Low temperature constrained electrodeposition micro-additive manufacturing system and method
By reducing the temperature in the electrodeposition micro-additive manufacturing technology and limiting the ion expansion of the electrodeposition micro-region, the problems of stray deposition and poor localization are solved, and the localization and forming quality of electrodeposition are significantly improved.
Patent Information
- Application Number
- CN202210548556.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-05-20
- Publication Date
- 2025-02-18
- Estimated Expiration
- 2042-05-20
AI Technical Summary
In the existing electrodeposition micro-additive manufacturing technology, the expansion of electrolyte and liquid environments leads to stray deposition, affecting the surface quality and dimensional accuracy of the structure, limiting the application of the technology.
By reducing the temperature, the Brownian motion in the liquid is weakened and the solution diffusion coefficient is reduced, thereby limiting the ion expansion range of the electrodeposition micro-region, slowing down the diffusion rate of metal ions, and improving the localization of the micro-region electrodeposition.
It significantly reduces stray deposition, improves electrodeposition localization and the forming quality of metal microstructures, and enhances dimensional accuracy and surface quality.
Smart Images
Figure CN115198316B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of metal micro-additive manufacturing, and relates to a low-temperature constrained electrodeposition micro-additive manufacturing system and method. Background Art
[0002] Many metal micro-nano structures are used in micro-nano photonics and electronic devices in the industrial field. These micro-nano structures are small in size, complex in structure and rich in functions, and play an important role in optoelectronic integration, bio-labeling and surface enhanced spectroscopy. In order to adapt to the development trend of such metal microstructures with miniaturization, diversified functions and complex structures, metal microstructures are developing in the direction of small size, multi-dimensionality, high quality and complex structure. The manufacturing technology involved is the research frontier and hot spot in the relevant fields.
[0003] In the near future, the industry has invested a lot of money in the research of metal micro-additive manufacturing technology to meet the growing demand for metal three-dimensional micro-nano structures in the rapid development of industry. Many metal micro-additive manufacturing technologies have emerged one after another, among which the most cutting-edge and highly concerned metal micro-additive manufacturing technology with the greatest development potential is electrodeposition micro-additive manufacturing technology.
[0004] Electrodeposition is theoretically very suitable for metal micro-additive manufacturing. As long as the metal ions generated by the reduction reaction are induced to accumulate in a controlled manner by certain means, metal three-dimensional micro-nano structures of any shape and size can be formed. In recent years, many researchers have devoted a lot of energy to the study of electrodeposition micro-additive manufacturing. The innovative technology they proposed can realize the free accumulation of deposited metals in three-dimensional space, making the electrodeposition micro-additive manufacturing technology emerge in the field of metal micro-additive manufacturing. At present, the most representative ones are FluidFM (fluidic force microscope) electrodeposition technology and SICM (scanningion conductance microscopy) electrodeposition technology. This type of technology uses a pipette to continuously construct a metal ion aqueous solution micro-area in a liquid environment (composed of a water-based conductive solution, generally a dilute solution of an amorphous acid), regulate the distribution area of the metal ion aqueous solution, and then realize local area electrodeposition, and finally achieve the purpose of forming a metal microstructure. Since the position of the electrolyte micro-area in the liquid environment can be quickly switched by controlling the movement path of the micro-nano probe, it can be competent for metal accumulation at any position, making this method the most promising electrodeposition three-dimensional micro-manufacturing technology at present.
[0005] However, since the electrolyte and the liquid environment are composed of water and electrolyte, the electrolyte micro-area is very easy to expand in the liquid environment, and the stray deposition in the process (the re-deposition of diffused metal ions on the surface of the formed structure) will seriously affect the surface quality and dimensional accuracy of the structure. This technology is currently the most promising three-dimensional micro-additive manufacturing technology for electrodeposition, but due to the existence of the above-mentioned problems, it has been stuck at this stage and cannot achieve a breakthrough, which greatly curbs the application of this technology in the practical engineering field. Whether the problem of stray deposition and poor localization can be solved has become the key to whether this technology can replace traditional electrodeposition technology and move from quasi-three-dimensional micro-additive manufacturing to true three-dimensional manufacturing. Relevant researchers have tried to reduce the expansion range of the electrodeposition micro-area in the liquid environment and improve the localization by changing the shape and diameter of the pipette, the electrolyte supply pressure, the electric field distribution and the deposition time, but all have little effect. The present invention reduces the Brownian motion speed of the solution by temperature change, limits the expansion range of the ions in the electrodeposition micro-area, and has achieved remarkable results in solving stray deposition and improving localization performance. Summary of the invention
[0006] The present invention is a low-temperature constrained electrodeposition micro-additive manufacturing system and method. Since low temperature will weaken the Brownian motion in the liquid, greatly reduce the liquid diffusion coefficient, and slow down the movement of ions in the solution. The invention applies this principle to the field of electrodeposition micro-additives, using low temperature to reduce the expansion coefficient of the electrolyte micro-region in the liquid environment, reduce the diffusion rate of metal ions in the liquid environment, slow down the expansion of the electrolyte micro-region, reduce stray deposition, and improve the localization of micro-region electrodeposition.
