CN111039675A - In-situ preparation of Cr by molten salt3C2And/or Mo2Method for preparing C powder - Google Patents

In-situ preparation of Cr by molten salt3C2And/or Mo2Method for preparing C powder Download PDF

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CN111039675A
CN111039675A CN201811188190.9A CN201811188190A CN111039675A CN 111039675 A CN111039675 A CN 111039675A CN 201811188190 A CN201811188190 A CN 201811188190A CN 111039675 A CN111039675 A CN 111039675A
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molten salt
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刘会军
杨凌旭
曾潮流
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Institute of Metal Research of CAS
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
    • C04B35/5607—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on refractory metal carbides
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    • C04B35/62605—Treating the starting powders individually or as mixtures
    • C04B35/62645—Thermal treatment of powders or mixtures thereof other than sintering
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Abstract

The invention relates to the technical field of preparation of transition metal carbide powder materials, in particular to in-situ preparation of Cr by utilizing molten salt disproportionation reaction3C2And/or Mo2And (C) powder preparation. 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 Cr and/or Mo, 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; removing molten salt in the product mixture to obtain Cr3C2And/or Mo2C, powder material. The invention can solve one or more problems of high synthesis temperature, complex preparation process and equipment, high cost, uncontrollable appearance and size and the like of the existing transition metal carbide, and has the advantages of high speed, high efficiency, energy conservation, environmental protection,Low cost, easy realization of large-scale production and the like.

Description

In-situ preparation of Cr by molten salt3C2And/or Mo2Method for preparing C powder
Technical Field
The invention relates to the technical field of preparation of transition metal carbide powder materials, in particular to in-situ preparation of Cr by utilizing molten salt disproportionation reaction3C2And/or Mo2And (C) powder preparation.
Background
Transition metal carbide Cr3C2And/or Mo2C is a kind of material with high melting point, high hardness, good electric and thermal conductivityChemical stability, and extremely high thermal and mechanical stability, it is these properties that make them widely used in the fields of metallurgy, machinery, electronics, nuclear industry, biomaterials, and aerospace. 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, Cr is prepared3C2And/or Mo2The method C mainly comprises the following steps: high-energy ball milling, self-propagating high-temperature synthesis, laser gas phase reaction, low-temperature synthesis, carbothermic reduction method, chemical vapor deposition method, high-energy ball milling and molten salt 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 Cr in situ by molten salt disproportionation reaction with low energy consumption and/or low cost3C2And/or Mo2The method of C powder solves at least one of the above disadvantages in the prior art. For example, one of the objects of the present invention is to solve the conventional Cr3C2And/or Mo2High C synthesis temperatureThe preparation process and equipment are complex, the cost is high, the appearance and the size are difficult to control, and the like.
In order to achieve the purpose, the technical scheme of the invention is as follows:
cr in-situ preparation method by utilizing molten salt3C2And/or Mo2The method for preparing the C powder comprises the following steps:
directly mixing first raw material powder and second raw material according to the stoichiometric ratio of transition metal carbide to form a raw material mixture, wherein the first raw material is carbon material, the second raw material contains two valence states of Cr and/or two valence states of Mo capable of carrying out disproportionation reaction, and the structural formula of the transition metal carbide is MxCyWherein M is a transition metal element Cr and/or Mo, 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;
removing the molten salt in the mixture of the reaction product and the solid molten salt to obtain Cr3C2And/or Mo2And C, powder.
The Cr is prepared by utilizing the molten salt in situ3C2And/or Mo2C powder method, which obtains Cr with desired size and morphology by controlling size and morphology of the carbon material3C2And/or Mo2And C, powder.
The Cr is prepared by utilizing the molten salt in situ3C2And/or Mo2C powder preparation method, which respectively obtains Cr with corresponding size by controlling the size of the carbon material to be millimeter scale, micron scale or nanometer scale3C2And/or Mo2And C, powder.
The Cr is prepared by utilizing the molten salt in situ3C2And/or Mo2The first material is one or more of nano carbon material, micron carbon material and millimeter carbon material.
