阅读说明：本技术 一种层状成分分布强化CuCr基触头材料的制备方法 (Preparation method of CuCr-based contact material with strengthened layered component distribution ) 是由 魏鑫 陈霖铅 曾杨鹏 王美琪 贾磊 张亚龙 陶世平 谢辉 于 2020-06-05 设计创作，主要内容包括：本发明公开了一种层状成分分布强化CuCr基触头材料的制备方法,该方法按配比称量Cr粉和Ni粉或Mo粉或W粉或Ti粉,在氩气气氛保护下球磨24小时后与Cu粉混合均匀,在0.5MPa下压制成2～4mm高的预制体A；将按配比将Cu粉与Cr粉混合30分钟后并在0.5MPa下压制成8～15mm高的基体B；将A放置B上,在40MPa压力下真空热压烧结制备成层状成分分布的CuCr基触头材料。本发明通过上述制备方法,生产CuCr基触头材料添加的强化元素种类和含量不受限；同时具有层状成分分布的CuCr基体触头材料在保证触头力学性能和电导率的前提下,节约原料成本并提高CuCr基触头材料的耐击穿电压强度,解决了现在感应熔炼制备方法存在的强化元素种类和含量添加受限及耐击穿电压强度提高有限的问题。(The invention discloses a preparation method of a laminar component distribution reinforced CuCr-based contact material, which comprises the steps of weighing Cr powder and Ni powder or Mo powder or W powder or Ti powder according to a ratio, ball-milling for 24 hours under the protection of argon atmosphere, uniformly mixing with Cu powder, and pressing under 0.5MPa to prepare a preform A with the height of 2-4 mm; mixing Cu powder and Cr powder according to a ratio for 30 minutes, and pressing under 0.5MPa to form a matrix B with the height of 8-15 mm; placing A on B, and carrying out vacuum hot-pressing sintering under the pressure of 40MPa to prepare the CuCr-based contact material with layered component distribution. According to the preparation method, the types and the contents of the added reinforcing elements for producing the CuCr-based contact material are not limited; meanwhile, the CuCr matrix contact material with layered component distribution saves the raw material cost and improves the breakdown voltage resistance strength of the CuCr matrix contact material on the premise of ensuring the mechanical property and the conductivity of the contact, and solves the problems of limited addition of the types and the contents of the strengthening elements and limited improvement of the breakdown voltage resistance strength of the existing induction smelting preparation method.)

1. A preparation method of a CuCr-based contact material with strengthened layered component distribution is characterized by comprising the following steps:

the method comprises the following steps: putting the weighed Cr powder and Ni powder or Mo powder or W powder or Ti powder into a ball milling tank according to the proportion in a vacuum glove box, adding a ball milling medium and milling balls into the tank, sealing and taking out the tank, and performing mechanical ball milling on a ball mill;

step two: ball milling is carried out for 24 hours, so that the Cr powder and the added powder are uniformly alloyed;

step three: adding Cu powder into the Cr alloy powder prepared in the ball milling tank in the step two according to the proportion in a vacuum glove box, sealing the ball milling tank, and mixing the powder on a ball mill for 30 min;

step four: prepressing the mixed powder of the Cu powder and the Cr alloy powder prepared in the step three into a sheet (A prefabricated body);

step five: weighing Cr powder and Cu powder according to a ratio, filling into a ball milling tank, adding a ball milling medium and milling balls into the tank, sealing, and mixing the powder on a ball mill for 30 min;

step six: prepressing the mixed powder of Cu and Cr prepared in the fifth step into a CuCr contact substrate (substrate B);

step seven: and placing the prefabricated body A prepared in the fourth step on the base body B prepared in the sixth step, and preparing the CuCr contact material with layered components by adopting vacuum hot-pressing sintering.