[0007] A low-temperature constrained electrodeposition micro-additive manufacturing system, wherein the low temperature is -2°C to 5°C, and the system comprises an electrodeposition microgroove, a cathode substrate disposed at the bottom of the electrodeposition microgroove, a quartz glass pipette disposed above the cathode substrate, a pressure pump connected to the inlet end of the quartz glass pipette, an anode and a reference electrode disposed in the electrodeposition microgroove; the system is characterized in that: the pipette orifice is located 50nm to 300nm above the deposition area on the surface of the cathode substrate; the system further comprises a cooling tube disposed in the electrodeposition microgroove, and a refrigeration circulating water bath connected to the cooling tube.
[0008] The manufacturing method using the low-temperature constrained electrodeposition micro-additive manufacturing system comprises the following steps: step 1, filling a metal ion aqueous solution into a quartz glass pipette, installing a cooling tube, a cathode substrate, an anode and a reference electrode in an electrodeposition microgroove, and moving the quartz glass pipette, with its orifice located above the deposition area on the surface of the cathode substrate; step 2, adding a water-based conductive solution into the electrodeposition microgroove, with its liquid level exceeding the orifice of the quartz glass pipette, the cathode substrate, the cooling tube, the anode and the reference electrode; step 3, opening a refrigeration circulating water bath externally connected to the cooling tube, allowing the coolant to flow into the cooling tube, and setting the temperature of the coolant; and The monitoring device monitors the temperature change of the water-based conductive solution in real time until its temperature is equal to the set temperature of the coolant; the set temperature is -2°C~5°C, which is higher than the freezing point temperature of the metal ion aqueous solution and the water-based conductive solution; step 4, controlling the pressure in the quartz glass pipette by adjusting the pressure pump, so that the metal ion aqueous solution in the quartz glass pipette slowly enters the water-based conductive solution, and constructs a metal ion aqueous solution micro-region in the deposition area on the surface of the cathode substrate; setting the cathode substrate voltage, together with the anode and the reference electrode immersed in the water-based conductive solution, constitute a closed electrical circuit, so that the metal ions are reduced on the cathode surface to form a metal layer.
[0009] In step 1, the pipette mouth is located 50nm~300nm above the deposition area on the surface of the cathode substrate. This distance determines the morphology of the electrodeposition micro-area and greatly affects the growth stability and growth trend of the metal deposit. In step 2, ensure that all conductive elements form a closed electrical circuit. In step 3, the temperature of the water-based conductive solution is equal to the temperature set by the coolant. At this time, the Brownian motion in the metal ion aqueous solution and the water-based conductive solution is weakened, and the ion diffusion rate is reduced, which creates favorable conditions for the formation of the metal ion aqueous solution micro-area. In step 4, the desired structure is finally obtained by controlling the moving path of the quartz glass pipette. The results of the metal columnar deposits obtained by this method show that the electrodeposition range is significantly reduced under low temperature constraints, the surface quality of the deposits is improved, and the localization of the electrolyte micro-area deposition is improved.
[0010] In the low-temperature constrained electrodeposition micro-additive manufacturing system and method, the coolant is generally a mixture of an organic solution and water, with a ratio range of 5:1 to 8:1, and a freezing point range of the mixture of -8°C to -20°C. Since the freezing point of water is 0°C, it is easy to freeze at the set temperature of the refrigeration circulation water bath, and organic solutions such as alcohols have a low ignition point and pose a safety hazard to the experiment. The use of the mixture of the two can achieve the effect of low-temperature confinement while ensuring the safety of the experiment, wherein the organic solvent is generally propylene glycol or ethylene glycol.
