CN1032679C - Method for preparing superfines - Google Patents

Method for preparing superfines Download PDF

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Publication number
CN1032679C
CN1032679C CN92109291A CN92109291A CN1032679C CN 1032679 C CN1032679 C CN 1032679C CN 92109291 A CN92109291 A CN 92109291A CN 92109291 A CN92109291 A CN 92109291A CN 1032679 C CN1032679 C CN 1032679C
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reaction
sih
temperature
ultrafine particles
reaction chamber
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CN1080222A (en
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许宇庆
丁子上
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Zhejiang University ZJU
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Zhejiang University ZJU
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/12—Making metallic powder or suspensions thereof using physical processes starting from gaseous material

Abstract

The present invention discloses a preparation method of tubular nanometer-scale fine particles. The preparation method comprises: metallic vapor or halide, hydride and organic metallic compound are used as raw materials; gas-phase heating and chemical reaction are carried out for inert gases and vacuum in a tubular high-temperature reaction furnace for compounding the fine particles; the fine particles are quickly cooled and pumped into a powder collection device. The metallic vapor comprises Ag, Ni and Cu, the halide comprises CH3SiCl3, SiCl4 and ACl3, the hydrides comprise SiH4, C2h4, Ch4 and NH3, and the organic metallic compound comprises LiOC2H5, Ba(OC2H5)2, and Cu (OC2 H5)2. The superfine particles produced by the method are beta-SiC nanometer-scale superfine particles with the chemical quantity that particle sizes are less than 100A in spherical dispersion. In addition, the method has the advantages of simple equipment, convenient operation, high yield rate and easy popularization in industries.