2. The method for preparing the contact material with laminar component distribution reinforced CuCr base according to claim 1, wherein: in the first step, weighing and ball milling are carried out under the protection of argon atmosphere, the particle size of Cr powder and reinforced powder is about 10-20 μm, wherein the reinforced powder: the adding mass percentage of the Ni or Mo or W or Ti powder is 1-15%; the ball milling medium is absolute ethyl alcohol; the ball material ratio is 20: 1; the grain diameter of the grinding ball is divided into 8mm and 5mm, and the mass ratio of the grinding ball to the grinding ball is 2: 1.

3. The method for preparing the contact material with laminar component distribution reinforced CuCr base according to claim 1, wherein: and in the second step, the rotating speed of the ball milling tank is 400r/min, and the Cr powder and the added powder are subjected to mechanical ball milling alloying.

4. The method for preparing the contact material with laminar component distribution reinforced CuCr base according to claim 1, wherein: in the third step, the Cu powder is added by 75 percent, 70 percent, 65 percent, 60 percent and 50 percent in percentage by mass, and the mixed powder is protected by argon atmosphere.

5. The method for preparing the contact material with laminar component distribution reinforced CuCr base according to claim 1, wherein: and in the fourth step, the A prefabricated body is pre-pressed in a glove box in argon atmosphere by adopting a cold pressing die, the pressure is about 0.5MPa, and the thickness is 2-4 mm.

6. The method for preparing the contact material with laminar component distribution reinforced CuCr base according to claim 1, wherein: in the fifth step, the mass ratio of the Cu powder to the Cr powder is 15:1, 7:3, 13:7, 3:2 and 1:1 respectively.

7. The method for preparing the contact material with laminar component distribution reinforced CuCr base according to claim 1, wherein: in the fifth step, the ball milling medium is absolute ethyl alcohol; the ball material ratio is 10: 1; the grain diameter of the grinding ball is divided into 8mm and 5mm, the mass ratio of the grinding ball to the grinding ball is 2:1, and the rotating speed of the ball milling tank is 100 r/min.

8. The method for preparing the contact material with laminar component distribution reinforced CuCr base according to claim 1, wherein: and step six, prepressing the base body B in a glove box in argon atmosphere by adopting a cold pressing die, wherein the pressure is about 0.5MPa, and the thickness is 8-10 mm.

9. The method for preparing CuCr-based contact material with enhanced lamellar component distribution according to claim 1, wherein the vacuum hot-pressing sintering in step seven adopts a high-strength graphite mold, the pressure is 40MPa, and the vacuum degree in the furnace is about 5 × 10^{- 2}Pa, the heating rate is 10 ℃/min, the heat preservation temperature is 950-980 ℃, and the heat preservation time is 3-4 h。

Technical Field

The invention relates to the technical field of CuCr-based contact materials, in particular to a preparation method of a CuCr-based contact material with strengthened layered component distribution.

Background

CuCr is used as a contact material, and because the CuCr has better breakdown voltage strength, stable arcing, fusion welding resistance and other properties, the CuCr contact is widely applied to medium-high voltage vacuum circuit breakers, at present, a commercial CuCr contact is mainly prepared by a medium-frequency vacuum induction melting preparation method, the basic process of the CuCr contact is that a Cu block and a Cr block are melted in a medium-frequency induction furnace, a small amount of strengthening elements (such as nickel elements with the mass percentage of less than 0.5) are added, the mixture is uniformly stirred and then cooled in a copper mold to prepare a CuCr-based alloy cast ingot, and finally the CuCr-based alloy ingot is mechanically processed into a contact, so that the CuCr contact is required to have higher breaking capacity along with the increase of voltage in a transmission and transformation circuit, namely higher breakdown voltage strength, but the CuCr contact material is more difficult to improve the voltage strength and ensure the conductivity due to the limitations of the preparation method, the types and the content of the added elements, and, because the CuCr contact only has the thickness of about 200-500 microns on the surface of the contact material under the action of electric arc in the switching-on and switching-off process, the preparation method for the layered component distribution reinforced CuCr-based contact material which is simple in process, low in cost and suitable for industrial production is found, and the preparation method has high market value.

