CN111039290A - Method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction - Google Patents

Method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction Download PDF

Info

Publication number
CN111039290A
CN111039290A CN201811188174.XA CN201811188174A CN111039290A CN 111039290 A CN111039290 A CN 111039290A CN 201811188174 A CN201811188174 A CN 201811188174A CN 111039290 A CN111039290 A CN 111039290A
Authority
CN
China
Prior art keywords
transition metal
molten salt
metal carbide
carbide powder
raw material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201811188174.XA
Other languages
Chinese (zh)
Inventor
刘会军
杨凌旭
曾潮流
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Institute of Metal Research of CAS
Original Assignee
Institute of Metal Research of CAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Institute of Metal Research of CAS filed Critical Institute of Metal Research of CAS
Priority to CN201811188174.XA priority Critical patent/CN111039290A/en
Publication of CN111039290A publication Critical patent/CN111039290A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/90—Carbides
    • C01B32/914—Carbides of single elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/90—Carbides
    • C01B32/914—Carbides of single elements
    • C01B32/921—Titanium carbide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/90—Carbides
    • C01B32/914—Carbides of single elements
    • C01B32/949—Tungsten or molybdenum carbides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
    • C01P2004/13—Nanotubes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity

Abstract

The invention relates to the technical field of preparation of transition metal carbide powder materials, in particular to a method for preparing transition metal carbide powder in situ by utilizing molten salt disproportionation reaction. The method comprises the following steps: directly forming a raw material mixture according to the stoichiometric ratio, wherein the structural formula of the transition metal carbide is MxCyWherein M is a transition metal element, and C is carbon; reacting the raw material mixture in molten salt under inert atmosphere, and cooling after the reaction is finished to obtain a product mixture; and removing the molten salt in the product mixture to obtain the transition metal carbide powder. The invention can solve the problems of high synthesis temperature, complex preparation process and equipment and the like of the existing transition metal carbideOne or more of the problems of high cost, uncontrollable appearance and size and the like, and has the advantages of rapidness, high efficiency, energy conservation, environmental protection, low cost, easy realization of large-scale production and the like.

