Silicon nitride-silicon carbide composite and preparing method thereof

A composite material, silicon carbide technology, applied in the field of ceramic materials, can solve the problems of high brittleness and low toughness of silicon nitride ceramics, and achieve the effect of increasing toughness and bending strength, increasing density and mechanical strength

Inactive Publication Date: 2018-08-24
江苏东浦精细陶瓷科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patented technology describes making materials with improved properties such as higher tensile stress or better impact absorption compared to existing composites made up entirely of SiC alone. These improvements can be achieved without adding other ingredients like carbon black (CB) or plasma treatment.

Problems solved by technology

The technical problem addressed by this patented method relates to improving materials that have superior mechanical characteristics such as being strong but prone to cracking or breaking down under severe conditions during use. This can be important because they may affect their overall durability over time if left untreated without proper protection from corrosive environments like water vapor.

Method used

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preparation example Construction

[0014] The embodiment of the present invention provides a method for preparing a silicon nitride-silicon carbide composite material, which includes:

[0015] S1. Combine 80 to 100 parts by weight of α-silicon nitride powder, 15 to 30 parts by weight of silicon carbide powder, 0.5 to 2 parts by weight of metal oxide, 1 to 5 parts by weight of rare earth oxide, and 7 to 10 parts by weight of β-silicon nitride seed crystals are uniformly mixed and pressed into a green body.

[0016] The inventors used α-silicon nitride powder as the main body, combined with metal oxides, rare earth oxides and other additives, and prepared silicon nitride ceramics through a reasonable proportion of the above substances. The metal oxide includes at least one of aluminum oxide, magnesium oxide, zirconium oxide, and titanium oxide. The rare earth oxide includes at least one of yttrium oxide, lanthanum oxide, cerium oxide, or lutetium oxide. Metal oxides, rare earth oxides and other additives form a liqu...

Embodiment 1

[0031] This embodiment provides a silicon nitride-silicon carbide composite material. In parts by weight, the raw materials include:

[0032] 100 parts of α-silicon nitride powder, 15 parts of silicon carbide powder, 0.5 parts of alumina, 1 part of cerium oxide, and 7 parts of β-silicon nitride seed crystals.

[0033] The specific preparation method is as follows:

[0034] S1. Mix the above-mentioned raw materials with 250 parts of anhydrous ethanol, and ball mill them in a ball mill for 1 hour to make a slurry.

[0035] S2. Dry the above slurry at 120°C to obtain ceramic powder. The organic solvent content in the ceramic powder is 0.6wt%.

[0036] S3. The above ceramic powder is made into a green body through a cold isostatic pressing machine.

[0037] S4. The green body is sintered under a nitrogen pressure of 0.1Mpa and a temperature of 1300°C for a period of 3h.

[0038] S5. Maintain the nitrogen pressure at 0.1Mpa, and raise the temperature to 1600°C for two-stage sintering for 12h....

Embodiment 2

[0042] This embodiment provides a silicon nitride-silicon carbide composite material. In parts by weight, the raw materials include:

[0043] 80 parts of α-silicon nitride powder, 30 parts of silicon carbide powder, 2 parts of magnesium oxide, 2 parts of yttrium oxide, 3 parts of lanthanum oxide, and 10 parts of β-silicon nitride seed crystals.

[0044] The specific preparation method is as follows:

[0045] S1. Mix the above-mentioned raw materials with 300 parts of acetone, and mill them in a ball mill for 2 hours to form a slurry.

[0046] S2. Dry the slurry at 150°C to obtain ceramic powder. The content of the organic solvent in the ceramic powder is 0.5wt%.

[0047] S3. The above ceramic powder is made into a green body through a cold isostatic pressing machine.

[0048] S4. The green body is sintered at a nitrogen pressure of 0.3Mpa and a temperature of 1500°C for a period of 1h.

[0049] S5. Maintain the nitrogen pressure at 0.3Mpa, and raise the temperature to 1800°C for two-stag...

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Abstract

The invention discloses a silicon nitride-silicon carbide composite and a preparing method thereof, and relates to the field of ceramic materials. Alpha-silicon nitride powder is sintered with the aidof a small amount of sintering aid, the crystal type transformation of the alpha-silicon nitride powder is induced through beta-silicon nitride seed crystals, and the density and mechanical strengthof the product are increased. Meanwhile, a biscuit is densified through three stages of sintering under the nitrogen atmosphere, the self-toughening effect is generated at high temperature and high pressure, and the high-strength and high-toughness silicon nitride ceramic is obtained in combination with the toughening effect of silicon carbide. The silicon nitride-silicon carbide composite is prepared through the method and has the advantages of being high in strength, high in toughness and resistant to wear and corrosion.

Description

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Claims

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Application Information

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Owner 江苏东浦精细陶瓷科技股份有限公司
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