Method for preparing beta-silicon nitride whiskers

A silicon nitride whisker and silicon nitride powder technology, applied in chemical instruments and methods, single crystal growth, single crystal growth, etc., can solve environmental pollution, low purity of silicon nitride whiskers, harsh reaction conditions, etc. question

Inactive Publication Date: 2011-11-23
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The existing commercial production of whiskers has problems such as environmental pollution and harmful to human health. Many manufacturers have stopped production or restricted production
Some new methods for preparing silicon nitride whiskers are still under study. For example, the raw materials used in these methods are toxic, or the price is relatively expensive, or the reaction conditions are relatively harsh, and the purity of the silicon nitride whiskers produced is not high. thereby affecting its performance

Method used

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  • Method for preparing beta-silicon nitride whiskers
  • Method for preparing beta-silicon nitride whiskers
  • Method for preparing beta-silicon nitride whiskers

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Add 59.5g of silicon nitride powder to 80mL of deionized water, add 2.5% of silicon nitride powder, 1.66g of alumina powder and 4.92g of 7.5% yttrium oxide powder, and 0.66g of alkaline water agent as a dispersant. The forming medium is PVA, and it is calcined at 1650°C and kept for 2 hours to obtain silicon nitride whiskers.

Embodiment 2

[0050] Add 112g of silicon nitride powder to 80mL of deionized water, add 2.5% of silicon nitride powder, 2.8g of alumina powder and 8.4g of 7.5% yttrium oxide powder, and 1.12g of ammonium citrate TAC as a dispersant. The molding medium is PVA, and it is calcined at 1750°C and kept for 2 hours to obtain silicon nitride whiskers.

Embodiment 3

[0052] Add 59.5g of silicon nitride powder to 80mL of deionized water, add 2.5% of silicon nitride powder, 1.66g of alumina powder and 4.92g of 7.5% yttrium oxide powder, and 0.66g of alkaline water agent as a dispersant. The molding medium is PVA, and it is calcined at 1650°C for molding, and kept for 2 hours to obtain silicon nitride whiskers.

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Abstract

The invention provides a method for preparing beta-silicon nitride whiskers. Based on the principle that aperture walls are utilized for supporting and aperture cavities provide growth spaces for whiskers, a porous ceramic block body composed of a mass of bird nest type microstructures is prepared through the method, wherein the bird nest type microstructure is constructed from a mass of beta-silicon nitride whiskers which are weakly combined together thus beta-silicon nitride whiskers can be obtained only by a grinding process. The method which can prepare a porous ceramic block body composed of a mass of bird nest type microstructures is a colloidal state foaming method. The silicon nitride whisker preparation method provided by the invention is a colloidal state foaming method which has the advantages of simple operation, high purity, high output, environmentally friendly characteristics, and no harm on human health.

Description

technical field [0001] The invention relates to a new method for preparing β-silicon nitride whiskers by a colloidal foaming method, which belongs to the technical field of new materials. Background technique [0002] Whisker is a high-strength beard-like single crystal synthesized under artificial control conditions. Its crystal structure is relatively complete, with few internal defects, and its strength and modulus are close to ideal crystals. Therefore, whiskers are often added as reinforcing components to metal matrix, ceramic matrix and polymer matrix to strengthen and toughen. The size of the whisker is closely related to the performance of the whisker. As the size increases, the number of defects increases and the performance of the whisker decreases. When the whisker diameter is less than 10 μm, its strength increases sharply. Si 3 N 4 Whiskers are considered as ideal reinforcing components for metal and ceramic materials because of their high temperature resis...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/62C30B1/10
Inventor 杨金龙蔡锴李合欣席小庆黄勇
Owner TSINGHUA UNIV
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