A high corrosion-resistant Ni-Sn-P three-layer film alloy coating and an electrochemical deposition preparation method thereof

Abstract

The application discloses a high-corrosion-resistance Ni-Sn-P three-layer film alloy coating and an electrochemical deposition preparation method thereof, and relates to the technical field of metal material surface treatment. The application sequentially prepares a Ni-P bottom layer and two kinds of Ni-Sn-P functional layers with different tin contents on the surface of a base material, constructs a composite three-layer film structure, forms an interlayer potential difference by utilizing the component difference of each coating layer, optimizes the interface structure, and cooperatively improves the corrosion resistance of the coating. The coating has excellent corrosion resistance, the preparation process is simple, stable, green and environment-friendly, and the coating is easy to produce on a large scale, so that the use requirement of electronic precision equipment in a severe corrosion environment can be met.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology for metallic materials, and in particular to a high corrosion-resistant Ni-Sn-P three-layer alloy coating and its electrochemical deposition preparation method. Background Technology

[0002] In the field of chip manufacturing, etching equipment cavities and key components are used for a long time in highly corrosive environments such as high-purity electronic special gases and plasmas. The material surface is extremely prone to corrosion failure and particulate contamination, which seriously restricts the chip manufacturing process accuracy and equipment lifespan. This places extremely stringent requirements on the corrosion resistance, structural stability and adaptability of the surface protective coating.

[0003] Currently, traditional surface treatment technologies mostly focus on binary nickel-based alloy coatings. These systems are singular, with limited performance improvement pathways, making it difficult to simultaneously achieve high corrosion resistance and structural stability, and thus failing to meet the long-term protection requirements of etching equipment under extreme operating environments. Conventional Ni-Sn-P coatings are mostly prepared using chemical plating, resulting in single-layer or homogeneous structures. These methods suffer from insufficient coating density, poor elemental distribution uniformity, and significant bottlenecks in corrosion resistance. Furthermore, they lack a corrosion resistance mechanism based on the synergistic effect of elemental ratios and interlayer potential. Related thermodynamic studies show that Sn possesses excellent passivation properties over a wide pH range, and its surface can form a dense and stable SnO2 protective film in situ, providing long-term corrosion protection for the alloy coating. However, existing technologies do not fully utilize the synergistic effect of Ni, Sn, and P elements and the advantages of multilayer film gradient structures. Significant technological gaps remain in the design and controllable preparation of Ni-Sn-P coatings.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a highly corrosion-resistant Ni-Sn-P three-layer alloy coating and its electrochemical deposition preparation method, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides an electrochemical deposition method for Ni-Sn-P three-layer alloy coatings, comprising the following steps: A first coating layer, a second coating layer, and a third coating layer are sequentially electrochemically deposited on the surface of a substrate material to form a three-layer film structure, thereby obtaining the Ni-Sn-P three-layer film alloy coating. The first coating is an alloy layer with an atomic percentage of Ni 99.25 at% and P 0.75 at%; The second coating is an alloy layer with an atomic percentage of Ni 74 at%, Sn 6 at%, and P 20 at%. The third coating is an alloy layer with atomic percentages of Ni 66 at%, Sn 16 at%, and P 18 at%.

[0007] This invention reduces the corrosion tendency and corrosion current density of the coating by controlling the potential difference between the three layers, thereby improving corrosion resistance.

[0008] Furthermore, the substrate material is copper or a copper alloy.

[0009] Furthermore, the electrochemical deposition uses platinum as the anode and the substrate material as the cathode.

[0010] Furthermore, the electrochemical deposition is carried out sequentially in Ni-P electroplating solution, first Ni-Sn-P electroplating solution and second Ni-Sn-P electroplating solution; The composition of the Ni-P electroplating solution is as follows: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 15-25 g / L C2H3NaO2, 5-20 g / L C3H6O3, 10-20 g / L C6H5Na3O7·2H2O, 2-8 g / L CH4N2S, and 15-25 g / L NaKC4H4O6; pH is 4-6. The first Ni-Sn-P electroplating solution has the following composition: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 10-30 g / L C6H5Na3O7·2H2O, 5-20 g / L C3H6O3, and 10-15 g / L C4H6O4; pH is 8-10. The composition of the second Ni-Sn-P electroplating solution is as follows: 26 g / L NiSO4·6H2O, 108 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 10-30 g / L C6H5Na3O7·2H2O, 5-20 g / L C3H6O3 and 10-15 g / L C4H6O4; pH is 8-10.

