Electrochemical polishing method and electrolyte

Abstract

The invention provides an electrochemical polishing method and an electrolyte for electrochemical polishing. The electrochemical polishing method comprises the following steps: preparing an electrolyte which comprises phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid and acetic acid according to the volume ratio of a: b: c: d: e: f: g: h: i, and adding 2-5ml of hydrogen peroxide into every 1000ml of the electrolyte, a belongs to (30, 100), b belongs to (3, 20), c belongs to (40, 180), d belongs to (10, 60), e belongs to (1, 5), f belongs to (2, 10), g belongs to (1, 5), h belongs to (5, 10) and i belongs to (10, 30); switching on a direct-current power supply for electrochemical polishing until the alloy achieves a preset polishing effect; and the alloy is taken out and subjected to aftertreatment, and the machined alloy is obtained.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical machining, and particularly to an electrochemical polishing method and an electrolyte for electrochemical polishing. Background Art

[0002] Electrochemical machining technology is a machining method that uses electrochemical reactions to change the surface morphology and properties of materials. This method has a wide range of applications in the field of material surface treatment technology, especially in the application field of noble metal alloys. In the surface treatment of noble metal alloys, electrochemical polishing is a commonly used method, which can effectively remove the micro defects on the material surface and improve the surface finish and properties of the material.

[0003] Existing electrochemical polishing methods add oxidizing acids to the electrolyte, which have certain safety hazards and relatively high experimental costs. Moreover, when processing some special materials (such as palladium alloys, etc.), existing electrochemical polishing methods often require special electrolytes and additives, increasing the complexity of the electrochemical polishing process and also raising the cost.

[0004] In order to overcome the above-mentioned defects existing in the prior art, there is an urgent need in the art for an electrochemical polishing method and an electrolyte for electrochemical polishing, which can achieve precise control of electrochemical reactions by optimizing the composition and ratio of the electrolyte, are applicable to processing various special materials, and can achieve better polishing effects. Summary of the Invention

[0005] The following gives a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0006] In order to overcome the above-mentioned defects existing in the prior art, the present invention provides an electrochemical polishing method and an electrolyte for electrochemical polishing, which can achieve precise control of electrochemical reactions by optimizing the composition and ratio of the electrolyte, are applicable to processing various special materials, and can achieve better polishing effects.

[0007] Specifically, the above-mentioned electrochemical polishing method provided according to the first aspect of the present invention includes the steps of: preparing an electrolyte, the electrolyte includes phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid and acetic acid, and phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid and acetic acid are prepared according to the volume ratio of a:b:c:d:e:f:g:h:i, and 2 to 5 ml of hydrogen peroxide is added to every 1000 ml of the electrolyte, wherein, a ∈ (30, 100), b ∈ (3, 20), c ∈ (40, 180), d ∈ (10, 60), e ∈ (1, 5), f ∈ (2, 10), g ∈ (1, 5), h ∈ (5, 10), i ∈ (10, 30); connecting a DC power supply to perform electrochemical polishing until the alloy reaches a preset polishing effect, wherein the alloy is connected to the anode of the DC power supply; and taking out the alloy and performing post-treatment to obtain the processed alloy.

[0008] Preferably, in an embodiment of the present invention, the upper limit of the voltage and the upper limit of the current of the DC power supply are set according to the type of the alloy and the temperature of the electrolyte.

[0009] Preferably, in an embodiment of the present invention, the upper limit of the voltage is 1 to 60 V, and the upper limit of the current is 0.1 to 10 A.

[0010] Preferably, in an embodiment of the present invention, the alloy is wrapped by a graphite fixture and connected to the anode of the DC power supply through the graphite fixture; and the cathode graphite is evenly distributed on the bottom plate of the electrolytic cell and surrounds the graphite fixture connected to the anode.

[0011] Preferably, in an embodiment of the present invention, the temperature of the electrolyte is controlled at 18 to 30 °C, and the temperature of the process environment is constant.

[0012] Preferably, in an embodiment of the present invention, the humidity of the process environment is 60% to 70%.

[0013] Preferably, in an embodiment of the present invention, the step of connecting a DC power supply to perform electrochemical polishing further includes: when the alloy does not reach the preset polishing effect, adjusting the power supply parameters; and connecting the DC power supply to perform electrochemical polishing according to the adjusted power supply parameters.

