Surface treatment method for a cobalt electrodeposition self-stripping cathode plate

Abstract

The present application provides a kind of surface treatment method of cobalt electrodeposition self-stripping cathode plate, the surface treatment method includes the following steps: providing cathode plate substrate;Surface roughening treatment is carried out to cathode plate substrate, and low riveting type roughened substrate is obtained;The surface of low riveting type roughened substrate is treated with inert plasma, and then chemical passivation isolation treatment is carried out, inert isolation film is generated on the surface of substrate, and passivated isolation substrate is obtained.The present application reduces the interfacial adhesion between the electro-cobalt layer and the cathode plate under the premise of ensuring uniform and stable deposition of electrodeposited cobalt, realizes the self-stripping effect of the electro-cobalt layer after electrodeposition;Cobalt electrodeposition stability and self-stripping performance are considered, product damage and production loss are reduced;The process has good process adaptability with the existing cobalt electrodeposition production line, and is easy to be applied in industrial scale.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically relating to a surface treatment method for a cobalt electrowinning self-peeling cathode plate. Background Technology

[0002] Cobalt electrodeposition is an important process for preparing metallic cobalt in hydrometallurgy. The cathode plate, as the deposition substrate for cobalt electrodeposition, directly affects the deposition quality and stripping efficiency of the cobalt.

[0003] In traditional processes, to ensure sufficient bonding strength between the electrolyzed cobalt and the cathode plate, a certain interlocking structure or high interfacial adhesion is usually required to prevent the cobalt layer from detaching during electrolysis. However, excessively high adhesion makes it difficult to peel the cobalt layer off the cathode plate after electrolysis. Forced separation is not only labor-intensive and inefficient, but also prone to causing deformation or damage to the cathode plate. On the other hand, simply pursuing easy peeling at the expense of reducing interfacial adhesion may result in a weak bond between the electrolyzed cobalt layer and the cathode plate during electrolysis, leading to deposition stability problems such as local warping, detachment, or even short circuits.

[0004] Therefore, how to solve the technical problems of excessive adhesion between the existing electroplated cobalt layer and the cathode plate, difficulty in peeling off, and difficulty in simultaneously taking into account the stability of electroplated cobalt deposition and self-peeling performance is an important direction of current research. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a surface treatment method for a cobalt electrowinning self-peeling cathode plate. This invention sequentially performs surface roughening treatment, inert plasma treatment, and chemical passivation isolation treatment on the cathode plate substrate surface. While ensuring uniform and stable cobalt deposition, it effectively reduces the interfacial adhesion between the cobalt layer and the cathode plate, achieving a self-peeling effect of the cobalt layer after electrodeposition. This invention balances cobalt electrowinning stability and self-peeling performance, avoiding production problems such as mechanical peeling difficulties and cathode plate deformation damage caused by excessive adhesion, as well as cobalt layer detachment and short circuits caused by insufficient adhesion, thus reducing product breakage and production losses. Furthermore, the process provided by this invention has good process compatibility with existing cobalt electrowinning production lines and is easy to apply on an industrial scale.

[0006] To achieve this objective, the present invention employs the following technical solution: This invention provides a surface treatment method for a cobalt electrowinning self-peeling cathode plate, the surface treatment method comprising the following steps: Provide cathode plate substrate.

[0007] The cathode plate substrate is subjected to surface roughening treatment to obtain a low-riveting roughened substrate.

[0008] The surface of the low-riveting roughened substrate is subjected to inert plasma treatment, followed by chemical passivation isolation treatment to generate an inert isolation film on the surface of the substrate, thereby obtaining a passivated isolation substrate.

[0009] This invention sequentially performs surface roughening, inert plasma treatment, and chemical passivation isolation treatment on the cathode substrate surface. While ensuring uniform and stable cobalt deposition, it effectively reduces the interfacial adhesion between the cobalt layer and the cathode plate, achieving a self-peeling effect of the cobalt layer after electrodeposition. This invention balances cobalt electrodeposition stability and self-peeling performance, avoiding production problems such as mechanical peeling difficulties and cathode plate deformation damage caused by excessive adhesion, and cobalt layer detachment and short circuits caused by insufficient adhesion, thus reducing product breakage and production losses. Furthermore, the process provided by this invention has good process compatibility with existing cobalt electrodeposition production lines and is easy to apply on an industrial scale.

