Silicon nitride nanowire preparation method, silicon nitride nanowire, silicon nitride powder and silicon nitride submicron powder

Abstract

The invention provides a preparation method for a silicon nitride nanowire. The method provided by the invention comprises the following steps: with cheap and easily-available silicon powder as a raw material, and without the need of using a catalyst, subjecting the silicon powder to granulating, then carrying out a nitridation reaction so as to prepare silicon nitride particles, and carrying out simple operations like grinding, crushing, washing, settling separation and drying so as to be able to simultaneously obtain a high-purity silicon nitride nanowire and a silicon nitride powder product. Thus, the preparation method is a simple and economical method applicable to industrial large-scale preparation of the silicon nitride nanowire.

Description

technical field [0001] The invention relates to the field of nanowire preparation, in particular to a method for preparing silicon nitride nanowires, silicon nitride nanowires, silicon nitride powder and silicon nitride submicron powder. Background technique [0002] Silicon nitride (Si 3 N 4 ) has a series of excellent thermal properties such as good thermal shock resistance, oxidation resistance, high temperature resistance, corrosion resistance, high chemical stability, high strength, and high hardness, and is an excellent high-temperature structural material. [0003] Silicon nitride (Si 3 N 4 ) nanowire is a one-dimensional nanostructure form of silicon nitride material, which not only has various excellent properties possessed by bulk materials, but also has many new characteristics as a one-dimensional nanomaterial. For example: the flexural strength (up to 3.6GPa) and elastic model (up to 570GPa) of silicon nitride nanowires are much higher than those of bulk mat...

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Problems solved by technology

In some existing methods, the raw materials used are expensive, such as nano-silicon powder, carbon nanotube template, etc.; while in other methods, the preparation of raw materials used is difficult or difficult to obtain on a large scale, such as metal sodium, polysilazane , sodium azide, etc.

2) The process conditions are harsh or the method is complicated

For example, in the combustion reaction method, the reaction temperature needs to reach 1400-1600 ° C, and the reaction pressure also needs to reach 1-30 MPa, which makes it difficult to enlarge the production equipment (such as patent CN02100195 - Synthesis of high α phase by combustion)

3) Separation or purification is difficult, that is, silicon nitride nanowires are often mixed with unreacted raw materials and silicon nitride powder, which is difficult to separate and purify; and if a metal catalyst is used in the raw materials, it will also make it difficult to purify silicon nitride in the later stage

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