A kind of ultra-long silicon nitride/silica core-shell structure nanofiber and its preparation method

Abstract

The invention provides an ultra-long silicon nitride / silicon dioxide core-shell nanofiber and a preparation method thereof, which belong to the technical field of ceramic matrix composite materials. In this method, the silicon source is added to the polar solvent, stirred at 20-100°C for 1-8h, and then the polymer-based carbon source is added, and the precursor solution is obtained after standing still or degassing under reduced pressure; the co-precipitation method is adopted One or more of casting method, spinning method to shape and solidify the precursor solution; then put it into a high-temperature furnace, carry out nitriding treatment in a nitrogen atmosphere, and then lower it to 20-25°C, Take it out to get ultra-long silicon nitride / silicon dioxide core-shell nanofibers. Compared with the prior art, the present invention does not need to consume rare earth metals, nor does it require metal catalysts or templates, the preparation process is simple and efficient, and the prepared silicon nitride / silica core-shell nanofibers have high purity and high yield, and the diameter and The length is controllable, suitable for mass production.

Description

technical field [0001] The invention relates to the technical field of ceramic matrix composite materials, in particular to an ultra-long silicon nitride / silicon dioxide core-shell nanofiber and a preparation method thereof. Background technique [0002] Silicon nitride (Si 3 N 4 ) is an important wide-bandgap high-performance ceramic material with a series of excellent properties such as high temperature resistance, oxidation resistance, high strength, high hardness, impact resistance, wear resistance, strong chemical stability, and good lubricating properties. It is used in the field of high-performance device fabrication and high-temperature resistant semiconductor materials. one-dimensional Si 3 N 4 Nanostructures not only have Si 3 N 4 The basic advantages of bulk materials, but also the unique geometric structure and special physical and chemical properties of one-dimensional nanomaterials. Si 3 N 4 Nanofibers, as the third-generation wide-bandgap (5.3 eV) sem...

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Problems solved by technology

This preparation method requires rare earth metal salts as catalysts. Most of the rare earths are distributed on the earth with relatively low concentrations. There are relatively few regions with rich rare earth reserves in the world, which are scarce resources. Therefore, most of the rare earth metal salts are expensive. The preparation method uses rare earth metal salts as catalysts, although it can be reused in theory, but in actual operation, the sparse metal salts need to be extracted again from the waste liquid, which undoubtedly increases the complexity and difficulty of the process, and also increases the preparation of nitriding. The overall cost of silicon nanofibers, and without effective recycling technology, the production method requires repeated consumption of rare earth resources

It can be seen that although the preparation method in the prior art can prepare one-dimensional Si 3 N 4 Nanostructure, but consumes rare earth resources, and the cost is high, this drawback has become an obstacle that cannot be ignored in large-scale production

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