Description

Preparation method of tubular nano-grade ultrafine particles
The invention relates to a method for preparing ultrafine particles, in particular to a method for preparing tubular nano ultrafine particles.
The siliconcarbide ultrafine particles are high-quality high-temperature structural ceramics and are widely used in the fields of ceramic engines and the like. The high-quality silicon carbide ultrafine powder not only is a prerequisite for preparing high-performance ceramics, but also can reduce sintering temperature, improve sintering performance and improve high-temperature mechanical properties. Compared with large particles and bulk silicon carbide, the nanometer silicon carbide ultrafine particles have many specific magnetic, electric, optical, thermal and other properties, and are mesoscopic materials which attract people to be interested widely. The development of nanometer ultrafine particles is the current leading research subject, and the development of new material characteristics and functions by utilizing the surface characteristics of silicon carbide ultrafine powder has attracted extensive attention. Therefore, the preparation of the nano-scale silicon carbide ultrafine powder is not only of great significance for preparing high-quality silicon carbide ceramics, but also of great significance for developing new applications of the nano-scale silicon carbide ultrafine particles.
Generally, one refers to ultrafine powders having particle diameters of less than 1 μm and nanoscale ultrafine powders having particle diameters of less than 100A.
The major technology for the commercial production of silicon carbide powder was originally invented by e.g. acheson and patented in 1893, who used quartz and carbon to react chemically to give a powder with a low chemical purity (<97%), a particle size>1 μm, and which is not suitable as a silicon carbide feedstock for advanced ceramics. Then, UK patent applied by A.W.Evans in 1967 was SiO2Steam and CH4And (3) preparing SiC powder with the particle size of 44-150 mu m by using a radio frequency plasma method as a reaction gas. Cleaver and Penisi applied plasma chemical vapor deposition method with SiCl in 19684、H2、CH4As a raw material gas, a powder having an SiC content of 81.3 ut% and a particle diameter of less than 1 μm was obtained. Bocher et al used nail in 1978Silane (CH)3SiH3) β -SiC ultrafine powder with the particle size of 0.1 to 0.5 mu m is prepared by chemical vapor thermal reaction at 10000 to 1800 ℃, and the β -SiC ultrafine powder with the particle size of 10 to 100 mu m can be obtained by using a gas evaporation method in 980 years by the people in the river of the university of famous city of Japan.
The Roman Pampuch of Poland uses a mixture of Si and C as reactants and adopts a solid combustion technology to ignite the reactants, and the method can obtain β -SiC powder with stoichiometric and better sinterability, and the corresponding grain size is 0.2-0.5 mu m.
Further, amorphous Si is used for Jade exhibition of Japan2N3Heating the mixture of H and carbon block at 1350-1650 ℃ for 0.5-4 hours to obtain a mixture of α -SiC and β -SiC, wherein the particles are spherical and have a size of 0.2-0.4 μm.
Some of the methods for producing SiC powder described above cannot obtain high-quality SiC powder having a particle size of the order of nanometers.
At present, various methods are explored for preparing ultrafine powder, and the methods are divided into three types, namely a solid phase method, a liquid phase method and a gas phase method. However, as described above, it is difficult to prepare ultrafine particles of nanometer order (100A) by the solid phase method, and thus attempts have been made to search for the preparation of ultrafine nanoparticles by the sol-gel method in the liquid phase method, the laser chemical vapor deposition in the vapor phase method, the glow chemical vapor deposition and the thermal chemical vapor deposition. However, there are few methods for preparing high quality and high purity nanoscale ultrafine powders in stoichiometric proportions. Therefore, a new process and a new method for preparing nanometer ultrafine powder are urgently needed.
The invention aims to provide a preparation method of tubular nanometer ultrafine particles.
The present invention has the advantages of simple apparatus, convenient operation, high yield and easy industrial popularization, and the prepared superfine particle is spherical, has the particle size of less than 100A DEG and is β -SiC nanometer grade superfine particle with the chemical quantity ratio.