Description

Method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction
Technical Field
The invention relates to the technical field of preparation of transition metal carbide powder materials, in particular to a method for preparing transition metal carbide powder in situ by utilizing molten salt disproportionation reaction.
Background
Transition metal carbides are substances with characteristics of high melting point, high hardness, good electrical and thermal conductivity, high chemical stability, high thermal stability, high mechanical stability and the like, and due to the properties, the transition metal carbides are widely applied to the fields of metallurgy, machinery, electronics, nuclear industry, biological materials, aerospace and the like. In addition, the transition metal carbide has attracted great attention as a new catalytic material in the catalytic discipline due to the unique electronic structure and excellent catalytic performance, and develops a brand new field for the research and development of the transition metal carbide. In many reactions catalyzed by noble metals, the transition metal carbide shows better catalytic activity, which is comparable to noble metals such as platinum, iridium and ruthenium, so the transition metal carbide is also known as a noble metal-like compound. However, powders with desirable size and controlled morphology are the basis for the preparation of the above advanced carbide materials.
At present, the methods for preparing transition metal carbide mainly comprise: high-energy ball milling, self-propagating high-temperature synthesis, laser gas phase reaction, low-temperature synthesis, carbothermic method, chemical vapor deposition method and the like. However, the high energy ball milling method consumes a large amount of energy and is liable to introduce impurities; the self-propagating high-temperature synthesis reaction process is not easy to control, and the performance of the product is influenced; the laser gas phase reaction equipment has expensive raw materials and high production cost; the low-temperature synthesis method has a plurality of influencing factors and unsatisfactory product purity. The raw materials used in the carbothermic reduction reaction are cheap, the production process is simple, and the carbothermic reduction reaction is suitable for industrial production, but the purity of the synthesized powder is not high due to the unsatisfactory uniformity of raw material mixing and incomplete reaction. In addition, the transition metal carbide prepared by the methods is mostly micron-sized powder due to high-temperature sintering, and the morphology of the transition metal carbide is difficult to control due to serious agglomeration among particles.
Disclosure of Invention
The invention aims to provide a method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction with low energy consumption and/or low cost, and solves at least one of the defects in the prior art. For example, one of the objectives of the present invention is to solve one or more of the problems of high synthesis temperature, complex preparation process and equipment, high cost, and difficult control of morphology and size of the existing transition metal carbides.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a method for preparing transition metal carbide powder in situ by utilizing molten salt disproportionation reaction comprises the following steps:
directly mixing a first raw material powder and a second raw material according to the stoichiometric ratio of the transition metal carbide to form a raw material mixture, wherein the first raw material is a carbon material, and the structural formula of the transition metal carbide is MxCyWherein M is a transition metal element, and C is a carbon element;
reacting the raw material mixture in molten salt under an inert atmosphere, and cooling after the reaction is finished to obtain a mixture containing a reaction product and the solid molten salt;
and removing the molten salt in the mixture of the reaction product and the solid molten salt to obtain the transition metal carbide powder.
The method for preparing the transition metal carbide powder in situ by utilizing the molten salt disproportionation reaction obtains the transition metal carbide powder with expected size and shape by controlling the size and shape of the carbon material.
The method for preparing the transition metal carbide powder in situ by utilizing the molten salt disproportionation reaction is characterized in that the transition metal carbide powder with corresponding size is respectively obtained by controlling the size of the carbon material to be millimeter scale, micrometer scale or nanometer scale.
The method for preparing the transition metal carbide powder in situ by utilizing the molten salt disproportionation reaction comprises the step of preparing the first raw material by one or more than two of a nano-scale carbon material, a micron-scale carbon material and a millimeter-scale carbon material.
The method for preparing the transition metal carbide powder in situ by utilizing the molten salt disproportionation reaction comprises the following steps that (1) a simple substance of an element M is used as a second raw material; (2) the simple substance of the element M and chloride salt or fluoride salt of the element M; (3) the simple substance of the element M and ammonium chloride or ammonium fluoride; (4) the simple substance of the element M, the oxide of the element M and chlorine; (5) the simple substance of the element M and at least one selected from the group consisting of oxide of M and hydrogen halide, wherein the hydrogen halide gas is one or two of hydrogen chloride and hydrogen fluoride, and the reaction mode is as follows:
formula 1: m + Mi+→Mj+；
Formula 2: mj++C→Mi++MC；
Wherein M isi+Represents a higher valent ion of M, Mj+Represents an ion of M in an intermediate valence state, and i is greater than j.
The method for preparing the transition metal carbide powder in situ by utilizing the molten salt disproportionation reaction has the reaction temperature of more than 700 ℃.
The method for preparing the transition metal carbide powder in situ by utilizing the molten salt disproportionation reaction has the reaction temperature of 750-1000 ℃.
According to the method for preparing the transition metal carbide powder in situ by utilizing the molten salt disproportionation reaction, the weight of the raw material mixture is 2-80% of the weight of the molten salt.
According to the method for preparing the transition metal carbide powder in situ by utilizing the molten salt disproportionation reaction, the weight of the raw material mixture is 5-60% of the weight of the molten salt.
In the method for preparing the transition metal carbide powder in situ by utilizing the disproportionation reaction of the molten salt, the molten salt is a unitary or binary or above metal chloride or fluoride.
Compared with the prior art, the invention has the advantages and beneficial effects that at least one of the following items is included: the method has the advantages of low raw material cost and process cost, simple process flow, safety, reliability, environmental friendliness, no pollution, convenience for large-scale production, controllable product appearance and size and the like.
Drawings
The above and/or other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 shows a schematic flow diagram of an exemplary embodiment of a transition metal carbide material of the present invention.
Fig. 2 shows an XRD pattern of NbC nanopowders prepared according to an exemplary embodiment of the preparation method of the present invention; in the figure, the abscissa 2 θ represents the diffraction angle (degree) and the ordinate Intensity represents the Intensity.
Fig. 3 shows an SEM image of the NbC nanopowder in fig. 2.
Figure 4 shows a TEM image of the NbC nanotubes of figure 2.
