In-situ preparation method for Y4Si2O7N2-BN ceramic base composite materials

A composite material, yttrium silicon oxynitride technology, applied in the field of ceramic matrix composite materials, can solve the problems of poor machinability, thermal shock resistance, need to be further improved, and reduced thermal conductivity, and achieve high density and low thermal conductivity The effect of low efficiency and cost

Active Publication Date: 2012-02-15
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

Although Y 4 Si 2 o 7 N 2 It has excellent thermal properties, but its poor processability, thermal shock resistance, and intrinsic brittleness greatly limit its application
in Y 4 Si 2 o 7 N 2 Adding BN to the matrix to prepare composite materials can improve the above unfavorable properties, however, the Y 4 Si 2 o 7 N 2 The composite material prepared from powder and BN powder needs to be further improved in terms of density and mechanical properties, and the thermal conductivity needs to be further reduced.

Method used

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  • In-situ preparation method for Y4Si2O7N2-BN ceramic base composite materials
  • In-situ preparation method for Y4Si2O7N2-BN ceramic base composite materials
  • In-situ preparation method for Y4Si2O7N2-BN ceramic base composite materials

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] h-BN powder (100 mesh, purity: 99wt.%) 4.45g, Y 2 o 3 Powder (300 mesh, purity: 99.5wt.%) 69.83g, SiO 2 Powder (200 mesh, purity: 99.5wt.%) 4.66g and Si 3 N 4 10.83 g of the powder (300 mesh, purity: 99 wt.%) was poured into a silicon nitride ball mill jar, wet-milled with silicon nitride balls and ethanol for 12 hours, and then dried at 50° C. for 48 hours. The dried powder is poured into a BN-coated graphite mold with a diameter of 50mm and cold-pressed. After cold pressing at a pressure of 12MPa for 5 minutes, put the mold into a hot-press furnace, under the protection of flowing nitrogen, raise the temperature to 1600°C at a heating rate of 5°C / min, keep it for 30 minutes, and then raise the temperature at a heating rate of 10°C / min to 1800°C, hot pressing for 60 minutes, and the hot pressing pressure is 30MPa. The obtained bulk material was analyzed by X-ray diffraction as Y 4 Si 2 o 7 N 2 and BN two phases, the volume ratio of the two is 90:10, basically ...

Embodiment 2

[0023] h-BN powder (100 mesh, purity: 99wt.%) 12.68g, Y 2 o 3 Powder (300 mesh, purity: 99.5wt.%) 88.3g, SiO 2 Powder (200 mesh, purity: 99.5wt.%) 5.89g and Si 3 N 4 13.7 g of the powder (200 mesh, purity: 99 wt.%) was poured into a silicon nitride ball mill jar, wet-milled with silicon nitride balls and ethanol for 24 hours, and then dried at 50° C. for 48 hours. The dried powder is poured into a BN-coated graphite mold with a diameter of 50mm and cold-pressed. After cold pressing at a pressure of 15MPa for 3 minutes, put the mold into a hot-press furnace of a graphite heating element, and under the protection of flowing nitrogen, raise the temperature to 1550°C at a heating rate of 15°C / min, keep it for 40min, and then raise the temperature to 1900°C , hot pressing for 50min, hot pressing pressure is 30MPa. The obtained composite material is analyzed by X-ray diffraction as Y 4 Si 2 o 7 N 2 and BN two phases, the volume ratio of the two is 80:20, basically no other ...

Embodiment 3

[0025] h-BN powder (300 mesh, purity: 99wt.%) 17.82g, Y 2 o 3 Powder (400 mesh, purity: 99.5wt.%) 46, 56g, SiO 2 Powder (200 mesh, purity: 99.5wt.%) 3.11g and Si 3 N 4 7.22 g of powder (300 mesh, purity: 99wt.%) was poured into a silicon nitride ball mill jar, wet-milled with silicon nitride balls and added with ethanol for 6 hours, and then dried at 50°C for 48 hours. The dried powder is poured into a BN-coated graphite mold with a diameter of 50mm and cold-pressed. After cold pressing at a pressure of 10MPa for 4 minutes, put the mold into a hot-press furnace of a graphite heating element, and under the protection of flowing nitrogen, raise the temperature to 1700°C at a heating rate of 30°C / min, keep it for 30min, and then raise the temperature to 2100°C , hot pressing for 30min, and the hot pressing pressure is 20MPa. The obtained composite material is analyzed by X-ray diffraction as Y 4 Si 2 o 7 N 2 and BN two phases, the volume ratio of the two is 60:40. The m...

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Abstract

The invention relates to the field of ceramic base composite materials, in particular to an in-situ preparation method for Y4Si2O7N2-BN ceramic base composite materials. The composite materials consist of two phases: Y4Si2O7N2 and BN, wherein the content of the BN in the composite materials is 5 to 95 percent through being metered in percentage by volume, and the balance is the Y4Si2O7N2. Yttriumoxide powder, silicon oxide powder, silicon nitride powder and BN powder are used as raw materials, material powder carries out ball milling for 1 to 24 hours, the materials are charged into a graphite mold after being baked and sieved, the cold pressing is carried out at 10 to 15MPa, then, the temperature is raised to 1500 to 1700 DEG C at a temperature rise velocity of 5 to 40 DEG C/min in a hot pressing furnace by using nitrogen gas as protection atmosphere, the temperature is preserved for 0.5 to 1 hour, then, the temperature is raised to 1800 to 2100 DEG C at a temperature rise velocity of 5 to 40 DEG C/min, the temperature is preserved for 1 to 3 hours, and the hot pressing pressure is 10 to 40 MPa. The Y4Si2O7N2-BN ceramic base composite materials with high purity, good density, high intensity and low heat conductivity can be sintered through hot pressing in a short time.

Description

technical field [0001] The invention relates to the field of ceramic matrix composite materials, in particular to a yttrium silicon oxynitride-boron nitride (Y 4 Si 2 o 7 N 2 -BN) in situ preparation method of ceramic matrix composites. Background technique [0002] Y 4 Si 2 o 7 N 2 It is a new type of quaternary low thermal conductivity ceramic material. It has many advantages in terms of thermal performance, it has low thermal conductivity (room temperature thermal conductivity 1.8-2.0W m -1 ·K -1 , 1000℃ high temperature thermal conductivity 1.4-1.6W m -1 ·K -1 ), lower coefficient of thermal expansion (4-6×10 -6 K -1 ), good high temperature resistance, oxidation resistance, low density (4.83g / cm 3 ) and modulus (Young's modulus 185GPa), medium strength (bending strength 157±7MPa), high hardness (Vickers hardness 10.3±0.3GPa), etc., in high-tech fields such as aviation, aerospace, and steel industry. Wide range of potential applications. Although Y 4 Si ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/597C04B35/622
Inventor 陈继新陈琳周延春
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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