WO2019037651A1

WO2019037651A1 - Boron-containing tungsten carbide copper alloy and method for manufacturing same

Info

Publication number: WO2019037651A1
Application number: PCT/CN2018/100782
Authority: WO
Inventors: 苏国平; 钟铭; 刘俊海; 张建伟; 卢豪豪; 张志坤
Original assignee: 安泰天龙（宝鸡）钨钼科技有限公司; 安泰天龙（天津）钨钼科技有限公司; 安泰科技股份有限公司
Priority date: 2017-08-23
Filing date: 2018-08-16
Publication date: 2019-02-28
Also published as: CN107619981B; CN107619981A

Abstract

A boron-containing tungsten carbide copper alloy and a method for manufacturing same. The alloy consists of the following components in percentage by weight: WC: 49.97-80%; Cu: 19.97-50%; B: 0.01-0.03%. The method for manufacturing the alloy comprises a material mixing step, a coating step using a forming agent, a press molding step, a sintering step, and a copper solution infiltration step. The method is high in production efficiency, and low in production costs. The manufactured boron-containing tungsten carbide copper alloy is uniform in structure, high in hardness, and good in wear resistance, and has a density of 12.5-12.9 g/cm3, hardness of 35-60 HRC, and an electrical conductivity of 16-35%.

Description

Boron-containing tungsten carbide copper alloy and preparation method thereof

Technical field

The invention belongs to the field of production of tungsten carbide copper composite materials, in particular to a boron-containing tungsten carbide copper alloy and a preparation method thereof.

Background technique

The electric contact is one of the key components of the switchgear, which is responsible for the conduction and breaking current, and its quality directly affects the service life and operational reliability of the switchgear. At the moment when the contacts are turned on or off, an arc discharge occurs between the contacts, causing arc burnout of the contacts or even welding. When a large rated current or short-circuit current is passed for a long time, the contact resistance between the contacts causes the contact to rise in temperature, oxidation, even welding, and the like. Therefore, the quality of a contact material should not only be evaluated from the physical and mechanical properties of the material, but also its electrical properties, such as arc erosion resistance, compressive strength, fusion resistance, interception level, and wear resistance. Sex and so on. When the switchgear is applied to different ranges and environments, the requirements for the contact materials are also different. For example, medium voltage vacuum circuit breakers require high breaking capacity of materials, but the requirements for cutoff values can be appropriately relaxed. Low pressure vacuum contactors require relatively low breaking capacity, but require very low shutoff values. Good wear resistance can be operated frequently to increase its service life. Different application applications use contact materials with different characteristics, which promotes the continuous development of contact materials.

Tungsten and tungsten carbide copper composites are a new type of functional materials with excellent comprehensive properties. They have excellent electrical conductivity, high strength, hardness and excellent high temperature performance due to their good resistance to electric corrosion and fusion welding. Characteristics such as properties and low interception values are widely used in high, medium and low voltage electrical appliances. Tungsten carbide copper is produced by high-quality tungsten carbide powder by press molding-high temperature sintering-permeating copper process. The content of tungsten carbide is from 50% to 80% by weight. The structure is uniform and compact, the performance is excellent, and it has high temperature resistance. , resistance to arc ablation, high strength, large specific gravity, good electrical conductivity, good thermal conductivity, easy to cut, etc. Compared with tungsten-copper alloy, tungsten carbide copper alloy has higher hardness, wear resistance and arc corrosion resistance, such as The hardness of WC70Cu30 is 37HRC. After adding nickel and silicon, the hardness is 47HRC, and the wear resistance is also more excellent.

