CN116200638A - Cathode material, preparation method and plasma torch cathode containing cathode material - Google Patents

Cathode material, preparation method and plasma torch cathode containing cathode material Download PDF

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Publication number
CN116200638A
CN116200638A CN202111433116.0A CN202111433116A CN116200638A CN 116200638 A CN116200638 A CN 116200638A CN 202111433116 A CN202111433116 A CN 202111433116A CN 116200638 A CN116200638 A CN 116200638A
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cathode
cathode material
temperature
sintering
plasma torch
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王文阁
胡智峰
张从阳
杨爽
李全
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ENN Science and Technology Development Co Ltd
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ENN Science and Technology Development Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
    • 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
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/105—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
    • 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
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/045—Alloys based on refractory metals
    • C22C1/0458—Alloys based on titanium, zirconium or hafnium
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • 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
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/105—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
    • B22F2003/1051—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding by electric discharge
    • 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
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B22F2009/043—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by ball milling

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  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Plasma & Fusion (AREA)
  • Optics & Photonics (AREA)
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  • Spectroscopy & Molecular Physics (AREA)
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Abstract

The present disclosure relates to a cathode material and a method of making, a plasma torch cathode comprising the same. The cathode material is prepared from metal hafnium and lanthanum hexaboride, wherein the content of the lanthanum hexaboride is 1-8% of the total mass of the preparation raw material. The cathode material provided by the disclosure has higher emitted electron density, lower electron work function, arc stability and high-temperature ablation resistance, and when the cathode material disclosed by the disclosure is applied in a plasma torch, the ablation life of the cathode of the plasma torch can be prolonged to a great extent.

Description

Cathode material, preparation method and plasma torch cathode containing cathode material
Technical Field
The disclosure relates to the technical field of plasma emitters, in particular to a cathode material and a preparation method thereof, and a plasma torch cathode comprising the cathode material.
Background
The plasma torch can generate high-temperature gas through electric arc, can work in oxidation, reduction or inert environment, and can provide heat source for industrial furnaces with various functions such as gasification, cracking, reaction, melting and smelting. Plasma torches consist mainly of an anode, a cathode, and a cooling system, wherein the cathode material is the core component of the plasma torch, which is in direct contact with the gas and receives the impact of positive ions or neutral particles to emit electrons. The quality of the cathode material directly affects the service life of the whole plasma torch, the service life of the cathode material directly affects the economical efficiency of the torch, and the working stability of the cathode material is more relevant to the stability of the whole torch system.
When the working gas of the plasma torch is air, it is called a direct current arc air plasma torch, and when superheated steam is used as the working gas, it is called a steam direct current arc plasma torch, and the generated plasma torch mainly consists of hydrogen and oxygen, which are active components in oxidation reaction. Compared with an air plasma torch (the nitrogen content is as high as 78%, and a large amount of nitrogen oxides are easy to generate), the steam plasma torch eliminates a nitrogen source, does not generate nitrogen oxides, and is a clean heat source which has no harmful substances, zero pollution, environmental protection and energy saving. Meanwhile, the temperature of the steam plasma torch can reach 5000 ℃, and most of high-temperature-resistant materials can be melted and even evaporated. Therefore, the method can be applied to industries such as deep drilling, hazardous waste treatment and the like in the future from the viewpoints of energy enthalpy value, application environment (high pressure, deep layer, high temperature) and the like.
However, due to the different working mediums, the water vapor as a medium brings great challenges to the relevant materials of the plasma torch, especially the cathode material, and the requirements on the system are more severe. Cathode materials developed in aqueous media, such as pure zirconium, pure silver, pure hafnium materials, have a short cathode life, severely restricting the application of the plasma torch, and therefore, development of cathode materials suitable for use in steam plasma torches is highly desired.
Disclosure of Invention
In order to solve the technical problems described above, or at least partially solve the technical problems described above, the present disclosure provides a cathode material and a method of manufacturing the same, and a plasma torch cathode comprising the same.
In a first aspect, the present disclosure provides a cathode material comprising hafnium metal and lanthanum hexaboride (LaB 6 ) The lanthanum hexaboride is present in an amount of 1-8%, e.g., 2%, 3%, 4%, 5%, 6%, 7%, etc., of the total mass of the starting materials.
