Preparation method of silicon nitride powder

By generating silane precursors through electrochemical ammonolysis and then purifying them, the problem of residual chlorine/oxygen impurities in silicon nitride powder was solved, resulting in high-purity, ultrafine, and narrow-particle-size silicon nitride powder, which improved the purity and performance of the product.

CN122127156APending Publication Date: 2026-06-02ZHONGKE HUAQING (QUANZHOU) FINE CERAMICS RESEARCH INSTITUTE CO LTD
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Patent Information

Application Number
CN202610347406.X
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-03-20
Publication Date
2026-06-02

AI Technical Summary

Technical Problem

In the preparation of silicon nitride powder, existing technologies often result in the difficulty of removing byproducts, leading to high levels of residual chlorine/oxygen impurities that affect product purity and performance.

Method used

An electrochemical ammonolysis method was adopted, which involves constructing an electrolysis system of liquid ammonia/ethylenediamine mixed solvent. Under the action of an electric field, soluble high-valence silicon-ammonia complex ions are generated, which react with NH2- ions to generate silane-amine precursors. Subsequently, purification and high-temperature thermal decomposition are carried out to avoid the introduction of chlorine and ensure the removal of impurities.

Benefits of technology

This method enables the preparation of high-purity, ultrafine silicon nitride powder with a narrow particle size distribution, avoiding Cl- residue and improving the purity and performance of the product.

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Abstract

The invention relates to the field of ceramic materials, provides a preparation method of silicon nitride powder, and solves the problem of high chlorine / oxygen impurity residue caused by difficult removal of byproducts during preparation of silicon nitride in the prior art. Comprising the following steps: S1, constructing an electrochemical cell, wherein an anode material is a high-purity monocrystalline silicon wafer; the cathode material is a graphite plate; the electrolyte adopts a mixed solvent of liquid ammonia and ethidene diamine and is added with LiCl electrolyte; s2, electrochemical ammonolysis reaction: under the action of an electric field, oxidizing a silicon anode to generate high-valence silicon-ammonia complex ions; nH2-dissociated from the liquid ammonia migrates to the anode and is combined to generate a silicon amine precursor containing Si-NH2 bonds; s3, purifying the precursor through liquid ammonia cleaning, organic solvent replacement and low-temperature drying; and S4, sequentially carrying out low-temperature pre-decomposition and high-temperature crystallization treatment on the precursor under the protection of nitrogen, so as to prepare the high-purity alpha-Si3N4.
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