Austria's Plansee Company has deep research on tungsten carbide copper alloys, and its products have occupied the major markets at home and abroad. The high hardness and good wear resistance of tungsten carbide copper have made it widely used. China has been conducting research on tungsten carbide copper alloy since the 1980s. The WC-Cu(40) alloy has been rapidly developed as a contact material for low-voltage (6kV or less) vacuum switch tubes. The alloy material combines the good conductivity of copper. Thermal conductivity and tungsten carbide's high melting point, high hardness, corrosion resistance and other excellent characteristics, as well as low cost, have been recognized by the manufacturers of vacuum switches. In the early 1990s, the Ministry of Machinery and Electronics Industry announced the standard SJ/T10168.4-91 of tungsten carbide copper alloy, which specified three grades of tungsten carbide copper alloy, namely F6000E, F6001E, F6002E, corresponding to a tungsten carbide content of 80. 70, 60%, after the standard update of tungsten carbide copper alloy, but with the promotion and use of the product, foreign countries have made new reforms on tungsten carbide copper alloy. Currently, the tungsten carbide copper alloy commonly used for production mainly has TC5, TC10, TC20, TC53 four grades, tungsten carbide content of 50, 56, 70, 70.12%, and excellent overall performance, as shown in Table 1.

Table 1 Grades and properties of tungsten carbide copper alloy

As can be seen from Table 1, in order to increase the hardness of the tungsten carbide copper alloy, nickel and silicon elements are added, and the addition of nickel and silicon increases the hardness of the tungsten carbide copper alloy and decreases the electrical conductivity. Therefore, in order to further improve the hardness, wear resistance and arc ablation resistance of the existing tungsten carbide copper alloy, it is necessary to find a tungsten carbide copper alloy which is more excellent in performance and a preparation method thereof.

Summary of the invention

In view of the defects of the prior art, the object of the present invention is to provide a boron-containing tungsten carbide copper alloy and a preparation method thereof, and the alloy product of the invention overcomes the problems of low conductivity and high cost of the existing alloy, and adopts the process of the invention The prepared tungsten carbide copper alloy has uniform structure, high hardness, high wear resistance, good electrical conductivity, high production process efficiency and greatly reduced production cost.

In order to achieve the above object, the present invention adopts the following technical solutions:

A boron-containing tungsten carbide copper alloy, the alloy is composed of the following components by weight: WC 49.97-80%, Cu 19.97-50%, B 0.01-0.03%.

In the above boron-containing tungsten carbide copper alloy, as a preferred embodiment, the weight percentage of B in the alloy is 0.01 to 0.024%.

In the above boron-containing tungsten carbide copper alloy, as a preferred embodiment, the boron-containing tungsten carbide copper alloy has the following performance parameters: a density of 12.5 to 12.9 g/cm ³ , a hardness of 40 to 60 HRC, and electrical conductivity. It is 18 to 35%.

In order to improve the hardness and wear resistance of the tungsten carbide copper alloy, and at the same time reduce the cost, a trace amount of boron element is added to the existing tungsten carbide copper alloy to improve its performance, and boron may exist in the copper matrix in a gap form or a replacement form. It contributes significantly to the purification of alloys and grain refinement. The addition of trace amounts of boron to tungsten carbide copper alloy can significantly improve its mechanical properties and improve corrosion resistance. Specifically, the invention adopts the addition of boron element to form a boron-copper binder phase in the tungsten carbide copper alloy, and the boron-copper dispersion dispersion strengthens the grain of the tungsten carbide copper structure, and the addition of a trace amount of boron element can increase the hardness of the tungsten carbide copper alloy. 10～20HRC, its wear resistance and corrosion resistance are also improved, but the solubility of boron in copper alloy is limited. When the solubility of boron in copper alloy exceeds 0.02%, it will precipitate in the form of boride inclusions to make the material plastic. The deterioration is accelerated and the corrosion is accelerated, so the content of B in the alloy of the present invention is selected to be 0.01 to 0.03 wt%.