[0014] Preferably, in an embodiment of the present invention, the post-treatment includes the steps of: rinsing the alloy with 5% hydrochloric acid for 1 to 3 min; ultrasonically polishing in a cleaning agent for 5 to 8 min; ultrasonically polishing in a 75% alcohol solution for 2 to 3 min; and drying in an oven at 40 to 60 °C.

[0015] Preferably, in an embodiment of the present invention, the alloy includes a palladium alloy, a copper alloy, and / or a silver alloy.

[0016] In addition, the electrolyte for electrochemical polishing provided according to the second aspect of the present invention includes phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid, and acetic acid. The phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid, and acetic acid are prepared according to a volume ratio of a:b:c:d:e:f:g:h:i, and 2 - 5 ml of hydrogen peroxide is added to every 1000 ml of the electrolyte, where a ∈ (30, 100), b ∈ (3, 20), c ∈ (40, 180), d ∈ (10, 60), e ∈ (1, 5), f ∈ (2, 10), g ∈ (1, 5), h ∈ (5, 10), and i ∈ (10, 30). BRIEF DESCRIPTION OF THE DRAWINGS

[0017] After reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above - mentioned features and advantages of the present invention can be better understood. In the drawings, the components are not necessarily drawn to scale, and components with similar relevant characteristics or features may have the same or similar reference numerals.

[0018] Figure 1 Shows a flowchart of an electrochemical polishing method provided according to some embodiments of the present invention;

[0019] Figure 2 Shows a schematic diagram of an anode body provided according to some embodiments of the present invention;

[0020] Figure 3 Shows a schematic diagram of a cathode body provided according to some embodiments of the present invention;

[0021] Figure 4 Shows a schematic diagram of an overall body provided according to some embodiments of the present invention;

[0022] Figure 5 Shows a schematic diagram of an electrolytic cell provided according to some embodiments of the present invention;

[0023] Figure 6 Shows an SEM photograph of the surface of a Pd - Ag alloy sample before electrochemical polishing provided according to Embodiment 1 of the present invention;

[0024] Figure 7 Shows an SEM photograph of the surface of a Pd - Ag alloy sample after electrochemical polishing provided according to Embodiment 1 of the present invention;

[0025] Figure 8 Shows an SEM photograph of the surface of a Pd - Cu alloy sample before electrochemical polishing provided according to Embodiment 2 of the present invention;

[0026] Figure 9 Shows the SEM photograph of the surface of the Pd-Cu alloy sample after electrochemical polishing provided by the second embodiment of the present invention;

[0027] Figure 10 Shows the SEM photograph of the surface of the Pd-Pt alloy sample before electrochemical polishing provided by the third embodiment of the present invention; and

[0028] Figure 11 Shows the SEM photograph of the surface of the Pd-Pt alloy sample after electrochemical polishing provided by the third embodiment of the present invention.

[0029] Reference numerals:

[0030] 200: Anode body;

[0031] 201: Alloy;

[0032] 210: Mosaic;

[0033] 220: Graphite rod;

[0034] 230: Anode chuck;

[0035] 231: Anode wire;

[0036] 300: Cathode body;

[0037] 310: Cathode graphite rod;

[0038] 320: Ring-shaped metal;

[0039] 321: Cathode wire;

[0040] 400: Total body;

[0041] 501, 502, 503: Arrows;

[0042] 510: Electrolytic cell;

[0043] 520: Electrolyte; and

[0044] S110~S130: Steps. Detailed implementation manners

[0045] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are only exemplary and should not be construed as imposing any limitation on the protection scope of the present invention.

[0046] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0047] In addition, the "upper", "lower", "left", "right", "top", "bottom", "horizontal", and "vertical" used in the following description should be understood as the orientations shown in this section and the relevant drawings. This relative term is only for convenience of description and does not represent that the device described needs to be manufactured or operated in a specific orientation, so it should not be understood as a limitation to the present invention.

[0048] It can be understood that although terms such as "first", "second", "third", etc. can be used here to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first component, region, layer, and / or part discussed below can be referred to as the second component, region, layer, and / or part without departing from some embodiments of the present invention.

[0049] As mentioned above, the existing electrochemical polishing method adds oxidizing acid to the electrolyte, which has certain safety hazards and relatively high experimental costs. Moreover, when processing some special materials (such as palladium alloys, etc.), the existing electrochemical polishing method often needs to use special electrolytes and additives, which increases the complexity of the electrochemical polishing process and also raises the cost.