The prior art has the defects that the CuCr contact material is prepared by adopting a vacuum induction melting method and adding a small amount of strengthening elements, the effect of improving the breakdown voltage resistance is limited, and the electric conductivity is sharply reduced due to the fact that part of the added elements are in solid solution with a Cu matrix part, so that the requirement of a vacuum circuit breaker on the electric conduction of the contact material cannot be met; firstly, under the protection of argon, weighing a certain amount of Cr powder, mixing the Cr powder with 1-15 mass percent of Ni powder, Mo powder, W powder or Ti powder respectively, preparing a Cr alloy by adopting a mechanical ball milling method, then uniformly mixing the Cr alloy powder and the Cu powder in proportion, and pressing the mixture into a Cu (Cr alloy) sheet (A prefabricated body) with the thickness of 2-4 mm; secondly, uniformly mixing Cu powder and Cr powder according to a required proportion (the Cr content is 10-50 percent) and pressing the mixture into a CuCr contact substrate (B substrate), placing A on the B substrate and performing vacuum hot-pressing sintering to prepare the CuCr substrate contact material with layered component distribution, and on the premise of ensuring the mechanical property and the conductivity of the contact, saving the cost and improving the breakdown voltage resistance of the CuCr substrate contact material.

Disclosure of Invention

The invention aims to provide a preparation method of a layered component distribution reinforced CuCr-based contact material, which has the characteristics of no limitation on the types and contents of reinforcing elements added for producing the CuCr-based contact material, and simultaneously prepares the CuCr matrix contact material with layered component distribution by vacuum hot-pressing sintering.

In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of a CuCr-based contact material with strengthened layered component distribution comprises the following steps:

the method comprises the following steps: putting the weighed Cr powder and Ni powder or Mo powder or W powder or Ti powder into a ball milling tank according to the proportion in a vacuum glove box, adding a ball milling medium and milling balls into the tank, sealing and taking out the tank, and performing mechanical ball milling on a ball mill;

step two: ball milling is carried out for 24 hours, so that the Cr powder and the added powder are uniformly alloyed;

step three: adding Cu powder into the Cr alloy powder prepared in the ball milling tank in the step two according to the proportion in a vacuum glove box, sealing the ball milling tank, and mixing the powder on a ball mill for 30 min;

step four: prepressing the mixed powder of the Cu powder and the Cr alloy powder prepared in the step three into a sheet (A prefabricated body);

step five: weighing Cr powder and Cu powder according to a ratio, filling into a ball milling tank, adding a ball milling medium and milling balls into the tank, sealing, and mixing the powder on a ball mill for 30 min;

step six: prepressing the mixed powder of Cu and Cr prepared in the fifth step into a CuCr contact substrate (substrate B);

step seven: and placing the prefabricated body A prepared in the fourth step on the base body B prepared in the sixth step, and preparing the CuCr contact material with layered components by adopting vacuum hot-pressing sintering.

Preferably, in the step one, the weighing and ball milling are carried out under the protection of argon atmosphere, the particle size of the Cr powder and the particle size of the reinforced powder are about 10-20 μm, wherein the reinforced powder: the adding mass percentage of the Ni or Mo or W or Ti powder is 1-15%; the ball milling medium is absolute ethyl alcohol; the ball material ratio is 20: 1; the grain diameter of the grinding ball is divided into 8mm and 5mm, and the mass ratio of the grinding ball to the grinding ball is 2: 1.

Preferably, the rotating speed of the ball milling tank in the step two is 400r/min, and the Cr powder and the added powder are subjected to mechanical ball milling alloying.

Preferably, the Cu powder is added in the third step by the mass percentage of 75%, 70%, 65%, 60% and 50%, and the mixed powder is protected by argon atmosphere.

Preferably, the preform A in the fourth step is pre-pressed in a glove box in argon atmosphere by using a cold pressing mold, the pressure is about 0.5MPa, and the thickness is 2-4 mm.