According to the method, on the basis of using metal hafnium as a cathode material, lanthanum hexaboride is introduced as a doping agent, and a strong covalent bond is formed among B atoms in a lanthanum hexaboride structure, so that a compact space grid can be formed, the electron work function of the cathode material can be reduced, the emission electron density of the cathode material can be improved, meanwhile, the arc stability and high-temperature ablation resistance can be improved, and the ablation life of the cathode material can be prolonged.
Meanwhile, the addition amount of lanthanum hexaboride needs to be within the range of 1-8% defined by the disclosure, and when the addition amount is within the range, the ablation life of the cathode material can be prolonged, and when the addition amount is too large or too small, the ablation life of the cathode material can be reduced.
In order to further increase the ablative lifetime of the cathode material, the present disclosure preferably the lanthanum hexaboride content is 2-5%, e.g., 2.5%, 3%, 3.5%, 4%, 4.5%, etc., more preferably 2-3% of the total mass of the starting materials for preparation.
The present disclosure found that the final cathode material has the highest ablative lifetime when lanthanum hexaboride was added in an amount of 2-3%.
In a second aspect, the present disclosure provides a method for preparing the cathode material according to the first aspect, the method comprising the steps of: and carrying out wet ball milling on the metal hafnium and lanthanum hexaboride, and sintering the mixed powder after ball milling to obtain the cathode material.
As a preferred technical scheme of the present disclosure, the preparation method includes the following steps:
(1) Mixing metal hafnium and lanthanum hexaboride, and sequentially performing wet ball milling, drying and sieving;
(2) Sintering the sieved mixed powder by using a discharge plasma sintering process to obtain the cathode material.
The cathode material prepared by adopting the SPS discharge plasma sintering method has the advantages of higher density (more than 95 percent), uniform structure, strong electron emission capability, brighter electric arc, better and slender arc shape, and more stable arc shape while maintaining good arcing performance, thereby further improving the ablation life of the material.
As a preferred embodiment of the present disclosure, in the wet ball milling, the ball-to-material ratio is (2-5): 1, for example, 3:1.
As a preferred embodiment of the present disclosure, the rotational speed of the ball mill is 200-800rpm, for example 300rpm, 500rpm, 600rpm, etc.
As a preferred technical scheme of the present disclosure, the ball milling time is 30-120min, such as 40min, 60min, 80min, 100min, etc.
As a preferred technical scheme of the present disclosure, the sintering temperature is 1100-1300 ℃, such as 1120 ℃, 1150 ℃, 1180 ℃, 1200 ℃, 1220 ℃, 1250 ℃, 1280 ℃, and the like, and the pressure is 30-50MPa, such as 35MPa, 40MPa, 45MPa, and the like.
As a preferable technical scheme of the present disclosure, in the sintering process, when the difference between the temperature and the set sintering temperature is more than 100 ℃, the temperature rising rate of the sintering is 50-100 ℃/min, such as 60 ℃/min, 70 ℃/min, 80 ℃/min, 90 ℃/min, etc., when the difference between the temperature and the set sintering temperature is less than or equal to 100 ℃, the temperature rising rate is 30-50 ℃/min, such as 35 ℃/min, 40 ℃/min, 45 ℃/min, etc., and after the temperature rising to the set sintering temperature, the temperature is kept for 5-15min, such as 8min, 10min, 12min, etc., so as to complete the sintering.
As a preferred technical solution of the present disclosure, the solvent of the wet ball milling is ethanol, and the drying method includes: drying at 40-45deg.C under vacuum, and drying at 65-70deg.C for more than 12 hr.
The temperature of 40-45deg.C may be 41 deg.C, 42 deg.C, 43 deg.C, 44 deg.C, etc., the temperature of 65-70deg.C may be 66 deg.C, 67 deg.C, 68 deg.C, 69 deg.C, etc., and the time of 12h may be 13h, 15h, 18h, etc.