[0010] In this invention, the cathode plate substrate is roughened to form shallow, flat micro-textures on its surface without deep interlocking grooves, thereby avoiding excessive mechanical bonding between the substrate and the electroplated cobalt layer and structurally reducing the interfacial adhesion.

[0011] In this invention, inert plasma treatment of the roughened substrate can remove surface contaminants and activate the surface, making the substrate surface clean and highly active, thereby promoting the uniform formation of the subsequent chemical passivation barrier film.

[0012] In this invention, chemical passivation isolation treatment is performed to generate an inert isolation film on the surface of the substrate. This allows the subsequently deposited cobalt electroplated layer to form a weak interfacial bond with the cathode substrate, effectively avoiding the formation of a strong metallurgical bond between the two. This precisely reduces the overall adhesion of the cobalt electroplated layer from the chemical bonding level.

[0013] Preferably, the cathode plate substrate includes any one of a copper plate, a copper-based alloy plate, an aluminum plate, an aluminum-based alloy plate, a nickel plate, or a nickel-based alloy plate.

[0014] Preferably, the surface roughening treatment includes a low-gradient sandblasting process followed by medium-fine sand homogenization grinding.

[0015] It should be noted that low-gradient sandblasting refers to a progressive sandblasting method in which the sandblasting pressure gradually increases from the initial value to the target pressure. This avoids the formation of excessively deep pits or stress concentrations on the substrate surface caused by instantaneous high-pressure impact. It provides certain microscopic anchor points while avoiding excessive mechanical locking between the cathode substrate and the electrolytic cobalt layer due to excessive roughness, thus achieving a "low-riveting" roughening effect. Medium-fine abrasive homogenization grinding refers to uniformly grinding the sandblasted surface with medium-fine abrasive to remove sharp edges, smooth the edges of microscopic pits, and homogenize the roughness, thereby further reducing mechanical locking force and promoting self-peeling.

[0016] Preferably, in the low-gradient sandblasting process, the increment of sandblasting pressure per unit time is less than 0.05 MPa / s, for example, it can be 0.04 MPa / s, 0.03 MPa / s, 0.02 MPa / s or 0.01 MPa / s, etc., and the range of sandblasting pressure is 0.1-0.3 MPa, for example, it can be 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa or 0.3 MPa, etc.

[0017] Preferably, during the homogenization and grinding process of the medium and fine sand, the particle size range of the medium and fine sand is 80-200 mesh, for example, it can be 80 mesh, 100 mesh, 120 mesh, 150 mesh or 200 mesh, etc.

[0018] Preferably, the surface roughness Ra of the low-riveting roughened substrate is 0.4-0.8 μm, for example, it can be 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm or 0.8 μm.

[0019] Preferably, the surface of the low-riveting roughened substrate has a microtexture structure, the groove depth of the microtexture structure is ≤0.03mm, for example, it can be 0.03mm, 0.02mm, 0.01mm, 0.005mm or 0.001mm, etc., and the spacing between adjacent microtexture structures is 0.5-1.5mm, for example, it can be 0.5mm, 0.8mm, 1.0mm, 1.2mm or 1.5mm, etc.

[0020] In this invention, the surface roughness Ra of the low-riveting roughened substrate is strictly controlled to be 0.4-0.8 μm, and the groove depth of the micro-texture structure is ≤0.03 mm, with the spacing between adjacent micro-texture structures being 0.5-1.5 mm. The substrate surface under the combined constraints of the above parameters can avoid the electro-deposited cobalt layer from falling off due to excessive smoothness, and will not form an excessively strong mechanical locking effect. This effectively controls the interface adhesion, ensures that the electro-deposited cobalt layer can be self-peeled after electro-deposition, avoids damage to the cathode plate, and achieves a balance between deposition stability and self-peeling performance.

[0021] Preferably, during the inert plasma treatment process, the power of the plasma generator is 800-1200W, for example, it can be 800W, 900W, 1000W, 1100W or 1200W.

[0022] Preferably, the inert plasma treatment time is 10-15 min, for example, it can be 10 min, 11 min, 12 min, 13 min, 14 min or 15 min.

[0023] Preferably, the working gas used in the inert plasma treatment process includes argon.

[0024] Preferably, the chemical passivation isolation treatment step includes: The substrate treated with inert plasma was immersed in a chemical passivation and isolation solution.