FIG. 5 shows an XRD pattern of a ZrC nanopowder prepared in accordance with another exemplary embodiment of the method of the present invention; in the figure, the abscissa 2 θ represents the diffraction angle (degree) and the ordinate Intensity represents the Intensity.
FIG. 6 shows an SEM image of the ZrC nanopowder in FIG. 5.
FIG. 7 shows Mo produced according to another exemplary embodiment of the method of the present invention2XRD spectrum of powder C; in the figure, the abscissa 2 θ represents the diffraction angle (degree) and the ordinate Intensity represents the Intensity.
FIG. 8 shows Mo in FIG. 72SEM image of C nanopowder.
FIG. 9 shows Cr produced according to yet another exemplary embodiment of a method of the present invention3C2XRD pattern of (a); in the figure, the abscissa 2 θ represents the diffraction angle (degree) and the ordinate Intensity represents the Intensity.
FIG. 10 shows Cr in FIG. 93C2SEM image of the powder;
figure 11 shows an XRD pattern of VC made according to yet another exemplary embodiment of the method of the present invention; in the figure, the abscissa 2 θ represents the diffraction angle (degree) and the ordinate Intensity represents the Intensity.
FIG. 12 shows an XRD pattern of TiC made in accordance with yet another exemplary embodiment of the method of the present invention; in the figure, the abscissa 2 θ represents the diffraction angle (degree) and the ordinate Intensity represents the Intensity.
FIG. 13 shows a TEM image of TiC made according to yet another exemplary embodiment of the method of the present invention.
Figure 14 shows an XRD pattern of TaC made according to yet another exemplary embodiment of a method of the present invention; in the figure, the abscissa 2 θ represents the diffraction angle (degree) and the ordinate Intensity represents the Intensity.
Fig. 15 shows an SEM image of TaC made according to yet another exemplary embodiment of the method of the present invention.
Detailed Description
Hereinafter, the method for preparing the transition metal carbide powder of the present invention will be described in detail with reference to exemplary examples.
FIG. 1 shows a schematic flow diagram of an exemplary embodiment of the method for preparing a transition metal carbide powder according to the invention.
As shown in fig. 1, in one exemplary embodiment of the present invention, the preparation method of the transition metal carbide may be achieved by the following steps:
(1) forming a raw material mixture
Directly mixing a first raw material powder and a second raw material according to the stoichiometric ratio of the transition metal carbide to form a raw material mixture, wherein the first raw material is a carbon material. Wherein the structural formula of the transition metal carbide is MxCyAnd M is a transition metal element. For example, M may be a transition metal element such as scandium (Sc), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), or tungsten (W), and C is a carbon element.
In an exemplary embodiment, the second raw material may be determined in its kind and compounding ratio in the raw material mixture by a stoichiometric ratio of the transition metal carbide, and the second raw material may include one kind of substance or two or more kinds of substances. It is noted that the first and second raw material powders may be mixed directly in forming the raw material mixture without pre-treatment (e.g., ball milling, pre-sintering, press forming) of the raw materials and their mixtures, and without forming precursors. This is favorable to improving production efficiency, reduction in production cost.
Specifically, the raw material mixture can be obtained by directly mixing the powder of the first raw material and the second raw material. The first raw material powder may be a carbon material powder of a nano scale such as graphene, carbon nanotubes, and carbon particles of a nano scale, or may be a carbon material powder of a micro scale, or may be carbon material particles of a millimeter scale. For example, the first raw material powder may be one or more of conductive carbon black, acetylene black, mesoporous carbon, microporous carbon spheres, hierarchical porous carbon, activated carbon, hollow carbon spheres, amorphous carbon, or carbon fibers. The second starting material may be a starting material consisting of (1) an element, M, which itself can be chlorinated or fluorinated to a higher valence state; (2) a chloride salt (or fluoride salt) of an element M with M; (3) the simple substance of the element M and ammonium chloride or ammonium fluoride (the effect of the ammonium chloride or the ammonium fluoride is to corrode the simple substance M to generate high-valence metal ions); (4) the simple substance of the element M reacts with the oxide of M and chlorine (the chlorine reacts with the oxide of M to generate high-valence M ions); (5) the simple substance of the element M and at least one selected from the group consisting of an oxide of M and a hydrogen halide (the hydrogen halide reacts with the oxide of M to generate high-valence M ions), wherein the hydrogen halide gas is one or two of hydrogen chloride and hydrogen fluoride, and the reaction mode is as follows:
formula 1: m + Mi+→Mj+；
Formula 2: mj++C→Mi++MC；
Wherein M isi+Represents a higher valent ion of M, Mj+Represents an ion of M in an intermediate valence state, and i is greater than j.
Specifically, the second raw material may be (1) a simple substance of the element M which itself can be chlorinated or fluorinated into an ionic state; (2) may be a chloride salt (or fluoride salt) of the simple substance of the element M with M; (3) the element M can be a simple substance and ammonium chloride or ammonium fluoride, and the ammonium chloride or ammonium fluoride can corrode the element M to generate metal ions; (4) can be the simple substance of the element M, the oxide of the element M and chlorine, and the chlorine reacts with the simple substance of the element M and/or the oxide of the element M to generate the ion of the metal M; (5) the simple substance of the element M, the oxide of the element M and the hydrogen halide can also be reacted to generate high-valence M ions. The hydrogen halide gas is one or two of hydrogen chloride and hydrogen fluoride. Of course, the second starting material may be a combination of the different species described above. For example, the second raw material may be Nb powder, or Nb powder and NbCl5Powder, or Nb powder and ammonium chloride powder. The second raw material is preferably a powder so that the reaction rate in the molten salt can be further increased, but the present invention is not limited thereto, and the second raw material may not be a powder, and may be, for example, a bulk, a pellet, or the like.
In the exemplary embodiment of the present invention, the first raw material powder is directly mixed with the second raw material without performing operations such as ball milling, high-temperature sintering, or pressing into a precursor, so that production efficiency can be improved, and energy consumption and cost can be reduced. In addition, the inventors have studied and found that a transition metal carbide having a desired size and morphology can be obtained by controlling the size and morphology of the carbon material. For example, if the carbon material in the raw material mixture is controlled to be graphene, a nano-film of a transition metal carbide can be obtained. The carbon material in the raw material mixture is controlled to be a carbon nanotube, and the nanofiber of the transition metal carbide can be obtained. By controlling the carbon material in the raw material mixture to be nano-scale carbon particles, nanoparticles of transition metal carbides can be obtained. In addition, if the first raw material powder is selected as the micron-scale carbon material powder, the transition metal carbide material in the micron scale can be obtained. For example, in one exemplary embodiment, transition metal carbides having corresponding scale levels may be obtained by controlling the size of the carbon material to be in the millimeter scale, the micrometer scale, or the nanometer scale, respectively. Of course, in exemplary embodiments of the present invention, the size of the obtained transition metal carbide material may be comparable to or slightly larger than the size of the first raw material powder, mainly due to, for example, growth and a weak degree of agglomeration during the molten salt reaction.