[0011] In the low-temperature constrained electrodeposition micro-additive manufacturing system and method, the outflow rate of the metal ion aqueous solution in the quartz glass pipette is determined by the pressure in the tube, the gravity of the solution, the driving force of the concentration gradient and the resistance of the tube wall. When the diameter of the quartz glass pipette is small or the concentration of the metal ion aqueous solution is too high, the gravity of the metal ion aqueous solution is not enough to resist the resistance of the tube wall, and the pressure in the quartz glass pipette can be set to positive pressure to accelerate the outflow of the metal ion aqueous solution; when the diameter of the quartz glass pipette is large or the concentration of the metal ion aqueous solution is small, the resistance of the tube wall is not enough to resist the gravity of the metal ion aqueous solution, and it can also be set to negative pressure to slow down the outflow of the metal ion aqueous solution. In any case, the outflow of trace metal ion aqueous solution can be guaranteed.
[0012] The present invention aims to construct a low-temperature solution environment, reduce the degree of Brownian motion of solution ions by low temperature, slow down the diffusion rate of metal ions in the liquid environment, limit the expansion range of the electrolyte micro-region, improve the localization of micro-region electrodeposition, and optimize the dimensional accuracy and forming quality of metal microstructures.
[0013] Beneficial results of the present invention: a low-temperature constrained electrodeposition micro-additive manufacturing system and method are proposed. This method applies the phenomenon that low temperature reduces the movement rate of solution ions to the electrodeposition micro-additive manufacturing technology process. This method has a simple system structure, convenient operation, low processing cost, and high recycling rate; by lowering the temperature, the expansion range of the electrolyte per unit time is limited, the electrodeposition reaction area is reduced, the stray deposition is effectively reduced, and the localization of micro-area electrodeposition is improved. After experimental demonstration, it was preliminarily shown that low temperature has the ability to reduce the expansion range of the electrolyte micro-area and slow down the diffusion rate of solution ions. The expansion rate of the electrolyte micro-area is reduced from 6um / s at room temperature of 30°C to 1.5~2um / s at -2°C~5°C, which significantly improves the localization of electrodeposition. In addition, low temperature can also refine the grain size and improve the surface finish of the metal deposition layer, which provides an effective means to improve the surface quality and forming accuracy of the electrodeposition product and assist the electrodeposition micro-additive manufacturing technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 :Schematic diagram of the principle of low-temperature confined electrodeposition micro-additive manufacturing;
[0015] Figure 2 :Diffusion range of micro-area electrodeposition at different temperatures;
[0016] The reference numerals in the figure are: 1-pressure pump, 2-metal ion aqueous solution, 3-quartz glass tube, 4-anode, 5-water-based conductive solution, 6-cathode substrate, 7-deposition microgroove, 8-reference electrode, 9-cooling tube, 10-refrigeration circulating water bath. DETAILED DESCRIPTION
[0017] The present invention patents a low temperature constrained electrodeposition micro-additive manufacturing system and method, combined with Figure 1 , Figure 2 The specific implementation process of the present invention is described in detail:
[0018] Step 1: Fill the metal ion aqueous solution 2 into the quartz glass pipette 3, install the cooling tube 9, cathode substrate 6, anode 4 and reference electrode 8 in the electrodeposition microgroove 7, and move the quartz glass pipette 3 so that its mouth is located above the deposition area on the surface of the cathode substrate 6.
[0019] Step 2: Add a water-based conductive solution 5 into the electrodeposition tank 7 so that its liquid level exceeds the mouth of the quartz glass pipette 3, the cathode substrate 6, the cooling tube 9, the anode 4 and the reference electrode 8.
[0020] Step 3, open the refrigeration circulation water bath 10 connected to the cooling tube 9, allow the coolant to flow into the cooling tube 9, and set the temperature of the coolant; monitor the temperature change of the water-based conductive solution in real time through the temperature monitoring device until its temperature is equal to the set temperature of the coolant.
