阅读说明：本技术 一种利用复杂脉冲电镀石墨烯-金属复合材料镀层的方法和一种pcb及电机 (Method for electroplating graphene-metal composite material coating by using complex pulse, PCB and motor ) 是由 黄迎春 刘焕明 于 2018-06-21 设计创作，主要内容包括：本发明涉及材料表面工程技术领域,提供了利用复杂脉冲电镀石墨烯-金属复合材料镀层的方法和一种PCB及电机。所述方法具体包括以离子液作为电镀液,所述离子液中分散有氧化石墨烯,所述离子液中还含有金属离子；由电流或电压控制脉冲,在阴极衬底上沉积得到石墨烯-金属复合材料镀层,所述电流或电压控制脉冲包括正向脉冲时期、反向脉冲时期和停顿时期。所述方法工艺简单、成本低、无传统电镀的环境污染,能应用于大面积涂层或薄膜生产。所述PCB包括基材板和底层导电线丝,利用上述方法制造石墨烯-金属复合材料镀层和导电线。本发明还将所述含石墨烯导电线印绕在PCB上做成无刷电机定子,从而提供了一种新型电机。(The invention relates to the technical field of material surface engineering, and provides a method for electroplating a graphene-metal composite material coating by using complex pulses, a PCB (printed circuit board) and a motor. The method specifically comprises the steps of taking an ionic liquid as an electroplating solution, wherein graphene oxide is dispersed in the ionic liquid, and the ionic liquid also contains metal ions; and depositing a graphene-metal composite material coating on the cathode substrate by current or voltage control pulses, wherein the current or voltage control pulses comprise a forward pulse period, a reverse pulse period and a pause period. The method has simple process and low cost, does not have the environmental pollution of the traditional electroplating, and can be applied to the production of large-area coatings or films. The PCB comprises a substrate plate and a bottom layer conductive wire, and the graphene-metal composite plating layer and the conductive wire are manufactured by the method. The invention also discloses a novel motor which is formed by printing and winding the graphene-containing conductive wire on a PCB (printed Circuit Board) to form a brushless motor stator.)

1. A method for electroplating a graphene-metal composite coating by using complex pulses is characterized by comprising the following steps:

taking an ionic liquid as an electroplating liquid, wherein graphene oxide is dispersed in the ionic liquid, and the ionic liquid also contains metal ions;

depositing a graphene-metal composite material coating on a cathode substrate by a current control pulse, wherein the current control pulse comprises a positive pulse period when current and voltage are negative on a deposition surface, a reverse pulse period when current and voltage are positive on the deposition surface, and a period comprising one or more of the following a-c, a pause period when the current is zero, b period when the current is negative and the voltage is positive, c period when the current is positive and the voltage is negative; alternatively, the first and second electrodes may be,

and depositing a graphene-metal composite coating on the cathode substrate by a voltage control pulse, wherein the voltage control pulse comprises a positive pulse period when the voltage and the current are negative on the deposition surface, a reverse pulse period when the voltage and the current are positive on the deposition surface, and a period comprising one or more of d-f, a pause period when the d voltage is zero, a period when the e voltage is negative and the current is positive, and a period when the f voltage is positive and the current is negative.

2. The method according to claim 1, wherein the ionic liquid is a choline chloride and ethylene glycol system, and the molar ratio of the choline chloride to the ethylene glycol is 1-4: 2; or the ionic liquid is a choline chloride and urea system, and the molar ratio of the choline chloride to the urea is 1-4: 2.

3. The method according to claim 2, wherein the ionic liquid is a choline chloride and ethylene glycol system, and the molar ratio of the choline chloride to the ethylene glycol is 1: 2.

4. The method according to claim 1, wherein the metal ions contained in the ionic liquid are any one or more of copper ions, chromium ions, gallium ions, indium ions, iron ions, nickel ions, silver ions, platinum ions, and gold ions.

5. The method according to claim 4, wherein the metal ions contained in the ionic liquid are copper ions, and the concentration of the copper ions in the ionic liquid is 1-60 mM; the concentration of the graphene oxide in the ionic liquid is 0.2-1.0 g/L.

