature rises to the temperature T1, carry out the cyclic sintering process of heating and pressurizing-cooling and pressureless in a vacuum environment to prepare graphene toughened carbonization Silicon ceramics.

[0061] In step (A), 85-99wt% silicon carbide powder, 0.025-5wt% graphene powder and 0.5-10wt% sintering aid are loaded into a b...

Embodiment 2

[0070] On the basis of Example 1, in step (D), the cyclic sintering process of described temperature rise and pressure-fall temperature without pressure comprises the following steps:

[0071] (D1) Pressurize the composite powder compact to P, and continue to heat up to T2;

[0072] (D2) holding time t1 at temperature T2;

[0073] (D3) Remove the pressure P applied to the composite powder compact, and lower the temperature to T1;

[0074] (D4) holding time t2 at temperature T1;

[0075] (D5) repeat steps (D1)-(D4);

[0076] In the above steps, the temperature T1 is 1500-1650°C, the temperature T2 is 1750-1900°C, the pressure P is 10-30MPa, the holding time t1 is 10-30min, and t2 is 30-60min.

[0077] In some embodiments, the temperature increase rate from T1 to T2 is 5-10°C / min; the temperature decrease and pressure removal from T2 to T1 are completed within 5 minutes.

[0078] The technical solution can be automatically realized through program setting, the process is sim...

Embodiment 3

[0081] Such as figure 2 As shown, the present embodiment adopts the following steps to prepare graphene toughened silicon carbide ceramics:

[0082] (A) Put 89 parts of graphene with a particle size of 50nm, 1 part of graphene with a particle size of 1-15 μm and a sheet thickness of 5 nm, 6 parts of alumina with a particle size of 0.5 μm, and 4 parts of yttrium oxide with a particle size of 0.6 μm in a ball mill jar, and add 120 parts of deionized water were ball milled for 24 hours to obtain a uniformly mixed silicon carbide slurry;

[0083] (B) Take out the above-mentioned silicon carbide slurry, place it in a drying oven and dry it at 60°C for 12 hours, and then sieve it with a 40-mesh sampling sieve after crushing to prepare a composite powder of graphene+sintering aid+silicon carbide;

[0084] (C) Put the above-mentioned composite powder into a graphite mould, install a pressure head and apply a unidirectional pressure of 5 MPa on the press to obtain a composite powder ...

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Abstract

The invention relates to a preparation method of graphene toughened silicon carbide ceramic. The preparation method comprises the following steps: (A) mixing silicon carbide powder, graphene powder, asintering aid and a solvent, and crushing to prepare silicon carbide slurry; (B) drying, crushing and sieving the silicon carbide slurry to prepare uniformly mixed composite powder; (C) putting the composite powder into a mold, and applying one-way pressure to obtain a composite powder compact; and (D) putting the mold filled with the composite powder compact into a sintering furnace, heating thefurnace to a temperature T1 in a vacuum environment, and carrying out a heating pressurization-cooling pressureless cyclic sintering process to prepare the graphene toughened silicon carbide ceramic.According to the method, the problems of high sintering temperature, low densification speed and low density in the prior art are effectively solved by utilizing a high-temperature pressurization-low-temperature non-pressure vacuum circulating sintering technology, and the graphene toughened silicon carbide ceramic with higher density is quickly obtained at a lower temperature.

Description

technical field [0001] The invention relates to the field of inorganic non-metallic materials, in particular to a method for preparing graphene-toughened silicon carbide ceramics. Background technique [0002] Silicon carbide ceramics have very high high-temperature strength, and can still maintain a relatively high bending strength at 1600 ° C. The heat resistance is better than other ceramics, and it is resistant to radiation, corrosion and oxidation. It is an important high-temperature structural material. , Widely used in high-performance engines, bulletproof armor, wear-resistant parts, refractory materials, sealing parts and other fields. The application in the nuclear industry also has a history of nearly fifty years, such as the cladding layer of high-temperature gas-cooled reactor TRISO fuel particles and the first wall structure material of fusion reactors. [0003] Silicon carbide, like other ceramics, is a brittle material with low tensile strength, poor plastic...

Claims

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Application Information

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IPC IPC(8): C04B35/565C04B35/64C04B35/645
CPCC04B35/565C04B35/64C04B35/645C04B2235/425C04B2235/66C04B2235/3217C04B2235/3225C04B2235/77C04B2235/96
Inventor 付道贵张瑞谦何宗倍吴松岭李刚李鸣邱绍宇姚力夫
Owner NUCLEAR POWER INSTITUTE OF CHINA
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