阅读说明：本技术 石墨烯铜镁合金接触线及其制备方法 (Graphene copper-magnesium alloy contact wire and preparation method thereof ) 是由 张海平 李炯利 孙庆泽 曹振 *** 于 2019-09-30 设计创作，主要内容包括：本发明涉及一种石墨烯铜镁合金接触线的制备方法,包括以下步骤：提供石墨烯铜镁的合金粉末；采用热等静压将所述石墨烯铜镁的合金粉末烧结为石墨烯铜镁合金锭坯；将所述石墨烯铜镁合金锭坯制成杆坯；将所述杆坯进行连续挤压,得到石墨烯铜镁合金杆材；以及按照预定尺寸和形状对所述石墨烯铜镁合金杆材进行冷拉拔,得到石墨烯铜镁合金接触线；其中,所述石墨烯以粉末形式加入,在所述石墨烯铜镁的合金粉末中,石墨烯的质量百分含量为0.01％～0.20％。本发明还公开上述方法制备的石墨烯铜镁合金接触线。石墨烯铜镁合金接触线的拉强度为520～580MPa,导电率为75～80％IACS,能同时满足更高速铁路对接触网导线线高强度和高导电率的要求,有效降低电力传输损耗。(The invention relates to a preparation method of a graphene copper-magnesium alloy contact wire, which comprises the following steps: providing alloy powder of graphene, copper and magnesium; sintering the graphene copper magnesium alloy powder into a graphene copper magnesium alloy ingot blank by adopting hot isostatic pressing; preparing the graphene copper-magnesium alloy ingot blank into a bar blank; continuously extruding the rod blank to obtain a graphene copper magnesium alloy rod material; performing cold drawing on the graphene copper magnesium alloy rod material according to a preset size and shape to obtain a graphene copper magnesium alloy contact line; the graphene is added in a powder form, and the mass percentage of the graphene in the graphene copper magnesium alloy powder is 0.01-0.20%. The invention also discloses the graphene copper-magnesium alloy contact line prepared by the method. The tensile strength of the graphene copper-magnesium alloy contact line is 520-580 MPa, the conductivity of the graphene copper-magnesium alloy contact line is 75-80% IACS, the requirements of a higher-speed railway on the high strength and the high conductivity of the contact network conductor line can be met, and the power transmission loss is effectively reduced.)

1. The preparation method of the graphene copper-magnesium alloy contact line is characterized by comprising the following steps:

providing alloy powder of graphene, copper and magnesium;

sintering the graphene copper magnesium alloy powder into a graphene copper magnesium alloy ingot blank by adopting hot isostatic pressing;

preparing the graphene copper-magnesium alloy ingot blank into a bar blank;

continuously extruding the rod blank to obtain a graphene copper magnesium alloy rod material; and

carrying out cold drawing on the graphene copper magnesium alloy rod material according to a preset size and shape to obtain a graphene copper magnesium alloy contact line;

the graphene is mixed with other components in a powder form, and the mass percentage of the graphene in the graphene copper magnesium alloy powder is 0.01-0.20%.

2. The preparation method according to claim 1, wherein the graphene-copper-magnesium alloy powder contains 0.05-0.15% by mass of graphene.

3. The preparation method according to claim 1 or 2, wherein the graphene-copper-magnesium alloy powder contains 0.05 to 1.0 mass% of magnesium.

4. The preparation method according to claim 1, wherein the providing of the graphene copper magnesium alloy powder comprises:

atomizing the copper-magnesium alloy melt through high-pressure fluid in a non-oxidizing atmosphere, and selecting powder with the particle size of 10-70 mu m to obtain copper-magnesium pre-alloy powder; and

and mixing the copper-magnesium pre-alloy powder with graphene powder to obtain graphene-copper-magnesium alloy powder.

5. The preparation method according to claim 4, wherein the copper-magnesium pre-alloy powder is mixed with graphene powder to obtain graphene-copper-magnesium alloy powder, and the method comprises the following steps:

adding the copper-magnesium pre-alloy powder and the graphene powder into a solvent, and sequentially performing ultrasonic stirring and stirring or simultaneously performing ultrasonic stirring to obtain a suspension; and

and filtering the suspension, and drying the solid obtained by filtering under a vacuum condition or drying the solid in a non-oxidizing atmosphere to obtain the graphene copper magnesium alloy powder.