[0011] Furthermore, the composition of the Ni-P electroplating solution is as follows: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 5-20 g / L C3H6O3, 10-20 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6; Furthermore, the first Ni-Sn-P electroplating solution comprises the following components: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 10-30 g / L C6H5Na3O7·2H2O, 5-20 g / L C3H6O3, and 12 g / L C4H6O4; the second Ni-Sn-P electroplating solution comprises the following components: 26 g / L NiSO4·6H2O, 108 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 10-30 g / L C6H5Na3O7·2H2O, 5-20 g / L C3H6O3, and 12 g / L C4H6O4.

[0012] Furthermore, the electrochemical deposition temperature is 60°C and the current density is 25 mA / cm².

[0013] Furthermore, the deposition time of the first coating is 6-12 min, the deposition time of the second coating is 6-12 min, and the deposition time of the third coating is 20-40 min.

[0014] Furthermore, a multi-tank electroplating method can be used.

[0015] Furthermore, before electrochemical deposition, the substrate material is pretreated to remove surface oxide layers, oil stains and impurities, thereby completing the fine cleaning and activation of the substrate surface, providing good interface conditions for subsequent electrochemical deposition, and effectively enhancing the bonding strength between the coating and the substrate.

[0016] The present invention also provides a Ni-Sn-P three-layer alloy coating prepared by the above-mentioned electrochemical deposition method.

[0017] Conventional Ni-Sn-P alloy coatings are mostly prepared using chemical plating processes, resulting in a single coating structure and generally suffering from defects such as insufficient corrosion resistance, low hardness, and easy surface breakage and failure, thus limiting their overall performance. This invention employs an electrochemical deposition process, combining a Ni-P functional underlayer with Ni-Sn-P functional surface layers of varying tin content to construct a multilayer film structure. The plating solution used has a simple composition, strong system stability, fast deposition rate, and controllable preparation cost. Compared to traditional single-layer and double-layer composite coatings, the multilayer alloy coating obtained by this invention possesses excellent corrosion resistance, weldability, ductility, repairability, and substrate bonding strength, resulting in a significant improvement in overall physicochemical properties.

[0018] Meanwhile, this invention utilizes the differentiated characteristics of different coating components to form a reasonable interlayer potential matching relationship. By leveraging the interlayer potential regulation effect, it synergistically optimizes the overall structural stability of the coating, effectively achieving a simultaneous and significant improvement in material hardness and corrosion resistance.

[0019] This invention is based on the Ni-Sn-P three-layer film design and the control of the potential difference between the three layers to reduce the corrosion current density, thereby realizing the combination of Ni-P layer and Ni-Sn-P layer and improving the corrosion resistance of Ni-Sn-P multilayer film surface.

[0020] The present invention discloses the following technical effects: This invention provides a Ni-Sn-P multilayer film structure design scheme and a preparation method that utilizes the potential difference between the multilayer films to synergistically improve the corrosion resistance of the material. The method employs an electrochemical deposition process to sequentially deposit Ni-P coatings and Ni-Sn-P coatings with different tin content on the substrate surface. By adjusting the electroplating process parameters, the potential difference between the multilayer films can be adjusted to effectively prepare a highly corrosion-resistant composite coating.

[0021] The preparation process of this invention is simple, controllable, green and environmentally friendly, with mature and reliable wastewater treatment technology, low production cost, and suitable for industrial continuous mass production needs; the resulting multilayer film coating has excellent comprehensive performance, can adapt to the special corrosive environment of electronic manufacturing for a long time, and has broad application prospects. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the preparation of the three-layer membrane structure of the present invention.

[0024] Figure 2 These are surface morphology images of the products of Comparative Examples 1-3 and Examples 1-3 of the present invention; wherein (a), (b), and (c) are surface morphology images of the products of Comparative Examples 1-3, respectively; and (d), (e), and (f) are surface morphology images of the products of Examples 1-3, respectively.

[0025] Figure 3 These are cross-sectional morphological images of the coatings of the products of Comparative Examples 1-3 and Examples 1-3 of the present invention; wherein, (a), (b), and (c) are cross-sectional morphological images of the coatings of the products of Comparative Examples 1-3, respectively; and (d), (e), and (f) are cross-sectional morphological images of the coatings of the products of Examples 1-3, respectively.

[0026] Figure 4 The Tafel curves (a) and Nyquist curves (b) of the products of Comparative Examples 1-3 of this invention are shown.

[0027] Figure 5The Tafel curve (a) and Nyquist curve (b) are the products of Examples 1-3 of this invention.

[0028] Figure 6 The images show the surface morphology of the products from Examples 1-3 of this invention under ammonia corrosion. Among them, (a) is a SEM image of the surface morphology of Ni-P (9min) / Ni-Sn-P (6min) / Ni-Sn-P (40min) under ammonia corrosion; (b) is a SEM image of the surface morphology of Ni-P (9min) / Ni-Sn-P (6min) / Ni-Sn-P (30min) under ammonia corrosion; and (c) is a SEM image of the surface morphology of Ni-P (9min) / Ni-Sn-P (6min) / Ni-Sn-P (20min) under ammonia corrosion.

[0029] Figure 7 EDS composition test of the three-layer film obtained in Example 3; (a) EDS spectrum of the bottom Ni-P coating, (b) EDS spectrum of the middle low Sn content coating, (c) EDS spectrum of the surface high Sn content coating. Figure 8 The images shown are surface morphology diagrams and metallographic thickness test diagrams of the products of Comparative Examples 4-6 of the present invention. (a), (b), and (c) are cross-sectional morphology diagrams of the coating of the products of Comparative Examples 4-6, respectively; (d), (e), and (f) are metallographic thickness test diagrams of the products of Comparative Examples 4-6, respectively.

[0030] Figure 9 The Tafel curves (a) and Nyquist curves (b) of the products of Comparative Examples 4-6 of this invention are shown.

[0031] Figure 10 The images show the surface morphology (a) and the cross-sectional morphology (b) of the coating of the product of Comparative Example 7 of the present invention.

[0032] Figure 11 The Tafel curve (a) and Nyquist curve (b) of the product of Comparative Example 7 of this invention are shown. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0038] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0039] A schematic diagram of the three-layer membrane structure of this invention is shown below. Figure 1 As shown.

[0040] In the following embodiments and comparative examples of the present invention, the Cu substrate used has a size of 30 mm × 50 mm × 0.8 mm.

[0041] In the three-layer film structure of this invention, the middle layer and the surface Ni-Sn-P coating have similar compositions and are fused at the interface. When measuring the thickness, it is impossible to measure the two layers separately. Only the bottom Ni-P layer and the Ni-Sn-P composite layer can be distinguished. Therefore, the thickness measurement is marked according to the thickness of the Ni-P layer and the total thickness of the Ni-Sn-P double film.

[0042] Comparative Example 1 This comparative example provides a method for preparing a Ni-Sn-P bilayer alloy coating, the steps of which are as follows: After pretreatment including polishing, washing, degreasing, acid pickling, and drying, the Cu substrate was plated using electrochemical deposition. Using a platinum sheet as the anode and the Cu substrate as the cathode, a bottom layer was first deposited in a Ni-P electroplating solution, followed by a surface layer deposition in a Ni-Sn-P electroplating solution containing 18 g / L SnCl2·2H2O. This resulted in a Ni-P / Ni-Sn-P bilayer alloy coating (labeled Ni-P(9min) / Ni-Sn-P(12min)), with a total thickness of 2.33 μm, including a 0.74 μm Ni-P layer and a 1.59 μm Ni-Sn-P layer. The deposition conditions were: temperature 60 ℃, current density 25 mA / cm², Ni-P layer deposition time 9 min, and Ni-Sn-P layer deposition time 12 min.

[0043] The Ni-P electroplating solution comprises the following components: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 20 g / L C3H6O3, 15 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6. The pH of the Ni-P electroplating solution is 4.8.

[0044] The Ni-Sn-P electroplating solution composition is as follows: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the Ni-Sn-P electroplating solution is 9.0.

[0045] The corrosion potential of the comparative product was tested to be -0.358 V, and the corrosion current density was 18.981 μA·cm. -2 The charge transfer resistance is 1087.0 Ω·cm. 2 .

[0046] Comparative Example 2 This comparative example provides a method for preparing a Ni-Sn-P bilayer alloy coating, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. Using a platinum sheet as the anode and a Cu substrate as the cathode, a Ni-P layer was first deposited in a Ni-P electroplating solution, followed by a surface layer deposition in an 18 g / L Ni-Sn-P electroplating solution (labeled Ni-P(9min) / Ni-Sn-P(9min)). The total thickness was 2.22 μm, with the Ni-P layer being 0.96 μm thick and the Ni-Sn-P layer being 1.26 μm thick. The deposition conditions were: temperature 60 ℃, current density 25 mA / cm², Ni-P layer deposition time 9 min, and Ni-Sn-P layer deposition time 9 min.

[0047] The Ni-P electroplating solution consists of the following components: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 20 g / L C3H6O3, 15 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6; the pH of the Ni-P electroplating solution is 4.8. The Ni-Sn-P electroplating solution composition is as follows: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the Ni-Sn-P electroplating solution is 9.0. The corrosion potential of the comparative product was tested to be -0.362 V, and the corrosion current density was 14.880 μA·cm. -2 The charge transfer resistance is 590.7 Ω·cm. 2 .

[0048] Comparative Example 3 This comparative example provides a method for preparing a Ni-Sn-P bilayer alloy coating, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. Using a platinum sheet as the anode and a Cu substrate as the cathode, a Ni-P layer was first deposited in a Ni-P electroplating solution, followed by a surface layer deposition in an 18 g / L Ni-Sn-P electroplating solution (labeled Ni-P(9 min) / Ni-Sn-P(6 min)), with a total thickness of 2.96 μm, including a 1.31 μm thick Ni-P layer and a 1.65 μm thick Ni-Sn-P layer. The deposition conditions were: temperature 60 ℃, current density 25 mA / cm², Ni-P layer deposition time 9 min, and Ni-Sn-P layer deposition time 6 min.

[0049] The Ni-P electroplating solution consists of the following components: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 20 g / L C3H6O3, 15 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6; the pH of the Ni-P electroplating solution is 4.8. The Ni-Sn-P electroplating solution composition is as follows: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the Ni-Sn-P electroplating solution is 9.0. The corrosion potential of the comparative product was tested to be -0.341 V, and the corrosion current density was 3.073 μA·cm. -2 The charge transfer resistance is 3939.0 Ω·cm. 2 .

[0050] Example 1 This embodiment provides a method for preparing a Ni-P / Ni-Sn-P / Ni-Sn-P three-layer alloy coating, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. Using a platinum sheet as the anode and a copper substrate as the cathode, the plating was sequentially deposited in Ni-P electroplating solution, Ni-Sn-P electroplating solution with 18 g / L SnCl2•2H2O, and Ni-Sn-P electroplating solution with 108 g / L SnCl2•2H2O. The deposition process conditions were as follows: temperature 60 ℃, current density 25 mA / cm²; the Ni-P layer deposition time was 9 min, the Ni-Sn-P layer deposition time of 18 g / L SnCl2•2H2O was 6 min, and the Ni-Sn-P layer deposition time of 108 g / L SnCl2•2H2O was 40 min, thus obtaining a Ni-Sn-P three-layer film alloy material (labeled as Ni-P(9min) / Ni-Sn-P(6min) / Ni-Sn-P(40min)), with a film thickness of 6.16 μm, of which the Ni-P layer thickness was 2.30 μm and the total thickness of the Ni-Sn-P bilayer film was 3.86 μm.

[0051] The Ni-P electroplating solution consists of the following components: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 20 g / L C3H6O3, 15 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6; the pH of the Ni-P electroplating solution is 4.8. The composition of the Ni-Sn-P electroplating solution with 18 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0. The composition of the Ni-Sn-P electroplating solution with a concentration of 108 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 108 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0. The corrosion potential of the product in this embodiment was tested to be -0.396 V, and the corrosion current density was 1.894 μA·cm. -2 The charge transfer resistance is 2550.1 Ω·cm. 2 .

[0052] Example 2 This embodiment provides a method for preparing a Ni-P / Ni-Sn-P / Ni-Sn-P three-layer alloy coating, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. Using a platinum sheet as the anode and a copper substrate as the cathode, the plating was sequentially deposited in Ni-P electroplating solution, Ni-Sn-P electroplating solution with 18 g / L SnCl2•2H2O, and Ni-Sn-P electroplating solution with 108 g / L SnCl2•2H2O. The deposition process conditions were as follows: temperature 60 ℃, current density 25 mA / cm²; the Ni-P layer deposition time was 9 min, the Ni-Sn-P layer deposition time of 18 g / L SnCl2•2H2O was 6 min, and the Ni-Sn-P layer deposition time of 108 g / L SnCl2•2H2O was 30 min, thus obtaining a Ni-Sn-P three-layer film alloy material (labeled as Ni-P(9min) / Ni-Sn-P(6min) / Ni-Sn-P(30min)), with a film thickness of 5.70 μm, of which the Ni-P layer thickness was 1.92 μm and the total thickness of the Ni-Sn-P bilayer film was 3.78 μm.

[0053] The Ni-P electroplating solution consists of the following components: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 20 g / L C3H6O3, 15 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6; the pH of the Ni-P electroplating solution is 4.8. The composition of the Ni-Sn-P electroplating solution with 18 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0. The composition of the Ni-Sn-P electroplating solution with a concentration of 108 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 108 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0. The corrosion potential of the product in this embodiment was tested to be -0.379 V, and the corrosion current density was 4.184 μA·cm. -2 The charge transfer resistance is 4689.8 Ω·cm. 2 .

[0054] Example 3 This embodiment provides a method for preparing a Ni-P / Ni-Sn-P / Ni-Sn-P three-layer alloy coating, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. Using a platinum sheet as the anode and a copper substrate as the cathode, the plating was sequentially deposited in Ni-P electroplating solution, Ni-Sn-P electroplating solution with 18 g / L SnCl2•2H2O, and Ni-Sn-P electroplating solution with 108 g / L SnCl2•2H2O. The deposition conditions were as follows: temperature 60 ℃, current density 25 mA / cm²; Ni-P layer deposition time was 9 min, Ni-Sn-P layer deposition time was 6 min with 18 g / L SnCl2•2H2O, and Ni-Sn-P layer deposition time was 20 min with 108 g / L SnCl2•2H2O, thus obtaining Ni-Sn-P three-layer film alloy material (labeled as Ni-P(9min) / Ni-Sn-P(6min) / Ni-Sn-P(20min)), with a film thickness of 4.83 μm, of which Ni-P layer thickness was 1.09 μm and total Ni-Sn-P bilayer film thickness was 3.74 μm.

[0055] The Ni-P electroplating solution consists of the following components: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 20 g / L C3H6O3, 15 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6; the pH of the Ni-P electroplating solution is 4.8. The composition of the Ni-Sn-P electroplating solution with 18 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0. The composition of the Ni-Sn-P electroplating solution with a concentration of 108 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 108 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0.

[0056] The EDS composition of the three-layer membrane obtained in Example 3 was tested as follows: Figure 7(a) is the EDS spectrum of the bottom Ni-P coating, (b) is the EDS spectrum of the middle layer with low Sn content, and (c) is the EDS spectrum of the surface layer with high Sn content. The atomic percentages of the first coating are Ni 99.25at%, Sn 0at%, P 0.75at%, the second coating is Ni 74at%, Sn 6at%, P 20at%, and the third coating is Ni 66at%, Sn 16at%, P 18at%. The corrosion potential of the product is -0.381 V, and the corrosion current density is 0.974 μA·cm. -2 The charge transfer resistance is 27800.0 Ω·cm. 2 .

[0057] Figure 2 These are surface morphology images of the products of Comparative Examples 1-3 and Examples 1-3 of the present invention; wherein (a), (b), and (c) are surface morphology images of the products of Comparative Examples 1-3, respectively; and (d), (e), and (f) are surface morphology images of the products of Examples 1-3, respectively.

[0058] Figure 3 These are cross-sectional morphological images of the coatings of the products of Comparative Examples 1-3 and Examples 1-3 of the present invention; wherein, (a), (b), and (c) are cross-sectional morphological images of the coatings of the products of Comparative Examples 1-3, respectively; and (d), (e), and (f) are cross-sectional morphological images of the coatings of the products of Examples 1-3, respectively.

[0059] The Tafel curves (a) and Nyquist curves (b) of the products of Comparative Examples 1-3 of this invention are as follows: Figure 4 As shown; the Tafel curves (a) and Nyquist curves (b) of the products from Examples 1-3 are as follows. Figure 5 As shown.

[0060] The ammonia corrosion surface morphology and EDS test images of the products in Examples 1-3 of this invention are shown below. Figure 6 Among them, a: SEM images of the surface morphology of Ni-P (9min) / Ni-Sn-P (6min) / Ni-Sn-P (40min) under ammonia corrosion; b: SEM images of the surface morphology of Ni-P (9min) / Ni-Sn-P (6min) / Ni-Sn-P (30min) under ammonia corrosion; c: SEM images of the surface morphology of Ni-P (9min) / Ni-Sn-P (6min) / Ni-Sn-P (20min) under ammonia corrosion.

[0061] Corrosion test conditions: The corrosive medium is 6 mol / L ammonia gas, the ammonia gas filling amount of a single sample is 20 kg, and the test pressure is 20 bar; the test container is made of 37Mn steel, the container is treated with high purification and dried, and the internal water and oxygen impurity content is ≤0.5ppm; the inner wall of the container is degreased and cleaned, and there is no oil residue or the residual oil on the inner wall is ≤25 mg / m² as detected by ultraviolet fluorescence. The ammonia corrosion test duration is 7 days.

[0062] Comparative Example 4 This comparative example provides a method for preparing a Ni-P single-layer alloy coating, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. Using a platinum sheet as the anode and a copper substrate as the cathode, a single-layer Ni 99.25at%-P 0.75at% alloy coating was prepared by deposition in a Ni-P electroplating solution. The deposition conditions were: temperature 60 ℃, current density 25 mA / cm², deposition time 9 min, and film thickness 1.31 μm.

[0063] The Ni-P electroplating solution consists of the following components: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 20 g / L C3H6O3, 15 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6; the pH of the Ni-P electroplating solution is 4.8.

[0064] The corrosion potential of the comparative product was tested to be -0.395 V, and the corrosion current density was 7.853 μA·cm. -2 The charge transfer resistance is 1066 Ω·cm 2 .

[0065] Comparative Example 5 This comparative example provides a method for preparing a single low-Sn-content Ni-Sn-P monolayer alloy coating, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. A Ni-Sn-P monolayer alloy coating was prepared by monolayer deposition in a Ni-Sn-P electroplating solution of 18 g / L SnCl2•2H2O using a platinum sheet as the anode and a copper substrate as the cathode. The deposition conditions were: temperature 60 ℃, current density 25 mA / cm², deposition time 6 min, and film thickness 1.55 μm.

[0066] The composition of the Ni-Sn-P electroplating solution with 18 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0.

[0067] The corrosion potential of the comparative product was tested to be -0.289 V, and the corrosion current density was 5.322 μA·cm. -2 The charge transfer resistance is 10119.4 Ω·cm. 2 .

[0068] Comparative Example 6 This comparative example provides a method for preparing a single high-Sn-content Ni-Sn-P monolayer alloy coating, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. A Ni-Sn-P monolayer alloy coating was prepared by monolayer deposition in a Ni-Sn-P electroplating solution of 108 g / L SnCl2•2H2O using a platinum sheet as the anode and a copper substrate as the cathode. The deposition conditions were: temperature 60 ℃, current density 25 mA / cm², deposition time 40 min, and film thickness 5.96 μm.

[0069] The composition of the Ni-Sn-P electroplating solution with a concentration of 108 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 108 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0.

[0070] The corrosion potential of the comparative product was tested to be -0.249 V, and the corrosion current density was 2.647 μA·cm. -2 The charge transfer resistance is 17629.4 Ω·cm. 2 .

[0071] Figure 8 The images show the surface morphology and metallographic thickness test results of the products of Comparative Examples 4-6 of this invention. (a), (b), and (c) are cross-sectional morphology images of the coating of the products of Comparative Examples 4-6, respectively; (d), (e), and (f) are metallographic thickness test results of the products of Comparative Examples 4-6, respectively. The Tafel curve (a) and Nyquist curve (b) of the products of Comparative Examples 4-6 of this invention are shown below. Figure 9As shown.

[0072] Comparative Example 7 This comparative example provides a method for preparing a Ni-Sn-P three-layer alloy coating with values ​​not limited by this invention, the steps of which are as follows: After pretreatment of the Cu substrate by grinding, washing, degreasing, pickling and drying, electrochemical deposition method is used to apply the plating. Using a platinum sheet as the anode and a copper substrate as the cathode, the plating was sequentially deposited in Ni-P electroplating solution, Ni-Sn-P electroplating solution with 34 g / L SnCl2•2H2O, and Ni-Sn-P electroplating solution with 72 g / L SnCl2•2H2O. The deposition conditions were: temperature 60 ℃, current density 25 mA / cm²; the Ni-P layer deposition time was 9 min, the Ni-Sn-P layer deposition time of 34 g / L SnCl2•2H2O was 6 min, and the Ni-Sn-P layer deposition time of 72 g / L SnCl2•2H2O was 40 min, thus obtaining a Ni-Sn-P three-layer film alloy material (labeled as Ni-P / Ni-Sn(34g / L)-P / Ni-Sn(72g / L)-P), with a film thickness of 4.96 μm, of which the Ni-P layer thickness was 1.36 μm and the total thickness of the Ni-Sn-P bilayer film was 3.60 μm.

[0073] The Ni-P electroplating solution consists of the following components: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 20 g / L C2H3NaO2, 20 g / L C3H6O3, 15 g / L C6H5Na3O7·2H2O, 7 g / L CH4N2S, and 20 g / L NaKC4H4O6; the pH of the Ni-P electroplating solution is 4.8. The composition of the Ni-Sn-P electroplating solution with a concentration of 34 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 34 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0. The composition of the Ni-Sn-P electroplating solution with 72 g / L SnCl2•2H2O is as follows: 26 g / L NiSO4·6H2O, 72 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 29 g / L C6H5Na3O7·2H2O, 5 g / L C3H6O3, and 12 g / L C4H6O4; the pH of the electroplating solution is 9.0.

[0074] The corrosion potential of the comparative product was tested to be -0.396 V, and the corrosion current density was 3.532 μA·cm. -2 The charge transfer resistance is 4150.1 Ω·cm. 2 .

[0075] Figure 10 The surface morphology (a) and cross-sectional morphology (b) of the product of Comparative Example 7 of the present invention are shown below; the Tafel curve (a) and Nyquist curve (b) of the product of Comparative Example 7 of the present invention are shown below. Figure 11 As shown.

[0076] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An electrochemical deposition method for a Ni-Sn-P three-layer alloy coating, characterized in that, Includes the following steps: A first coating layer, a second coating layer, and a third coating layer are sequentially electrochemically deposited on the surface of a substrate material to form a three-layer film structure, thereby obtaining the Ni-Sn-P three-layer film alloy coating. The first coating is an alloy layer with an atomic percentage of Ni 99.25 at% and P 0.75 at%; The second coating is an alloy layer with an atomic percentage of Ni 74 at%, Sn 6 at%, and P 20 at%. The third coating is an alloy layer with atomic percentages of Ni 66 at%, Sn 16 at%, and P 18 at%.

2. The electrochemical deposition method according to claim 1, characterized in that, The substrate material is copper or a copper alloy.

3. The electrochemical deposition method according to claim 1, characterized in that, The electrochemical deposition uses platinum as the anode and the substrate material as the cathode.

4. The electrochemical deposition method according to claim 1, characterized in that, The electrochemical deposition was carried out sequentially in Ni-P electroplating solution, first Ni-Sn-P electroplating solution and second Ni-Sn-P electroplating solution. The composition of the Ni-P electroplating solution is as follows: 25 g / L NiSO4·6H2O, 16 g / L NaH2PO2, 15-25 g / L C2H3NaO2, 5-20 g / L C3H6O3, 10-20 g / L C6H5Na3O7·2H2O, 2-8 g / L CH4N2S, and 15-25 g / L NaKC4H4O6; pH is 4-6. The first Ni-Sn-P electroplating solution has the following composition: 26 g / L NiSO4·6H2O, 18 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 10-30 g / L C6H5Na3O7·2H2O, 5-20 g / L C3H6O3, and 10-15 g / L C4H6O4; pH is 8-10. The composition of the second Ni-Sn-P electroplating solution is as follows: 26 g / L NiSO4·6H2O, 108 g / L SnCl2·2H2O, 10 g / L NaH2PO2, 10-30 g / L C6H5Na3O7·2H2O, 5-20 g / L C3H6O3 and 10-15 g / L C4H6O4; pH is 8-10.

5. The electrochemical deposition method according to claim 1, characterized in that, The electrochemical deposition temperature was 60°C and the current density was 25 mA / cm².

6. The electrochemical deposition method according to claim 5, characterized in that, The deposition time for the first coating is 6-12 min, the deposition time for the second coating is 6-12 min, and the deposition time for the third coating is 20-40 min.

7. The Ni-Sn-P three-layer alloy coating prepared by the electrochemical deposition method according to any one of claims 1-6.

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