A method for preparing the above boron-containing tungsten carbide copper alloy, which comprises:

In the mixing step, the raw material tungsten carbide powder and the boron powder are mixed according to the above boron-containing tungsten carbide copper alloy group distribution ratio to obtain a mixture;

a molding agent coating step, adding a molding agent to the mixture and mixing, so that the molding agent is uniformly coated on the outer surface of the mixture powder, and then dried and sieved to obtain a coating material;

Press molding step, molding the coating material according to a predetermined shape or isostatic pressing to obtain a compact;

a sintering step of sintering the green compact to obtain a sintered boron-containing tungsten carbide skeleton;

In the copper liquid infiltration step, the boron-containing tungsten carbide skeleton is placed on a copper piece of a certain weight for infiltration treatment to obtain a boron-containing tungsten carbide copper alloy.

The method of the invention places the boron-containing tungsten carbide skeleton on the copper sheet, and does not cause the external copper to be intrinsic, the internal gas cannot be removed, the copper liquid does not penetrate, and the internal copper is deficient, and the infiltration effect is very satisfactory.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, the preparation method further includes a machining step of processing the boron-containing tungsten carbide copper alloy obtained by the copper liquid infiltration step. Formed into a boron-containing tungsten carbide copper alloy; more preferably, the machine is turned and/or ground.

In the method for preparing the boron-containing tungsten carbide copper alloy, as a preferred embodiment, the tungsten carbide powder has a Vickers particle size of 3.0 to 12.0 μm (for example, 3.5 μm, 4.0 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm); the boron powder has a Vickers particle size of 1-5 μm (for example, 1.5 μm, 2.0 μm, 3 μm, 4 μm); more preferably, the tungsten carbide powder has a purity of 99.8% or more. The boron powder has a purity of 96% or more; further, the boron powder has a Vickers particle size of 3 μm. The above-mentioned Vickers particle size tungsten carbide powder can obtain a more suitable skeleton density. If the particle size is too small, the skeleton density will be too high. If the particle size is too large, the skeleton density will be too low; and in order to ensure the mixing of the boron powder and the tungsten carbide powder. The uniformity, the Fahrenheit particle size of the boron powder is preferably 1-5 μm.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, in the mixing step, the mixing is performed by using a V-type mixer; in order to ensure the uniformity of the mixture and Economically, more preferably, the mixing time is 10-16 h (such as 11 h, 12 h, 13 h, 14 h, 15 h), and further preferably, the mixing time is 12 h.

In the preparation method of the above-mentioned boron-containing tungsten carbide copper alloy, as a preferred embodiment, the molding agent is one or more of sodium butadiene rubber, polyethylene glycol, paraffin wax, and methyl ethyl ketone oxime, but is formed by molding. For the purpose of good performance and easy removal, it is preferably methyl ethyl ketone oxime; more preferably, the amount of the molding agent added to the mixture is: 40-60 mL of molding agent per kilogram of the mixture (40- 60 mL/kg, such as 42 mL/kg, 46 mL/kg, 50 mL/kg, 55 mL/kg, 58 mL/kg, 59 ml/kg), further preferably, 50 mL of a molding agent (50 mL/kg) is added per kg of the mixture. If the amount of the molding agent is too small, the powder is still in the form of granules, and the molding property is not good; if the amount of the molding agent is too large, the density and strength of the compact are insufficient, and the blank is easily cracked when removed.