Preferably, the mass ratio of the Cu powder to the Cr powder in the fifth step is 15:1, 7:3, 13:7, 3:2 and 1:1 respectively.

Preferably, in the step five, the ball milling medium is absolute ethyl alcohol; the ball material ratio is 10: 1; the grain diameter of the grinding ball is divided into 8mm and 5mm, the mass ratio of the grinding ball to the grinding ball is 2:1, and the rotating speed of the ball milling tank is 100 r/min.

Preferably, in the sixth step, the base body B is pre-pressed in a glove box in argon atmosphere by using a cold pressing die, the pressure is about 0.5MPa, and the thickness is 8 mm-10 mm.

Preferably, the vacuum hot-pressing sintering in the seventh step adopts a high-strength graphite mold, the pressure is 40MPa, and the vacuum degree in the furnace is about 5 × 10^-2Pa, the heating rate is 10 ℃/min, the heat preservation temperature is 950-980 ℃, and the heat preservation time is 3-4 h.

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

1. according to the preparation method, the addition of the reinforcing elements for producing the CuCr-based contact material is not limited, and the CuCr-based contact material with layered component distribution is prepared by vacuum hot-pressing sintering, so that the cost is saved, the breakdown voltage resistance of the CuCr-based contact material is improved on the premise of ensuring the mechanical property and the conductivity of the contact, the problems of the limitation of the addition of the reinforcing elements and the content and the limitation of the breakdown voltage resistance in the existing induction smelting preparation method are solved, and the preparation method is worthy of popularization.

2. The CuCr-based contact material with the laminated component distribution strengthening function, which is produced by the invention, takes Cu powder, Cr powder, Ni powder, W powder, Mo powder and Ti powder as raw materials, prepares Cr alloy through mechanical alloying, then prepresses the Cr alloy after being uniformly mixed with the Cu powder to prepare a preform A, places the preform A on a CuCr substrate B obtained by uniformly mixing and prepressing the Cu powder and the Cr powder, and then adopts vacuum hot-pressing sintering, so that the CuCr-based contact material has no special requirements on the raw materials and preparation equipment, saves the raw materials and has normal atmosphere.

3. According to the invention, the voltage resistance of the surface layer in the CuCr contact material and the content of the added elements in the arc ablation layer are improved by the preparation method, the raw material cost is saved on the premise of improving the electric breakdown voltage resistance and the strength without reducing the conductivity as much as possible, and the CuCr-based contact material has high values in improving the service voltage level of the CuCr-based contact material and industrial mass production.

Drawings

FIG. 1 is an X-ray diffraction pattern of Cr alloy powder prepared by the present invention;

FIG. 2 is a scanning electron microscope backscattered electron photograph of a laminar composition distribution strengthened CuCr-based contact material prepared from CrNi alloying powder of the invention, the surface of which is magnified by 200 times;

FIG. 3 is a scanning electron micrograph of a longitudinal section of a laminar composition distribution reinforced CuCr-based contact material prepared by the present invention, which is 30 times that of the contact material.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-3, a method for preparing a contact material with a laminar composition distribution strengthened CuCr-based structure includes the following steps:

the method comprises the following steps: putting the weighed Cr powder and Ni powder or Mo powder or W powder or Ti powder into a ball milling tank according to the proportion in a vacuum glove box, adding a ball milling medium and milling balls into the tank, sealing and taking out the tank, and performing mechanical ball milling on a ball mill;

step two: ball milling is carried out for 24 hours, so that the Cr powder and the added powder are uniformly alloyed;

step three: adding Cu powder into the Cr alloy powder prepared in the ball milling tank in the step two according to the proportion in a vacuum glove box, sealing the ball milling tank, and mixing the powder on a ball mill for 30 min;

step four: prepressing the mixed powder of the Cu powder and the Cr alloy powder prepared in the step three into a sheet (A prefabricated body);