The said advantageIn-situ preparation of Cr from molten salt3C2And/or Mo2The second raw material is a chloride salt or fluoride salt of (1) M and M; (2) the simple substance of M and ammonium chloride or ammonium fluoride; (3) the simple substance of M, the oxide of M and chlorine; (4) the simple substance of M and at least one selected from the group consisting of oxide of M and hydrogen halide, wherein the hydrogen halide-containing gas is one or more 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 Cr is prepared by utilizing the molten salt in situ3C2And/or Mo2The reaction temperature of the C powder is over 800 ℃.
The Cr is prepared by utilizing the molten salt in situ3C2And/or Mo2C powder, the reaction temperature is 850-1000 ℃.
The Cr is prepared by utilizing the molten salt in situ3C2And/or Mo2And C, in the method for preparing the powder C, the weight of the raw material mixture is 2-80% of the weight of the molten salt.
The Cr is prepared by utilizing the molten salt in situ3C2And/or Mo2The weight of the raw material mixture is 5-60% of the weight of the molten salt.
The Cr is prepared by utilizing the molten salt in situ3C2And/or Mo2The fused salt is a monobasic or binary or above metal chloride or fluoride fused salt.
Compared with the prior art, the invention has the advantages and beneficial effects that at least one of the following items is included: the raw material cost and the process cost are low, the process flow is simple, safe and reliable, green and pollution-free, and the like, and is convenient for large-scale production.
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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 Cr prepared according to an exemplary embodiment of the preparation method of the present invention3C2XRD spectrum of the powder; in the figure, the abscissa 2 θ represents the diffraction angle (degree) and the ordinate Intensity represents the Intensity.
FIG. 3 shows Cr in FIG. 23C2SEM image of powder.
FIG. 4 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. 5 shows Mo in FIG. 52SEM image of powder C.
Detailed Description
Hereinafter, Cr of the present invention will be described in detail with reference to exemplary embodiments3C2And/or Mo2A preparation method of C powder.
FIG. 1 shows Cr of the present invention3C2And/or Mo2A schematic flow diagram of an exemplary embodiment of a method for preparing powder C.
As shown in FIG. 1, in one exemplary embodiment of the invention, Cr3C2And/or Mo2The preparation method of C can be realized by the following steps:
(1) forming a raw material mixture
According to Cr3C2And/or Mo2And C, directly mixing the first raw material powder and the second raw material to form a raw material mixture, wherein the first raw material is a carbon material.
In one exemplary embodiment, the second raw material may be Cr3C2And/or Mo2The stoichiometric ratio of C determines the type and proportion of C in the mixture of the raw materials, and the second raw material may comprise one substance or more than two substances. It is noted that the source is formedIn the process of mixing the materials, the first raw material powder and the second raw material powder can be directly mixed without performing pretreatment (such as ball milling, presintering and compression molding) on the raw materials and the mixture thereof and forming a precursor. 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, for example: the carbon material powder of nano-scale such as graphene, carbon nanotubes, and carbon particles of nano-scale may be carbon material powder of micron-scale or carbon material particles of 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 raw material contains two valence states of Cr and/or two valence states of Mo which can be subjected to disproportionation reaction. For example, the second raw material may be at least one selected from the group consisting of (1) a chloride salt (or a fluoride salt) of M, an element of M, ammonium chloride or ammonium fluoride (the action of ammonium chloride or ammonium fluoride corrodes the element of M to generate high-valence M ions), an element of M, an oxide of M, chlorine gas (the action of chlorine gas and the oxide of M to generate high-valence M ions), an element of M, an oxide of M, and hydrogen halide (the action of hydrogen halide and the oxide of M to generate high-valence M ions), wherein the hydrogen halide gas is one or both of hydrogen chloride and hydrogen fluoride, and the reaction 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.