6. The method according to claim 5, wherein the drying temperature is 50 ℃ to 70 ℃ and the drying temperature in the non-oxidizing atmosphere is 150 ℃ to 220 ℃.

7. The method of claim 5 or 6, wherein the copper-magnesium pre-alloy powder is replaced with elemental copper powder and elemental magnesium powder.

8. The method according to claim 5, wherein the solvent is one or more selected from the group consisting of deionized water, absolute ethanol, an aqueous ethanol solution, acetone, and N-methylpyrrolidone.

9. The preparation method according to claim 5, wherein the power of the ultrasound is 2kW to 3kW, the power of the ultrasound is 20kHz to 25kHz, and the time of the ultrasound is 10min to 30 min.

10. The method of claim 1, wherein the hot isostatic pressing is performed at a pressure of 120MPa to 140MPa, at a temperature of 800 ℃ to 900 ℃ and for a period of 3h to 5 h.

11. The method according to claim 1, wherein the step of forming the graphene copper magnesium alloy ingot blank into a bar blank comprises:

and extruding the graphene copper-magnesium alloy ingot blank at the temperature of 800-920 ℃ to obtain a rod blank.

12. The graphene copper magnesium alloy contact line is characterized by being obtained by the preparation method of any one of claims 1 to 11.

Technical Field

The invention relates to the field of power supply type wires, in particular to a graphene copper-magnesium alloy contact wire and a preparation method thereof.

Background

The contact wire is also called as a trolley wire and is an important component in a contact network of the electrified railway, the contact wire directly transmits current to the electric locomotive through sliding friction with a pantograph slide plate on the electric locomotive, and the performance of the contact wire directly influences the current collection quality of the electric locomotive and the safe operation of the locomotive. The contact wire is the worst working environment of all power supply type wires, and needs to bear impact, vibration, temperature difference change, environmental corrosion, abrasion, spark erosion and great working tension when in normal work, so the performance of the contact wire directly influences the safe operation of a high-speed train. In order to meet the requirements of the contact network of the electrified railway, the contact line is generally prepared from materials such as copper, copper-silver alloy, high-strength copper-silver alloy, copper-tin alloy, copper-magnesium alloy, high-strength copper-magnesium alloy and the like.

At present, the main problem of the copper alloy contact line material is the contradiction between high strength and high conductivity. For example, the conductivity of a pure copper contact line can reach 97% IACS, but the tensile strength is only 360 MPa; the strength of the copper-magnesium alloy contact line can reach 530MPa, but the conductivity of the copper-magnesium alloy contact line is greatly reduced and is only 65% IACS. The line loss power of the pure copper contact line per kilometer is about 82.5kW, and the line loss power of the high-strength copper magnesium alloy contact line per kilometer is as high as 101.9 kW. Therefore, it is difficult to achieve both high strength and high conductivity for the conventional copper-magnesium alloy contact line.

Therefore, how to obtain a novel contact wire which meets the requirements of high strength and high conductivity at the same time is a key technical problem faced by the material of the contact wire of the high-speed railway.

Disclosure of Invention

Therefore, it is necessary to provide a graphene copper magnesium alloy contact line having both high strength and high conductivity and a method for preparing the same.

The invention provides a preparation method of a graphene copper-magnesium alloy contact wire, which comprises the following steps:

providing alloy powder of graphene, copper and magnesium, wherein the graphene is added in a powder form;

sintering the graphene copper magnesium alloy powder into a graphene copper magnesium alloy ingot blank by adopting hot isostatic pressing;

preparing the graphene copper-magnesium alloy ingot blank into a bar blank;

continuously extruding the rod blank to obtain a graphene copper magnesium alloy rod material; and

carrying out cold drawing on the graphene copper magnesium alloy rod material according to a preset size and shape to obtain a graphene copper magnesium alloy contact line;

the graphene is mixed with other components in a powder form, and the mass percentage of the graphene in the graphene copper magnesium alloy powder is 0.01% -0.20%.

In one embodiment, in the graphene copper magnesium alloy powder, the mass percentage of graphene is 0.05% -0.15%.

In one embodiment, in the graphene-copper-magnesium alloy powder, the mass percentage of magnesium is 0.05% -1.0%.

In one embodiment, the alloy powder for providing graphene copper magnesium includes:

atomizing the copper-magnesium alloy melt through high-pressure fluid in a non-oxidizing atmosphere, and selecting powder with the particle size of 10-70 mu m to obtain copper-magnesium pre-alloy powder; and

and mixing the copper-magnesium pre-alloy powder with graphene powder to obtain graphene-copper-magnesium alloy powder.

In one embodiment, the mixing the copper-magnesium pre-alloy powder with graphene powder to obtain graphene-copper-magnesium alloy powder includes:

adding the copper-magnesium pre-alloy powder and the graphene powder into a solvent, and sequentially performing ultrasonic stirring and stirring or simultaneously performing ultrasonic stirring to obtain a suspension; and

and filtering the suspension, and drying the solid obtained by filtering under a vacuum condition or drying the solid in a non-oxidizing atmosphere to obtain the graphene copper magnesium alloy powder.

In one embodiment, the drying temperature is 50-70 ℃, and the drying temperature in the non-oxidizing atmosphere is 150-220 ℃.

In one embodiment, the copper-magnesium pre-alloy powder is replaced by elemental copper powder and elemental magnesium powder.

In one embodiment, the solvent is one or more selected from the group consisting of deionized water, absolute ethanol, aqueous ethanol, acetone, and N-methylpyrrolidone.

In one embodiment, the power of the ultrasound is 2kW to 3kW, the power of the ultrasound is 20kHz to 25kHz, and the time of the ultrasound is 10min to 30 min.

In one embodiment, the hot isostatic pressing pressure is 120 MPa-140 MPa, the temperature is 800-900 ℃, and the hot isostatic pressing time is 3-5 h.

In one embodiment, the step of forming the graphene copper magnesium alloy ingot blank into a bar blank includes: and extruding the graphene copper-magnesium alloy ingot blank at the temperature of 800-920 ℃ to obtain a rod blank.

A graphene copper magnesium alloy contact line is obtained by any one of the preparation methods.

According to the preparation method of the graphene copper magnesium alloy contact wire, the graphene copper magnesium alloy powder is used as a raw material, and the graphene copper magnesium alloy contact wire is obtained through the processes of hot isostatic pressing sintering, continuous extrusion, cold drawing and the like. The tensile strength of the obtained graphene copper-magnesium alloy contact line is 520-580 MPa, the conductivity of the obtained graphene copper-magnesium alloy contact line is 75-80% IACS, the requirements of a higher-speed railway on the high strength and the high conductivity of the contact line can be met, and the power transmission loss is effectively reduced.

Detailed Description

To facilitate an understanding of the invention, the invention is described more fully below with reference to the preferred embodiments. The invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The embodiment of the invention provides a preparation method of a graphene copper-magnesium alloy contact line, which comprises the following steps:

s100: providing alloy powder of graphene, copper and magnesium;

s200: sintering the graphene copper magnesium alloy powder into a graphene copper magnesium alloy ingot blank by adopting hot isostatic pressing;

s300: preparing the graphene copper-magnesium alloy ingot blank into a bar blank;

s400: continuously extruding the rod blank to obtain a graphene copper magnesium alloy rod material;

s500: carrying out cold drawing on the graphene copper magnesium alloy rod material according to a preset size and shape to obtain a graphene copper magnesium alloy contact line;

the graphene is mixed with other components in a powder form, and the mass percentage of the graphene in the graphene copper magnesium alloy powder is 0.01-0.20%.

The preparation method of the graphene copper magnesium alloy contact line in the embodiment of the invention takes graphene copper magnesium alloy powder as a raw material, wherein the graphene is mixed with other components in a powder form, and the mass percentage of the graphene is 0.01-0.20%. The method comprises the steps of sintering by hot isostatic pressing, and then adopting the technical steps of preparing a rod blank, continuously extruding, cold drawing and the like to ensure that the obtained graphene copper magnesium alloy contact line has excellent mechanical property and high conductivity. In the embodiment of the invention, through the combination of the above process steps, although the graphene content in the alloy powder of graphene, copper and magnesium is only 0.01-0.20% by mass, the contribution of the graphene content to the strength and the conductivity of the contact line of the graphene, copper and magnesium alloy can be fully exerted.