step five: weighing Cr powder and Cu powder according to a ratio, filling into a ball milling tank, adding a ball milling medium and milling balls into the tank, sealing, and mixing the powder on a ball mill for 30 min;

step six: prepressing the mixed powder of Cu and Cr prepared in the fifth step into a CuCr contact substrate (substrate B);

step seven: placing the A prefabricated body prepared in the fourth step on the B substrate prepared in the sixth step, and preparing the CuCr contact material with layered component distribution by adopting vacuum hot-pressing sintering, wherein the type and the content of the reinforcing elements added when the CuCr-based contact material is produced are not limited by the preparation method, and the CuCr substrate contact material with layered component distribution is prepared by adopting vacuum hot-pressing sintering, so that the cost is saved, the breakdown voltage resistance strength of the CuCr-based contact material is improved on the premise of ensuring the mechanical property and the conductivity of the contact, and the problems of limited addition of the reinforcing elements and the content and limited improvement of the breakdown voltage resistance strength existing in the existing induction smelting preparation method are solved;

in the first step, weighing and ball milling are carried out under the protection of argon atmosphere, the particle size of Cr powder and reinforced powder is about 10-20 μm, wherein the reinforced powder: the adding mass percentage of the Ni or Mo or W or Ti powder is 1-15%; the ball milling medium is absolute ethyl alcohol; the ball material ratio is 20: 1; the grain diameter of the grinding ball is divided into 8mm and 5mm, and the mass ratio of the grinding ball to the grinding ball is 2: 1;

in the second step, the rotating speed of the ball milling tank is 400r/min, and the Cr powder and the added powder are subjected to mechanical ball milling alloying;

in the third step, the Cu powder is added by 75 percent, 70 percent, 65 percent, 60 percent and 50 percent in percentage by mass, and the mixed powder is protected by argon atmosphere;

in the fourth step, the A prefabricated part is pre-pressed in a glove box in argon atmosphere by adopting a cold pressing die, the pressure is about 0.5MPa, and the thickness is 2-4 mm;

in the fifth step, the mass ratio of the Cu powder to the Cr powder is 15:1, 7:3, 13:7, 3:2 and 1:1 respectively;

in the fifth step, the ball milling medium is absolute ethyl alcohol; the ball material ratio is 10: 1; the grain diameter of the grinding ball is divided into 8mm and 5mm, the mass ratio of the grinding ball to the grinding ball is 2:1, and the rotating speed of the ball milling tank is 100 r/min;

in the sixth step, the base body B is pre-pressed in a glove box in argon atmosphere by adopting a cold pressing die, the pressure intensity is about 0.5MPa, and the thickness is 8 mm-10 mm;

the vacuum hot-pressing sintering in the seventh step adopts a high-strength graphite die, the pressure is 40MPa, and the vacuum degree in the furnace is about 5 × 10^-2Pa, the heating rate is 10 ℃/min, the heat preservation temperature is 950-980 ℃, the heat preservation time is 3-4 h, the produced layered component distribution reinforced CuCr-based contact material takes Cu powder, Cr powder, Ni powder, W powder, Mo powder and Ti powder as raw materials, and the Cu powder, the Cr powder, the Ni powder, the W powder, the Mo powder and the Ti powder are prepared by mechanical alloyingThe method comprises the following steps of preparing a prefabricated body A by uniformly mixing and prepressing Cr alloy with Cu powder, placing the prefabricated body A on a CuCr substrate B obtained by uniformly mixing and prepressing the Cu powder and the Cr powder, and then carrying out vacuum hot-pressing sintering, wherein the raw materials and preparation equipment have no special requirements, and the raw materials are saved, and the communicated atmosphere is normal-pressure atmosphere; the preparation method improves the content of the added elements in the CuCr contact material, greatly reduces the cost of raw materials on the premise of improving the electric breakdown voltage resistance and strength performance of the CuCr contact material and simultaneously not reducing the conductivity of the CuCr contact material as far as possible, and has high value for improving the service voltage level of the CuCr-based contact material and realizing industrial large-scale production.