6. The method according to claim 5, wherein the concentration of copper ions in the ionic liquid is 10 to 20 mM; the concentration of the graphene oxide in the ionic liquid is 0.4-0.6 g/L.

7. The method according to claim 1, wherein the current control pulse has a forward pulse period of 10ms to 100ms on time, a current density of-5.5 ASD to-0.1 ASD; the working time of the reverse pulse period is 1-50 ms, and the current density is 0.1-1.5 ASD; the pause time is 10 ms-100 ms.

8. The method according to claim 7, wherein the current control pulse has a forward pulse period of 30ms to 50ms on time, a current density of-3.5 to-1.5 ASD; the working time of the reverse pulse period is 5-20 ms, and the current density is 0.1-1.0 ASD; the dwell time is 50ms to 70 ms.

9. The method according to claim 1, wherein the working time of the positive pulse period of the voltage control pulse is 10ms to 100ms, the voltage is-4.5 to-0.1V; the working time of the reverse pulse period is 1-50 ms, and the voltage is 0.1-2.0V; the pause time is 10 ms-100 ms.

10. The method according to claim 1, further comprising stirring the ionic liquid with a stirrer at a speed of 50 to 200r/min during the pulse plating.

11. The method of claim 1, wherein all or a portion of the metal ions in the ionic liquid are introduced into the ionic liquid by anodic oxidation.

12. A PCB comprising one or more substrate sheets and a bottom conductive filament on a surface of the substrate sheets, the bottom conductive filament having a graphene-metal composite layer electroplated by the method of any of claims 1-11.

13. The PCB of claim 12, wherein the metal element in the graphene-metal composite layer is any one or more of copper, chromium, gallium, indium, iron, nickel, silver, platinum, and gold.

14. The PCB of claim 13, wherein the metal element in the graphene-metal composite layer is copper, and the graphene-metal composite is a copper-graphene-in-copper composite.

15. The PCB of claim 14, wherein a base of the bottom layer conductive wire is a copper-containing wire.

16. An electrical machine comprising a machine stator, wherein the machine stator comprises a PCB as claimed in any one of claims 12 to 15.

Technical Field

The invention relates to the technical field of material surface engineering, in particular to a method for electroplating a graphene-metal composite material coating by using complex pulses, a PCB manufactured by using the method, and a motor using the PCB.

Background

Graphene is an ultra-thin graphite containing only a single atomic layer or a few atomic layers, each atomic layer consisting of sp²The hybridized carbon atoms form a regular hexagonal lattice, a honeycomb two-dimensional structure, and were first prepared and characterized in 2004 by Kostya Novoselov and Andre Geim, university of manchester, england, using a simple method known as mechanical microstress technology.

Graphene is the highest strength substance known to humans, and has many novel physical properties. Graphene is the best material known at present for conducting at normal temperature, and the conductivity of graphene far exceeds that of a common conductor. In addition, graphene can be used to produce composite materials which have been used in the production of batteries/supercapacitors, hydrogen storage, photovoltaic devices and systems, sensors, etc. The graphene composite metal material is prepared by adding a small amount of graphene into a metal material, so that the conductivity and other properties of the metal material are optimized at low cost.

At present, a plurality of methods for preparing graphene composite metal materials are available, wherein a bulk casting and pressing workpiece can be prepared by adopting a powder sintering technology and then pressed into sheets, for example, a patent with the publication number of CN 104264000B provides a graphene modified high-heat-conductivity aluminum-based composite material and a powder metallurgy preparation method thereof, and for example, a patent in the pending publication number of CN201611082597.4 provides a high-electric-conductivity graphene/copper-based layered composite material and a preparation method thereof, wherein the latter comprises the steps of firstly wrapping metal copper nano powder by a chemical vapor deposition method and then sintering the metal copper nano powder into a compact block by powder sintering. Although plates and pipes made by this type of technique are widely used, they are not suitable for applications requiring large area coatings or films.