[0025] The chemical passivation isolation solution includes organic acids, silicates, and organic inert film-forming aids.

[0026] In the chemical passivation isolation solution provided by this invention, the role of organic acid is to adjust the pH value of the solution system, providing a suitable environment for the deposition of inert isolation film; silicate, as the film-forming host, forms a dense inorganic silicon-oxygen network structure on the surface of the plasma-activated substrate after hydrolysis and condensation, constituting the main barrier of the isolation film; organic inert film-forming aid fills the gaps in the silicate network, improves the density and flexibility of the film layer, and reduces the surface energy to enhance hydrophobicity, so that the film layer cohesive destruction rather than interfacial destruction occurs during the electrolytic cobalt stripping, thereby achieving self-stripping.

[0027] Preferably, the organic acid includes any one or a combination of at least two of citric acid, oxalic acid, acetic acid, or tartaric acid.

[0028] Preferably, the silicate includes any one or a combination of at least two of sodium silicate, potassium silicate, or lithium silicate.

[0029] Preferably, the organic inert film-forming aid includes any one or a combination of at least two of polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), or polyethylene glycol (PEG).

[0030] Preferably, the concentration of silicate in the chemical passivation isolation solution is 10-100 g / L, for example, it can be 12 g / L, 27 g / L, 39 g / L, 52 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L or 100 g / L.

[0031] Preferably, the concentration of the organic inert film-forming aid in the chemical passivation isolation solution is 1-30 g / L, for example, it can be 2 g / L, 5 g / L, 10 g / L, 17 g / L, 27 g / L or 30 g / L, etc.

[0032] Preferably, the pH of the chemical passivation isolation solution is 8-11, for example, it can be 8.2, 9.1, 10.5, 10.7 or 11.

[0033] In this invention, a suitable pH of the chemical passivation and isolation solution is beneficial for forming a continuous, dense and controllable thickness inert isolation film on the substrate surface, while avoiding excessive corrosion of the substrate due to excessively low pH or precipitation due to excessively high pH, ​​thus taking into account both the film formation quality and the control of interfacial adhesion.

[0034] Preferably, the soaking temperature is 20-80℃, for example, it can be 20℃, 30℃, 40℃, 60℃ or 80℃.

[0035] Preferably, the soaking time is 5-15 minutes, for example, 5 minutes, 7 minutes, 10 minutes, 12 minutes or 15 minutes.

[0036] Preferably, the thickness of the inert isolation film is 5-200nm, for example, it can be 5nm, 50nm, 100nm, 150nm or 200nm.

[0037] In this invention, the appropriate thickness of the inert separator film can effectively block direct contact between the electroplated cobalt layer and the cathode substrate, and control the interfacial adhesion within the range required for self-peeling. If the thickness is too small, the inert separator film will not be able to completely isolate the bonding force between the cathode substrate and the electroplated cobalt layer, making it difficult to achieve self-peeling. If the thickness is too large, it will affect the nucleation and conductivity uniformity of cobalt ions during the electroplating process, resulting in a decrease in cobalt deposition quality, and even making it difficult to form a continuous electroplated cobalt layer on the cathode substrate.

[0038] Preferably, the surface treatment method includes the following steps: (1) Provide a cathode plate substrate; the cathode plate substrate includes any one of a copper plate, a copper-based alloy plate, an aluminum plate, an aluminum-based alloy plate, a nickel plate, or a nickel-based alloy plate.

[0039] The cathode plate substrate is surface treated by first soaking it in an alkaline degreasing agent (such as sodium hydroxide solution) to remove oil stains, and then neutralizing it with a weak acid solution (such as dilute sulfuric acid, dilute hydrochloric acid, citric acid, oxalic acid or acetic acid) to obtain a clean cathode plate substrate.

[0040] (2) The clean cathode plate substrate surface is subjected to low gradient sandblasting and medium-fine sand homogenization grinding in sequence to form shallow and small micro-textures on the substrate surface, resulting in a low-riveting roughened substrate with a surface roughness Ra of 0.4-0.8μm.

[0041] The groove depth of the microtexture is ≤0.03mm, and the spacing between adjacent microtextures is 0.5-1.5mm.

[0042] (3) The surface of the low-riveting roughened substrate is subjected to inert plasma treatment. A high-frequency plasma generator is used, the power is controlled at 800-1200W, the treatment time is 10-15min, and the working gas includes argon to obtain a clean modified cathode plate substrate.

[0043] (4) The cleaned and modified cathode plate substrate is immersed in a chemical passivation isolation solution at 20-80°C for 5-15 minutes to generate an inert isolation film with a thickness of 5-200 nm on the surface of the substrate; wherein, the organic acid includes any one or a combination of at least two of citric acid, oxalic acid, acetic acid or tartaric acid; the silicate includes any one or a combination of at least two of sodium silicate, potassium silicate or lithium silicate; the organic inert film-forming aid includes any one or a combination of at least two of polyvinyl alcohol, carboxymethyl cellulose or polyethylene glycol; in the chemical passivation isolation solution, the concentration of silicate is 10-100 g / L, the concentration of organic inert film-forming aid is 1-30 g / L; and the pH of the chemical passivation isolation solution is 8-11.

[0044] After the immersion treatment, the substrate is rinsed with cold water and then hot water in sequence, and then dried to obtain a passivated isolation substrate.

[0045] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0046] Compared with the prior art, the present invention has the following beneficial effects: This invention sequentially performs surface roughening, inert plasma treatment, and chemical passivation isolation treatment on the cathode substrate surface. While ensuring uniform and stable cobalt deposition, it effectively reduces the interfacial adhesion between the cobalt layer and the cathode plate, achieving a self-peeling effect of the cobalt layer after electrodeposition. This invention balances cobalt electrodeposition stability and self-peeling performance, avoiding production problems such as mechanical peeling difficulties and cathode plate deformation damage caused by excessive adhesion, and cobalt layer detachment and short circuits caused by insufficient adhesion, thus reducing product breakage and production losses. Furthermore, the process provided by this invention has good process compatibility with existing cobalt electrodeposition production lines and is easy to apply on an industrial scale. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0048] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0049] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0050] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0051] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0052] Example 1 This embodiment provides a surface treatment method for a cobalt electrowinning self-peeling cathode plate, the surface treatment method including the following steps: (1) Provide a cathode plate substrate; the cathode plate substrate is a copper plate.

[0053] The cathode plate substrate is surface treated by first soaking it in an alkaline degreasing agent (i.e., sodium hydroxide solution) to remove oil stains, and then neutralizing it with a weak acid solution (i.e., dilute sulfuric acid) to obtain a clean cathode plate substrate.

[0054] (2) The clean cathode plate substrate surface is subjected to low gradient sandblasting and medium-fine sand homogenization grinding in sequence to form a shallow and flat micro-texture structure on the substrate surface. After treatment, the residual sand on the surface is blown away to obtain a low riveting type roughened substrate with a surface roughness Ra of 0.6μm.

[0055] In the low-gradient sandblasting process, the sandblasting pressure increment per unit time is 0.01 MPa / s, and the sandblasting pressure range is 0.1-0.3 MPa; in the medium-fine sand homogenization and grinding process, the particle size range of the medium-fine sand is 80-200 mesh; the groove depth of the microtexture structure is ≤0.03 mm, and the spacing between adjacent microtexture structures is 0.5-1.5 mm.

[0056] (3) The surface of the low-riveting roughened substrate is subjected to inert plasma treatment. A high-frequency plasma generator is used, the power is controlled at 1000W, the treatment time is 12min, and the working gas is argon to obtain a clean modified cathode plate substrate.

[0057] (4) The cleaned and modified cathode plate substrate is immersed in a chemical passivation isolation solution at 50°C for 10 minutes to generate an inert isolation film with a thickness of 100 nm on the surface of the substrate; wherein, the weak passivation composite isolation solution includes an organic acid, a silicate and an organic inert film-forming aid; the organic acid is citric acid, the silicate is sodium silicate and the organic inert film-forming aid is PVA; in the chemical passivation isolation solution, the concentration of silicate is 20 g / L and the concentration of organic inert film-forming aid is 5 g / L; the pH of the chemical passivation isolation solution is 9.

[0058] After the immersion treatment, the substrate is rinsed with cold water and then hot water in sequence, and then dried to obtain a passivated isolation substrate.

[0059] Example 2 This embodiment provides a surface treatment method for a cobalt electrowinning self-peeling cathode plate, the surface treatment method including the following steps: (1) Provide a cathode plate substrate; the cathode plate substrate is a copper plate.