(2) Reaction in molten salts
And reacting the raw material mixture in molten salt under an inert atmosphere, and cooling after the reaction is finished to obtain a mixture containing a reaction product and solid molten salt. Specifically, an inert atmosphere may be formed using argon or the like in a reaction furnace (e.g., a shaft furnace), and a molten salt in a molten state may be formed in a refractory reaction vessel (e.g., a corundum crucible). Here, the molten salt may be a binary or ternary or higher metal compound molten salt. For example, binary or multi-component metal chloride molten salts, such as LiCl, KCl, CaCl2-NaCl、NaCl-KCl、LiCl-KCl、LiCl-KCl-NaCl、KF-KCl、LiF-KF、LiCl-KCl-CaCl2And the like. However, the present invention is not limited to the above-mentioned chloride or fluoride molten salt, and other metal compound molten salts may be used as long as the present invention can be achievedThe reaction is carried out in a molten salt environment.
Specifically, the reaction temperature of the raw material mixture in the molten salt may be controlled to 700 ℃ or higher. However, the present invention is not limited thereto as long as the reaction can be caused to occur and continue. For example, the reaction temperature may be 750 ℃ to 1000 ℃. The method of the invention has lower reaction temperature, which is beneficial to reducing energy consumption and reducing the requirement of equipment on high temperature resistance, thereby greatly reducing production cost. In addition, in an exemplary embodiment of the present invention, the weight of the raw material mixture may be 2% to 80% of the weight of the molten salt.
(3) Separating and obtaining the target product
And removing the molten salt in the product mixture to obtain the transition metal carbide ceramic material. In particular, molten salts in the product mixture can be removed by cleaning means such as soaking in deionized water, rinsing, etc. to obtain a pure reaction product. Of course, the remainder after the molten salt is removed by cleaning may be dried or baked at a low temperature to obtain the transition metal carbide powder. It should be noted that, although the three steps are performed in sequence in the above exemplary embodiment, the present invention is not limited thereto. For example, in other embodiments of the present invention, the first two steps may be performed simultaneously, or the raw material mixing and the reaction in multiple additions to the molten salt may be performed continuously and repeatedly in an industrial production process.
Exemplary embodiments of the present invention will be further described below with reference to specific examples.
Example 1
In this example, 20 unit weight (e.g., kg) of NaCl-KCl eutectic salt was weighed and mixed with 2 unit weight of Nb powder (400 mesh), 0.34 unit weight of Nb2O5Powder (300 mesh), NaF (1.0 unit weight), and nano C powder (average particle size 50nm) of 0.36 unit weight were mixed, and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 750 deg.C at 5 deg.C/min with a temperature controller, maintaining the temperature for 6h, and cooling to room temperature with the furnace. Subjecting the obtained product toAnd taking out the product, soaking and washing the product by using deionized water to remove residual molten salt, and drying the product at 80 ℃ to obtain the target product NbC.
The obtained target product was tested, and the XRD spectrum and SEM photograph are shown in fig. 2 and 3, respectively. As can be seen from FIGS. 2 and 3, the obtained nano-powder is NbC, and through further detection, the particle size of the NbC nano-powder in the obtained product is 50-80 nm, and the purity is 99.4 wt%.
Example 2
In this example, 50 unit weight of NaCl-KCl eutectic salt was weighed and mixed with 2 unit weight of Nb powder (325 mesh) and 0.7 unit weight of NbCl5The powder and 0.32 unit weight of carbon nanotubes (average diameter 50nm) were mixed, and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 925 deg.C at 8 deg.C/min, holding at this temperature for 5h, and cooling to room temperature. And taking out the obtained product, soaking and washing the product by using deionized water to remove residual molten salt, and drying the product at 100 ℃ to obtain the NbC nanotube, wherein a TEM result is shown in figure 4, the size of the NbC nanotube in the obtained product is equivalent to that of the carbon nanotube in the raw material, and the purity is 95.5 wt%.
Example 3
In this example, 50 unit weight of LiCl-KCl eutectic salt was weighed, mixed with 3.0 unit weight of Zr powder (200 mesh) and 0.4 unit weight of nano-sized acetylene black powder (average particle size 40nm), and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 940 deg.C at a speed of 10 deg.C/min by using a temperature controller, maintaining the temperature for 2h, and cooling to room temperature along with the furnace after power failure. And taking out the obtained product, soaking and washing the product by using deionized water to remove residual molten salt, and drying the product at 80 ℃ to obtain ZrC nano powder.
The obtained target product was tested, and the XRD spectrum and SEM photograph are shown in fig. 5 and 6, respectively. As can be seen from FIGS. 5 and 6, the obtained nano powder is ZrC, and through further detection, the particle size of the ZrC nano powder in the obtained product is 40-60 nm, and the purity is 99.1 wt%.
Example 4
In this example, 30 units of NaCl-CaCl were weighed2Eutectic salt, and 1.6 unit weight of Mo powder (300 mesh), 1.12 unit weight of NH4Cl and 0.2 unit weight of C powder (average particle size 50nm) were mixed, and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 930 deg.C at 10 deg.C/min with a temperature controller, maintaining at this temperature for 3h, and cooling to room temperature with the furnace after power failure. Taking out the obtained product, soaking and washing the product by deionized water to remove residual molten salt, and then drying the product at 120 ℃ to obtain a target product Mo2C, Mo in the obtained product2The granularity of the C powder is 100-250 nm, and the purity is 96.8 wt%.
XRD detection shows that the target product is Mo2C. The obtained target product was subjected to SEM characterization, and the SEM thereof is shown in fig. 8. As can be seen from FIGS. 7 and 8, Mo2C is preferably crystallized.
Example 5
In this example, LiCl-KCl eutectic salt of 20 unit weight was weighed and mixed with Cr powder of 1.3 unit weight (325 mesh) and NH of 0.34 unit weight4Cl and 0.2 unit weight of graphite (average particle size 1 μm) were mixed, and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 920 ℃ by a temperature controller at the speed of 8 ℃/min, preserving heat for 3h at the temperature, and then cooling to room temperature along with the furnace after power failure. Taking out the obtained product, soaking and washing the product by deionized water to remove residual molten salt, and drying the product at 80 ℃ to obtain Cr3C2Cr in the obtained product3C2The granularity of the powder is 1-2 mu m, and the purity is 98 wt%.
XRD detection shows that the target product is Cr3C2. The obtained target product was subjected to SEM characterization, and the SEM thereof is shown in fig. 10.
Example 6