Chemical vapor deposition methods commonly used for preparing large-area thin films are also adopted for preparing copper/graphene/copper multilayer composite films, such as "Strength characterization effect of single-atomic-layer graphene atomic-layer composites" (Nature Communication 4, 2114(2013)) of Kim and "Thermal properties of graphene-coppers-graphene multilayer composites" (Nano Letters 14,1497(2014)) of Goli. However, the preparation method has high cost, complex process and needs high-temperature high-vacuum and other preparation environments, so that large-area industrial production of the graphene composite metal material is not realized.

Electroplating methods widely used for producing metal Thin and thick Films are also used to trial produce graphene composite metal coatings, such as those provided by Jagannadham "Thermal conductivity of Copper-graphene composite plated Films" (Metal. Mater. Trans. B43, 316(2012)), Maharana "Surface-mechanical and electrical properties of plated Copper-graphene oxide composite plated Films" (J. Mater. Sci.52, 2019 (2017)) and Raghupath "Copper-graphene oxide composite plated Films for coating Films" (NaCl 3, 636% NaCl). In addition, for example, the pending patent publication No. CN 201410848015.3 provides an aluminum-based copper-plated graphene thin film composite material with high thermal conductivity and a preparation method thereof, the pending patent publication No. CN 201710247094.6 provides a method for preparing a graphene/copper composite material by using aerobic sintering, and the pending patent publication No. CN 201710680997.3 provides a reduced graphene oxide-copper composite coating and a preparation method and application thereof. Although the methods can deposit the graphene composite copper coating, the traditional water-based electroplating is adopted, the development of the method is limited due to environmental pollution, graphene oxide needs to be deposited and converted into reduced graphene in the water-based metal electroplating process, and hydrogen is prevented from being released by electrolysis of water, so far, the difficulties can not be overcome by the practical production technology.

Disclosure of Invention

The invention aims to provide a method for electroplating a graphene-metal composite material coating by using complex pulses, a PCB manufactured by using the method, and an application of the PCB to a motor. The method has simple process and lower cost, does not relate to the problem of environmental pollution, and can be applied to the production of large-area coatings or films.

In order to achieve the purpose, the invention provides the following technical scheme:

in one aspect, an embodiment of the present invention provides a method for electroplating a graphene-metal composite plating layer by using a complex pulse, where the method includes:

taking an ionic liquid as an electroplating liquid, wherein graphene oxide is dispersed in the ionic liquid, and the ionic liquid also contains metal ions;

depositing a graphene-metal composite material coating on a cathode substrate by a current control pulse, wherein the current control pulse comprises a positive pulse period when current and voltage are negative on a deposition surface, a reverse pulse period when current and voltage are positive on the deposition surface, and a period comprising one or more of the following a-c, a pause period when the current is zero, b period when the current is negative and the voltage is positive, c period when the current is positive and the voltage is negative; alternatively, the first and second electrodes may be,

and depositing a graphene-metal composite coating on the cathode substrate by a voltage control pulse, wherein the voltage control pulse comprises a positive pulse period when the voltage and the current are negative on the deposition surface, a reverse pulse period when the voltage and the current are positive on the deposition surface, and a period comprising one or more of d-f, a pause period when the d voltage is zero, a period when the e voltage is negative and the current is positive, and a period when the f voltage is positive and the current is negative.

In the technical scheme, during the pause period, the graphene oxide is adsorbed on the surface of the cathode substrate by Van der Waals force; in a forward pulse period, graphene oxide adsorbed on the surface of a cathode substrate releases an oxidation functional group and is firstly reduced into graphene, then metal ions in ionic liquid are reduced on the cathode substrate, and the reduced graphene oxide and the metal ions form a graphene-metal composite material coating on the surface of the cathode substrate; in the reverse pulse period, the graphene dendritic structure on the surface of the graphene-metal composite coating is more easily deplated into the ionic liquid due to the tip effect. After the graphene dendritic structure is deplated, the surface of the graphene-metal composite material coating is smoother, the graphene-metal composite material coating formed in the next pulse period is combined with a substrate more compactly, and finally a high-quality graphene-metal composite material coating is formed. In addition, after the electrodeposition in the positive pulse period, the concentrations of the metal ions and the graphene oxide in the ionic liquid near the cathode substrate are lower than those of the metal ions and the graphene oxide in the whole ionic liquid, so that the concentrations of the metal ions and the graphene oxide in the ionic liquid can be recovered and balanced in the pause period, and the electrodeposition can be continued. Because of the capacitance and resistance values included in the electrodeposition system, the current and voltage have periods of opposite positive and negative values during the pulse, such as when the current has turned from a negative value to a positive value and immediately back to a negative value, and the voltage has not had time to turn from a negative value to a positive value and the current has already turned back to a negative value, both will have periods of opposite positive and negative values, which also function as the above-mentioned rest periods.

Preferably, the ionic liquid is a choline chloride and ethylene glycol system, and the molar ratio of the choline chloride to the ethylene glycol is 1-4: 2; or the ionic liquid is a choline chloride and urea system, and the molar ratio of the choline chloride to the urea is 1-4: 2.

Preferably, the ionic liquid is a choline chloride and ethylene glycol system, and the molar ratio of the choline chloride to the ethylene glycol is 1: 2.

Preferably, the metal ions contained in the ionic liquid are any one or more of copper ions, chromium ions, gallium ions, indium ions, iron ions, nickel ions, silver ions, platinum ions, and gold ions.

Preferably, the metal ions contained in the ionic liquid are copper ions, and the concentration of the copper ions in the ionic liquid is 1-60 mM; the concentration of the graphene oxide in the ionic liquid is 0.2-1.0 g/L.

Preferably, the concentration of copper ions in the ionic liquid is 10-20 mM; the concentration of the graphene oxide in the ionic liquid is 0.4-0.6 g/L.

Preferably, the working time of the forward pulse period of the current control pulse is 10 ms-100 ms, and the current density is-5.5 ASD to-0.1 ASD; the working time of the reverse pulse period is 1-50 ms, and the current density is 0.1-1.5 ASD; the pause time is 10 ms-100 ms.

Preferably, the working time of the forward pulse period of the current control pulse is 30 ms-50 ms, and the current density is-3.5 ASD to-1.5 ASD; the working time of the reverse pulse period is 5-20 ms, and the current density is 0.1-1.0 ASD; the dwell time is 50ms to 70 ms.

Preferably, the working time of the forward pulse period of the voltage control pulse is 10 ms-100 ms, and the voltage is-4.5 to-0.1V; the working time of the reverse pulse period is 1-50 ms, and the voltage is 0.1-2.0V; the pause time is 10 ms-100 ms.

Further, the method comprises the step of stirring the ionic liquid by using a stirrer during the pulse electroplating, wherein the stirring speed is 50-200 r/min. Through stirring, the concentration of metal ions and graphene oxide in the ionic liquid is more favorably recovered to be balanced, and the electrodeposition is favorably continued.

Preferably, all or part of the metal ions in the ionic liquid enter the ionic liquid after being oxidized by the anode.

In another aspect, an embodiment of the present invention provides a PCB, where the PCB includes one or more substrate boards and a bottom conductive filament on the surface of the substrate board, where the bottom conductive filament has a graphene-metal composite layer, and the graphene-metal composite layer is formed by electroplating according to any one of the above technical solutions.

Preferably, the metal element in the graphene-metal composite material layer is any one or more of copper, chromium, gallium, indium, iron, nickel, silver, platinum and gold. It should be understood that the above-mentioned metal elements should correspond to metal ions contained in the ionic liquid.

Preferably, the metal element in the graphene-metal composite material layer is copper, and the graphene-metal composite material is a composite material containing graphene in copper.

Preferably, the base of the bottom layer conductive wire is a copper-containing wire.

In another aspect, an embodiment of the present invention further provides a motor, where the motor includes a motor stator, and the motor stator includes the PCB in any one of the above embodiments. Any one of the graphene-containing conductive wires is printed and wound on a PCB to form a brushless motor stator, so that a novel motor is provided.

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

1. the ion liquid electroplating is used for replacing water-based electroplating in the prior art, firstly, graphene oxide is easy to disperse uniformly in the ion liquid, and sufficient graphene oxide can be adsorbed on the surface of the ultrathin metal coating of the cathode substrate due to Van der Waals force; the ion liquid contains no water and is used as electroplating liquid, so that hydrogen evolution reaction in electrodeposition can be avoided, hydrogen embrittlement of the coating can be avoided, and no wastewater is discharged. The ionic liquid almost has no evaporation and volatilization, and the ionic liquid is easy to regenerate and can be recycled, so that the green and environment-friendly production can be really realized.