In the preparation method of the above boron-containing tungsten carbide copper alloy, as a preferred embodiment, in the molding agent coating step, the mixing means: repeatedly pressing the molding agent with a shovel and the In order to ensure uniform mixing of the powder, it is more preferable that the number of repeated rolling is 8-15 times, more preferably 10 times.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, the molding agent coating step is replaced by a spray granulation step. Spray granulation can achieve more desirable results.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, in the molding agent coating step, the drying temperature is 120-180 ° C (such as 125 ° C, 130 ° C, 140 ° C, 150 ° C, 160 ° C, 170 ° C, 178 ° C), the drying time is 15-25min (such as 16h, 18h, 20h, 22h, 24h), more preferably, the drying temperature is At 150 ° C, the drying time was 20 min.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, in the molding agent coating step, the sieving means passing through a 55-65 mesh sieve, and taking the sieve blank as The coating material; more preferably, a 60 mesh screen. In order to ensure the pressing effect, the agglomerated powder needs to be broken and sieved after drying. Further, if the mesh size is too small, the tungsten carbide particles are too coarse, which tends to cause uneven density of the green compact; the mesh size is too large, and the particles are too fine, resulting in insufficient strength of the green compact.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, the molding means that the coating material is placed in a mold corresponding to a predetermined shape and pressed on a press. More preferably, the pressing pressure is 200-300 MPa (such as 205 MPa, 210 MPa, 215 MPa, 220 MPa, 230 MPa, 238 MPa, 250 MPa, 260 MPa, 270 MPa, 280 MPa, 290 MPa, 298 MPa), and the pressing time is 1 to 2 minutes. (eg 1 min, 1.1 min, 1.2 min, 1.4 min, 1.5 min, 1.7 min, 1.8 min, 1.9 min); further, the density of the compact is the theoretical boron-containing tungsten carbide skeleton density (ie boron-containing carbonization) 85-95% of the theoretical density of the tungsten material (such as 86%, 88%, 90%, 91%, 92%, 92%, 94%); more preferably: the density of the compact is theoretical boron-containing carbonization 90% of the tungsten skeleton density.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, the isostatic pressing means: placing the coating material in an isostatic pressing rubber sleeve for isostatic pressing; More preferably, the pressing pressure of the isostatic pressing is 200-240 MPa (such as 205 MPa, 210 MPa, 215 MPa, 220 MPa, 230 MPa, 238 MPa), and the dwell time is 5-10 min (such as 6 min, 7 min, 8 min, 9 min); Further, the density of the green compact is 85-95% (such as 86%, 88%, 90%, 91%, 92%, 92%, 94%) of the theoretical boron-containing tungsten carbide skeleton density; further, The density of the compact is 90% of the theoretical boron-containing tungsten carbide skeleton density.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, the sintering treatment temperature is 1400 to 1900 ° C (for example, 1410 ° C, 1450 ° C, 1500 ° C, 1550 ° C, 1600 ° C, 1650). °C, 1700 ° C, 1750 ° C, 1800 ° C, 1850 ° C, 1890 ° C), the insulation is 2-5h (such as 2.5h, 3h, 3.5h, 4h, 4.5h), more preferably, the temperature of the sintering treatment is 1600 ~ 1700 ° C, insulation for 3h. For about 70% of tungsten carbide, the sintering temperature is too low, the strength or density of the skeleton is insufficient; if the sintering temperature is too high, the density will be too high, or decarburization will seriously affect the hardness. Excessive or too low sintering temperatures can affect the accuracy of the composition.

In the above-described method for producing a boron-containing tungsten carbide copper alloy, as a preferred embodiment, the atmosphere of the sintering treatment is a reducing atmosphere; more preferably, the reducing atmosphere is a hydrogen atmosphere.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, the sintering treatment is performed in an intermediate frequency furnace.

In the above method for producing a boron-containing tungsten carbide copper alloy, as a preferred embodiment, in the copper liquid infiltration step, the copper sheet is an electrolytic copper sheet, and more preferably has a purity of 99.95% or more.

In the above method for preparing a boron-containing tungsten carbide copper alloy, in consideration of volatilization of copper during copper infiltration and residue on the surface of the alloy, as a preferred embodiment, in the copper liquid infiltration step, The copper piece of a certain weight refers to the amount of copper calculated according to the distribution ratio of the boron-containing tungsten carbide copper alloy group × (110-120)%, preferably: copper calculated according to the distribution ratio of the boron-containing tungsten carbide copper alloy group described above. Quantity × 115%.