In this example, 30 unit weight of NaCl-KCl eutectic salt was weighed and mixed with 2.6 unit weight of Cr powder (325 mesh) and 2.1 unit weight of CrCl30.4 carbon black (average particle diameter: 200nm) by weightAnd placing the mixture in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 860 deg.C at 8 deg.C/min by using a temperature controller, maintaining the temperature for 5h, and cooling to room temperature with the furnace after power failure. Taking out the obtained product, soaking and washing the product by deionized water to remove residual molten salt, and then drying the product at 120 ℃ to obtain Cr3C2Cr in the obtained product3C2The particle size of the powder is 300-500 nm, and the purity is 99 wt%.
Example 7
In this example, 40 parts by weight of KF-KCl eutectic salt was weighed and mixed with 2.6 parts by weight of Cr powder (325 mesh) and 1.08 parts by weight of Cr powder2O30.25 parts by weight of flake graphite (average particle diameter: 500nm) was mixed, and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 980 deg.C at a speed of 10 deg.C/min by using a temperature controller, maintaining the temperature for 2h, and cooling to room temperature with the furnace after power failure. Taking out the obtained product, soaking and washing the product by deionized water to remove residual molten salt, and drying the product at 80 ℃ to obtain Cr3C2Cr in the obtained product3C2The particle size of the powder is 1-2 μm, and the purity is 99.5 wt%.
Example 8
In this example, 30 unit weight of NaCl-KCl eutectic salt was weighed, mixed with 4.3 unit weight of V powder (300 mesh) and 1.0 unit weight of acetylene black (average particle size 40nm), and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 950 deg.C at 5 deg.C/min with a temperature controller, maintaining the temperature for 4h, and cooling to room temperature with the furnace. And taking out the obtained product, soaking and washing the product by using deionized water to remove residual molten salt, drying the product at 100 ℃, and detecting the product by XRD (X-ray diffraction) as shown in figure 11, wherein the target product is VC nano powder, the granularity of the VC nano powder in the obtained product is 50-80 nm, and the purity of the VC nano powder is 98 wt%.
Example 9
In this example, 60 units of NaCl-KCl eutectic salt was weighed, mixed with 12 units of Ti powder (300 mesh) and 3 units of nano-graphite powder (average particle size 50nm), and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 800 deg.C at 8 deg.C/min by using a temperature controller, maintaining the temperature for 3h, and cooling to room temperature with the furnace after power failure. And taking out the obtained product, soaking and washing the product by using deionized water to remove residual molten salt, and then drying the product at 80 ℃ to obtain TiC nano powder, wherein the XRD result is shown in figure 12, and the TiC nano powder in the obtained product has the granularity of 50nm and the purity of 99.5 wt%.
Example 10
In this example, 30 unit weight of NaCl-KCl eutectic salt was weighed, mixed with 12 unit weight of Ti powder (300 mesh) and 3 unit weight of carbon nanotubes (tube diameter 50nm, tube length 5 to 10 μm), and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 880 ℃ at the speed of 8 ℃/min by using a temperature controller, preserving heat for 3h at the temperature, and then cutting off the power and cooling to room temperature along with the furnace. And taking out the obtained product, soaking and washing the product by using deionized water to remove residual molten salt, and drying the product at 100 ℃ to obtain the TiC nanotube, wherein the TEM result is shown in figure 13, and the pipe diameter of the TiC nanotube in the obtained product is 50 nm.
Example 11
In this example, 80 unit weight of NaCl-KCl-Li eutectic salt was weighed and mixed with 15 unit weight of Ta powder (300 mesh) and 11.2 unit weight of NH4Cl and 1 unit weight of acetylene black (average particle diameter 50nm) were mixed, and the mixture was placed in a corundum crucible. The crucible is placed in a stainless steel reactor, sealed and protected by Ar gas. Heating to 960 deg.C at 5 deg.C/min by using a temperature controller, maintaining the temperature for 5h, and cooling to room temperature with the furnace after power failure. And taking out the obtained product, soaking and washing the product by using deionized water to remove residual molten salt, and drying the product at 100 ℃ to obtain the target product TaC.
The obtained target product was tested, and its XRD spectrum and SEM photograph are shown in fig. 14 and 15, respectively. As can be seen from FIGS. 14 and 15, the obtained nano powder is TaC, and further detection shows that the granularity of the TaC nano powder in the obtained product is 40-80 nm, and the purity is 98.8 wt%.
In addition, the obtained nano-powder such as NbC nano-powder, NbC nano-tube, ZrC nano-powder, TiC nano-tube, VC nano-powder, TaC nano-powder, Mo2C powder and Cr3C2The transition metal carbide such as powder has excellent hydrophilicity and dispersibility. For example, after ultrasonic dispersion in water, no sedimentation occurs for 36 h. In view of the NbC, ZrC, TiC, VC and Mo of the invention2C、Cr3C2The transition metal carbide with nano-scale such as powder has excellent hydrophilicity and dispersibility and good conductivity, so the conductive ceramic material can be widely applied to the field of battery materials. In addition, the method can also prepare high-purity nano powder, nano fiber, nano film, nano block and the like with unique structures.
Furthermore, although NbC nanopowders, NbC nanotubes, ZrC nanopowders, TiC nanotubes, VC nanopowders, Mo are given above2C powder and Cr3C2The preparation of the powder is exemplified, but it should be noted that other types of transition metal carbides can be realized by the above preparation method. For example, Hf, Ta, W, etc. may also be prepared by the above-exemplified method, but the reaction temperature and time of the preparation process thereof may need to be appropriately adjusted with respect to the above-exemplified reaction temperature and time.
In summary, the invention can solve one or more of the problems of high synthesis temperature, complex preparation process and equipment, high cost and the like of the existing transition metal carbide powder, and has the advantages of rapidness, high efficiency, energy conservation, environmental protection, low cost, easy realization of large-scale production and the like, and the detailed effects are described as follows:
1. the conventional transition metal carbide is mostly prepared in a high-pressure or sintering way and the like, so that the preparation temperature is high and the cost is high; the first raw material and the second raw material are directly mixed without operations such as high-temperature sintering or pressing into a precursor, so that the production efficiency can be improved, and the energy consumption and the cost can be reduced.
2. The mixed raw materials are put into molten salt for reaction, and the reaction temperature can be not higher than 1000 ℃ or even as low as 750 ℃. The process has lower reaction temperature, which is beneficial to reducing energy consumption and requirements of equipment on high temperature resistance, thereby greatly reducing production cost. The whole process is safe and reliable, green and pollution-free, and is convenient for large-scale production.
3. The method can prepare the nano-scale transition metal carbide ceramic material (for example, the nano-scale transition metal carbide ceramic powder with the dimension of about 40nm or even smaller), and has wider application range compared with the conventional micron-scale material.
4. The transition metal carbide ceramic material prepared by the invention can be applied to various fields such as conductive additives and/or electrode materials of battery materials, electrode materials of super capacitors, catalysis and the like.
While the present invention has been described above in connection with exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims (10)