[0060] The cathode plate substrate is surface treated by first soaking it in an alkaline degreasing agent (i.e., sodium hydroxide solution) to remove oil stains, and then neutralizing it with a weak acid solution (i.e., dilute sulfuric acid) to obtain a clean cathode plate substrate.

[0061] (2) The clean cathode plate substrate surface is subjected to low gradient sandblasting and medium-fine sand homogenization grinding in sequence to form shallow and small micro textures on the substrate surface. After treatment, the residual sand on the surface is blown away to obtain a low riveting type roughened substrate with a surface roughness Ra of 0.4μm.

[0062] In the low-gradient sandblasting process, the sandblasting pressure increment per unit time is 0.005 MPa / s, and the sandblasting pressure range is 0.1-0.3 MPa; in the medium-fine sand homogenization and grinding process, the particle size range of the medium-fine sand is 80-200 mesh; the groove depth of the microtexture is ≤0.03 mm, and the spacing between adjacent microtextures is 0.5-1.5 mm.

[0063] (3) The surface of the low-riveting roughened substrate is subjected to inert plasma treatment. A high-frequency plasma generator is used, the power is controlled at 800W, the treatment time is 15min, and the working gas is argon to obtain a clean modified cathode plate substrate.

[0064] (4) The cleaned and modified cathode plate substrate is immersed in a chemical passivation isolation solution at 30°C for 15 minutes to generate an inert isolation film with a thickness of 200 nm on the surface of the substrate; wherein, the weak passivation composite isolation solution includes an organic acid, a silicate and an organic inert film-forming aid; the organic acid is oxalic acid, the silicate is potassium silicate and the organic inert film-forming aid is CMC; in the chemical passivation isolation solution, the concentration of silicate is 40 g / L and the concentration of organic inert film-forming aid is 10 g / L; the pH of the chemical passivation isolation solution is 10.

[0065] After the immersion treatment, the substrate is rinsed with cold water and then hot water in sequence, and then dried to obtain a passivated isolation substrate.

[0066] Example 3 This embodiment provides a surface treatment method for a cobalt electrowinning self-peeling cathode plate, the surface treatment method including the following steps: (1) Provide a cathode plate substrate; the cathode plate substrate is a copper plate.

[0067] The cathode plate substrate is surface treated by first soaking it in an alkaline degreasing agent (i.e., sodium hydroxide solution) to remove oil stains, and then neutralizing it with a weak acid solution (i.e., dilute sulfuric acid) to obtain a clean cathode plate substrate.

[0068] (2) The clean cathode plate substrate surface is subjected to low gradient sandblasting and medium-fine sand homogenization grinding in sequence to form shallow and small micro textures on the substrate surface. After treatment, the residual sand on the surface is blown away to obtain a low riveting type roughened substrate with a surface roughness Ra of 0.8μm.

[0069] In the low-gradient sandblasting process, the sandblasting pressure increment per unit time is 0.02 MPa / s, and the sandblasting pressure range is 0.1-0.3 MPa; in the medium-fine sand homogenization and grinding process, the particle size range of the medium-fine sand is 80-200 mesh; the groove depth of the microtexture is ≤0.03 mm, and the spacing between adjacent microtextures is 0.5-1.5 mm.

[0070] (3) The surface of the low-riveting roughened substrate is subjected to inert plasma treatment. A high-frequency plasma generator is used, the power is controlled at 1200W, the treatment time is 10min, and the working gas is argon to obtain a clean modified cathode plate substrate.

[0071] (4) The cleaned and modified cathode plate substrate is immersed in a chemical passivation isolation solution at 80°C for 5 minutes to generate an inert isolation film with a thickness of 10 nm on the surface of the substrate; wherein the weak passivation composite isolation solution includes an organic acid, a silicate and an organic inert film-forming aid; the organic acid is acetic acid, the silicate is lithium silicate and the organic inert film-forming aid is PEG; in the chemical passivation isolation solution, the concentration of silicate is 70 g / L and the concentration of organic inert film-forming aid is 17 g / L; the pH of the chemical passivation isolation solution is 11.

[0072] After the immersion treatment, the substrate is rinsed with cold water and then hot water in sequence, and then dried to obtain a passivated isolation substrate.

[0073] Example 4 The difference between this embodiment and Embodiment 1 is that the process parameters of the low-gradient sandblasting treatment and the medium-fine sand homogenization grinding are adjusted so that the groove depth of the micro-texture is >0.03mm.

[0074] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0075] Example 5 The difference between this embodiment and Embodiment 1 is that the process parameters of the low-gradient sandblasting treatment and the medium-fine sand homogenization grinding are adjusted so that the surface roughness Ra of the low-riveting roughened substrate is 0.2μm.

[0076] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0077] Example 6 The difference between this embodiment and Embodiment 1 is that the process parameters of the low-gradient sandblasting treatment and the medium-fine sand homogenization grinding are adjusted so that the surface roughness Ra of the low-riveting roughened substrate is 1μm.

[0078] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0079] Example 7 The difference between this embodiment and Embodiment 1 is that the chemical passivation isolation solution does not contain PVA.

[0080] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0081] Example 8 The difference between this embodiment and Embodiment 1 is that the pH of the chemical passivation isolation solution is 5.

[0082] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0083] Example 9 The difference between this embodiment and Embodiment 1 is that the pH of the chemical passivation isolation solution is 12.

[0084] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0085] Example 10 The difference between this embodiment and Embodiment 1 is that the immersion process is adjusted so that the thickness of the inert isolation film is 3nm.

[0086] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0087] Example 11 The difference between this embodiment and Embodiment 1 is that the immersion process is adjusted so that the thickness of the inert isolation film is 220 nm.

[0088] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0089] Comparative Example 1 The difference between this comparative example and Example 1 is that step (2) is omitted.

[0090] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0091] Comparative Example 2 The difference between this comparative example and Example 1 is that step (3) is omitted.

[0092] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0093] Comparative Example 3 The difference between this comparative example and Example 1 is that step (4) is omitted.

[0094] The remaining surface treatment methods and parameters are consistent with those in Example 1.

[0095] Performance testing Based on the surface-treated cathode substrates provided in the above embodiments and comparative examples, cobalt electrowinning is performed. The steps include: placing the cathode substrates in an electrowinning tank, using an inert anode (such as titanium-plated lead dioxide) as the anode plate, and using a cobalt sulfate electrolyte (concentration of 150 g / L) at a current density of 250 A / m. 2 Electrodeposition of cobalt is performed at a temperature of 60°C to deposit a 6mm thick electrodeposition cobalt layer on the surface of the cathode substrate.

[0096] After electrowinning, the following tests are performed: 1) Self-peeling performance test: Observe whether the electro-deposited cobalt layer automatically detaches from the substrate surface and record the conclusion.

[0097] 2) Interface adhesion test: For samples that failed to completely peel off, a peel tester (universal material testing machine) was used to test the peel force between the electro-cobalt layer and the cathode substrate in a 180° peeling manner.

[0098] The test results are shown in Table 1.

[0099] Table 1 analyze: As shown in Table 1, the present invention sequentially performs surface roughening treatment, inert plasma treatment, and chemical passivation isolation treatment on the surface of the cathode plate substrate. Under the premise of ensuring uniform and stable deposition of electro-cobalt, it effectively reduces the interfacial adhesion between the electro-cobalt layer and the cathode plate, and achieves the self-peeling effect of the electro-cobalt layer after electrodeposition. The present invention takes into account both the stability of cobalt electrodeposition and the self-peeling performance, avoiding production problems such as mechanical peeling difficulties, cathode plate deformation and damage caused by excessive adhesion, and cobalt layer detachment and short circuit caused by insufficient adhesion, thereby reducing product breakage and production losses.

[0100] As can be seen from the comparison between Example 1 and Example 4, if the groove depth of the micro-texture is too deep, the electro-deposited cobalt layer will be embedded in the deep pit, forming a strong mechanical locking effect, which leads to a significant increase in the interface adhesion, and the cobalt layer is difficult to peel off after electro-deposition.

[0101] A comparison of Examples 1 and 5-6 shows that if the surface roughness of the low-riveting roughened substrate is too small, the surface will be too smooth, resulting in insufficient mechanical anchor points between the electro-deposited cobalt layer and the substrate. This will lead to low adhesion of the cobalt layer during electro-deposit and premature detachment, affecting the stability of the electro-deposit. If the surface roughness of the low-riveting roughened substrate is too large, the electro-deposited cobalt layer will be embedded too deeply, resulting in excessively high interface adhesion. This will prevent the cobalt layer from peeling off after electro-deposit.

[0102] A comparison of Examples 1 and 7 shows that if the chemical passivation separator does not contain organic inert film-forming aids, the inert separator will become more brittle and dry and crack due to the lack of organic framework support, and its density and flexibility will decrease significantly. Cobalt atoms can easily penetrate the defects in the film layer and come into direct contact with the cathode substrate, resulting in increased interfacial adhesion, the inability of electroplated cobalt to peel off automatically, and problems such as difficulty in plating and film debris inclusion.

[0103] A comparison of Examples 1 and 8-9 shows that if the pH of the chemical passivation separator is too low and the acidity is too strong, it will corrode the surface of the cathode substrate, leading to surface dissolution, roughening, and even pitting, thus damaging the integrity of the cathode substrate surface. If the pH of the chemical passivation separator is too high and the alkalinity is too strong, it will easily cause alkaline corrosion or surface oxidation of the substrate, and at the same time cause abnormal silicate film formation. Both will reduce the adhesion and uniformity of the inert separator film, affecting the quality of cobalt electroplating and the self-peeling effect.

[0104] As can be seen from the comparison between Example 1 and Examples 10-11, if the thickness of the inert separator is too small, the film layer will be incomplete, with missing coating points or micropores, and will not be able to effectively block the direct contact between the electrodeposited cobalt layer and the substrate. Cobalt atoms will undergo local chemical bonding with the substrate, resulting in strong interfacial adhesion and making self-peeling impossible. If the thickness of the inert separator is too large, the internal resistance of the film layer will increase, the drying shrinkage pressure will increase, and cracking or peeling will easily occur. Moreover, an excessively thick inert separator layer will affect the nucleation and conductivity uniformity of cobalt ions during the electrodeposition process, leading to a decrease in the quality of cobalt deposition, and even making it difficult to form a continuous electrodeposited cobalt layer on the cathode substrate.

[0105] As can be seen from the comparison between Example 1 and Comparative Example 1, if step (2) is not performed, that is, if the surface roughening treatment is not performed, the electroplated cobalt layer and the substrate lack the necessary mechanical anchor points, resulting in low adhesion of the electroplated cobalt layer during the electroplating process, premature local detachment, looseness or warping, which affects the uniformity and stability of deposition.

[0106] As can be seen from the comparison between Example 1 and Comparative Example 2, if step (3) is not performed, that is, if the inert plasma treatment is not performed, the substrate surface activity is insufficient and the wettability is poor, and the isolation liquid is difficult to spread and adhere evenly, resulting in an incomplete inert isolation film and missing coating points; at the same time, the contaminants or oxide layer on the substrate surface are not effectively removed, further reducing the bonding force and density between the isolation film and the substrate, resulting in increased adhesion between the electroplated cobalt layer and the substrate interface, and failure of the self-peeling function.

[0107] As can be seen from the comparison between Example 1 and Comparative Example 3, if step (4) is not performed, that is, if chemical passivation isolation treatment is not performed, there is no inert isolation film on the surface of the cathode plate substrate. During the electrodeposition process, cobalt atoms directly contact the substrate and form a metallurgical bond at the interface, which significantly improves the adhesion, causing the electroplated cobalt layer to be unable to automatically peel off from the surface of the cathode plate.

[0108] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A surface treatment method for a cobalt electrowinning self-peeling cathode plate, characterized in that, The surface treatment method includes the following steps: Provide cathode plate substrate; The cathode plate substrate is subjected to surface roughening treatment to obtain a low-riveting roughened substrate; The surface of the low-riveting roughened substrate is subjected to inert plasma treatment, followed by chemical passivation isolation treatment to generate an inert isolation film on the surface of the substrate, thereby obtaining a passivated isolation substrate.

2. The surface treatment method according to claim 1, characterized in that, The cathode plate substrate includes any one of the following: a copper plate, a copper-based alloy plate, a aluminum plate, an aluminum-based alloy plate, a nickel plate, or a nickel-based alloy plate.

