Silicon carbide graphite composite material and preparation method thereof

A technology for silicon carbide graphite and composite materials, which is applied in powder metallurgy, hot pressing sintering to prepare silicon carbide graphite composite materials and its preparation field, can solve the problems of low relative density and uneven material composition, and achieve low porosity and product strength. High, crack-eliminating effect

Active Publication Date: 2014-06-04
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is that the reasons for the preparation method of silicon carbide graphite in the prior art lead to shortcomings such as uneven composition and low relative density of the material; the present invention adopts powder metallurgy technolog

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 600g of colloidal graphite with a particle size of 1200 mesh, 200g of silicon carbide powder, and 18g of alumina were added to 1200mL of absolute ethanol, and ball milled for 6 hours to obtain a uniformly mixed slurry for use;

[0027] Put the ball-milled slurry in a blast drying oven, adjust the temperature to 100°C, dry for 5 hours, then pulverize, pass through a 200-mesh sieve, and obtain a mixed fine powder for use;

[0028] Put the sieved mixture into the steel mold, apply a unidirectional pressure of 150MPa on the press, hold the pressure for 30s, and demould to obtain the green body;

[0029] Put the biscuit in a vacuum tube furnace, pass in argon, raise the temperature from room temperature to 800°C at a rate of 5°C / min, keep it warm for 1h for degumming, and then cool down to room temperature at 8°C / min;

[0030] The degummed green body is placed in a vacuum sintering furnace, and the temperature is raised to 1200°C at 10°C / min in a vacuum state, 1600°C at ...

Embodiment 2

[0032] 510g of colloidal graphite with a particle size of 1500 mesh, 300g of silicon carbide powder, and 20g of yttrium oxide were added to 1000mL of absolute ethanol, and ball milled for 6 hours to obtain a uniformly mixed slurry for use;

[0033] Put the ball-milled slurry in a blast drying oven, adjust the temperature to 130°C, dry for 3 hours, then pulverize, pass through a 200-mesh sieve, and obtain a mixed fine powder for use;

[0034] Put the sieved mixture into the steel mold, apply a unidirectional pressure of 200MPa on the press, hold the pressure for 30s, and demould to obtain the green body;

[0035] Put the biscuit in a vacuum tube furnace, pass in argon, raise the temperature from room temperature to 800°C at a rate of 8°C / min, keep it warm for 1h for degumming, and then cool down to room temperature at a rate of 8°C / min;

[0036] The degummed green body is placed in a vacuum sintering furnace, and the temperature is raised to 1200°C at 15°C / min, 1600°C at 10...

Embodiment 3

[0038] Add 170g of colloidal graphite with a particle size of 1200 mesh, 150g of silicon carbide powder, 9g of alumina, and 4.5g of yttrium oxide into 1000mL of absolute ethanol, and ball mill the mixture for 6 hours to obtain a uniformly mixed slurry for use;

[0039] Put the ball-milled slurry in a blast drying oven, adjust the temperature to 120°C, dry for 4 hours, then pulverize, pass through a 200-mesh sieve, and obtain a mixed fine powder for use;

[0040] Put the sieved mixture into the steel mold, apply a unidirectional pressure of 250MPa on the press, hold the pressure for 30s, and demould to obtain the green body;

[0041]Put the biscuit in a vacuum tube furnace, pass in argon, raise the temperature from room temperature to 750°C at a rate of 10°C / min, keep it warm for 30 minutes for degumming, and then cool down to room temperature at 10°C / min;

[0042] The degummed green body is placed in a vacuum sintering furnace, and the temperature is raised to 1200°C at 15°C / m...

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Abstract

The invention belongs to the technical field of material preparation, and particularly relates to a silicon carbide graphite composite material and a preparation method thereof. According to the invention, the preparation raw materials of graphite powder, silicon carbide powder, and a sintering aid are subjected to ball milling mixing, drying, crushing, sieving, and compression molding; after compression molding, degumming treatment and hot pressing sintering are carried out; the sintering process is a temperature-controlled pressure-controlled two-stage pressure-maintaining sintering process; and furnace cooling is performed to obtain the silicon carbide graphite composite material. The method greatly shortens the production period, and improves the product yield; the sintering aid of submicron silicon carbide powder, alumina and yttrium oxide is used for liquid phase sintering under pressure; the high density and low porosity of the product are ensured; the high strength and high wear resistance of the product are improved; no free silicon is contained, which improves the corrosion resistance of the product; temperature increasing and temperature maintaining control are carried out at key sections, which inhibits and eliminates defects of cracks and deformation during sintering. The preparation process is low in time consumption which is 48-72 hours, and the product has high strength, has a bending strength of up to 181 MPa, and has a relative density of up to 95%.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and in particular relates to a silicon carbide graphite composite material prepared by powder metallurgy and hot pressing sintering and a preparation method thereof. [0002] Background technique [0003] Graphite material has many unique properties, such as: good conductor of heat and electricity, high chemical stability, no melting point, high temperature resistance, small thermal expansion coefficient, strong thermal shock resistance, etc. It is an important inorganic non-metallic material . The special layered structure of graphite itself has only weak Van der Waals force bonding along the C-axis direction, and it is easy to slide between layers, so that graphite materials have excellent lubricating properties. [0004] The traditional production process of graphite materials is to use solid raw materials such as coke and binders such as coal tar pitch to manufacture through pr...

Claims

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Application Information

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IPC IPC(8): C04B35/52C04B35/622C04B35/645
Inventor 燕青芝韩永军李青彬
Owner UNIV OF SCI & TECH BEIJING
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