Method for synthesizing isotropic silicon nitride powder adopting layer type material-distribution

A technology of combustion synthesis and silicon nitride powder, applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc., can solve the problems of high production efficiency and low impurity content, achieve consistent phase content, high purity, and increase nitrogen penetration. sexual effect

Inactive Publication Date: 2008-09-03
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The object of the present invention is to provide a method for the combustion synthesis of homogeneous silicon nitride powder in layered cloth, which solves the problems of phase composition, impurity content, microstructure and grain size of the internal and external combustion products of the conventional combustion synthesis method. There is a problem of large inhomogeneity, so that the phase composition of the prepared silicon nitride powder product is uniform, the sintering activity is good, the powder particles are fine and uniform, the impurity content is low, and the operation is convenient, the equipment is simple, and the production efficiency is high.

Method used

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  • Method for synthesizing isotropic silicon nitride powder adopting layer type material-distribution
  • Method for synthesizing isotropic silicon nitride powder adopting layer type material-distribution
  • Method for synthesizing isotropic silicon nitride powder adopting layer type material-distribution

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Comparison scheme
Effect test

Embodiment 1

[0053] Silicon powder with an average particle size of 25μm (purity greater than 98.5%) and silicon nitride powder with an average particle size of 2.2μm (purity greater than 96%, alpha phase content about 93%), respectively, according to different weight ratios (in this example It is three kinds of ingredient ratios) after the ingredients are mixed in the ball milling tank of the roller ball mill for 72 hours, three parts of the reaction mixture with different composition ratios are obtained, namely the reaction mixture A (the ingredient ratio is Si:Si 3 N 4 =45:55), reaction mixture B (the ratio of ingredients is Si:Si 3 N 4 =47.5:52.5) ​​and the reaction mixture C (the batching ratio is Si:Si 3 N 4 =50:50), the total weight of the reaction mixtures A, B, and C is 4.8 kg. The reaction mixtures A, B, and C were put into an electric heating oven and dried at 70°C. Then put the three reaction mixtures with different component ratios in a cylindrical porous graphite crucible accordi...

Embodiment 2

[0056]The raw materials used in this embodiment are silicon powder with an average particle size of 17 μm (purity greater than 98.5%) and silicon nitride powder with an average particle size of 1.5 μm (purity greater than 98%, alpha phase content about 95%). Respectively carry out ingredients according to different weight ratios and grind and mix to obtain three reaction mixtures with different composition ratios, namely reaction mixture A (the ingredient ratio is Si:Si 3 N 4 =45:55), reaction mixture B (the batching ratio is Si:Si 3 N 4 =50:50) and reaction mixture C (the batching ratio is Si:Si 3 N 4 =55:45), the total weight of the reaction mixtures A, B, and C is 1.2 kg. The above-mentioned grinding and mixing of the three reaction mixtures is carried out in the following manner: first, the silicon powder is milled and mixed in the ball mill barrel of the agitated ball mill with absolute ethanol as the ball milling medium for 10 hours, and then the inert diluent silicon nitrid...

Embodiment 3

[0058] The raw materials used in this embodiment are silicon powder with an average particle size of 5 μm (purity greater than 98.5%) and silicon nitride powder with an average particle size of 3 μm (purity greater than 96%, alpha phase content about 90%). Respectively carry out ingredients according to different weight ratios and grind and mix to obtain three reaction mixtures with different composition ratios, namely reaction mixture A (the ingredient ratio is Si:Si 3 N 4 =42.5:57.5), reaction mixture B (the ratio of ingredients is Si:Si 3 N 4 =47.5:52.5) ​​and reaction mixture C (the batching ratio is Si:Si 3 N 4 =52.5:47.5), the total weight of the reaction mixtures A, B, and C is 5 kg. The above-mentioned grinding and mixing of the three reaction mixtures is carried out in the following manner: firstly, the silicon powder is milled and mixed in the ball mill barrel of the agitated ball mill using absolute ethanol as the ball milling medium for 6 hours, and then dried in a vac...

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Abstract

The invention discloses a homogeneous silicon nitride powder synthetic method of hollow ring-shaped cloth combustion in the inorganic non-metal material domain, which is characterized by the following: grinding to mix the silicon powder and silicon nitride powder at different proportions; placing the material in the combustion synthetic reaction device after drying; charging 1-20 Mpa nitrogen gas in the vacuum device; inducing the combustion synthetic reaction through igniting. The invention solves the problem that different parts of object-phase component and microcosmic topography are uneven, which improves the purity and alpha-phase content.

Description

Technical field [0001] The invention belongs to the field of inorganic non-metallic materials, and in particular provides a method for layered cloth combustion synthesis (Combustion Synthesis, CS) homogeneous silicon nitride powder. Background technique [0002] Silicon nitride is a synthetic non-oxide ceramic. It has the characteristics of low density, low specific gravity, high hardness, high strength, corrosion resistance, oxidation resistance, abrasion resistance, large elastic modulus, high temperature resistance, small thermal expansion coefficient, large thermal conductivity, thermal shock resistance and good electrical insulation performance. , Its mechanical properties and thermal properties are significantly better than general oxide ceramics. Silicon nitride ceramic products and silicon nitride-based composite ceramic products manufactured through different sintering processes can be widely used in cutting tools, bearings, engine parts, as well as chemical, metallurgy,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B21/068C04B35/584C04B35/626
Inventor 葛昌纯王飞
Owner UNIV OF SCI & TECH BEIJING
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