In the above preparation method of the boron-containing tungsten carbide copper alloy, as a preferred embodiment, in the copper liquid infiltration step, the temperature of the infiltration treatment is 1300-1500 ° C (such as 1310 ° C, 1350 ° C , 1380 ° C, 1400 ° C, 1420 ° C, 1450 ° C, 1480 ° C, 1490 ° C), the infiltration treatment time is 90 ~ 120min (such as 95min, 100min, 105min, 110min, 115min, 119min); more preferably, The temperature of the infiltration treatment was 1400 °C. If the infiltration temperature is too high, the evaporation and evaporation are severe, and excessive vapor pressure will be formed inside the infiltrated billet, resulting in pores; if the infiltration temperature is too low, the wettability will be insufficient, the infiltration effect is not good, and the defect is easy.

In the above-described method for producing a boron-containing tungsten carbide copper alloy, as a preferred embodiment, the infiltration treatment is carried out in a push boat furnace.

In the above method for producing a boron-containing tungsten carbide copper alloy, as a preferred embodiment, the infiltration treatment atmosphere is a reducing atmosphere; more preferably, the reducing atmosphere is a hydrogen atmosphere.

Compared with the prior art, the present invention has the following beneficial effects:

The invention improves the hardness of the material by ensuring the compact density is 85-95% of the density of the theoretical boron-containing tungsten carbide skeleton, and the sintered body shrinks during the sintering, and the density and strength increase, compared with the direct When compacting, the density of the blank is pressed to the same as the theoretical skeleton density, and the copper is directly infiltrated, and the hardness is high, the uniformity is good, and the porosity is low.

In the invention, the sintering process changes the traditional push-slung sintering, but the medium-frequency furnace is used for sintering. The intermediate frequency furnace has a slow heating rate and a uniform temperature field during the sintering process, which can improve the structure and performance of the sintered product.

The shielding gas in the sintering and copper infiltration process of the present invention is hydrogen. On the one hand, hydrogen is frequently used in industrial production. The more important reason is that hydrogen is a reducing gas, and carbonization in the tungsten carbide copper alloy can be performed at a high temperature. The oxidized portion of the tungsten surface is re-reduced to ensure sufficient wetting of the tungsten carbide skeleton by the liquid electrolytic copper in the copper infiltration process.

The boron-containing tungsten carbide copper material provided by the invention has uniform structure, high hardness and good wear resistance, and has a density of 12.5 to 12.9 g/cm ³ , a hardness of 35 to 60 HRC, and an electrical conductivity of 16 to 35%. The method of the invention has high production efficiency and low production cost.

DRAWINGS

1 is a scanning electron micrograph of an alloy material prepared in Example 1 of the present invention;

2 is a scanning electron micrograph of an alloy material prepared in Example 2 of the present invention.

Detailed ways

In order to make the objects, technical solutions and advantages of the present invention more comprehensible, the present invention will be further described in detail below with reference to the embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The raw materials involved in the following examples include tungsten carbide powder (purity ≥ 99.8, Fisher's particle size 3.0 to 12.0 μm), boron powder (purity ≥ 96%, average Fischer particle size 3 μm), electrolytic copper sheet (purity) ≥99.95%).

Example 1

The boron-containing tungsten carbide copper alloy prepared in this example is composed of the following components in terms of weight percentage, tungsten carbide 70%, copper 29.978%, and boron 0.022%. The preparation process comprises the following steps:

(1) Powder preparation

A tungsten carbide powder having a purity of ≥99.8% and an average Vickers particle size of 3.0 μm was taken; boron powder having a purity of ≥96% and an average Vickers particle size of 3 μm was used.

(2) Mixing

The tungsten carbide powder in the step (1) and the boron powder were mixed at a weight ratio of 3182:1, and mixed in a V-type mixer for 12 hours for use.

(3) Adding molding agent

To the mixture obtained in the step (2), a methyl ethyl ketone oxime forming agent was added to the mixture obtained in the step (2) in an amount of 50 ml of the molding agent/kg of the mixture obtained in the step (2), and the methyl ketone oxime was uniformly coated on the powder granules by repeatedly rolling 10 times with a shovel. The surface was then dried in a 150 ° C oven for 20 min, and the dried powder was sieved through a 60 mesh sieve to be used.