2. In the reverse pulse period, the graphene dendritic structure on the surface of the graphene-metal composite coating is more easily deplated into the ionic liquid due to the tip effect. After the graphene dendritic structure is deplated, the surface of the graphene-metal composite material coating is smoother, the graphene-metal composite material coating formed in the next pulse period is combined with a substrate more compactly, and finally a high-quality graphene-metal composite material coating is formed. And the pause period is favorable for the recovery and the balance of the ion concentration in the ionic liquid, so that the recovery of the metal ions and the graphene oxide near the cathode substrate is improved.

3. Compared with the powder sintering technology, the method provided by the invention can be applied to the production of large-area graphene composite material coatings or films.

4. Compared with a chemical vapor deposition method, the method provided by the invention has the advantages of low cost, simple process and no need of preparation environments such as high temperature and high vacuum, and the like, so that the large-area industrial production of the graphene composite metal material can be realized.

5. The conductive circuit of the existing PCB is usually formed by etching an inner layer to form a bottom copper circuit and electroplating on a bottom copper substrate to form secondary copper, and finally a copper conductive circuit with proper thickness is formed, so that the light weight of the PCB is restricted due to the large total weight of the copper conductive circuit. Compared with a copper material, the density of the graphene-metal composite material is lower and the conductivity is higher due to the addition of the electroplated graphene-metal composite material to the bottom copper (or other metals) formed by etching the inner layer of the PCB provided by the invention, so that the conductive circuit of the PCB provided by the invention can reduce the metal consumption and still ensure the calibrated current bearing, and overcomes the shortages that the PCB is further lightened and the current bearing is further improved.

6. The graphene-metal composite material has good mechanical property and heat conducting property, compared with the existing PCB, the PCB provided by the invention has the advantages of wear resistance, mechanical damage resistance and heat dissipation, and can avoid the obvious change of the wiring resistance of the conducting circuit due to severe temperature rise during the use period of the PCB or after the PCB is used for a long time, thereby avoiding the influence on the transmission of electric signals.

7. The conductive wire containing graphene is printed and wound on the PCB to form the brushless motor stator which is lighter and thinner and can bear higher current than the brushless motor stator manufactured by winding the conductive wire by using a mold frame or by using other methods.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and it will be apparent to those skilled in the art that other relevant drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a graph showing the change in pulse current density according to the first embodiment of example 1.

Fig. 2 is a graph showing the change of the pulse voltage according to the first embodiment in example 1.

Fig. 3 is a macroscopic view of a graphene-metal composite plating layer prepared in the first embodiment of example 1.

Fig. 4 is a raman spectrum of a graphene-metal composite plating layer prepared in the first embodiment of example 1.

Fig. 5 is a graph showing the change in the pulse current density according to the second embodiment in example 1.

Fig. 6 is a graph showing the change of the pulse voltage according to the second embodiment in example 1.

Fig. 7 is a raman spectrum of a graphene-metal composite plating layer prepared in the second embodiment of example 1.

Fig. 8 is a graph showing the change in the pulse current density according to the third embodiment in example 1.

Fig. 9 is a graph showing the change in pulse voltage according to the third embodiment in example 1.

Fig. 10 is a raman spectrum of a plating layer of a graphene-metal composite material prepared in the third embodiment of example 1.

Fig. 11 is a raman spectrum of a graphene-metal composite plating layer prepared in the fourth embodiment of example 1.

Fig. 12 is a raman spectrum of a graphene-metal composite plating layer prepared in the fifth embodiment of example 1.

Fig. 13 is a schematic structural diagram of a PCB provided in embodiment 2.

The reference numbers in the figures illustrate:

10-a substrate sheet; 20-a bottom layer conductive filament; 30-graphene-metal composite layer.

Detailed Description

The technical solution 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. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention without inventive step, are within the scope of the invention.