3. The surface treatment method according to claim 1 or 2, characterized in that, The surface roughening treatment includes a low-gradient sandblasting process and a medium-fine sand homogenization grinding process performed sequentially. In the low-gradient sandblasting process, the increment of sandblasting pressure per unit time is less than 0.05 MPa / s, and the range of sandblasting pressure is 0.1-0.3 MPa. During the homogenization and grinding process of the medium and fine sand, the particle size range of the medium and fine sand is 80-200 mesh.

4. The surface treatment method according to any one of claims 1-3, characterized in that, The surface roughness Ra of the low-riveting roughened substrate is 0.4-0.8 μm; And / or, the surface of the low-riveting roughened substrate has a microtexture structure, the groove depth of the microtexture structure is ≤0.03mm, and the spacing between adjacent microtexture structures is 0.5-1.5mm.

5. The surface treatment method according to any one of claims 1-4, characterized in that, During the inert plasma treatment process, the power of the plasma generator is 800-1200W; And / or, the inert plasma treatment time is 10-15 min; And / or, during the inert plasma treatment, the working gas includes argon.

6. The surface treatment method according to any one of claims 1-5, characterized in that, The chemical passivation isolation process includes the following steps: The substrate treated with inert plasma was immersed in a chemical passivation and isolation solution. The chemical passivation isolation solution includes organic acids, silicates, and organic inert film-forming aids.

7. The surface treatment method according to claim 6, characterized in that, The organic acid includes any one or a combination of at least two of citric acid, oxalic acid, acetic acid or tartaric acid; And / or, the silicate includes any one or a combination of at least two of sodium silicate, potassium silicate, or lithium silicate; And / or, the organic inert film-forming aid includes any one or a combination of at least two of polyvinyl alcohol, carboxymethyl cellulose, or polyethylene glycol; And / or, in the chemical passivation isolation solution, the concentration of silicate is 10-100 g / L; And / or, in the chemical passivation and isolation solution, the concentration of the organic inert film-forming aid is 1-30 g / L.

8. The surface treatment method according to claim 6 or 7, characterized in that, The pH of the chemical passivation isolation solution is 8-11.

9. The surface treatment method according to any one of claims 6-8, characterized in that, The soaking temperature is 20-80℃; And / or, the soaking treatment time is 5-15 minutes; And / or, the thickness of the inert isolation membrane is 5-200 nm.

10. The surface treatment method according to any one of claims 1-9, characterized in that, The surface treatment method includes the following steps: (1) Provide a cathode plate substrate; the cathode plate substrate includes any one of a copper plate, a copper-based alloy plate, an aluminum plate, an aluminum-based alloy plate, a nickel plate, or a nickel-based alloy plate; The cathode plate substrate is surface treated by first soaking it in an alkaline degreasing agent to remove oil stains, and then neutralizing it with a weak acid solution to obtain a clean cathode plate substrate. (2) The clean cathode plate substrate surface is subjected to low gradient sandblasting and medium-fine sand homogenization grinding in sequence to form a shallow and flat micro-texture structure on the substrate surface, resulting in a low-riveting roughened substrate with a surface roughness Ra of 0.4-0.8μm. Wherein, the groove depth of the microtexture structure is ≤0.03mm, and the spacing between adjacent microtexture structures is 0.5-1.5mm; (3) The surface of the low-riveting roughened substrate is subjected to inert plasma treatment. A high-frequency plasma generator is used, the power is controlled at 800-1200W, the treatment time is 10-15min, and the working gas includes argon to obtain a clean modified cathode plate substrate. (4) The cleaned and modified cathode plate substrate is immersed in a chemical passivation isolation solution at 20-80°C for 5-15 minutes to form an inert isolation film with a thickness of 5-200 nm on the surface of the substrate; wherein, the chemical passivation isolation solution includes organic acid, silicate and organic inert film-forming aid; the organic acid includes any one or a combination of at least two of citric acid, oxalic acid, acetic acid or tartaric acid; the silicate includes any one or a combination of at least two of sodium silicate, potassium silicate or lithium silicate; the organic inert film-forming aid includes any one or a combination of at least two of polyvinyl alcohol, carboxymethyl cellulose or polyethylene glycol; in the chemical passivation isolation solution, the concentration of silicate is 10-100 g / L, the concentration of organic inert film-forming aid is 1-30 g / L; the pH of the chemical passivation isolation solution is 8-11; After the immersion treatment, the substrate is rinsed with cold water and then hot water in sequence, and then dried to obtain a passivated isolation substrate.

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