Preparation method for compact solid-phase sintered silicon carbide by using particle-size blended powder as raw material

A technology of solid-phase sintering and nano-scale silicon carbide, which is applied in the field of preparing dense solid-phase sintered silicon carbide, to achieve the effects of reducing slurry viscosity, consistent size, and inhibiting abnormal grain growth

Active Publication Date: 2016-06-15
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0007] Aiming at the problems caused by the use of submicron or nanometer SiC powders in the preparation process of solid-phase sintered silicon carbide ceramics, the present invention proposes a method for preparing dense solid-phase sintered silicon carbide using particle-graded powders as raw materials. method

Method used

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  • Preparation method for compact solid-phase sintered silicon carbide by using particle-size blended powder as raw material
  • Preparation method for compact solid-phase sintered silicon carbide by using particle-size blended powder as raw material

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Embodiment 1

[0040] The 5 μm and 0.5 μm SiC powders are mixed according to the mass ratio of 2:1 by roller milling to obtain particle-graded powders. Next, add 0.1wt.% of B that accounts for the total mass of the particle-graded powder 4 C, 5wt.% carbon powder to obtain a composite powder. Afterwards, hydroxymethyl cellulose was added to the composite powder as a binder, and dry-pressed at 200 MPa to obtain a green body. Finally, put the green body into the graphite furnace, under Ar atmosphere, heat up to 2100°C for sintering to obtain dense solid-phase sintered silicon carbide ceramics. The microstructure photos are shown in Figure 1(a) and Figure 1(b). and performance parameters are listed in Table 1:

[0041] The structure and performance parameters of the dense solid-phase sintered silicon carbide ceramics obtained in Table 1 Example 1

[0042] .

Embodiment 2

[0044] The 1 μm and 0.1 μm SiC powders are mixed according to the mass ratio of 1:1 by roller milling to obtain particle-graded powders. Next, add 1wt.% of B 4 C. 7wt.% carbon powder to obtain a composite powder. Afterwards, phenolic resin was added to the composite powder as a binder, and dry-pressed at 200 MPa to obtain a green body. Finally, the green body is put into a graphite furnace, and heated up to 2000°C for sintering under an Ar atmosphere to obtain a dense solid-phase sintered silicon carbide ceramic.

Embodiment 3

[0046] The 50 μm and 1 μm SiC powders are mixed according to the mass ratio of 0.5:1 by roller milling to obtain particle-graded powders. Add 3wt.% of B to the particle grading powder to account for its total mass 4 C. 0.5wt.% carbon powder to obtain a composite powder. Next, using tetramethylammonium hydroxide as a dispersant, the composite powder was added into an aqueous solution containing polyvinyl alcohol and stirred to obtain a stable SiC-B 4 C-C slurry. After testing, the slurry has a viscosity of 1 Pa·s and a volume solid content of 54 vol%. Afterwards, the slurry is poured into a plaster mold of a specific shape, cast into a mold, demoulded, and dried to obtain a green body. Finally, put the green body into a graphite furnace, and heat it up to 2100°C for sintering under an Ar atmosphere to obtain a dense solid-phase sintered silicon carbide ceramic.

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Abstract

The invention relates to a preparation method for compact solid-phase sintered silicon carbide by using a particle-size blended powder as a raw material. The method comprises the following step: subjecting a compound powder of a particle-size silicon carbide blended powder and a sintering auxiliary agent to molding and sintering so as to prepare compact solid-phase sintered silicon carbide ceramic, wherein the particle-size silicon carbide blended powder comprises a micron-size silicon carbide powder, and a submicron-size silicon carbide powder and / or a nanometer-size silicon carbide powder; and a mass ratio of the micron-size silicon carbide powder to the submicron-size silicon carbide powder and / or the nanometer-size silicon carbide powder is (2-0.05): 1. According to the invention, through introduction of a micron-size powder with low cost, production cost of the solid-phase sintered silicon carbide ceramic is reduced; meanwhile, density of a ceramic body is improved; shrinkage is reduced; and the method facilitates to reducing sintering deformation or cracking of a large-size sample.

Description

technical field [0001] The invention relates to a method for preparing dense solid-phase sintered silicon carbide by using particle-graded powder as a raw material. Background technique [0002] Solid-phase sintered silicon carbide ceramics have the characteristics of high temperature strength, high thermal conductivity, and excellent chemical corrosion resistance. In 1975, Prochazka et al. used boron and carbon as sintering aids for the first time to realize the densification of silicon carbide ceramics. Since then, in the process of research and production of solid phase sintered SiC ceramics, all the raw materials used are submicron or nanometer SiC powder, and cheap micron SiC powder has never been used, which leads to the following deficiencies : [0003] 1) Due to the sub-micron powder or nano-powder, the particle size is small, the specific surface area is large, the surface energy is high, and the sintering activity is strong. Under high temperature conditions (205...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565C04B35/622
Inventor 黄政仁吴海波刘学建姚秀敏陈健
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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