In order to achieve the above purpose, the following measures are taken, and the invention has three methods I, II and III.
I (1), firstly, heating a corundum tube type high-temperature reaction furnace to raise the temperature of a reaction chamber to 1200-1400 ℃, keeping the temperature for 0.5-1 hour, and simultaneously, starting a vacuum pumping system to reactThe chamber is pumped to 10-3～10-5A torr;
i (2) Next, SiH is opened4And C2H4Steel cylinder, adjusted to C by mass flow meter2H4/SiH4The molar ratio is 0.5-2, the total gas flow is 200-600 ml/min, and the reaction pressure is controlled to be 0.1-1 atmospheric pressure;
i (3) then, introducing the raw material SiH4And C2H4Chemical reaction occurs in the reaction furnace to generate SiC ultrafine particles, and the SiC ultrafine particles are quenched and pumped into a powder collecting device.
Or II (1). first, theHeating the corundum tube high-temperature reaction furnace toraise the temperature of the reaction chamber to 1200-1400 ℃, keeping the temperature for 0.5-1 hour, and simultaneously starting a vacuum pumping system to pump the reaction chamber to 10 DEG C-3～10-5A torr;
II (2) Next, NH is opened3And SiH4The steel cylinder is adjusted to NH by a mass flow meter3/SiH4The molar ratio is 5-20, the total gas flow is 100-400 ml/min, and the reaction pressure is controlled to be 0.1-1 atmospheric pressure;
II (3) then, introduction of the starting material NH3And SiH4In the reaction furnace, chemical reaction takes place to produce Si3N4The ultrafine particles are quenched and pumped into a powder collecting device.
Or III (1), firstly, heating the corundum tube high-temperature reaction furnace to raise the temperature of the reaction chamber to 1200-1400 ℃, keeping the temperature for 0.5-1 hour, and simultaneously, starting a vacuum pumping system to pump the reaction chamber to 10 DEG-3～10-5A torr;
III (2) subsequently, the SiH is opened4、C2H4And NH3Steel cylinder, adjusted to C by mass flow meter2H4/SiH4And NH3/SiH4The molar ratio is 0.2-1.2 and 1-7, the total gas flow is 100-500 ml/min, and the reaction pressure is controlled to be 0.1-1 atmospheric pressure;
III (3) then, the introduced raw material SiH4、C2H4And NH3Chemical reaction occurs in the reaction furnace to generate SiC-Si3N4The composite superfine particles are quenched and pumped into a powder collecting device.
The following detailed description is made with reference to the accompanying drawings.
The attached figure is a schematic diagram of the operating system of the equipment designed according to the method.
The specific preparation method of the tubular nanometer ultrafine particles comprises the following steps:
i (1'). The reaction temperature in the above I (1) was raised to 1300 ℃ and maintained at the same temperature for 0.5 hourThe chamber is pumped to 10-3A torr;
i (2'). C in the above-mentioned I (2)2H4/SiH4The molar ratio was 1.2, the total gas flow rate was 350 ml/min, and the reaction pressure was controlled to 0.7 atm.
Or II (1'). In II (1) above the reaction temperature to 1350 ℃, constant temperature for 0.5 hours, the reaction chamber is pumped to 10-3A torr;
II (2'), NH in the above II (2)3/SiH4The molar ratio is 12, the total gas flow is 250 ml/min, and the reaction pressure is controlled to be 0.7 atmospheric pressure;
or III (1'). In III (1) above, the temperature of the reaction chamber is raised to 1350 ℃ and kept constant for 0.5 hour, and the reaction chamber is pumped to 10-3A torr;
III (2'). C in III (2) above2H4/SiH4And NH3/SiH4The molar ratio was 0.6 and 2.5, the total gas flow was 400 ml/min, and the reaction pressure was controlled to 0.7 atm.
The equipment operation system designed according to the method comprises mass flowmeters 1 and 2, a mixing chamber 3, a thermocouple 4, a silicon carbide rod high-temperature furnace 5, a reaction chamber 6, a vacuum-pressure gauge 7, a powder collecting device 8, a filtering membrane 9 and a vacuum filtration system.
The method can use metal steam or halide gas, hydride gas and organic metal compound as raw materials, and synthesize particles through gas phase heating and chemical reaction in vacuum and inert gas of a tubular high-temperature reaction furnace, namely, the particles are quenched and pumped into a powder collecting device.
The method uses Ag, Ni and Cu as reaction raw materials and CH as halide3SiCl3，SiCl4，AlCl3The hydride being SiH4，C2H4，CH4，NH3The organometallic compound is LiOC2H5，Ba(OC2H5)2，Cu(OC2H5)2。
The first embodiment is as follows:
