Method for preparation of high purity alpha phase silicon nitride powder from recovered silicon chip cut sawdust

A technology for phase silicon nitride powder and silicon wafer cutting, applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc. Oxygen content is high, and the effect of reducing production cost, high powder sintering activity and high purity is achieved.

Inactive Publication Date: 2014-02-05
NANCHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, because the particle size of the silicon powder is too fine and the oxygen content is too high, it cannot be directly used as a raw material for Czochralski monocrystalline silicon rods and cast polycrystalline silicon ingots.

Method used

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  • Method for preparation of high purity alpha phase silicon nitride powder from recovered silicon chip cut sawdust
  • Method for preparation of high purity alpha phase silicon nitride powder from recovered silicon chip cut sawdust
  • Method for preparation of high purity alpha phase silicon nitride powder from recovered silicon chip cut sawdust

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The silicon wafer diamond wire sawdust was taken, and the silicon wafer wire sawdust powder was recovered and purified as the raw material. The analysis results of the main metal impurities are shown in Table 1.

[0028] Take 100 grams of the raw material powder and loosely pack it in an atmosphere protection furnace; take the method of section heat preservation, the heat preservation temperature is respectively selected as 1000°C, 1300°C and 1350°C, and the heat preservation time is 2 hours, 2 hours and 6 hours respectively; The volume fraction of hydrogen is 5% of the total amount of nitrogen and hydrogen, and the total flow of nitrogen-hydrogen mixed gas is controlled at 200ml / min; the initial volume fraction of argon content is 50% of the total amount of gas, and gradually decreases to zero with the reaction process. Cool down to about 700°C and stop ventilation, then cool down to room temperature with the furnace and leave the furnace.

[0029] The synthesized prod...

Embodiment 2

[0033] The silicon wafer diamond wire sawdust was taken, and the silicon wafer wire sawdust powder was recovered and purified as the raw material. The analysis results of the main metal impurities are shown in Table 1.

[0034] Take 160 grams of the raw material powder and loosely pack it in an atmosphere protection furnace; take the method of segmented heat preservation, the heat preservation temperature is respectively selected as 800 ° C, 1200 ° C, 1300 ° C and 1370 ° C, and the heat preservation time is respectively 1 hour, 1 hour, 1 hour and 4 hours; the volume fraction of hydrogen is 15% of the total amount of nitrogen and hydrogen, and the total flow of nitrogen-hydrogen mixed gas is controlled at 150ml / min; the initial volume fraction of argon content is 60% of the total amount of gas, gradually increasing with the reaction process down to zero. Cool down to about 700°C and stop ventilation, then cool down to room temperature with the furnace and leave the furnace.

...

Embodiment 3

[0039] The silicon wafer diamond wire sawdust was taken, and the silicon wafer wire sawdust powder was recovered and purified as the raw material. The analysis results of the main metal impurities are shown in Table 1.

[0040] Take 200 grams of the raw material powder and loosely pack it in an atmosphere protection furnace; take the method of section heat preservation, the heat preservation temperature is respectively selected as 900°C, 1250°C and 1350°C, and the heat preservation time is 2 hours, 2 hours and 8 hours respectively; The volume fraction of hydrogen is 10% of the total amount of nitrogen and hydrogen, and the total flow rate of nitrogen-hydrogen mixed gas is controlled at 100ml / min; the initial volume fraction of argon content is 20% of the total amount of gas, and gradually decreases to zero with the reaction process. Cool down to about 700°C and stop ventilation, then cool down to room temperature with the furnace and leave the furnace.

[0041] The synthesized...

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Abstract

The invention provides a method for preparation of high purity alpha phase silicon nitride powder from recovered silicon chip cut sawdust. The method is characterized by: subjecting silicon chip sawdust powder to nitridation to obtain silicon nitride, then carrying out grinding, pickling, washing, drying and other processes, thus obtaining the high purity alpha phase silicon nitride powder. The obtained product has high purity, an alpha phase content of greater than 93%, an oxygen content of less than 1.5%, and high powder sintering activity. The method provided by the invention has the characteristics of no need for diluent and catalyst during production, simple process, low cost and easy mass production, and can be used for realizing high value-added utilization of silicon chip cut sawdust.

Description

technical field [0001] The invention relates to a method for directly nitriding and synthesizing silicon nitride powder at normal pressure, in particular to a method for synthesizing silicon nitride powder by nitriding at one time under the condition of no diluent and catalyst, using recycled silicon wafer sawdust powder as raw material, The invention belongs to the technical field of preparation of inorganic non-metallic materials. Background technique [0002] Silicon nitride ceramics have unique physical and mechanical properties, such as low density, high strength, high hardness, wear resistance, corrosion resistance, and excellent thermal stability. They are used in aviation, aerospace, chemical industry, energy, machinery manufacturing, weapon industry, Metallurgy and other fields have broad application prospects. However, the high cost of silicon nitride ceramics and the quality of silicon nitride powder restrict the large-scale application of silicon nitride. [00...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/068
Inventor 尹传强魏秀琴周浪
Owner NANCHANG UNIV
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