1. A method for preparing transition metal carbide powder in situ by utilizing molten salt disproportionation reaction is characterized by comprising the following steps:
directly mixing a first raw material powder and a second raw material according to the stoichiometric ratio of the transition metal carbide to form a raw material mixture, wherein the first raw material is a carbon material, and the structural formula of the transition metal carbide is MxCyWherein M is a transition metal element, and C is a carbon element;
reacting the raw material mixture in molten salt under an inert atmosphere, and cooling after the reaction is finished to obtain a mixture containing a reaction product and the solid molten salt;
and removing the molten salt in the mixture of the reaction product and the solid molten salt to obtain the transition metal carbide powder.
2. The method for preparing transition metal carbide powder in situ using molten salt disproportionation reaction as claimed in claim 1, wherein the method obtains transition metal carbide powder with desired size and morphology by controlling the size and morphology of the carbon material.
3. The method for preparing transition metal carbide powder in situ using molten salt disproportionation reaction according to claim 1, wherein the method obtains transition metal carbide powder with corresponding size by controlling the size of the carbon material to be millimeter scale, micrometer scale or nanometer scale.
4. The method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction according to claim 1, wherein the first raw material is one or more of nano-scale carbon material, micro-scale carbon material and millimeter-scale carbon material.
5. The method for in-situ preparation of transition metal carbide powder using molten salt disproportionation reaction according to claim 1, wherein the second raw material is a mixture of (1) elemental M; (2) the simple substance of the element M and chloride salt or fluoride salt of the element M; (3) the simple substance of the element M and ammonium chloride or ammonium fluoride; (4) the simple substance of the element M, the oxide of the element M and chlorine; (5) the simple substance of the element M and at least one selected from the group consisting of oxide of M and hydrogen halide, wherein the hydrogen halide gas is one or two of hydrogen chloride and hydrogen fluoride, and the reaction mode is as follows:
formula 1: m + Mi+→Mj+；
Formula 2: mj++C→Mi++MC；
Wherein M isi+Represents a higher valent ion of M, Mj+Represents an ion of M in an intermediate valence state, and i is greater than j.
6. The method for preparing transition metal carbide powder in situ using molten salt disproportionation reaction as claimed in claim 1 or 5, wherein the reaction temperature is 700 ℃ or higher.
7. The method for preparing transition metal carbide powder in situ using molten salt disproportionation reaction as claimed in claim 1 or 5, wherein the reaction temperature is 750-1000 ℃.
8. The method for preparing the transition metal carbide powder in situ by molten salt disproportionation reaction according to claim 1, wherein the weight of the raw material mixture is 2-80% of the molten salt in a molten state.
9. The method for preparing the transition metal carbide powder in situ by using molten salt disproportionation reaction according to claim 1, wherein the weight of the raw material mixture is 5-60% of the molten salt in a molten state.
10. The method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction according to claim 1, 5, 8 or 9, wherein the molten salt is a metal chloride or fluoride of unitary or binary or higher.
CN201811188174.XA 2018-10-12 2018-10-12 Method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction Pending CN111039290A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811188174.XA CN111039290A (en) 2018-10-12 2018-10-12 Method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811188174.XA CN111039290A (en) 2018-10-12 2018-10-12 Method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction

Publications (1)

Publication Number Publication Date
CN111039290A true CN111039290A (en) 2020-04-21

Family

ID=70229765

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811188174.XA Pending CN111039290A (en) 2018-10-12 2018-10-12 Method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction

Country Status (1)

Country Link
CN (1) CN111039290A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112591752A (en) * 2020-12-30 2021-04-02 松山湖材料实验室 Rapid preparation of V by molten salt chemical reaction2AlC powder preparation method and powder application thereof
CN112777597A (en) * 2021-03-23 2021-05-11 上海简巨医学生物工程有限公司 Niobium carbide nano material and preparation method thereof
CN112919911A (en) * 2021-04-23 2021-06-08 西安航空学院 SiC/ZrC laminated block composite material and preparation method thereof
CN113136585A (en) * 2021-03-10 2021-07-20 北京工业大学 Method for in-situ synthesis of tungsten carbide powder
CN113174621A (en) * 2021-04-29 2021-07-27 广西大学 Cr (chromium)xCyMethod for preparing ceramic coating

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20030053122A (en) * 2001-12-22 2003-06-28 주식회사 포스코 A method for manufacturing TMCP heavy plate using soft reduction
CN1511803A (en) * 2002-12-27 2004-07-14 石油大学(北京) Method for preparing TiC micro nano ceramic powder via refinery coke salt bath synthesis
CN1751990A (en) * 2005-11-03 2006-03-29 武汉科技大学 Preparation method of transition metal carbide material
CN103556167A (en) * 2013-10-23 2014-02-05 攀钢集团攀枝花钢铁研究院有限公司 Method for preparing titanium carbide through molten salt electrolysis
CN105200458A (en) * 2015-10-27 2015-12-30 攀钢集团攀枝花钢铁研究院有限公司 Method for preparing titanium carbide
CN106430195A (en) * 2016-10-14 2017-02-22 北京大学 MXene material and preparation method and application thereof
CN106463192A (en) * 2014-03-03 2017-02-22 辉光能源公司 Photovoltaic power generation systems and methods regarding same
CN108614023A (en) * 2018-06-05 2018-10-02 西南大学 A kind of preparation and application of Mxene- manganese phosphates combination electrode material

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20030053122A (en) * 2001-12-22 2003-06-28 주식회사 포스코 A method for manufacturing TMCP heavy plate using soft reduction
CN1511803A (en) * 2002-12-27 2004-07-14 石油大学(北京) Method for preparing TiC micro nano ceramic powder via refinery coke salt bath synthesis
CN1751990A (en) * 2005-11-03 2006-03-29 武汉科技大学 Preparation method of transition metal carbide material
CN103556167A (en) * 2013-10-23 2014-02-05 攀钢集团攀枝花钢铁研究院有限公司 Method for preparing titanium carbide through molten salt electrolysis
CN106463192A (en) * 2014-03-03 2017-02-22 辉光能源公司 Photovoltaic power generation systems and methods regarding same
CN105200458A (en) * 2015-10-27 2015-12-30 攀钢集团攀枝花钢铁研究院有限公司 Method for preparing titanium carbide
CN106430195A (en) * 2016-10-14 2017-02-22 北京大学 MXene material and preparation method and application thereof
CN108614023A (en) * 2018-06-05 2018-10-02 西南大学 A kind of preparation and application of Mxene- manganese phosphates combination electrode material