the preparation method of the nanometer SiC ultrafine particles comprises the following steps:
1. heating a silicon carbide rod high-temperature furnace to gradually raise the temperature of a reaction chamber to 1300 ℃, keeping the temperature for half an hour, and simultaneously starting a mechanical pump to pre-vacuumize the reaction chamber to ensure that the vacuum degree reaches 10-3And (5) torr.
2. SiH is opened4And C2H4Steel cylinder, regulated by mass flow meter to C2H4Gas and SiH4The molar ratio of the gas is 1.2, and the gas is introduced into the gas storage chamber. The mass flow meter of the gas storage chamber was opened to allow the feed gas to be introduced into the 1300 ℃ isothermal zone of the reaction chamber. The mass flow meter and the vacuum pumping system valve are sized (i.e., the amount of pumping) to allow mixing through the reaction chamberThe flowrate of the gas was 350 ml/min, and the pressure in the reaction chamber was kept constant at 0.7 atm.
3. Introduced SiH4And C2H4A chemical reaction takes place in the reaction chamber: the generated SiC nanometer ultrafine particles are pumped into a powder collecting bottle before aggregation and growth. A filter membrane is arranged between the powder collecting bottle and the vacuum system to prevent the powder from diffusing to the vacuum system, and the powder collected in the collecting bottle has a cyclone effect and is in a mist shape.
The composition and structure of the SiC ultrafine powder obtained according to the preparation conditions are as follows:
1, the powder is spherical, has good dispersivity, no agglomeration, uniform particle size distribution and granularity less than 100A degrees.
The SiC powder was β -SiC, having a high purity of chemical composition, and having an Si/C atomic ratio of 1.044, which was close to the stoichiometric ratio of β -SiC of 1.049.
Chemical composition SiC free silicon free carbon SiO2
Content (ut%) 96.471.510.531.33
Example two:
nanoscale Si3N4The preparation method of the ultrafine particles comprises the following steps:
1. starting the silicon carbide rod heating furnace to gradually heat a certain constant temperature area in the reaction chamber to 1350 ℃ and keep the temperature halfIn the hour, the mechanical pump is started to ensure that the pre-vacuum degree of the reaction chamber reaches 103And (5) torr.
2. NH is adjusted by a mass flow meter in front of the gas storage chamber3/SiH4Is 12 and mixed in the air reservoir. The flow rate of the mixed gas is controlled to be 250 ml/min by a mass flow meter, and air is introduced into a constant-temperature area of the reaction chamber by a corundum small pipe. The pressure of the reaction chamber is controlled to be 0.7 atmosphere by controlling the size of the valves of the air inlet and the air outlet.
3. Introduced SiH4And NH3The gas undergoes a chemical reaction in a constant temperature zone:
formed Si3N4The particles are quenched and drawn into a powder collection bottle.
According to the above-mentioned process we can obtain high-quality Si3N4Powder:
1. the particles are spherical, dispersed and not agglomerated, the particle diameter is uniform, and the granularity is less than 100A DEGSi3N4And (3) powder.
2. The chemical composition is as follows:
powder composition Si3N4Free silicon SiO2
Content (ut%) 97.640.391.97
Example three:
nanoscale SiC-Si3N4The preparation method of the composite ultrafine particles comprises the following steps:
1. the procedure is as above.
2. SiH is turned on4、C2H4And NH3A steel cylinder, a mass flow meter connected to each gas path is adjusted to make the concentration ratio of each gas introduced into the gas storage chamber be C2H4/SiH4Molar ratio of 0.6, NH3/SiH4The molar ratiowas 2.5, the gases were mixed in the gas holder and the total gas flow was controlled to 400 ml/min by a mass flow meter. Introducing the mixed gas into the constant-temperature region of the reaction chamber by a small corundum tube, andthe pressure in the reaction chamber was controlled to 0.7 atm.
3. SiH introduced into the reaction chamber4、C2H4And NH3The gas undergoes a chemical reaction in a constant temperature zone:
can be prepared to contain Si3N4And composite superfine powder of SiC.
SiC-Si can be obtained according to the reaction conditions3N4The composite superfine powder is as follows:
1. the particles are spherical, dispersed, the granularity is less than 100A, and the particle size is uniformly distributed.
2. The chemical composition is as follows: si3N4：22.16ut％、SiC：69.81ut％、C：7.97ut％。

Claims (7)

1. A method for preparing tubular nanometer ultrafine particles is characterized in that:
(1) firstly, heating a corundum tube type high-temperature reaction furnace to raise the temperature of a reaction chamber to 1200-1400 ℃, keeping the temperature for 0.5-1 hour, and simultaneously starting a vacuum pumping system to pump the reaction chamber to 10 DEG-3～10-5A torr;
(2) then, opening SiH4And C2H4Steel cylinder, adjusted to C by mass flow meter2H4/SiH4The molar ratio is 0.5-2, the total gas flow is 200-600 ml/min, and the reaction pressure is controlled to be 0.1-1 atmospheric pressure;
(3) then, the introduced raw material SiH4And C2H4Chemical reaction occurs in the reaction furnace to generate SiC ultrafine particles, and the SiC ultrafine particles are quenched and pumped into a powder collecting device.
2. The method for preparing the tubular nanometer-scale ultrafine particles according to claim 1, wherein:
(1) the reaction temperature in claim 1(1) is raised to 1Keeping the temperature at 300 ℃ for 0.5 hour, and pumping the reaction chamber to 10 DEG C-3A torr;
(2) c in claim 1(2)2H4/SiH4The molar ratio was 1.2, the total gas flow rate was 350 ml/min, and the reaction pressure was controlled to 0.7 atm.
3. A method for preparing tubular nanometer ultrafine particles is characterized in that:
(1) firstly, heating a corundum tube high-temperature reaction furnace to raise the temperature of a reaction chamber to 1200-1400 ℃, keeping the temperature for 0.5-1 hour, and simultaneously starting a vacuum pumping system to pump the reaction chamber to 10 DEG-3～10-5A torr;
(2) then, NH is opened3And SiH4The steel cylinder is adjusted to NH by a mass flow meter3/SiH4The molar ratio is 5-20, the total gas flow is 100-400 ml/min, and the reaction pressure is controlled to be 0.1-1 atmospheric pressure;
(3) then, the introduced raw material NH3And SiH4In the reaction furnace, chemical reaction takes place to produce Si3N4The ultrafine particles are quenched and pumped into a powder collecting device.
4. The method for preparing the tubular nanometer-scale ultrafine particles according to claim 3, characterized in that:
(1) the reaction temperature in claim 3(1) was raised to 1350 ℃ and maintained at the temperature for 0.5 hour, and the reaction chamber was evacuated to 10 degrees centigrade-3A torr;
(2) NH in claim 3(2)3/SiH4The molar ratio is 12, the total gas flow is 250 ml/min, and the reaction pressure is controlled to be 0.7 atmospheric pressure;
5. a method for preparing tubular nanometer ultrafine particles is characterized in that:
(1) firstly, heating a corundum tube high-temperature reaction furnace to raise the temperature of a reaction chamber to 1200-1400 ℃, keeping the temperature for 0.5-1 hour, and simultaneously starting a vacuum pumping system to pump the reaction chamber to 10 DEG-3～10-5A torr;
(2) then, opening SiH4、C2H4And NH3Steel cylinder, adjusted to C by mass flow meter2H4/SiH4And NH3/SiH4The molar ratio is 0.2-1.2 and 1-7, the total gas flow is 100-500 ml/min, and the reaction pressure is controlled to be 0.1-1 atmospheric pressure;
(3) then, the introduced raw material SiH4、C2H4And NH3Chemical reaction occurs in the reaction furnace to generate SiC-Si3N4The composite superfine particles are quenched and pumped into a powder collecting device.
6. The method for preparing the tubular nanometer-scale ultrafine particles according to claim 5, wherein:
(1) the reaction chamber of claim 5(1) is heated to 1350 ℃ and kept at the same temperature for 0.5 hour, and the reaction chamber is pumped to 10 ℃-3A torr;
(2) c in claim 5(2)2H4/SiH4And NH3/SiH4The molar ratio was 0.6 and 2.5, the total gas flow was 400 ml/min, and the reaction pressure was controlled to 0.7 atm.
7. The method for preparing ultrafine particles of tubular nanometer size as claimed in claim 1, 3 or 5, wherein said raw material is CH3SiCl3，SiCl4。
CN92109291A 1992-08-07 1992-08-07 Method for preparing superfines Expired - Fee Related CN1032679C (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6688494B2 (en) 2001-12-20 2004-02-10 Cima Nanotech, Inc. Process for the manufacture of metal nanoparticle
DE10297575T5 (en) * 2001-12-20 2005-01-13 Aveka, Inc., Woodbury Process for the preparation of reacted aluminum or copper nanoparticles
TWI547657B (en) * 2014-12-09 2016-09-01 Kwang Yang Motor Co Engine gearbox
CN105236410B (en) * 2015-09-15 2017-07-18 扬州大学 The preparation method of luminous amorphism nano silicon particles
CN114260458A (en) * 2021-12-28 2022-04-01 西安交通大学 Device and method for preparing superfine high-purity spherical magnesium powder

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