[0050] In order to overcome the above-mentioned defects existing in the prior art, the present invention provides an electrochemical polishing method and an electrolyte for electrochemical polishing, which can achieve precise control of the electrochemical reaction by optimizing the composition and ratio of the electrolyte, are applicable to processing various special materials, and can achieve better polishing effects.

[0051] Next, it will be combined with Figure 1 to describe in detail the electrochemical etching processing method of a palladium alloy tip provided by some embodiments of the present invention.

[0052] First, as Figure 1 shown, perform step S110: Prepare the electrolyte.

[0053] The electrolyte may include phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid, and acetic acid. Among them, phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid, and acetic acid can be prepared according to the volume ratio of a:b:c:d:e:f:g:h:i, and 3 ml of hydrogen peroxide is added to every 1000 ml of the electrolyte. Here, a ∈ (30, 100), b ∈ (3, 20), c ∈ (40, 180), d ∈ (10, 60), e ∈ (1, 5), f ∈ (2, 10), g ∈ (1, 5), h ∈ (5, 10), i ∈ (10, 30).

[0054] Specifically, first, phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid, and acetic acid can be prepared according to the volume ratio of a:b:c:d:e:f:g:h:i. Then, the prepared components are mixed evenly and stirred until completely dissolved. Then hydrogen peroxide is added and stirred continuously to make it evenly dispersed. Thus, the preparation of the electrolyte is achieved.

[0055] In a preferred embodiment for reference, the volume fraction of water in the electrolyte can be 2 times the volume fraction of phosphoric acid; the volume fraction of water can be 10 times the volume fraction of polyethylene glycol; the volume fraction of water can be 3 times the volume fraction of edible rock sugar syrup; the volume fraction of water can be 40 times the volume fraction of ethylene glycol; the volume fraction of water can be 20 times the volume fraction of hydrochloric acid; the volume fraction of water can be 40 times the volume fraction of sulfuric acid; the volume fraction of water can be 15 times the volume fraction of formic acid; in addition, the volume fraction of water can be 5 times the volume fraction of acetic acid. During the electrochemical reaction process, the proportion of water in the electrolyte is relatively large, which can reduce the instability caused by the increase in solute concentration due to the evaporation of the electrolyte.

[0056] The components of the prepared electrolyte include hydrochloric acid and sulfuric acid. Hydrochloric acid and sulfuric acid are strong oxidizing acids, which can improve the conductivity of the electrolyte and accelerate the dissolution of the anode metal to improve the polishing efficiency.

[0057] In the electrolyte, the volume fractions of hydrochloric acid and sulfuric acid are related to the surface area of the sample. Under the same current condition, the larger the surface area of the sample, the higher the conductivity required for the electrolyte. In this case, the proportion of the added oxidizing acid can be appropriately increased to improve the conductivity of the electrolyte. Otherwise, only by increasing the current can the polishing efficiency be improved.

[0058] Phosphoric acid is a medium-strong acid. Polyethylene glycol and edible rock sugar syrup can act as passivators to produce an anodic passivation phenomenon. Phosphoric acid and the passivator can cause a viscous film layer to form on the surface of the anodic metal. Moreover, the viscous film layer is relatively thin at the convex portions of the metal surface and relatively thick at the concave portions. The relatively thin viscous film layer formed at the convex portions has a relatively low resistance and a relatively large current, so the convex portions will be preferentially corroded; the relatively thick mucous film layer formed at the concave portions has a relatively high resistance and a relatively small current, so the degree of corrosion of the concave portions is relatively low.

[0059] In addition, edible rock sugar syrup can also act as a brightening agent, which can improve the polishing effect.

[0060] Formic acid and acetic acid can be used as pH regulators. Formic acid and acetic acid are weak acids, which can adjust the pH value of the electrolyte to improve the corrosion effect of the electrolyte on the metal. And, the conductivity can be appropriately increased by the added formic acid and acetic acid, whereby the energized current can be appropriately reduced. In addition, formic acid and acetic acid are volatile, which can improve the heat dissipation efficiency of the electrolyte, thereby improving the temperature stability of the electrolyte.

[0061] The addition of hydrogen peroxide can promote the cathodic reaction, increase the energized current, and enhance the chemical action of the electrolyte on the metal to improve the polishing efficiency.

[0062] By electrochemically polishing with the preferred components and their ratios of the electrolyte, an ideal alloy polishing quality can be obtained, and the surface roughness of the polished alloy is significantly improved.

[0063] The above electrolyte can be applicable to treating various special materials, such as palladium alloys, copper alloys, and / or silver alloys.

[0064] Existing electrochemistry polishing methods often need to use special electrolytes and additives, such as additives with too high toxicity or too high danger, including chromic anhydride, hydrofluoric acid, ethylene thiourea, nitric acid, surfactants, etc. Surfactants such as cetyltrimethyl bromide are usually added to the electrolyte as brightening agents, and this component has hygroscopicity; surfactants such as polyvinylpyrrolidinium ammonium and sodium polydithiopropanesulfonate are usually added to the electrolyte as passivators, and these components have biological toxicity and relatively high danger.

[0065] The electrolyte provided by the present invention uses polyethylene glycol and edible rock sugar syrup as combined passivators and brightening agents, which is safer and can also achieve the polishing of various special materials.

[0066] After that, as Figure 1 shown, step S120 is executed: Connect a DC power supply to perform electrochemistry polishing until the alloy reaches a preset polishing effect, wherein the alloy is connected to the anode of the DC power supply.

[0067] Specifically, the alloy can be wrapped by a graphite fixture and connected to the anode of a DC power supply through the graphite fixture. The cathode graphite is evenly distributed on the bottom plate of the electrolytic cell and surrounds the graphite fixture connected to the anode.

[0068] The following will be combined with Figures 2 to 5 to detail the electrolytic cell used in the electrochemical polishing method.

[0069] As Figure 2 shown, the anode body 200 can include an alloy 201 and a graphite fixture. The alloy 201 can be wrapped by the inlay 210 of the graphite fixture. The graphite rod 220 is connected to the alloy 201, and the anode chuck 230 is clamped on the graphite rod 220. The anode chuck 230 is connected to an anode wire 231, thereby realizing the connection between the alloy 201 and the anode of the DC power supply.

[0070] As Figure 3 shown, the cathode body 300 can include a cathode graphite rod 310 and a ring-shaped metal 320 in which the cathode graphite rod 310 is embedded. The lower part of the cathode graphite rod 310 protrudes from the ring-shaped metal 320 and extends to the bottom plate of the electrolytic cell. The lower part of the cathode graphite rod 310 is round-headed. The cathode graphite rods 310 can be evenly embedded in the ring-shaped metal 320 and equal gaps can be left between adjacent cathode graphite rods 310, so that the cathode graphite rods 310 extending to the bottom plate of the electrolytic cell can be evenly distributed on the bottom plate of the electrolytic cell. Multiple cathode wires 321 can be connected to the ring-shaped metal 320.

[0071] As Figure 4 shown, the total body 400 includes an anode body 200 and a cathode body 300. The anode body 200 is located in the middle of the cathode body 300 and is surrounded by the cathode body 300. Specifically, the graphite fixture and the alloy 201 of the anode body 200 are located in the middle of the ring-shaped metal 320, and the cathode graphite rods 310 surround the anode body 200.

[0072] As Figure 5 shown, the alloy 201 and the inlay 210 wrapping the alloy 201 are located in the electrolyte 520 of the electrolytic cell 510. The graphite rod 220 of the graphite fixture extends out of the electrolyte, and the anode chuck 230 is clamped on the part of the graphite rod 220 extending out of the electrolyte 520. The cathode graphite rods 310 are evenly distributed on the bottom plate of the electrolytic cell 510, and the ring-shaped metal 320 in which the cathode graphite rods 310 are embedded is not immersed in the electrolyte 520.

[0073] Figure 5A schematic diagram showing the anode gas, cation movement direction, and anion movement direction in the electrolytic cell 510 is shown. The gap left between adjacent cathode graphite rods 310 facilitates the discharge of the anode gas. The round head at the lower part of the cathode graphite rod 310 facilitates the discharge of the cathode gas, and the flow direction of the cathode gas is as shown by the arrow 501 in Figure 5 .

[0074] The uniform surrounding of the anode body 200 by the cathode graphite rods 310 can regulate the ion flow. The cation movement direction is as shown by the arrow 502 in Figure 5 , and the anion movement direction is as shown by the arrow 503 in Figure 5 . The cations flow outwards and drive the electrolyte 520 to flow outwards, which is beneficial to the discharge of the anode gas and the cathode gas. At the same time, the driven electrolyte 520 can also make the electrolyte 520 at the bottom of the electrolytic cell 510 flow upwards, making the solute distribution of the electrolyte 520 more uniform.

[0075] In this way, the present invention can make the flow and distribution of the electrolyte more uniform during the polishing process by adopting a reasonable design of the cathode body, improving the efficiency and consistency of the polishing treatment.

[0076] In some embodiments, during the electrochemical polishing process, the optimization of external conditions can also be achieved by controlling the process environment and the electrolyte temperature. Specifically, the temperature control of the process environment can be constant temperature. Preferably, the temperature of the process environment is 25 °C. The humidity of the process environment can be 60% - 70%. The temperature of the electrolyte can be controlled at 18 - 30 °C.

[0077] By optimizing the external conditions, the effect of electrochemical polishing can be further improved. When the electrolyte is electrified, the water in the electrolyte will evaporate and electrolyze. During the long-term use of the electrolyte, the components in the electrolyte will be consumed. For example, consuming water will increase the solute concentration, and consuming acid will reduce the conductivity of the solution. Therefore, when the first polishing experiment is completed using a set of control parameters, and then the second polishing is carried out using these control parameters and the electrolyte that has completed one polishing experiment, there will be differences between the two polishings, affecting the consistency of the polishing. So, the stability of the polishing can be improved by enhancing the "service life" of the electrolyte.

[0078] Controlling the humidity of the process environment during the electrochemical polishing process within 60% - 70% can slow down the evaporation of water in the electrolyte, thus ensuring the stability of the polishing effect. In addition, the component polyethylene glycol included in the electrolyte formulated in the present invention has the function of absorbing moisture in the air. Combining with the increase in the humidity of the process environment, the evaporation of water in the electrolyte can be reduced together.

[0079] In addition, controlling the temperature of the process environment at a constant 25°C and the temperature of the electrolyte between 18 and 30°C can effectively control the heat dissipation rate of the electrolyte during the electrochemical polishing process to match the heat generation rate of the electrolyte. When the heat generation and heat dissipation reach a stable state, the temperature of the electrolyte can remain unchanged.

[0080] Thus, by optimizing external conditions such as the electrolyte temperature, process environment temperature, and process environment humidity, the electrochemical reaction conditions can be effectively controlled, further improving the polishing stability of the alloy.

[0081] According to the type of alloy and the temperature of the electrolyte, the upper limits of the voltage and current of the DC power supply can be set. Preferably, the upper limit of the voltage can be 1 - 60V, and the upper limit of the current can be 0.1 - 10A.

[0082] The magnitude of the voltage is directly related to the total resistance of the total circuit. The resistance of the total circuit can include wire resistance, contact resistance between conductors, the resistance of the electrolyte itself, anode resistance, and cathode resistance. Among them, the resistance of the electrolyte itself is prone to change. During the electrochemical polishing process, the resistance of the electrolyte is not a fixed value. Therefore, in the case of constant current, the magnitude of the voltage will fluctuate with the change of this resistance.

[0083] The actual applied current is directly related to the heat generation efficiency of the electrolyte. As the polishing process progresses, the electrolyte continuously generates heat, the solute is continuously consumed, and the resistance of the electrolyte continuously increases. At the same time, the electrolyte is also continuously dissipating heat. When the heat generation and heat dissipation reach a stable state, the temperature of the electrolyte remains unchanged. Within a certain range, the smaller the current, the smaller the surface roughness of the polished metal and the longer the polishing time. However, when the current is less than the above range, it will cause the electrolyte to not flow sufficiently, affecting the polishing effect. The above current range can be determined according to the type of alloy.

[0084] Preferably, in some embodiments, when the surface roughness of the alloy sample exceeds 0.5 mm, a rough polishing can be first performed with a large current of more than 5A before electrochemical polishing, and then the current can be adjusted to a smaller value and polishing can be continued.

[0085] In the constant voltage or constant current mode, the electrochemical polishing process can indirectly control the rate and degree of the electrochemical reaction by controlling the values of the voltage or current, thereby achieving the polishing of the material surface. However, due to reasons such as the conductivity of the electrolyte, indirectly controlling the electrochemical reaction by controlling the voltage or current may not be able to achieve precise control of the degree and rate of the electrochemical reaction, and may lead to unstable polishing effects.

[0086] When the existing electrolyte is used for electrochemical polishing, the set voltage is relatively small (e.g., 10V). When debugging parameters, considering experimental influencing factors such as the surface area of the sample energized, temperature, cathode, anode, solution, and energization time, many power supply parameters suitable for the sample may be obtained, such as a voltage of 10V and a current of 1A, or a voltage of 13V and a current of 2A. The higher the voltage, the faster the dissolution rate of the anode. When other conditions are relatively stable, since the voltage variation range is 30%, the polishing time estimated roughly to achieve the same polishing amount will differ by about 30%. It can be seen that voltage fluctuations will have a greater impact on the rate and degree of the electrochemical reaction. Therefore, precise control of the rate and degree of the electrochemical reaction cannot be achieved by controlling the voltage or current. Moreover, during the constant-current polishing process, due to the continuous change of the resistance of the electrolyte, the voltage fluctuation is relatively large, and the cost of indirectly controlling the electrochemical reaction by adjusting the current or voltage is very high.

[0087] According to the set upper limit of voltage and upper limit of current, and in combination with the provided electrolyte, the present invention can precisely control the rate and degree of the electrochemical reaction, thereby ensuring the stability and repeatability of the polishing effect.

[0088] The polyethylene glycol and edible rock sugar syrup added to the electrolyte can increase the viscosity of the electrolyte, increase the electrolyte resistance, and reduce the surface tension of the electrolyte. Thereby, it can be made that when the same current is passed, the voltage increases significantly. In some embodiments, the voltage can increase significantly by about 30V. It can be seen that through the prepared electrolyte, the voltage regulation can be amplified during the electrochemical polishing process, thereby reducing the sensitivity. In this case, the influence of the fluctuating voltage of the power supply on the polishing stability is reduced, and it is also easier to control and adjust the polishing time.

[0089] Connect the DC power supply for electrochemical polishing until the alloy reaches the preset polishing effect. In some embodiments, when the alloy does not reach the preset polishing effect, adjust the power supply parameters, and connect the DC power supply for electrochemical polishing according to the adjusted power supply parameters, and then judge whether the alloy reaches the preset polishing effect. If it still does not reach, repeat the electrochemical polishing process after adjusting the power supply parameters until the alloy reaches the preset polishing effect.

[0090] Then, as Figure 1 shown, execute step S130: Take out the alloy and perform post-treatment to obtain the processed alloy.

[0091] In some embodiments, the post-treatment process may first rinse the alloy with 5% hydrochloric acid for 1 min, then perform ultrasonic polishing in the cleaning agent for 5 min, then perform ultrasonic polishing of the alloy in 75% alcohol solution for 2 min, and finally dry it in an oven at 60 °C. By performing post-treatment on the alloy, the brightness of the polished surface can be further improved.

[0092] Thus, through the electrochemical polishing method provided by the present invention, the minute defects on the surface of the material can be effectively removed, and the surface finish and performance of the material can be improved.

[0093] The following are three specific non-limiting preferred embodiments, based on which the electrochemical polishing method proposed by the present invention and its effects are described.

[0094] In Example 1, phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid, and acetic acid are prepared according to a volume ratio of 60:5:150:20:1:5:5:10:20, and 3 ml of hydrogen peroxide is added to every 1000 ml of the electrolyte.

[0095] Then, after turning on the DC power supply, electrochemical polishing is carried out until the alloy reaches the preset polishing effect.

[0096] Here, the alloy is wrapped by a graphite fixture and connected to the anode of the DC power supply through the graphite fixture. The cathode graphite is evenly distributed on the bottom plate of the electrolytic cell and surrounds the graphite fixture connected to the anode.

[0097] During the electrochemical polishing process, the temperature of the process environment is controlled at 25 °C and kept constant, the humidity of the process environment is controlled at 60% - 70%, and the temperature of the electrolyte is controlled at 18 - 30 °C.

[0098] Reasonable voltage and current parameters are set according to the type of palladium alloy and the temperature of the electrolyte. Here, the alloy is Pd-Ag (palladium-silver) alloy, and the temperature of the electrolyte is 25 °C. Thus, the upper limit of the voltage is set to 50 V, and the upper limit of the current is set to 2 A.

[0099] Then, the alloy that has reached the preset polishing effect is taken out and subjected to the following post-treatments in sequence: rinsed with 5% hydrochloric acid for 1 min, ultrasonically polished in a cleaning agent for 5 min, ultrasonically polished in a 75% alcohol solution for 2 min, and finally dried in an oven at 60 °C.

[0100] Please refer to Figure 6 and Figure 7 , Figure 6 which shows the SEM (scanning electron microscope) photograph of the surface of the Pd-Ag alloy sample before electrochemical polishing provided by Example 1 of the present invention, Figure 7 which shows the SEM photograph of the surface of the Pd-Ag alloy sample after electrochemical polishing provided by Example 1 of the present invention.

[0101] Figure 6 The scale (length unit) in Figure 6 is 10 μm. As Figure 6 shown, before polishing, there are many minute defects on the surface of the Pd-Ag alloy sample, and it is relatively rough.Figure 7 The scale (length unit) is 10 μm. As Figure 7 shown, after polishing, the surface of the Pd-Ag alloy sample is very smooth, and the tiny defects on the surface are effectively removed, thereby improving the material properties of the Pd-Ag alloy sample.

[0102] In Example 2, phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid, and acetic acid are prepared according to a volume ratio of 40:10:100:30:1:5:5:10:10, and 2 ml of hydrogen peroxide is added to every 1000 ml of the electrolyte.

[0103] Specifically, each component can be prepared by using a measuring cylinder according to the dosages of 400 g of phosphoric acid, 50 g of polyethylene glycol, 400 ml of water, 200 g of edible rock sugar syrup, 10 ml of ethylene glycol, 50 ml of hydrochloric acid, 50 ml of sulfuric acid, 100 ml of formic acid, and 100 ml of acetic acid. Then, the components are mixed evenly and stirred until completely dissolved. After that, hydrogen peroxide is added to every 1000 ml of the electrolyte, and then stirring is continued to make it evenly dispersed.

[0104] Then, after turning on the DC power supply, electrochemical polishing is carried out until the alloy reaches the preset polishing effect.

[0105] Here, the alloy is wrapped by a graphite fixture and connected to the anode of the DC power supply through the graphite fixture. The cathode graphite is evenly distributed on the bottom plate of the electrolytic cell and surrounds the graphite fixture connected to the anode.

[0106] During the electrochemical polishing process, the humidity of the process environment is 65%, the temperature of the process environment is controlled at 25 °C and is constant temperature, and the temperature of the electrolyte is controlled at 20 - 25 °C.

[0107] Reasonable voltage and current parameters are set according to the type of palladium alloy and the temperature of the electrolyte. Here, the alloy is a Pd-Cu (palladium-copper) alloy, and the temperature of the electrolyte is 22 °C. Therefore, the upper limit of the voltage is set to 30 V, and the upper limit of the current is set to 1 A.

[0108] Then, the alloy that has reached the preset polishing effect is taken out and subjected to the following post-treatment in sequence: rinsed with 5% hydrochloric acid for 1 min, ultrasonically polished in a cleaning agent for 5 min, ultrasonically polished in a 75% alcohol solution for 2 min, and finally dried in an oven at 60 °C.

[0109] Please refer to Figure 8 and Figure 9 , Figure 8 shows the SEM photograph of the surface of the Pd-Cu alloy sample before electrochemical polishing provided in Example 2 of the present invention, Figure 9 shows the SEM photograph of the surface of the Pd-Cu alloy sample after electrochemical polishing provided in Example 2 of the present invention.

[0110] Figure 8 The scale (length unit) is 10 μm. As Figure 8 shown, before polishing, the surface of the Pd-Cu alloy sample is uneven and has a high roughness. Figure 9 The scale (length unit) is 6 μm. As Figure 9 shown, after polishing, the surface of the Pd-Cu alloy sample is very smooth, and the surface defects are effectively removed. The polishing effect is very excellent, thereby improving the material properties of the Pd-Cu alloy sample.

[0111] In Example 3, phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid, and acetic acid are prepared according to a volume ratio of 40:5:60:15:1:15:5:10:30, and 5 ml of hydrogen peroxide is added to every 1000 ml of the electrolyte.

[0112] Then, after turning on the DC power supply, electro-chemical polishing is carried out until the alloy reaches the preset polishing effect.

[0113] Here, the alloy is wrapped by a graphite fixture and connected to the anode of the DC power supply through the graphite fixture. The cathode graphite is evenly distributed on the bottom plate of the electrolytic cell and surrounds the graphite fixture connected to the anode.

[0114] During the electro-chemical polishing process, the humidity of the process environment is 60%, the temperature of the process environment is controlled at 25 °C and is constant temperature, and the temperature of the electrolyte is controlled at 25 - 30 °C.

[0115] According to the type of palladium alloy and the temperature of the electrolyte, reasonable voltage and current parameters are set. Here, the alloy is Pd-Pt (palladium-platinum) alloy, and the temperature of the electrolyte is 28 °C. Therefore, the upper limit of the voltage is set to 30 V, and the upper limit of the current is set to 5 A.