[0021] Step 4, by regulating the pressure pump 1 to control the pressure in the quartz glass pipette 3, the metal ion aqueous solution 2 in the quartz glass pipette 3 slowly enters the water-based conductive solution 5, and a metal ion aqueous solution micro-region is constructed in the deposition area on the surface of the cathode substrate 6; the cathode substrate voltage is set to reduce the metal ions on the cathode surface to form a metal layer;
[0022] The cooling tube of the present invention needs to be placed below the liquid surface of the water-based conductive solution to ensure the best thermal conductivity. Preliminary verification through micro-area electrodeposition test, the metal ion aqueous solution is a copper sulfate solution (220g / LCuSO4, 60g / LH2SO4), the water-based conductive solution is a 20g / L sulfuric acid solution, the inner diameter of the quartz glass pipette is 500um, the distance between the quartz glass pipette and the cathode substrate is 500nm, the electrodeposition time is 5s, the cathode substrate voltage is -0.7V, the pressure in the tube is 1mbar, the test results are as follows Figure 2 As shown in the figure, when the solution temperature is 30℃, 5℃ and -2℃, the diameter of the micro-region electrodeposition range is about 60um, 20um and 15um respectively. The radius of the electrodeposition micro-region divided by the electrodeposition time is defined as the expansion rate of the electrolyte micro-region. The corresponding micro-region expansion rates at three different solution temperatures are 6um / s, 2um / s and 1.5um / s respectively. The experiment shows that under low temperature environment, the expansion range of the electrolyte micro-region in the liquid environment is reduced, and the localization of electrodeposition is improved.
Claims
1. A low-temperature constrained electrodeposition micro-additive manufacturing system, wherein the low temperature is -2°C to 5°C, the system comprising an electrodeposition microgroove (7), a cathode substrate (6) disposed at the bottom of the electrodeposition microgroove (7), a quartz glass pipette (3) located above the cathode substrate (6), a pressure pump (1) connected to the inlet end of the quartz glass pipette (3), an anode (4) disposed in the electrodeposition microgroove (7), and a reference electrode (8); Features : The pipette mouth is located 50nm~300nm above the deposition area on the surface of the cathode substrate (6); the system also includes a cooling tube (9) placed in the electrodeposition microgroove (7), and a refrigeration circulation water bath (10) connected to the cooling tube (9).
2. The manufacturing method using the low temperature confined electrodeposition micro-additive manufacturing system of claim 1 comprises the following steps: Step 1, filling a metal ion aqueous solution (2) into a quartz glass pipette (3), installing a cooling tube (9), a cathode substrate (6), an anode (4) and a reference electrode (8) in an electrodeposition microtrough (7), and moving the quartz glass pipette (3) so that its orifice is located 50 nm to 300 nm above the deposition area on the surface of the cathode substrate (6); Step 2, adding a water-based conductive solution (5) into the electrodeposition microtrough (7) so that the liquid level exceeds the mouth of the quartz glass pipette (3), the cathode substrate (6), the cooling tube (9), the anode (4) and the reference electrode (8); Step 3, opening the refrigeration circulating water bath (10) connected to the cooling tube (9), allowing the coolant to flow into the cooling tube, and setting the temperature of the coolant; monitoring the temperature change of the water-based conductive solution in real time through the temperature monitoring device until the temperature thereof is equal to the set temperature of the coolant; the set temperature is -2°C to 5°C, which is higher than the freezing point temperature of the metal ion aqueous solution (2) and the water-based conductive solution (5); Step 4: by regulating the pressure pump (1) to control the pressure in the quartz glass pipette (3), the metal ion aqueous solution (2) in the quartz glass pipette slowly enters the water-based conductive solution (5), and a metal ion aqueous solution micro-region is constructed in the deposition area on the surface of the cathode substrate (6); the voltage of the cathode substrate (6) is set to form a closed electrical circuit together with the anode and the reference electrode immersed in the water-based conductive solution, so that the metal ions are reduced on the cathode surface to form a metal layer.
3. The manufacturing method of the low temperature confined electrodeposition micro-additive manufacturing system according to claim 2 is characterized in that The coolant is a mixture of an organic solution and water in a ratio range of 5:1 to 8:1, and the freezing point range of the mixture is -8°C to -20°C.
4. The manufacturing method of the low temperature confined electrodeposition micro-additive manufacturing system according to claim 3 is characterized in that : The organic solvent is propylene glycol or ethylene glycol.
5. The manufacturing method of the low temperature confined electrodeposition micro-additive manufacturing system according to claim 2, characterized in that: The pressure of the quartz glass pipette (3) is adjusted by a pressure pump (1), and the pressure in the pipette is set to a positive pressure to accelerate the outflow of the metal ion aqueous solution (2), or to a negative pressure to slow down the outflow speed of the metal ion aqueous solution (2).