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
TAKEO OKI: "Disproportionation Reaction in Molten Salts and Their Application to Surface Coating Treatment", 《PROCEEDINGS OF THE ELECTROCHEMICAL SOCITY》 *
YU. V. STULOV ET AL.: "Synthesis of chromium carbide coatings on carbon steels in molten salts and their properties", 《GLASS PHYSICS AND CHEMISTRY》 *
李宝让: "《纳米熔盐合成技术》", 30 September 2014 *
肖丹: "Cr2AlC层状陶瓷制备及酸碱腐蚀剥离探索", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 *
闫帅: "熔盐法合成TaC、NaTaO3陶瓷粉体的研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112591752A (en) * 2020-12-30 2021-04-02 松山湖材料实验室 Rapid preparation of V by molten salt chemical reaction2AlC powder preparation method and powder application thereof
CN113136585A (en) * 2021-03-10 2021-07-20 北京工业大学 Method for in-situ synthesis of tungsten carbide powder
WO2022188240A1 (en) * 2021-03-10 2022-09-15 北京工业大学 Method for in-situ synthesis of tungsten carbide powder
CN112777597A (en) * 2021-03-23 2021-05-11 上海简巨医学生物工程有限公司 Niobium carbide nano material and preparation method thereof
CN112919911A (en) * 2021-04-23 2021-06-08 西安航空学院 SiC/ZrC laminated block composite material and preparation method thereof
CN113174621A (en) * 2021-04-29 2021-07-27 广西大学 Cr (chromium)xCyMethod for preparing ceramic coating
CN113174621B (en) * 2021-04-29 2023-06-23 广西大学 Cr (chromium) x C y Preparation method of ceramic coating

Similar Documents

Publication Publication Date Title
CN111039290A (en) Method for preparing transition metal carbide powder in situ by molten salt disproportionation reaction
CN111039291A (en) Method for preparing NbC and/or TaC powder in situ by molten salt disproportionation reaction
Liu et al. Salt melt synthesis of ceramics, semiconductors and carbon nanostructures
Zhang et al. Layer-controllable WS 2-reduced graphene oxide hybrid nanosheets with high electrocatalytic activity for hydrogen evolution
JP5191571B2 (en) Method for producing one or more of silicon nanopowder, silicon nanowire and silicon nanotube by electrochemical method
US20220235474A1 (en) Methods, apparatuses, and electrodes for carbide-to-carbon conversion with nanostructured carbide chemical compounds
CN113880580B (en) High-entropy carbide ultra-high temperature ceramic powder and preparation method thereof
CN110304632A (en) Sheet MXene material and preparation method thereof and energy storage material
Li et al. Coordination complex pyrolyzation for the synthesis of nanostructured GeO 2 with high lithium storage properties
CN111039676A (en) Method for preparing zirconium carbide, hafnium or vanadium powder in situ by utilizing molten salt disproportionation reaction
Yin et al. Highly-reactive Al/CuO nanoenergetic materials with a tubular structure
CN110304922A (en) The preparation method and its energy storage material of polynary conducting ceramic material
BRPI9911008B1 (en) process for the production of metal powder capacitor, niobium powder, capacitor anode, alloy powder for use in electrolytic capacitor manufacturing, process for alloy powder manufacturing
Zou et al. Solid oxide membrane-assisted controllable electrolytic fabrication of metal carbides in molten salt
Li et al. In-situ homogeneous synthesis of carbon nanotubes on aluminum matrix and properties of their composites
Mir et al. A review on recent advances and progress in Mo2C@ C: a suitable and stable electrocatalyst for HER
Yan et al. Molten salt synthesis of titanium carbide using different carbon sources as templates
Kumaresan et al. Single-step synthesis of Mn3N2, MnxON and Mn3O4 nanoparticles by thermal plasma arc discharge technique and their comparative study as electrode material for supercapacitor application
Abdelkader et al. Synthesis of self-passivated, and carbide-stabilized zirconium nanopowder
CN111039675A (en) In-situ preparation of Cr by molten salt3C2And/or Mo2Method for preparing C powder
Shang et al. Synthesis of homogeneous WC–Co nanoparticles using carbon-coated WO2. 72 precursors
CN115717254A (en) Method for preparing high-purity metal niobium by molten salt electrolysis
Khatun Progresses and Challenges in 2D MXenes: Synthesis, Intercalation/Delamination, and Storage
Yu et al. Synthesis methods and surface chemistry/functionalization of MXene
Yuan et al. Titanium nitride nanopowders produced via sodium reductionin liquid ammonia

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination