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Fast microwave sintering process of combined silicon nitride-silicon carbide refractorg material

A refractory material and rapid sintering technology, applied in the field of refractory materials, can solve the problems of difficult control of internal and external quality of products, slow gas diffusion reaction, difficult to ensure internal and external components, etc. The effect of shortening the production cycle

Inactive Publication Date: 2005-04-27
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The previous reaction sintering method has the disadvantages of long sintering cycle (general laboratory or industrial production often takes one week), high energy consumption, and low thermal efficiency.
At the same time, under the traditional sintering method, since the surface of the blank is preferentially heated and reacted to form dense silicon nitride bonded silicon carbide, while the inside of the blank relies on slow gas diffusion reaction, the internal and external quality of the product is not easy to control, especially for thicker parts. It is difficult to ensure the uniformity of internal and external components, tissue structure and performance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (1) The purity of raw materials is: the mass percentage is greater than 95wt%, the particle size distribution is 1μm-2mm, and the particle size is in accordance with a certain gradation of silicon carbide powder; silicon powder: the particle size distribution is 0.1-50μm, and the purity is 99wt% ; Calcium lignosulfonate is selected as the binder, and the purity is 98wt% by mass.

[0022] (2) The above-mentioned silicon carbide powder is 90wt% by mass, silicon powder is 8wt% by mass, the binder is added according to 2wt% by mass, an appropriate amount of water is added, and the wet method is fully mechanically stirred and mixed.

[0023] (1) The above-mentioned mixture is formed into a blank of a certain shape by vibration and pressure molding.

[0024] (2) Heat and dry the blank in an air atmosphere for 24 hours, the temperature does not exceed 100°C, the heating is heated by resistance wire, and the heating rate is 2°C / min. Then, in the degreasing furnace, the tempera...

Embodiment 2

[0028] (1) The purity of raw materials is: the mass percentage is greater than 95wt%, the particle size distribution is 1μm-2mm, and the particle size is in accordance with a certain gradation of silicon carbide powder; silicon powder: the particle size distribution is 0.1-50μm, and the purity is 99wt% ; Calcium lignosulfonate is selected as the binder, and the purity is 98wt% by mass.

[0029] (2) The above silicon carbide powder is 85wt% by mass, silicon powder is 13wt% by mass, the amount of binder is 2wt% by mass, appropriate amount of water, and fully mechanically stirred and mixed by wet method.

[0030] (3) The above-mentioned mixture is formed into a blank of a certain shape by means of vibratory pressure molding.

[0031] (4) Heat and dry the blank in an air atmosphere for 24 hours, the temperature does not exceed 100°C, heating is performed by resistance wire, and the heating rate is 2°C / min. Then, in the degreasing furnace, the temperature was raised to 300° C. at ...

Embodiment 3

[0035] (1) The purity of raw materials is: the mass percentage is greater than 95wt%, the particle size distribution is 1μm-2mm, and the particle size is in accordance with a certain gradation of silicon carbide powder; silicon powder: the particle size distribution is 0.1-50μm, and the purity is 99wt% ; Calcium lignosulfonate is selected as the binder, and the purity is 98wt% by mass.

[0036] (2) The above silicon carbide powder is 80wt% by mass, silicon powder is 18wt% by mass, the amount of binder is 2wt% by mass, appropriate amount of water, and fully mechanically stirred and mixed by wet method.

[0037] (3) The above-mentioned mixture is formed into a blank of a certain shape by means of vibratory pressure molding.

[0038] (4) Heat and dry the blank in an air atmosphere for 24 hours, the temperature does not exceed 100°C, heating is performed by resistance wire, and the heating rate is 2°C / min. Then, in the degreasing furnace, the temperature was raised to 300° C. at ...

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Abstract

The present invention relates to refractory material technology. By means of the fast homogeneous heating of microwave to material and reaction promoting effect of microwave field on nitriding reaction, homogeneously mixed silicon nitride, silicon powder and small amount of organic adhesive pressed into blank, stoved and defatted are heated with microwave of industrial microwave source of 900-3000 MHz frequency to 1100-1500 deg.c under the nitrogen atmosphere for nitriding reaction and sintering to densify. After cooling naturally to room temperature, combined refractory silicon nitride-silicon carbide material in specific shape and with bulk weight 2.65-2.80 g / cu cm, compression strength higher than 250 MPa, bending strength higher than 60 MPa, porosity lower than 15 % and excellent heat shock resistance is prepared.

Description

technical field [0001] The invention relates to a method for quickly reacting and sintering silicon nitride combined with silicon carbide refractory materials by using microwave technology, which belongs to the technical field of refractory materials. Background technique [0002] Silicon nitride combined with silicon carbide is a new type of non-oxide refractory material widely used in metal smelting and casting, kiln furniture in high-temperature kilns such as ceramics, and various high-temperature equipment such as waste incinerators. Compared with traditional oxide refractory materials, it has the characteristics of high technical content and large market demand. [0003] So far, a lot of research and development work has been done on the formulation and sintering process of silicon nitride combined with silicon carbide refractories at home and abroad. has been widely used. However, the sintering technology currently used in production mainly adopts silicon-molybdenum ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565C04B35/583C04B35/64
Inventor 潘伟彭虎张晓东黄朝晖齐龙浩
Owner TSINGHUA UNIV
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