(4) Press molding

The coated powder treated in the step (3) is placed in a mold corresponding to a predetermined shape, and press-molded on a press, the press pressure is 200 MPa, and the pressing time is 1 min, and the obtained green compact density is theoretically boron-containing carbonization. 90% of the tungsten skeleton density.

(5) High temperature sintering

The boron-containing tungsten carbide green body formed by the step (4) is sintered in a hydrogen furnace at 1700 ° C for 3 hours to obtain a dense sintered boron-containing tungsten carbide skeleton, and the skeleton density is a theoretical skeleton density, that is, 8.88 g/cm. ³ .

(6) Copper infiltration

First, according to the ratio of the alloy composition of the present embodiment, the amount of copper infiltration is calculated according to the boron-containing tungsten carbide skeleton obtained in the step (5), and a certain weight of the copper sheet is cut, wherein the predetermined weight of the copper sheet is as follows. Boron-containing tungsten carbide copper alloy group distribution ratio calculated copper amount × 115%, then the electrolytic copper sheet with purity ≥ 99.95% is placed under the tungsten carbide skeleton to infiltrate copper, which is placed in the molybdenum boat, and molybdenum is used for copper infiltration. The boat is infiltrated, the infiltration temperature is 1400 ° C, and the length is about 1.5 hours. After the copper infiltration is completed, a tungsten carbide copper alloy is obtained.

(7) Double-sided grinding

The tungsten carbide copper alloy obtained in the step (6) was subjected to double-side grinding processing, and each time 0.02 mm was fed to obtain a finished tungsten carbide copper alloy.

The performance parameters of the tungsten carbide copper alloy prepared in this embodiment are: density 12.67 g/cm ³ (relative density 98.5%), hardness 56HRC, electrical conductivity 20%, porosity 1.3%; alloy material prepared by the method of the present embodiment With good uniformity, see Figure 1.

The porosity in the present invention is calculated by weighing the weight of the boron-containing tungsten carbide skeleton after copper infiltration, calculating the theoretical density of the bulk, obtaining the relative density by the actual density/theoretical density, and then using the 1-relative density. It is the porosity.

Example 2

The boron-containing tungsten carbide copper alloy prepared in this embodiment is composed of the following components in terms of weight percentage: tungsten carbide 70%, copper 29.976%, and boron 0.024%. The preparation process comprises the following steps:

(1) Powder preparation

A tungsten carbide powder having a purity of ≥99.8 and an average particle size of 5.8 μm was taken; boron powder having a purity of ≥96% and an average Vickers particle size of 3 μm was used.

(2) Mixing

The tungsten carbide powder in the step (1) and the boron powder were mixed at a weight ratio of 2917:1, and mixed in a V-type mixer for 12 hours for use.

(3) Adding molding agent

To the mixture obtained in the step (2), the methyl ethyl ketone oxime forming agent was added to the mixture obtained in the step (2) in an amount of 50 ml of the molding agent/kg of the mixture obtained in the step (2), and the ketone was repeatedly pressed 12 times with a shovel to uniformly coat the methyl ethyl ketone oxime to the powder granules. The surface was then dried in a 150 ° C oven for 20 min, and the dried powder was sieved through a 60 mesh sieve to be used.

(4) Press molding

The coated powder treated in the step (3) is placed in an isostatically pressed rubber sleeve mold corresponding to a predetermined shape, and is press-formed on an isostatic pressing machine, the press pressure is 240 MPa, the holding pressure is 10 min, and the pressure is 10 min. The billet density is 95% of the theoretical boron-containing tungsten carbide skeleton density.

(5) High temperature sintering

The boron-containing tungsten carbide green body formed by the step (4) is sintered in a hydrogen intermediate frequency furnace at 1600 ° C for 3 hours to obtain a dense sintered boron-containing tungsten carbide skeleton, and the skeleton density is a theoretical skeleton density, that is, 8.88 g/cm. ³ .