As a specific implementation method of the present disclosure, the preparation method includes the steps of:
(1) Weighing lanthanum hexaboride in a formula amount, and then weighing metal hafnium powder for three times to gradually mix and dilute the lanthanum hexaboride in a weighing boat so as to mix two materials;
(2) Putting the mixed powder obtained in the step (1) into a ball milling tank, ball milling the mixed powder with a ball material ratio of 3:1 by adopting two zirconium beads with different diameters (mass ratio of 1:1) at a rotating speed of 300-600rpm for 30-120min, and adopting absolute ethyl alcohol as a solvent, wherein the mixed powder is prepared in an argon glove box just without passing the materials and the beads;
(3) Placing the ball-milled material in a vacuum drying oven, firstly drying the material at a low temperature of 45 ℃ until the alcohol volatilizes, and then drying the material at 65 ℃ for more than 12 hours;
(4) Taking out after drying, sieving the materials on a sieving machine by adopting a 200-mesh sieve to ensure the uniformity of the composition of the materials;
(5) Placing the sieved mixed powder into a graphite mould, placing the mould into a cavity sintered by SPS discharge plasma, and sintering and forming by adopting a discharge plasma sintering method, wherein the sintering process is as follows: the sintering temperature is 1100-1200 ℃, the pressure is 30-50MPa, the heating rate is 50-100 ℃/min before the sintering temperature is lower than the set sintering temperature by 100 ℃, and when the sintering temperature reaches the set sintering temperature (within 100 ℃ and including 100 ℃), the cathode material is obtained by heating to 1100-1200 ℃ at 30-50 ℃/min and preserving the temperature for 5-15 min.
In a third aspect, the present disclosure provides a plasma torch cathode comprising the cathode material of the first aspect.
In a fourth aspect, the present disclosure provides a method for preparing the cathode of a plasma torch according to the third aspect, the method comprising: machining the cathode material of the first aspect to obtain a cathode core, and fixing the cathode core on a base to obtain the plasma torch cathode.
As a preferred embodiment of the present disclosure, the machining method includes wire cutting, turning, and polishing.
The cathode material provided by the disclosure can be processed into wires or bars through simple mechanical processing, and then welded on a base, so that the plasma torch cathode can be obtained.
In a fifth aspect, the present disclosure provides a plasma torch comprising the plasma torch cathode of the third aspect.
As a preferred technical solution of the present disclosure, the plasma torch is a plasma water vapor torch.
Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:
(1) The cathode material provided by the disclosure has higher electron emission density, lower electron work function, and also has better arc stability and high-temperature ablation resistance;
(2) When the cathode material disclosed by the disclosure is applied to a plasma torch, the ablation life of the cathode of the plasma torch can be greatly prolonged, and the cathode material is particularly suitable for a plasma water vapor torch.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure.
In order to more clearly illustrate the embodiments of the present disclosure or the solutions in the prior art, the drawings that are required for the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
FIG. 1 is a flow chart of steps of a method of preparing a cathode material according to an embodiment of the present disclosure;
fig. 2 is a back-scattering scanning electron microscope image of a cathode material provided in example 5 of the present disclosure.
Detailed Description
In order that the above objects, features and advantages of the present disclosure may be more clearly understood, a further description of aspects of the present disclosure will be provided below. It should be noted that, without conflict, the embodiments of the present disclosure and features in the embodiments may be combined with each other.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced otherwise than as described herein; it will be apparent that the embodiments in the specification are only some, but not all, embodiments of the disclosure.
Fig. 1 is a step flowchart of a method for preparing a cathode material according to an embodiment of the present disclosure, where the method for preparing a cathode material includes steps S01) to S05):
s01) weighing the formula amount of metal hafnium and lanthanum hexaboride to mix;
in the step, the metal hafnium powder can be weighed for three times, so that the hafnium powder is gradually mixed and diluted in a weighing boat to mix the two materials;
s02) carrying out wet ball milling on the mixed powder;
in the wet ball milling process, two zirconium beads with different diameters (mass ratio of 1:1) are adopted, the ball-to-material ratio is 3:1, the rotating speed is 300-600rpm, the ball milling powder mixing time is 30-120min, absolute ethyl alcohol is adopted as a solvent, and the materials and the beads are just not needed, and the experimental process is prepared in an argon glove box;
s03) drying;
in this step, the drying may be performed in a vacuum drying oven, which is first baked at a low temperature of 45 ℃ until the alcohol is volatilized (the boiling point of alcohol under vacuum is 48 ℃), and then dried at 65 ℃ for more than 12 hours;
s04) sieving;
this step is to ensure uniformity of the particle size of the powder;
s05) sintering and forming by using a discharge plasma sintering method;
the sintering process is as follows: the sintering temperature is 1100-1200 ℃, the pressure is 30-50MPa, the heating rate is 50-100 ℃/min before the sintering temperature is lower than the set sintering temperature by 100 ℃, and when the sintering temperature reaches the set sintering temperature (within 100 ℃ and including 100 ℃), the cathode material is obtained by heating to 1100-1200 ℃ at 30-50 ℃/min and preserving the temperature for 5-15 min.
The following is a more detailed description of specific embodiments.
Example 1
The embodiment provides a cathode material and a preparation method thereof.
(1) Weighing 0.5g of lanthanum hexaboride (with an average particle size of 500 meshes), adding 24.5g of hafnium powder (with an average particle size of 0.8 mu m) three times, gradually mixing the hafnium powder in a weighing boat to dilute the lanthanum hexaboride, and mixing the two materials;
(2) Putting the mixed powder which is primarily mixed into a ball milling tank, adding 75g of zirconium beads with the diameters of 5mm and 1mm (the mass ratio of the zirconium beads with different diameters is 1:1), performing wet ball milling by using absolute ethyl alcohol as a solvent, wherein the rotating speed is 400rpm, and the ball milling powder mixing time is 60min;
(3) Then placing the mixture in a vacuum drying oven, firstly drying the mixture at a low temperature of 45 ℃ until the alcohol volatilizes, and then drying the mixture at 65 ℃ for more than 12 hours;
(4) Sieving with 200 mesh sieve;
(5) Placing the sieved mixed powder into a graphite mould, placing the mould into an SPS plasma sintering cavity, and performing sintering molding by adopting a spark plasma sintering method, wherein the sintering process is as follows: the sintering temperature is 1200 ℃, the pressure is 30MPa, the heating rate is 80 ℃/min when the temperature is less than 1100 ℃ and is 40 ℃/min when the temperature is more than or equal to 1100 ℃ in the sintering process, and then the cathode material is obtained after the temperature reaches 1200 ℃ and is preserved for 10 min.
Examples 2 to 4
The embodiment provides a cathode material and a preparation method thereof.
The difference from example 1 is that in this example, the mass percentage of lanthanum hexaboride in the raw material was changed to 1wt% (example 2), 4wt% (example 3) and 8wt% (example 4).
Example 5
The embodiment provides a cathode material and a preparation method thereof.
(1) Weighing 1.25g of lanthanum hexaboride, adding 23.75g of hafnium powder in three times, gradually mixing the hafnium powder in a weighing boat to dilute the lanthanum hexaboride, and mixing the two materials;
(2) Putting the mixed powder which is primarily mixed into a ball milling tank, adding 75g of zirconium beads with the diameters of 5mm and 1mm (the mass ratio of the zirconium beads with different diameters is 1:1), performing wet ball milling by using absolute ethyl alcohol as a solvent, wherein the rotating speed is 500rpm, and the ball milling powder mixing time is 60min;
(3) Then placing the mixture in a vacuum drying oven, firstly drying the mixture at a low temperature of 45 ℃ until the alcohol volatilizes, and then drying the mixture at 65 ℃ for more than 12 hours;
(4) Sieving with 200 mesh sieve;
(5) Placing the sieved mixed powder into a graphite mould, placing the mould into an SPS plasma sintering cavity, and performing sintering molding by adopting a spark plasma sintering method, wherein the sintering process is as follows: the sintering temperature is 1150 ℃, the pressure is 30MPa, the heating rate is 80 ℃/min when the temperature is less than 1050 ℃ and 40 ℃/min when the temperature is more than or equal to 1050 ℃ in the sintering process, and then the cathode material is obtained after the temperature reaches 1150 ℃ and the temperature is kept for 10 min.
Example 6
The embodiment provides a cathode material and a preparation method thereof.
(1) Weighing 0.75g of lanthanum hexaboride, adding 24.25g of hafnium powder three times, gradually mixing the hafnium powder in a weighing boat to dilute the lanthanum hexaboride, and mixing the two materials;
(2) Putting the mixed powder which is primarily mixed into a ball milling tank, adding 75g of zirconium beads with the diameters of 5mm and 1mm (the mass ratio of the zirconium beads with different diameters is 1:1), performing wet ball milling by using absolute ethyl alcohol as a solvent, wherein the rotating speed is 800rpm, and the ball milling powder mixing time is 60min;
(3) Then placing the mixture in a vacuum drying oven, firstly drying the mixture at a low temperature of 45 ℃ until the alcohol volatilizes, and then drying the mixture at 65 ℃ for more than 12 hours;
(4) Sieving with 200 mesh sieve;
(5) Placing the sieved mixed powder into a graphite mould, placing the mould into an SPS plasma sintering cavity, and performing sintering molding by adopting a spark plasma sintering method, wherein the sintering process is as follows: the sintering temperature is 1300 ℃, the pressure is 30MPa, the heating rate is 80 ℃/min when the temperature is less than 1200 ℃ in the sintering process, the heating rate is 40 ℃/min when the temperature is more than or equal to 1200 ℃, and then the cathode material is obtained after the temperature reaches 1300 ℃ and the temperature is kept for 10 min.
Comparative example 1
This comparative example provides a cathode material and a method of preparing the same.
The difference from example 1 is that in this comparative example, only the mass percentage of lanthanum hexaboride in the preparation raw material was changed to 0.5wt%.
Comparative example 2
This comparative example provides a cathode material and a method of preparing the same.
(1) Weighing 2.5g of lanthanum hexaboride, adding 22.5g of hafnium powder in three times, gradually mixing the hafnium powder in a weighing boat to dilute the lanthanum hexaboride, and mixing the two materials;
(2) Putting the mixed powder which is primarily mixed into a ball milling tank, adding 75g of zirconium beads with the diameters of 5mm and 1mm (the mass ratio of the zirconium beads with different diameters is 1:1), performing wet ball milling by using absolute ethyl alcohol as a solvent, wherein the rotating speed is 500rpm, and the ball milling powder mixing time is 60min;
(3) Then placing the mixture in a vacuum drying oven, firstly drying the mixture at a low temperature of 45 ℃ until the alcohol volatilizes, and then drying the mixture at 65 ℃ for more than 12 hours;
(4) Sieving with 200 mesh sieve;
(5) Placing the sieved mixed powder into a graphite mould, placing the mould into an SPS plasma sintering cavity, and performing sintering molding by adopting a spark plasma sintering method, wherein the sintering process is as follows: the sintering temperature is 1200 ℃, the pressure is 30MPa, the heating rate is 80 ℃/min when the temperature is less than 1100 ℃ and is 40 ℃/min when the temperature is more than or equal to 1100 ℃ in the sintering process, and then the cathode material is obtained after the temperature reaches 1200 ℃ and is preserved for 10 min.
Comparative example 3
This comparative example provides a cathode material and a method of preparing the same.
The only difference from example 1 is that in this comparative example, the cathode material was prepared starting from only metallic hafnium, i.e. lanthanum hexaboride was replaced with metallic hafnium Hf of equal mass.
Performance testing
(1) The cathode material provided in one of the examples was randomly selected and its back-scattered pattern was observed by a scanning electron microscope, and the result was as follows:
FIG. 2 is a back-scattered electron microscope image of the cathode material provided in example 5, in which there is a clear contrast, light gray is hafnium, dark gray is hafnium-lanthanum alloy phase, black material is boron-rich region, and interface between hafnium-based and lanthanum-rich phase is clear.
(2) The cathode materials provided in examples 1 to 6 and comparative examples 1 to 3 were subjected to the same machining methods (wire cutting, turning and metallographic polishing) to obtain cathode cores, which were 16mm long, and then the cathode cores were air-welded on a copper base to obtain plasma torch cathodes, which were tested on a steam torch;
ablation lifetime: the ETP00 plasma torch device is adopted for testing, the test is carried out under the power of 2kW, the water vapor flow is 4.5-6.5mL/min, in order to ensure the continuous operation of the test, the chromatographic pump with high-precision control flow is adopted for continuous water supply, and the water supply flow is set to be 4.5-6.8mL/min.
High temperature ablation resistance: the ablative life of the cathode core per unit length.
The test results are shown in Table 1:
TABLE 1
Figure BDA0003380979050000101
Examples and performance tests show that the cathode material provided by the present disclosure has a higher ablation life, preferably up to more than 98h, most preferably up to more than 100h, and also has higher high temperature ablation resistance.
As can be seen from the comparison of examples 1-6, in the cathode material disclosed by the invention, when the addition amount of lanthanum hexaboride is 2-5%, the ablation life of the cathode of the plasma torch can be obviously improved, and can reach more than 98 hours, and the ablation life is obviously improved; when the adding amount of lanthanum hexaboride is 2-3%, the ablation life of the cathode of the plasma torch can optimally reach more than 100 hours.