For example, in the case of preparing chromium carbide, the second raw material may be (1) Cr powder and CrCl3Powder, (2) Cr powder and ammonium chloride powder, (3) Cr powder and ammonium fluoride powder, (4) Cr powder and chromic oxide powder, chlorine gas is introduced into the molten salt at the same time, and (5) Cr powder and chromic oxide powder, and one or more of hydrogen halide and the like are introduced into the molten salt at the same timeAnd (4) seed preparation. In the preparation of molybdenum carbide, the second raw material may be (1) Mo powder and MoCl5The method comprises the following steps of (1) mixing the raw materials, (2) Mo powder and ammonium chloride powder, (3) Mo powder and ammonium fluoride powder, (4) mixing the Mo powder and molybdenum trioxide powder, introducing chlorine gas into the molten salt, and simultaneously introducing one or more of (5) the Mo powder and the molybdenum trioxide powder, and introducing hydrogen halide gas into the molten salt, wherein the hydrogen halide gas is one or two of hydrogen chloride and hydrogen fluoride. 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 Cr having a desired size and morphology can be obtained by controlling the size and morphology of the carbon material3C2And/or Mo2And C, powder. For example, if the carbon material in the raw material mixture is controlled to graphene, Cr can be obtained3C2And/or Mo2C, a nano-film. By controlling the carbon material in the raw material mixture to be carbon nanotubes, Cr can be obtained3C2And/or Mo2C, a nanofiber. Cr can be obtained by controlling the carbon material in the raw material mixture to be nano-scale carbon particles3C2And/or Mo2C. In addition, if the first raw material powder is selected as the carbon material powder of the micrometer scale, Cr in the micrometer scale can be obtained3C2And/or Mo2C, powder material. For example, in one exemplary embodiment, Cr having a corresponding scale level may be obtained by controlling the size of the carbon material to be in a millimeter scale, a micrometer scale, or a nanometer scale, respectively3C2And/or Mo2C. Of course, in exemplary embodiments of the present invention, Cr is obtained3C2And/or Mo2The size of C will be comparable to or slightly larger than the size of the first feedstock powder, mainly due to, for example, growth during the molten salt reactionLong and weak degrees of agglomeration.
(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, molten salts of binary or multi-component metal chlorides and/or fluorides, 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 this chloride or fluoride molten salt, and as for other metal compound molten salts, as long as a molten salt environment that can provide melting for the reaction of the present invention is provided.
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
Removing the molten salt in the product mixture to obtain Cr3C2And/or Mo2C 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 can be dried or baked at low temperature to obtain Cr3C2And/or Mo2And C, 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.
The present invention will be further described with reference to the following specific examples.
Example 1
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. 3.
Example 2
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 parts by weight of carbon black (average particle diameter: 200nm) 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 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 3
This implementationIn the example, 40 unit weight of KF-KCl eutectic salt was weighed and mixed with 2.6 unit weight of Cr powder (325 mesh) and 1.08 unit 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 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. 5. As can be seen from FIGS. 4 and 5, Mo2C is preferably crystallized.
Example 5
In this example, 40 unit weight of NaCl-KCl eutectic salt was weighed and mixed with 1.3 unit weight of Cr powder (325 mesh) and 1.05 unit weight of CrCl31.6 Mo powder (300 mesh) in unit weight, 1.12 NH in unit weight4Cl and 0.4 unit weight of carbon black (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. Using a temperature controller to rise at a speed of 8 ℃/minThe temperature is increased to 920 ℃, the temperature is kept for 5 hours, and then the furnace is cooled to the room temperature 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 100 ℃ to obtain Cr3C2And Mo2And C, the granularity of powder in the obtained product is 100-300 nm, and the purity is 98.5 wt%.
In addition, the resultant Cr such as3C2Powder and Mo2The C powder and the like have excellent hydrophilicity and dispersibility. For example, after ultrasonic dispersion in water, no sedimentation occurs for 36 h. In view of the Cr of the present invention3C2Powder and Mo2The C powder and the like have 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.