(6) Copper infiltration

First, according to the ratio of the alloy composition of the present embodiment, the amount of copper infiltration is calculated according to the boron-containing tungsten carbide skeleton obtained in the step (5), and a certain weight of the copper sheet is cut, wherein the predetermined weight of the copper sheet is as follows. Boron-containing tungsten carbide copper alloy group distribution ratio calculated copper amount × 115%, then the electrolytic copper sheet with purity ≥ 99.95% is placed under the tungsten carbide skeleton to infiltrate copper, and the copper is infiltrated with copper molybdenum. The temperature was 1400 ° C and the length was about 1.8 hours. After the copper infiltration was completed, a tungsten carbide copper alloy was obtained.

(7) Double-sided grinding

The performance parameters of the tungsten carbide copper alloy prepared in this embodiment are: density 12.65 g/cm ³ (relative density 98.4%), hardness 48HRC, electrical conductivity 22%, porosity 1.4%; alloy material prepared by the method of the present embodiment With good uniformity, see Figure 2.

Examples 3-10 and Comparative Examples 1-3

Examples 3-10 and Comparative Examples 1-3 were the same as in Example 1 except that the alloy group distribution ratio was different from that of Example 1. The alloy group distribution ratios of Examples 3-10 and Comparative Examples 1-3 are shown in Table 2, and the performance parameters of the obtained alloys are shown in Table 2.

Table 2 Alloy group distribution ratio and alloy properties of Examples 3-10 and Comparative Examples 1-3

Examples 11-13 and Comparative Examples 4, 5

Examples 11-13 and Comparative Examples 4, 5 The target components and other preparation steps were the same as in Example 1 except that the isostatic molding and sintering process of Table 3 was different from that of Example 1. The performance parameters of the alloys obtained in Examples 11-13 and Comparative Examples 4, 5 are shown in Table 3.

Table 3 Isostatic press forming and sintering process parameters and alloy properties of Examples 11-13 and Comparative Examples

Examples 14-18 and Comparative Examples 6, 7

Examples 14-18 and Comparative Examples 6, 7 Except that the infiltration process in Table 4 was different from that in Example 1, the target components and other preparation process steps were the same as in Example 1. The performance parameters of the alloys obtained in Examples 14-18 and Comparative Examples 6, 7 are shown in Table 4.

Table 4 Infiltration process parameters and alloy properties of Examples 14-18 and Comparative Examples

Claims

A boron-containing tungsten carbide copper alloy characterized in that the alloy is composed of the following components in a weight percentage: WC 49.97 to 80%, Cu 19.97 to 50%, and B 0.01 to 0.03%.
The boron-containing tungsten carbide copper alloy according to claim 1, wherein the alloy has a weight percentage of B of 0.01 to 0.024%.
The boron-containing tungsten carbide copper alloy according to claim 1, wherein the boron-containing tungsten carbide copper alloy has the following performance parameters: a density of 12.5 to 12.9 g/cm 3 , a hardness of 40 to 60 HRC, and a conductive property. The rate is 18 to 35%.
The method for preparing a boron-containing tungsten carbide copper alloy according to any one of claims 1 to 3, which comprises, in order:

The mixing step, the boron-containing tungsten carbide copper alloy group distribution ratio according to any one of claims 1-3, mixing the raw material tungsten carbide powder and the boron powder to obtain a mixture;

a molding agent coating step, adding a molding agent to the mixture and mixing, so that the molding agent is uniformly coated on the outer surface of the mixture powder, and then dried and sieved to obtain a coating material;

Press molding step, molding the coating material according to a predetermined shape or isostatic pressing to obtain a compact;

a sintering step of sintering the green compact to obtain a sintered boron-containing tungsten carbide skeleton;

In the copper liquid infiltration step, the boron-containing tungsten carbide skeleton is placed on a copper piece of a certain weight for infiltration treatment to obtain a boron-containing tungsten carbide copper alloy.
The preparation method according to claim 4, wherein the preparation method further comprises a machining step of processing the boron-containing tungsten carbide copper alloy obtained by the copper liquid infiltration step into boron-containing tungsten carbide copper. Finished alloy; preferably, the machining is turning and/or grinding;

Preferably, the molding agent coating step is replaced by a spray granulation step.
The preparation method according to claim 4, wherein

The tungsten carbide powder has a Vickers particle size of 3.0 to 12.0 μm; the boron powder has a Vickers particle size of 1-5 μm; preferably, the tungsten carbide powder has a purity of 99.8% or more, and the boron powder has a purity of 96% or more; further preferably, the boron powder has a Vickers particle size of 3 μm;

Preferably, in the mixing step, the mixing is carried out using a V-type mixer; preferably, the mixing time is 10-16 h, and further preferably, the mixing time is 12 h.
The preparation method according to claim 4, wherein the molding agent is one or more of sodium butadiene rubber, polyethylene glycol, paraffin wax, and methyl ethyl ketone oxime, preferably methyl ethyl ketone oxime; more preferably, The amount of the molding agent in the mixture is: 40-60 mL of molding agent per kg of the mixture, and further preferably, 50 mL of molding agent is added per kg of the mixture;

Preferably, in the molding agent coating step, the mixing means: repeatedly pressing the molding agent and the mixture with a shovel; more preferably, the number of repeated rolling is 8-15 Second, further preferably 10 times;

Preferably, in the molding agent coating step, the drying temperature is 120-180 ° C, the drying time is 15-25 min, and more preferably, the drying temperature is 150 ° C, The drying time is 20 min;

Preferably, in the molding agent coating step, the sieving means passing through a 55-65 mesh sieve, and taking the sieve blank as the coating material; preferably, passing through a 60 mesh sieve.
The preparation method according to claim 4, wherein

The molding means that the coating material is placed in a mold corresponding to a predetermined shape and press-molded on a press; preferably, the pressing pressure is 200 to 300 MPa, and the pressing time is 1 to 2min; further, the density of the green compact is 85-95% of the theoretical boron-containing tungsten carbide skeleton density; more preferably: the compact has a density of 90% of the theoretical boron-containing tungsten carbide skeleton density;

The isostatic pressing means that the coating material is placed in an isostatic pressing rubber sleeve for isostatic pressing; preferably, the isostatic pressing has a pressing pressure of 200 to 240 MPa, and the holding time is 5 to 10 min; further preferably, the density of the green compact is 85 to 95% of the theoretical boron-containing tungsten carbide skeleton density; further preferably, the green compact has a density of 90% of the theoretical boron-containing tungsten carbide skeleton density.
The preparation method according to claim 4, wherein the sintering treatment temperature is 1400 to 1900 ° C, the heat retention is 2 to 5 hours, and more preferably, the sintering treatment temperature is 1600 to 1700 ° C, and the heat retention is 3h;

Preferably, the sintering treatment atmosphere is a reducing atmosphere; more preferably, the reducing atmosphere is a hydrogen atmosphere; further preferably, the sintering treatment is performed in an intermediate frequency furnace.
The preparation method according to claim 4, wherein in the copper liquid infiltration step,

The temperature of the infiltration treatment is 1300-1500 ° C, the time of the infiltration treatment is 90-120 min; more preferably, the temperature of the infiltration treatment is 1400 ° C;

Preferably, the infiltration treatment is carried out in a push boat furnace;

Preferably, the infiltrated atmosphere is a reducing atmosphere; more preferably, the reducing atmosphere is a hydrogen atmosphere;

Preferably, the copper sheet is an electrolytic copper sheet, more preferably having a purity of 99.95% or more;

Preferably, in the copper liquid infiltration step, the certain weight of copper sheet refers to the amount of copper calculated according to the distribution ratio of the boron-containing tungsten carbide copper alloy group according to any one of claims 1-3. 110-120)%, more preferably: the amount of copper calculated by the distribution ratio of the boron-containing tungsten carbide copper alloy group according to any one of claims 1 to 3 × 115%.