In the conventional method for preparing the graphene copper alloy contact line, graphene powder is added into a molten copper alloy, and the graphene powder can float on the surface of the molten copper alloy and is difficult to enter the copper alloy. Therefore, graphene and copper alloy cannot be uniformly mixed, and the enhancement effect of graphene on the overall properties of the contact line is greatly reduced.

In the invention, the graphene-copper-magnesium alloy contact wire is mixed with other components in a powder form, so that the uniformity of each component in the graphene-copper-magnesium alloy contact wire is ensured, and the enhancement effect of the graphene on the overall performance of the contact wire can be realized under the condition of lower graphene consumption.

In the invention, powder graphene is adopted, and preferably physically stripped graphene is adopted, wherein the sheet diameter of the graphene is 5-15 mu m, and the number of layers is less than or equal to 5.

In an embodiment, in the graphene copper magnesium alloy powder, the mass percentage of graphene is 0.05% to 0.15%.

In an embodiment, in the graphene copper magnesium alloy powder, the mass percentage of magnesium is 0.05% to 1.0%.

In the embodiment of the invention, magnesium can also play a role in increasing the contact line strength, but the influence on the conductivity is large, and the content of magnesium is controlled to be 0.05-1.0%. Preferably, the magnesium content is controlled to be 0.05-0.5% by weight, so that the comprehensive performance of the obtained graphene copper-magnesium alloy contact line is ensured to be high. The contact line has high strength and high conductivity.

In an embodiment, in the graphene-copper-magnesium alloy powder, the mass percentage of graphene is 0.01% to 0.20%, the mass percentage of magnesium is 0.05% to 1.0%, and the balance is copper. Further, in the graphene-copper-magnesium alloy powder, the mass percentage of graphene is 0.05% -0.15%, the mass percentage of magnesium is 0.05% -0.5%, and the balance is copper.

In an embodiment, in the graphene-copper-magnesium alloy powder, a mass ratio of graphene to magnesium is 1:100 to 4: 1. Preferably, the mass ratio of the graphene to the magnesium is 1: 20-3: 1. More preferably, the mass ratio of the graphene to the magnesium is 1: 8-3: 1.

In the embodiment of the application, the mass ratio of graphene to magnesium is limited, and the matching of high strength and high conductivity is realized through the combined action of graphene and magnesium elements.

The step S100 of providing graphene copper magnesium alloy powder, which may be obtained by mixing copper magnesium alloy powder and graphene powder; or mixing the copper simple substance powder, the magnesium simple substance powder and the graphene powder.

In an embodiment, the step S100 of providing the alloy powder of graphene, copper and magnesium may include:

s110: atomizing the copper-magnesium alloy melt through high-pressure fluid in a non-oxidizing atmosphere, and selecting powder with the particle size of 10-70 mu m to obtain copper-magnesium pre-alloy powder;

s120: and mixing the copper-magnesium pre-alloy powder with graphene powder to obtain graphene-copper-magnesium alloy powder.

In the embodiment of the present invention, the high pressure fluid refers to a non-oxidizing gas with a gas pressure of 2 to 10 atmospheres, for example, the non-oxidizing gas may be nitrogen or argon.

In an embodiment, step S120 is further optimized, where step S120 mixes the copper-magnesium pre-alloy powder with graphene powder, and obtaining the graphene-copper-magnesium alloy powder includes:

s121: adding the copper-magnesium pre-alloy powder and the graphene powder into a solvent, and sequentially performing ultrasonic stirring and stirring or simultaneously performing ultrasonic stirring to obtain a suspension;

s122: and filtering the suspension, and drying the solid obtained by filtering under a vacuum condition or drying the solid in a non-oxidizing atmosphere to obtain the graphene copper magnesium alloy powder.

In the embodiment of the invention, in the process of adding the copper-magnesium pre-alloy powder and the graphene powder into the solvent to obtain the suspension, the ultrasound is introduced to enable the powder to be mixed in the solvent more uniformly, so that the agglomeration of graphene is avoided. In operation, the ultrasonic treatment can be carried out firstly, and then the stirring can be carried out; or sonication while stirring.

In one embodiment, the ultrasonic time in step S121 is 10min to 30min, the ultrasonic power is 2kW to 3kW, the ultrasonic power is 20kHz to 25kHz, and the stirring time is 2h to 3 h.

