CN112170862A - Preparation method of silver-tungsten contact material - Google Patents
Preparation method of silver-tungsten contact material Download PDFInfo
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- CN112170862A CN112170862A CN202011059844.5A CN202011059844A CN112170862A CN 112170862 A CN112170862 A CN 112170862A CN 202011059844 A CN202011059844 A CN 202011059844A CN 112170862 A CN112170862 A CN 112170862A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/16—Making metallic powder or suspensions thereof using chemical processes
- B22F9/30—Making metallic powder or suspensions thereof using chemical processes with decomposition of metal compounds, e.g. by pyrolysis
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/14—Treatment of metallic powder
- B22F1/145—Chemical treatment, e.g. passivation or decarburisation
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- 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
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- 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
- C22C1/0475—Impregnated alloys
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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
- C22C27/04—Alloys based on tungsten or molybdenum
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/02—Contacts characterised by the material thereof
- H01H1/021—Composite material
- H01H1/023—Composite material having a noble metal as the basic material
Abstract
The invention discloses a preparation method of a silver-tungsten contact material, which comprises the step of obtaining a pressed compact, and is characterized in that the step of obtaining the pressed compact comprises the following steps: soaking tungsten powder with silver nitrate solution, drying the obtained mixed material, performing thermal decomposition reaction, crushing, reducing, and pressing the obtained silver-tungsten mixed powder to obtain a pressed blank; wherein the silver nitrate solution is a silver nitrate aqueous solution. The method has the advantages of simple process, short production period, low molding difficulty, uniform metallographic structure of the obtained contact, higher density and hardness and lower resistivity.
Description
Technical Field
The invention relates to a preparation method of a contact material, in particular to a preparation method of a silver-tungsten contact material.
Background
In the contact industry, a common silver-tungsten contact with low tungsten content (20-40%) is produced by a pressing-sintering-repressing process to obtain a contact with high density and meeting the performance requirements of an electric appliance; the silver-tungsten contact with high tungsten content (50-80%) is difficult to meet the requirements of electric appliances because the difficulty of press forming is multiplied due to the increase of the tungsten content, so that the silver-tungsten contact with high density cannot be obtained, and the performance of the contact is linearly reduced, therefore, the silver-tungsten contact with high tungsten content usually needs to be processed by adopting an infiltration process to obtain a high-density contact with excellent performance.
In the infiltration process, the tungsten powder is usually pressed and molded to produce a tungsten skeleton, and then the skeleton and the needed silver infiltration blocks are put into a high-temperature furnace together for infiltration, so that the silver infiltration blocks are melted and infiltrated into the tungsten skeleton to fill the pores in the skeleton. Infiltration generally has two requirements on the framework: firstly, the strength is enough, and the cracking and the scattering of the frame cannot occur; and secondly, the total volume of the reserved pores in the framework can just contain the silver amount in the required contact material components, such as silver tungsten (65).
In the silver-tungsten contact material with high tungsten content, the original particle size of tungsten powder directly influences the formability of a framework and the permeability of subsequent infiltration, and when the tungsten particles are finer, such as 1um or below, the framework is difficult to form, and the silver-tungsten contact close to compactness is difficult to obtain through infiltration. For tungsten powder with thicker particles, such as 3um and above, the permeability during infiltration is better, a silver-tungsten contact close to compact can be obtained more easily, but limited by the final component proportion of the contact material, the tungsten powder with thicker particles can not be processed without limit in order to obtain the silver-tungsten contact close to compact, because the thicker tungsten powder is selected to form a framework, the framework needs to be pressed to be more compact to ensure that the framework has enough strength, so the total volume of pores in the framework is reduced, the amount of silver which can be infiltrated during infiltration is reduced, and the final proportion of silver and tungsten components after infiltration can not be ensured to meet the requirements. Nevertheless, coarse-grained carbide powder is still the simplest way to obtain a nearly dense silver-tungsten contact after infiltration. Therefore, when former people select tungsten powder with coarse particles to form the framework, a small amount of silver (usually not more than 20 wt% based on the raw material silver-tungsten mixed powder for obtaining the infiltration framework) is added into the tungsten powder in advance to improve the formability of the framework and ensure that the qualified infiltration framework is obtained.
At present, there are two common methods for pre-adding silver to tungsten powder, one of which is to uniformly add silver to the surface of tungsten powder particles in a desired ratio by using a chemical coating method or an electroplating method, such as:
the invention patent with publication number CN110129603A discloses a method for manufacturing a silver-tungsten contact material, which specifically comprises the following steps: (1) obtaining the amount of silver wrapping tungsten powder particles; (2) converting silver into the using amount of silver nitrate, preparing a silver nitrate solution by using water, adding tungsten powder and the silver nitrate solution into a reaction container, adding polyethylene glycol, sodium hydroxide and a glucose solution into the reaction container, carrying out reduction reaction under the conditions of ultrasonic oscillation and stirring, separating out silver, and wrapping the silver outside the tungsten powder to form composite powder, wherein the composite powder has the structure that: covering a pure silver shell layer with the thickness of 10-200 nm outside the tungsten particles; (3) mixing the composite powder with silver powder to obtain silver-tungsten powder containing 4% of silver, and pressing the silver-tungsten powder into a contact green compact with porosity of 5-45%; (4) and placing the contact pressed compact and the silver block in a sintering furnace protected by ammonia decomposition atmosphere for sintering and infiltration so as to obtain the silver-tungsten contact material with specified size and components. The method can prepare the high-compactness infiltration type silver-tungsten material with high tungsten content (the mass ratio of tungsten is 50-90%).
The invention patent with publication number CN102392170A discloses a processing method for manufacturing a silver-tungsten composite contact material, which specifically comprises the following steps: placing tungsten powder in a reaction vessel, adding water and a proper amount of reducing agent, slowly spraying silver-ammonia complexing solution under the condition of stirring, cleaning silver-tungsten coated powder until the silver-tungsten coated powder is neutral and dried, then carrying out uniform ball milling treatment by a high-energy ball mill, carrying out initial pressure forming after stress removal treatment on the silver-tungsten powder, and carrying out presintering, infiltration sintering and re-pressing under the protection of reducing atmosphere to obtain the silver-tungsten composite contact material. The invention utilizes the coating process of the chemical plating principle to improve the distribution of tungsten particles in a silver matrix, and adopts the high-energy ball milling process to repeatedly generate cold welding and fracture on the powder particles, so that the atoms in the powder particles are diffused, and the mechanical property, the physical property, the electrical property and the like of the material are improved; and a high-temperature pre-sintering process is adopted, so that the compactness of the material is improved, the conductivity is greatly optimized, the resistivity is low, and the arc corrosion resistance can be improved.
Although the mode of pre-adding silver by adopting a chemical coating method or an electroplating method can be helpful for improving the forming strength during the preparation of the tungsten framework and finally obtaining the silver-tungsten contact material with high compactness and high tungsten content by infiltration treatment, the silver-tungsten contact material has the following defects: 1) after the silver-tungsten coated mixed slurry is prepared through chemical reaction, purified water is needed for cleaning, a large amount of wastewater is generated in the process, and the problems of sewage treatment and environmental pollution exist; 2) a large amount of chemical reagents (such as sodium hydroxide, polyethylene glycol or hydrazine hydrate and the like) are consumed in the preparation process, so that the health of production operators is influenced, and the problem of environmental pollution also exists; 3) the chemical coating reaction needs to be carried out in a liquid system, and because the density difference between the tungsten powder and the silver powder is too large, the tungsten powder sinks at a high speed in a reaction liquid, so that the phenomenon of serious agglomeration exists, and the uniform composite powder is difficult to obtain in a real sense.
The other method is a method for mixing silver powder and tungsten powder according to a proportion, and is represented as the invention patent with the publication number of CN104480335A, and discloses a preparation method of a silver-tungsten contact material, which comprises the steps of mixing the silver powder and the tungsten powder, placing the obtained silver-tungsten mixed powder, high-purity nickel balls and water into a ball mill for ball milling, and drying, annealing, forming and infiltrating the obtained silver-tungsten mixed powder after ball milling to obtain the silver-tungsten contact material; wherein: the weight ratio of the high-purity nickel balls to the silver-tungsten mixed powder is 4-10: 1; the amount of the water is calculated by adding 120-200 ml of water into each 1kg of silver-tungsten mixed powder; the ball milling time is 12-50 h. The silver-tungsten mixed powder, high-purity nickel balls and water are placed in a ball mill according to a specific proportion and are subjected to ball milling for a specific time, so that the silver powder and the tungsten powder are mixed more uniformly; ball milling and adding additive nickel are simultaneously carried out; nickel lost by ball milling on the high-purity nickel balls can be uniformly coated on the surfaces of tungsten particles, so that the aim of effectively improving the wettability of silver on tungsten is fulfilled; the obtained material has uniform tissue, high density and low resistivity. However, the ball milling treatment process is added, so that on one hand, the production period of the product is prolonged, and the energy consumption is increased; on the other hand, impurities introduced during ball milling still have an adverse effect on the properties of the resulting contact.
Therefore, there is a need for a method for preparing a silver-tungsten contact material with high tungsten content, which has simple process and short production period, can reduce the molding difficulty and can obtain a high-density framework.
Disclosure of Invention
The invention aims to solve the technical problem of providing a preparation method of a silver-tungsten contact material with high tungsten content, which has the advantages of simple process, short production period, low forming difficulty and uniform metallographic structure of the obtained contact.
In order to solve the technical problems, the invention adopts the following technical scheme:
a preparation method of a silver-tungsten contact material comprises the step of obtaining a pressed compact, and is characterized in that the step of obtaining the pressed compact comprises the following steps: soaking tungsten powder with silver nitrate solution, drying the obtained mixed material, performing thermal decomposition reaction, crushing, reducing, and pressing the obtained silver-tungsten mixed powder to obtain a pressed blank; wherein the silver nitrate solution is a silver nitrate aqueous solution.
The raw materials used by the method are silver nitrate crystals and coarse tungsten powder, and the tungsten powder is soaked by silver nitrate solution, so that the phenomenon of agglomeration and aggregation caused by high tungsten density and high sinking speed in chemical coating reaction does not exist. Therefore, silver nitrate crystals precipitated by drying and dewatering the obtained mixed material are uniformly distributed around tungsten powder particles, and after thermal decomposition, fine silver particles are attached to the surfaces of the tungsten particles, so that silver aggregation is avoided. Meanwhile, the addition of silver can ensure that the coarse-grained tungsten powder is pressed to the designed skeleton density, the strength of the pressed skeleton can be effectively improved, the processing difficulty of forming and sintering is reduced, and finally the silver-tungsten contact obtained after infiltration can easily reach the designed value in the aspect of component proportion.
In the above preparation method, when preparing the silver nitrate solution, the amount of the solvent water is determined according to the weight of the tungsten powder mixed with the silver nitrate solution as required. In experiments, the applicant finds that when the using amount of solvent water is determined according to the proportion of 60-120 mL for every 1Kg of tungsten powder to prepare the silver nitrate solution, a good infiltration effect can be achieved on the tungsten powder (the effect of complete infiltration can be achieved, and excessive liquid residue cannot occur), and silver nitrate crystals precipitated by drying and dewatering can be uniformly distributed around tungsten powder particles.
In the preparation method, in the step of obtaining the pressed blank, the drying is usually carried out at the temperature of less than or equal to 100 ℃, preferably 80-100 ℃, and the time is 2-5 hours. Silver ions in the silver nitrate solution and tungsten powder are fully and uniformly mixed in a solution form, and then the mixture is dried at a lower temperature to remove water, so that silver nitrate crystals are slowly separated out, and the possible silver nitrate aggregation phenomenon caused by rapid separation is avoided. Preferably, the drying is carried out under stirring conditions, thereby further ensuring that the mixed material enables the precipitated silver nitrate crystals to be uniformly distributed around the tungsten particles.
In the above preparation method, in the step of obtaining a green compact, the reaction formula of the thermal decomposition reaction is:
the temperature during thermal decomposition is not easy to be too high or too low, when the reaction temperature is too high, the decomposition reaction can be caused to occur quickly, the generated heat is difficult to dissipate, and when the temperature is accumulated to a certain degree, the tungsten powder can be agglomerated and can be oxidized seriously, so that the self property of the powder is changed, and the subsequent use is influenced; while too low a temperature is not favorable for the thermal decomposition reaction. In the present application, the thermal decomposition reaction is preferably carried out at 120 to 150 ℃. In the reaction process, whether the thermal decomposition reaction is finished or not can be judged by whether the yellow smoke disappears or not.
After the thermal decomposition reaction is finished, the obtained powder is preferably crushed to 60-100 meshes and then reduced to ensure that the silver nitrate is completely decomposed. The reduction is usually carried out under the condition of atmosphere protection (specifically hydrogen or ammonia decomposition atmosphere) and at the temperature of 500-600 ℃, and the time is preferably 1-2 h. Preferably, the silver-tungsten mixed powder obtained by reduction is firstly crushed to 60-100 meshes and then pressed.
In the preparation method, in the step of obtaining the pressed compact, the density of the obtained pressed compact is controlled to be 10.8-13.4 g/cm during pressing3. The forming pressure during pressing is the same as that of the prior art, such as 3.5-5T/cm2(ii) a If necessary, a molding agent (e.g., paraffin wax, etc.) may be added in an amount conventionally used in the art.
In the preparation method, in the step of obtaining the pressed compact, the amount of silver nitrate in the silver nitrate solution can be specifically controlled to be 3-12 wt% of silver in the obtained silver-tungsten mixed powder.
In the preparation method, the average particle size of the tungsten powder is usually 3-10 μm.
The preparation method further comprises the steps of carrying out conventional sintering and infiltration on the obtained compact. Specifically, the sintering is to put the pressed blank in a protective atmosphere (hydrogen or ammonia decomposition gas atmosphere) at a temperature of 850-950 ℃ and keep the temperature for 1-2 h to obtain the tungsten skeleton. In the infiltration step, the tungsten framework and the silver blocks with corresponding weights are placed in a protective atmosphere (hydrogen or ammonia decomposition gas atmosphere) at 1050-1150 ℃, and heat preservation is carried out for 30-90 min; wherein the corresponding weight is the total weight of silver in the contact material to be prepared minus the weight of silver in the silver-tungsten mixed powder in the compacting step.
In the application, the silver-tungsten contact material refers to a silver-tungsten contact material with the tungsten content of 65-80% or even higher.
Compared with the prior art, the invention is characterized in that:
1. by adopting the tungsten powder with coarse particles and combining a method of adding silver by a wet method, 3-12 wt% of silver can be uniformly pre-added to the surfaces of tungsten particles, so that a high-strength tungsten framework is pressed, the obtained framework is free from the problems of crushing and scattering, the pores in the framework are fine and are uniformly distributed, and the problem that the tungsten framework is difficult to form when the tungsten content is more than 65% in the prior art is solved.
2. The method of adding silver by using a silver nitrate solution wet method is adopted, only a small amount of nitrogen dioxide and oxygen are released when the silver nitrate is thermally decomposed, pure water is not needed to wash the powder subsequently, and the environment is not polluted. Compared with a chemical coating method or an electroplating method for pre-silver adding, the method has the advantages that a large amount of chemical reagents are not consumed in the production process, a large amount of waste water is not generated, and the problem of environmental pollution is solved.
3. The tungsten powder is not subjected to ball milling treatment, so that impurities are prevented from being brought in, and the performance of the obtained contact material is improved.
4. Compared with the existing mode of pre-adding silver by mixed powder, the silver-tungsten contact prepared by the method disclosed by the invention has the advantages that the metallographic structure is finer and more uniform, and the composition segregation caused by silver aggregation due to nonuniform pre-added silver powder mixing is avoided.
5. Compared with the existing infiltration method, the contact material obtained by the invention has the advantages of more uniform metallographic structure, higher density and hardness and lower resistivity.
Drawings
Fig. 1 is a metallographic structure diagram of a contact material obtained in example 1 of the present invention.
FIG. 2 is a metallographic structure of a contact material obtained in comparative example 1 of the present invention.
Fig. 3 is a metallographic structure diagram of a contact material obtained in example 2 of the present invention.
Fig. 4 is a metallographic structure diagram of a contact material obtained in example 3 of the present invention.
Fig. 5 is a metallographic structure diagram of a contact material obtained in example 4 of the present invention.
Detailed Description
The present invention will be better understood from the following detailed description of specific examples, which should not be construed as limiting the scope of the present invention.
Example 1: preparation of AgW (65) contact
1) 3Kg of tungsten powder (average particle size of 3 μm) and AgNO were weighed out separately30.645Kg of crystal and 360mL of deionized water (the solid-to-liquid ratio of the tungsten powder to the water is 1 Kg: 120mL) for later use;
2) mixing AgNO3Dissolving the crystal in deionized water to obtain silver nitrate solution;
3) placing tungsten powder in a container, slowly pouring a silver nitrate solution into the container under the condition of stirring, and continuously stirring until the silver nitrate solution is completely poured in to obtain a mixed material in which the silver nitrate solution is completely immersed in the tungsten powder;
4) drying the obtained mixture in water bath at 85 deg.C under stirring for 5 hr, taking out, and mashing to obtain dried powder;
5) placing the dried powder in an oven, performing thermal decomposition at 120 ℃ until yellow smoke disappears (about 4h), taking out after thermal decomposition, crushing, sieving with a 100-mesh sieve, and collecting undersize;
6) placing the undersize product in a reducing furnace, reducing for 2h under the conditions of hydrogen atmosphere and 600 ℃, taking out, crushing, and sieving with a 100-mesh sieve to obtain silver-tungsten mixed powder (the silver content is about 12 wt%);
7) pressing the obtained silver-tungsten mixed powder into a powder with a density of 10.8g/cm3The green compact (i.e., a green compact of 50 mm. times.10 mm. times.3 mm (length. times.width. times.height) prepared by weighing 16.2g of silver-tungsten mixed powder and molding at a molding pressure of 3.5T/cm2；
8) Sintering the pressed compact for 2h under the conditions of hydrogen and 850 ℃ to obtain a silver-tungsten framework;
9) according to 27: 73 silver block: weighing silver blocks according to the weight ratio of the silver-tungsten framework, namely weighing 6g of silver blocks, stacking the silver blocks and the silver-tungsten framework together, placing the silver blocks and the silver-tungsten framework into a graphite boat, placing the graphite boat into a high-temperature furnace for infiltration, and carrying out the infiltration in a hydrogen atmosphere at 1050 ℃ for 30min to obtain the AgW (65) contact material.
Comparative example 1: the AgW (65) contact is prepared by adopting the technical scheme in the invention patent with the publication number of CN104480335A
Selecting tungsten powder with the average particle size of 5 mu m and silver powder with the particle size of-120 meshes according to the weight percentage of tungsten: weighing 20kg of silver-tungsten powder in a weight ratio of 85:15, putting the powder into a 30L V-shaped mixer for mixing for 2 hours, putting the mixed silver-tungsten powder, 160kg of high-purity nickel balls (the nickel content is 99.9%) with the diameter of 10mm and 3600ml of deionized water into a 100L roller ball mill for ball milling (the rotating speed is 45 r/min), ball milling for 20 hours, taking out the powder, drying the powder for 2 hours at 100 ℃, putting the dried powder into a 100L roller ball mill, and putting the dried powder into a containerAnnealing at 850 deg.C for 3 hr in ammonia decomposition gas atmosphere (nickel content in the obtained powder material is 0.35% by detection), and annealing at 3.5T/cm2The annealed powder is pressed into a pressed compact in a steel die, the pressed compact and the silver sheet are placed in a graphite boat according to the structure that the silver sheet is on the lower pressed compact, and the silver-tungsten 65 contact can be prepared by infiltration for 30 minutes at 1150 ℃ in hydrogen atmosphere.
Example 2: preparation of AgW (70) contact
1) 3Kg of tungsten powder (average particle size of 5 μm) and AgNO were weighed out separately30.414Kg of crystal and 231mL of deionized water (the solid-to-liquid ratio of the tungsten powder to the water is 1 Kg: 77mL) for later use;
2) mixing AgNO3Dissolving the crystal in deionized water to obtain silver nitrate solution;
3) placing tungsten powder in a container, slowly pouring a silver nitrate solution into the container under the condition of stirring, and continuously stirring until the silver nitrate solution is completely poured in to obtain a mixed material in which the silver nitrate solution is completely immersed in the tungsten powder;
4) drying the obtained mixture in water bath at 90 deg.C under stirring for 4 hr, taking out, and mashing to obtain dried powder;
5) placing the dried powder in an oven, performing thermal decomposition at 130 ℃ until yellow smoke disappears (about 3h), taking out after thermal decomposition, crushing, sieving with a 80-mesh sieve, and collecting undersize;
6) placing the undersize product in a reducing furnace, reducing for 1.5h under the conditions of hydrogen atmosphere and 550 ℃, taking out, crushing, and sieving by a 80-mesh sieve to obtain silver-tungsten mixed powder (the silver content is about 8 wt%);
7) pressing the obtained silver-tungsten mixed powder into a powder with a density of 11.62g/cm3The green compact (namely, a green compact of 50 mm. times.10 mm. times.3 mm (length. times.width. times.height) obtained by weighing 17.26g of the powder and molding it under a molding pressure of 4T/cm2；
8) Sintering the pressed compact for 1.5h under the conditions of hydrogen and 900 ℃ to obtain a silver-tungsten framework;
9) according to the following steps of 25: 75 silver block: weighing silver blocks according to the weight ratio of the silver-tungsten framework, namely weighing 5.75g of the silver blocks, stacking the silver blocks and the silver-tungsten framework together, placing the silver blocks and the silver-tungsten framework into a graphite boat, putting the graphite boat into a high-temperature furnace for infiltration, and carrying out the infiltration in a hydrogen atmosphere at the temperature of 1100 ℃ for 40min to obtain the AgW (70) contact material.
Example 3: preparation of AgW (75) contact
1) 3Kg of tungsten powder (average particle size of 6 μm) and AgNO were weighed out separately30.249Kg of crystal and 180mL of deionized water (the solid-to-liquid ratio of the tungsten powder to the water is 1 Kg: 60mL) for later use;
2) mixing AgNO3Dissolving the crystal in deionized water to obtain silver nitrate solution;
3) placing tungsten powder in a container, slowly pouring a silver nitrate solution into the container under the condition of stirring, and continuously stirring until the silver nitrate solution is completely poured in to obtain a mixed material in which the silver nitrate solution is completely immersed in the tungsten powder;
4) drying the obtained mixture in water bath at 95 deg.C under stirring for 3 hr, taking out, and mashing to obtain dried powder;
5) placing the dried powder in an oven, performing thermal decomposition at 140 ℃ until yellow smoke disappears (the time is about 3h), taking out after thermal decomposition, crushing, sieving with a 80-mesh sieve, and collecting undersize;
6) placing the undersize product in a reducing furnace, reducing for 1.5h under the conditions of hydrogen atmosphere and 550 ℃, taking out, crushing, and sieving by a 80-mesh sieve to obtain silver-tungsten mixed powder (the silver content is about 5 wt%);
7) pressing the obtained silver-tungsten mixed powder into a powder with a density of 11.62g/cm3The green compact (namely, 18.52g of the powder is weighed and pressed into a green compact of 50 mm. times.10 mm. times.3 mm (length. times.width. times.height)) under a molding pressure of 4.5T/cm2；
8) Sintering the pressed compact for 1.5h under the conditions of hydrogen and 900 ℃ to obtain a silver-tungsten framework;
9) according to the following steps of 22: silver block of 78: weighing silver blocks according to the weight ratio of the silver-tungsten framework, namely weighing 5.22g of the silver blocks, stacking the silver blocks and the silver-tungsten framework together, placing the silver blocks and the silver-tungsten framework into a graphite boat, putting the graphite boat into a high-temperature furnace for infiltration, and carrying out the infiltration in a hydrogen atmosphere at the temperature of 1100 ℃ for 60min to obtain the AgW (75) contact material.
Example 4: preparation of AgW (80) contact
1) 3Kg of tungsten powder (average particle size of 8 μm) and AgNO were weighed out separately30.150Kg of crystal and 180mL of deionized water (the solid-to-liquid ratio of the tungsten powder to the water is 1 Kg: 60mL) for later use;
2) mixing AgNO3Dissolving the crystal in deionized water to obtain silver nitrate solution;
3) placing tungsten powder in a container, slowly pouring a silver nitrate solution into the container under the condition of stirring, and continuously stirring until the silver nitrate solution is completely poured in to obtain a mixed material in which the silver nitrate solution is completely immersed in the tungsten powder;
4) drying the obtained mixture in water bath at 95 deg.C under stirring for 3 hr, taking out, and mashing to obtain dried powder;
5) placing the dried powder in an oven, performing thermal decomposition at 150 ℃ until yellow smoke disappears (about 2h), taking out after thermal decomposition, crushing, sieving with a 60-mesh sieve, and collecting undersize;
6) placing the undersize in a reducing furnace, reducing for 1h under the conditions of hydrogen atmosphere and 500 ℃, taking out, crushing, and sieving by a 60-mesh sieve to obtain silver-tungsten mixed powder;
7) pressing the obtained silver-tungsten mixed powder into a powder with a density of 13.4g/cm3The green compact (namely, 20.06g of the powder is weighed and pressed into a green compact of 50 mm. times.10 mm. times.3 mm (length. times.width. times.height)), and the molding pressure is 5T/cm2；
8) Sintering the pressed compact for 1h under the conditions of hydrogen and the temperature of 950 ℃ to obtain a silver-tungsten framework;
9) according to the following steps of 18: silver block of 82: weighing silver blocks according to the weight ratio of the silver-tungsten framework, namely weighing 4.4g of the silver blocks, stacking the silver blocks and the silver-tungsten framework together, placing the silver blocks and the silver-tungsten framework in a graphite boat, putting the graphite boat in a high-temperature furnace for infiltration, and carrying out the infiltration in a hydrogen atmosphere at the temperature of 1150 ℃ for 90min to obtain the AgW (80) contact material.
The AgW (65) contact materials prepared in example 1 and comparative example 1, the AgW (70) contact material prepared in example 2, the AgW (75) contact material prepared in example 3, and the AgW (80) contact material prepared in example 4 were sampled and examined for their metallographic phase, and their metallographic structure diagrams are shown in fig. 1 to 5, respectively. The mechanical and physical properties of the contact materials obtained in the above examples and comparative examples were measured, and the results are shown in table 1 below.
Table 1:
Claims (10)
1. a preparation method of a silver-tungsten contact material comprises the step of obtaining a pressed compact, and is characterized in that the step of obtaining the pressed compact comprises the following steps: soaking tungsten powder with silver nitrate solution, drying the obtained mixed material, performing thermal decomposition reaction, crushing, reducing, and pressing the obtained silver-tungsten mixed powder to obtain a pressed blank; wherein the silver nitrate solution is a silver nitrate aqueous solution.
2. The preparation method of claim 1, wherein when preparing the silver nitrate solution, the amount of the solvent water is determined according to the weight of the tungsten powder mixed with the silver nitrate solution as required, and specifically, the amount of the solvent water is determined according to a proportion of 60-120 mL per 1Kg of tungsten powder.
3. The method according to claim 1, wherein the drying is performed at 100 ℃ or less in the step of obtaining a green compact.
4. The method according to claim 1, wherein the drying is performed at 80 to 100 ℃ for 2 to 5 hours in the step of obtaining a green compact.
5. The method according to claim 1, wherein the thermal decomposition reaction is performed at 120 to 150 ℃ in the step of obtaining a green compact.
6. The method according to claim 1, wherein the reduction is performed under an atmosphere and at a temperature of 500 to 600 ℃ in the step of obtaining the green compact.
7. The method according to claim 1, wherein in the step of obtaining a green compact, the density of the obtained green compact is controlled to 10.8 to 13.4g/cm at the time of compaction3。
8. The method according to any one of claims 1 to 7, wherein in the step of obtaining the green compact, the amount of silver nitrate in the silver nitrate solution is controlled so that the content of silver in the obtained silver-tungsten mixed powder is 3 to 12 wt%.
9. The production method according to any one of claims 1 to 7, wherein the tungsten powder has an average particle size of 3 to 10 μm.
10. The method according to any one of claims 1 to 7, further comprising a step of sintering and infiltrating the green compact.
Priority Applications (1)
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114192774A (en) * | 2021-11-23 | 2022-03-18 | 浙江福达合金材料科技有限公司 | Silver-tungsten electrical contact material with high dispersion degree and high compactness and preparation method thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6508980B1 (en) * | 1997-09-26 | 2003-01-21 | Massachusetts Institute Of Technology | Metal and ceramic containing parts produced from powder using binders derived from salt |
| US20030059680A1 (en) * | 2001-08-09 | 2003-03-27 | Randolph Leising | Preparation for a cathode material by a two-step reduction/oxidation synthesis process |
| CN101633986A (en) * | 2008-07-25 | 2010-01-27 | 比亚迪股份有限公司 | Method for preparing silver-tungsten composite material |
| CN104384512A (en) * | 2014-11-28 | 2015-03-04 | 桂林电器科学研究院有限公司 | Silver tungsten carbide contact material preparing method |
| CN105798319A (en) * | 2014-12-31 | 2016-07-27 | 施耐德电气工业公司 | Preparation method and device for silver-tungsten electrical contact material as well as electrical contact material and electrical contact |
| CN110064762A (en) * | 2019-05-21 | 2019-07-30 | 福达合金材料股份有限公司 | A kind of silver-tungsten carbide contact material and preparation method thereof |
| CN111432961A (en) * | 2017-09-19 | 2020-07-17 | 艾蓝腾欧洲有限公司 | Method for producing open-porous molded bodies made of metal and molded body produced using said method |
-
2020
- 2020-09-30 CN CN202011059844.5A patent/CN112170862A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6508980B1 (en) * | 1997-09-26 | 2003-01-21 | Massachusetts Institute Of Technology | Metal and ceramic containing parts produced from powder using binders derived from salt |
| US20030059680A1 (en) * | 2001-08-09 | 2003-03-27 | Randolph Leising | Preparation for a cathode material by a two-step reduction/oxidation synthesis process |
| CN101633986A (en) * | 2008-07-25 | 2010-01-27 | 比亚迪股份有限公司 | Method for preparing silver-tungsten composite material |
| CN104384512A (en) * | 2014-11-28 | 2015-03-04 | 桂林电器科学研究院有限公司 | Silver tungsten carbide contact material preparing method |
| CN105798319A (en) * | 2014-12-31 | 2016-07-27 | 施耐德电气工业公司 | Preparation method and device for silver-tungsten electrical contact material as well as electrical contact material and electrical contact |
| CN111432961A (en) * | 2017-09-19 | 2020-07-17 | 艾蓝腾欧洲有限公司 | Method for producing open-porous molded bodies made of metal and molded body produced using said method |
| CN110064762A (en) * | 2019-05-21 | 2019-07-30 | 福达合金材料股份有限公司 | A kind of silver-tungsten carbide contact material and preparation method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114192774A (en) * | 2021-11-23 | 2022-03-18 | 浙江福达合金材料科技有限公司 | Silver-tungsten electrical contact material with high dispersion degree and high compactness and preparation method thereof |
| CN114192774B (en) * | 2021-11-23 | 2023-05-09 | 浙江福达合金材料科技有限公司 | Silver-tungsten electrical contact material with high dispersity and high compactness and preparation method thereof |
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