In conclusion, the invention can solve the problem of the existing Cr3C2And/or Mo2The method has the advantages of high synthesis temperature of the C powder, complex preparation process and equipment, high cost and the like, and has the advantages of rapidness, high efficiency, energy conservation, environmental protection, low cost, easiness in realizing large-scale production and the like, and the detailed effects are described as follows:
1. conventional Cr3C2And/or Mo2The preparation of C mostly adopts high pressure or sintering and other modes, 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 reducing the requirement of equipment on high temperature resistance, thereby greatly reducing production cost, and the whole process is safe and reliable, green and pollution-free and is convenient for large-scale production.
3. The method of the invention can prepare the nanometer rulerDegree of Cr3C2And/or Mo2Cceramic material (e.g., nanoscale Cr with dimensions of about 40nm or even less3C2And/or Mo2C ceramic powder) has a wider application range compared with the conventional micron-sized material.
4. Cr prepared by the invention3C2And/or Mo2The C ceramic material can be applied to various fields such as conductive additives and/or electrode materials of battery materials, electrode materials of supercapacitors, 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. Cr in-situ preparation method by utilizing molten salt3C2And/or Mo2The method for preparing the C powder is characterized by comprising the following steps:
directly mixing first raw material powder and second raw material according to the stoichiometric ratio of transition metal carbide to form a raw material mixture, wherein the first raw material is carbon material, the second raw material contains two valence states of Cr and/or two valence states of Mo capable of carrying out disproportionation reaction, and the structural formula of the transition metal carbide is MxCyWherein M is a transition metal element Cr and/or Mo, 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;
removing the molten salt in the mixture of the reaction product and the solid molten salt to obtain Cr3C2And/or Mo2And C, powder.
2. The in-situ preparation of Cr using molten salt according to claim 13C2And/or Mo2A method of producing C powder, characterized in that the method is carried out by controlling the size and shape of the carbon materialMorphology to obtain Cr of desired size and morphology3C2And/or Mo2And C, powder.
3. The in-situ preparation of Cr using molten salt according to claim 13C2And/or Mo2The method for preparing the C powder is characterized in that the method respectively obtains Cr with corresponding size by controlling the size of the carbon material to be millimeter scale, micron scale or nanometer scale3C2And/or Mo2And C, powder.
4. The in-situ preparation of Cr using molten salt according to claim 13C2And/or Mo2The method for preparing the carbon powder is characterized in that the first raw material is one or more than two of a nano-scale carbon material, a micron-scale carbon material and a millimeter-scale carbon material.
5. The in-situ preparation of Cr using molten salt according to claim 13C2And/or Mo2The method for preparing the C powder is characterized in that the second raw material is a mixture of (1) a simple substance of M and a chloride salt or fluoride salt of M; (2) the simple substance of M and ammonium chloride or ammonium fluoride; (3) the simple substance of M, the oxide of M and chlorine; (4) the simple substance of M and at least one selected from the group consisting of oxide of M and hydrogen halide, wherein the hydrogen halide-containing gas is one or more 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. In-situ Cr preparation by molten salt according to claim 1 or 53C2And/or Mo2The method of C powder is characterized in that the reaction temperature is above 800 ℃.
7. In-situ Cr preparation by molten salt according to claim 1 or 53C2And/or Mo2The method of C powder is characterized in that the reaction temperature is 850-1000 ℃.
8. The in-situ preparation of Cr using molten salt according to claim 13C2And/or Mo2The method for preparing the C powder is characterized in that the weight of the raw material mixture is 2-80% of the weight of the molten salt.
9. The in-situ preparation of Cr using molten salt according to claim 13C2And/or Mo2The method for preparing the C powder is characterized in that the weight of the raw material mixture is 5-60% of the weight of the molten salt.
10. In-situ Cr production using molten salts according to claims 1, 5, 8 or 93C2And/or Mo2The method for preparing the C powder is characterized in that the molten salt is a monobasic or binary or above metal chloride or fluoride molten salt.
CN201811188190.9A 2018-10-12 2018-10-12 In-situ preparation of Cr by molten salt3C2And/or Mo2Method for preparing C powder Pending CN111039675A (en)

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