In step S122, the drying temperature for drying under the vacuum condition is 50-70 ℃, and the drying time is 15-20 h; if the drying is carried out in the non-oxidizing atmosphere, the drying temperature is 150-220 ℃, and the drying time is 0.5-5 min. Therefore, drying is carried out in a blow-drying mode, the time consumption is shorter, and the treatment period can be shortened.

In one embodiment, the solvent is a polar solvent, and the polar solvent can promote uniform mixing of the copper-magnesium pre-alloy powder and the graphene powder.

Further, the polar solvent is one or more selected from deionized water, absolute ethyl alcohol, acetone or N-methyl pyrrolidone. Preferably, in the case of using the above solvent, the uniform mixing of the copper-magnesium pre-alloy powder and the graphene powder can be promoted, i.e., the copper-magnesium pre-alloy powder and the graphene powder can be sufficiently mixed without adding a surfactant.

Further, the solvent is deionized water, absolute ethyl alcohol or a mixture of the two. The deionized water and the absolute ethyl alcohol have the advantages of low cost and low toxicity.

In the embodiment of the invention, the graphene is dispersed more uniformly in the finally obtained graphene-copper-magnesium alloy powder by adopting the introduction of the ultrasonic wave. Further, the ultrasonic condition is preferably that the ultrasonic power is 2kW to 3kW, the ultrasonic power is 20kHz to 25kHz, and the ultrasonic time is 10min to 30 min.

In an embodiment, in step S122, filtering the suspension, and drying the filtered solid under a vacuum condition to obtain the graphene-copper-magnesium alloy powder, which may be replaced by:

s122': and filtering the suspension, drying the solid obtained by filtering at the temperature of 150-220 ℃ in a non-oxidizing atmosphere, and obtaining the graphene copper magnesium alloy powder. Wherein the non-oxidizing atmosphere can be inert gas or nitrogen, etc.

The drying time required by the drying in the step S122' can be reduced, and the drying time is 0.5 min-5 min.

In an embodiment, the step S100 of providing the alloy powder of graphene, copper and magnesium may further include:

s110': adding copper simple substance powder, magnesium simple substance powder and graphene powder into a solvent, and sequentially performing ultrasonic stirring or simultaneously performing ultrasonic stirring to obtain a suspension;

s120': and filtering the suspension, and drying the solid obtained by filtering under a vacuum condition to obtain the graphene copper magnesium alloy powder.

In this embodiment, in step S200, the graphene copper magnesium alloy powder is sintered into a graphene copper magnesium alloy ingot blank by using hot isostatic pressing. Wherein the hot isostatic pressing is carried out under the conditions that the pressure is 120MPa to 140MPa and the temperature is 800 ℃ to 900 ℃, and the hot isostatic pressing time is 3h to 5 h.

Sintering is carried out in a hot isostatic pressing mode preferably in the process of obtaining the graphene copper magnesium alloy ingot blank through powder sintering. The hot isostatic pressing sintering method can realize the density of more than 99 percent and effectively realize the molding of the graphene copper-magnesium alloy. The reduction of the tensile strength and the electric conductivity of the material caused by the internal holes is reduced. Meanwhile, the hot isostatic pressing sintering can further avoid the agglomeration of the graphene, and the exertion of the graphene enhancement effect is ensured.

In the embodiment of the present invention, step S300 makes the graphene copper magnesium alloy ingot into a bar blank, wherein the process of preparing the bar blank from the ingot blank can be implemented in various ways. For example, the graphene copper magnesium alloy ingot blank can be cut into a bar blank by a wire cutting or turning process; the graphene copper magnesium alloy ingot blank can also be extruded into a rod blank by adopting an extrusion process.

In one embodiment, the graphene copper magnesium alloy ingot blank is extruded at 800-920 ℃ to obtain a rod blank with a diameter of 15-30 mm. And then, feeding the rod blank into a continuous extruder, and carrying out large plastic deformation under the action of friction force to obtain the graphene copper magnesium alloy rod material with the diameter of 20-32 mm.

In an embodiment, in step S500, the graphene copper magnesium alloy bar material is subjected to cold drawing for 6 to 15 times according to a predetermined size and shape, so as to obtain a graphene copper magnesium alloy contact line.

The embodiment of the invention also provides the graphene copper magnesium alloy contact line, which is obtained by adopting the preparation method.