As can be seen from the comparison of the example 1 and the comparative examples 1-2, when the addition amount of lanthanum hexaboride is too large or too small, not only the ablation life of the cathode material is not increased, but also the decrease of the ablation life of the cathode material is affected; as can be seen from the comparison of the example 1 and the comparative example 3, the use of hafnium metal and lanthanum hexaboride as the raw materials for preparing the cathode material can obviously prolong the ablation life of the plasma cathode, and also improve the high-temperature ablation resistance.
It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is merely a specific embodiment of the disclosure to enable one skilled in the art to understand or practice the disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown and described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The cathode material is characterized in that the preparation raw materials of the cathode material comprise metal hafnium and lanthanum hexaboride, and the content of the lanthanum hexaboride is 1-8% of the total mass of the preparation raw materials.
2. Cathode material according to claim 1, characterized in that the lanthanum hexaboride content is 2-5%, further preferably 2-3% of the total mass of the preparation raw material.
3. A method for producing a cathode material according to claim 1 or 2, characterized in that the method comprises the steps of: and carrying out wet ball milling on the metal hafnium and lanthanum hexaboride, and sintering the mixed powder after ball milling to obtain the cathode material.
4. A method of preparation according to claim 3, characterized in that the method of preparation comprises the steps of:
(1) Mixing metal hafnium and lanthanum hexaboride, and sequentially performing wet ball milling, drying and sieving;
(2) Sintering the sieved mixed powder by using a discharge plasma sintering process to obtain the cathode material.
5. The method according to claim 3 or 4, wherein in the wet ball milling, the ball-to-material ratio is (2-5): 1;
and/or the rotation speed of the ball milling is 200-800rpm;
and/or the ball milling time is 30-120min.
6. The method according to claim 3 or 4, wherein the sintering temperature is 1100-1300 ℃ and the pressure is 30-50MPa;
preferably, in the sintering process, when the difference between the temperature and the set sintering temperature is more than 100 ℃, the temperature rising rate of sintering is 50-100 ℃/min, when the difference between the temperature and the set sintering temperature is less than or equal to 100 ℃, the temperature rising rate is 30-50 ℃/min, and after the temperature rises to the set sintering temperature, the temperature is kept for 5-15min, so that sintering is completed.
7. The method according to claim 4, wherein the solvent for wet ball milling is ethanol, and the drying method comprises: drying at 40-45deg.C under vacuum, and drying at 65-70deg.C for more than 12 hr.
8. A plasma torch cathode comprising the cathode material of claim 1 or 2.
9. The method of preparing a plasma torch cathode of claim 8, comprising: machining the cathode material of claim 1 or 2 to obtain a cathode core, and fixing the cathode core on a base to obtain the plasma torch cathode.
10. A plasma torch comprising the plasma torch cathode of claim 8.
CN202111433116.0A 2021-11-29 2021-11-29 Cathode material, preparation method and plasma torch cathode containing cathode material Pending CN116200638A (en)

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JPH0525579A (en) * 1991-07-16 1993-02-02 Mitsubishi Heavy Ind Ltd Electrode material for plasma cutting
JPH06200360A (en) * 1991-05-07 1994-07-19 Mitsubishi Heavy Ind Ltd Plasma electrode material
JPH10158822A (en) * 1996-12-06 1998-06-16 Ulvac Japan Ltd Hollow cathode for generating plasma
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CN111825463A (en) * 2020-06-29 2020-10-27 井冈山大学 LaB6-CrB2Composite cathode material and preparation method thereof
CN112481538A (en) * 2019-09-12 2021-03-12 新奥科技发展有限公司 Cathode material and preparation method thereof, plasma torch cathode and preparation method thereof
CN112974834A (en) * 2019-12-16 2021-06-18 新奥科技发展有限公司 Plasma torch cathode material precursor powder, preparation method thereof and plasma torch cathode

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JPH06200360A (en) * 1991-05-07 1994-07-19 Mitsubishi Heavy Ind Ltd Plasma electrode material
JPH0525579A (en) * 1991-07-16 1993-02-02 Mitsubishi Heavy Ind Ltd Electrode material for plasma cutting
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