[0116] Then, the alloy that has reached the preset polishing effect is taken out and subjected to the following post-treatments in sequence: rinsed with 5% hydrochloric acid for 1 min, ultrasonically polished in a cleaning agent for 5 min, ultrasonically polished in a 75% alcohol solution for 2 min, and finally dried in an oven at 60 °C.

[0117] Please refer to Figure 10 and Figure 11 , Figure 10 shows the SEM photograph of the surface of the Pd-Pt alloy sample before electro-chemical polishing provided in Example 3 of the present invention, Figure 11 shows the SEM photograph of the surface of the Pd-Pt alloy sample after electro-chemical polishing provided in Example 3 of the present invention.

[0118] Figure 10 The scale (length unit) is 10 μm. As Figure 10As shown, before polishing, the surface of the Pd-Pt alloy sample has defects in the shape of cross stripes and other shapes, with high roughness. Figure 11 The scale (length unit) in the figure is 10 μm. As Figure 11 shown, after polishing, the surface of the Pd-Pt alloy sample is very smooth, and the uneven surface has been effectively improved, thereby improving the material properties of the Pd-Pt alloy sample.

[0119] In summary, according to the electrochemical polishing method and an electrolyte for electrochemical polishing provided by the present invention, precise control of the electrochemical reaction can be achieved by optimizing the composition and ratio of the electrolyte, and it is applicable to treating various special materials, and a better polishing effect can be achieved.

[0120] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions not illustrated and described herein but understood by those skilled in the art.

[0121] The foregoing description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electrochemical polishing method, characterized in that: Includes steps: preparing an electrolyte, wherein the electrolyte comprises phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid and acetic acid, Phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid and acetic acid are prepared according to the volume ratio of a:b:c:d:e:f:g:h:i, and 2-5 ml of hydrogen peroxide is added to every 1000 ml of electrolyte. Among them, a∈(30,100), b∈(3,20), c∈(40,180), d∈(10,60), e∈(1,5), f∈(2,10), g∈(1,5), h∈(5,10), i∈(10,30); Connecting a DC power supply to perform electrochemical polishing until the alloy reaches a preset polishing effect, wherein the alloy is connected to an anode of the DC power supply; and The alloy is taken out and post-processed to obtain the processed alloy.

2. The electrochemical polishing method according to claim 1, characterized in that: The upper voltage limit and the upper current limit of the DC power supply are set according to the type of the alloy and the temperature of the electrolyte.

3. The electrochemical polishing method according to claim 2, characterized in that: The voltage upper limit is 1 to 60V, and the current upper limit is 0.1 to 10A.

4. The electrochemical polishing method according to claim 1, characterized in that: The alloy is wrapped by a graphite fixture and connected to the anode of the DC power supply through the graphite fixture; and The cathode graphite is evenly distributed on the bottom plate of the electrolytic cell and surrounds the graphite fixture connected to the anode.

5. The electrochemical polishing method according to claim 1, characterized in that: The temperature of the electrolyte is controlled at 18-30° C., and the temperature of the process environment is constant.

6. The electrochemical polishing method according to claim 1, characterized in that: The process environment humidity is 60% to 70%.

7. The electrochemical polishing method according to claim 1, characterized in that: The step of connecting a DC power supply to perform electrochemical polishing also includes: When the alloy does not achieve a preset polishing effect, adjusting power supply parameters; and The DC power supply is turned on according to the adjusted power supply parameters to perform electrochemical polishing.

8. The electrochemical polishing method according to claim 1, characterized in that: The post-processing comprises the steps of: Rinse the alloy with 5% hydrochloric acid for 1 to 3 minutes; Ultrasonic polishing in a cleaning agent for 5 to 8 minutes; Ultrasonic polishing in 75% alcohol solution for 2 to 3 minutes; as well as Dry in an oven at 40-60℃.

9. The electrochemical polishing method according to claim 1, characterized in that: The alloy includes a palladium alloy, a copper alloy and / or a silver alloy.

10. An electrolyte for electrochemical polishing, characterized in that: The electrolyte includes phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid and acetic acid. Phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, ethylene glycol, hydrochloric acid, sulfuric acid, formic acid and acetic acid are prepared according to the volume ratio of a:b:c:d:e:f:g:h:i, and 2-5 ml of hydrogen peroxide is added to every 1000 ml of electrolyte. Among them, a∈(30,100), b∈(3,20), c∈(40,180), d∈(10,60), e∈(1,5), f∈(2,10), g∈(1,5), h∈(5,10), i∈(10,30).

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