Electrolyte for electrodepositing FeCoNiCu high-entropy alloy coating and application thereof

Abstract

This invention belongs to the field of functional coating technology, specifically relating to an electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings and its application. The electrolyte includes FeSO4·7H2O, CoSO4·7H2O, NiSO4·6H2O, CuSO4·5H2O, H3BO3, sodium citrate, citric acid, NaCl, and additives. The additives are selected from at least one of o-phenanthroline, o-chlorobenzaldehyde, potassium thiocyanate, sodium 3-mercapto-1-propanesulfonate, and 4-(2-pyridinium azo)resorcinol. This electrolyte can prepare FeCoNiCu high-entropy alloy coatings with similar atomic ratios of metal elements in a one-step electrodeposition process, achieving co-deposition of four elements. The addition of additives can improve cathodic polarization, refine grains, and prepare a dense coating exhibiting excellent wear resistance. Simultaneously, the process is simple, low-cost, environmentally friendly, non-toxic, and safe.

Description

Technical Field

[0001] This invention belongs to the field of functional coating technology, specifically relating to an electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings and its application. Background Technology

[0002] Metallic materials have played a crucial role in human history, serving as a vital material foundation for societal development. With the continuous advancement of materials science and the emergence of new materials, traditional alloys have gradually become insufficient to meet human needs, making novel alloys a hot research topic. Traditional alloy design primarily uses one or two elements as the matrix, adding small amounts of other elements to improve alloy properties. High-entropy alloys (HEAs) are a rapidly developing new type of metallic material in recent years, possessing numerous superior properties. In 2004, Yeh et al. formally proposed the concept of high-entropy alloys, defining them as alloys composed of five or more elements with equiatomic or near-equiatomic ratios, with each element's atomic fraction ranging from 5% to 35%. The crystal structure of high-entropy alloys is typically a simple face-centered cubic (FCC), body-centered cubic (BCC), or hexagonal close-packed (HCP) structure, where different atoms randomly occupy lattice positions, forming a simple solid solution. High-entropy alloys are primarily composed of solid solution structures and do not contain complex intermetallic compounds. High-entropy alloys (HEAs) possess four core effects: thermodynamic high-entropy effect, kinetic slow diffusion effect, severe lattice distortion effect, and a performance "cocktail effect." Compared to traditional metallic materials, HEAs exhibit higher strength and hardness, as well as excellent oxidation resistance, abrasion resistance, corrosion resistance, and soft magnetic properties. The emergence of HEAs has provided new design concepts for developing new materials with superior properties and has become an important direction in cutting-edge materials science research.

[0003] Currently, the main methods for preparing high-entropy alloys include magnetron sputtering, laser cladding, vacuum melting, and plasma spraying. These methods are costly in terms of instruments and production equipment, and consume a lot of energy, which hinders their widespread application. Electrochemical deposition, on the other hand, is a feasible and cost-effective material preparation method. It does not require complex and expensive equipment, and the electrolyte composition is simple and easy to prepare. Alloy coatings prepared by electrodeposition have advantages such as low cost, simple operation, fast deposition rate, and environmental friendliness. Electrodeposition can be used to deposit an alloy coating on the surface of a workpiece, improving its wear resistance, and has become an ideal choice for preparing high-performance alloy coatings and thin films. Furthermore, electrodeposition technology offers diverse operating methods, making it widely adaptable and flexible. It can control the nucleation and growth of metal nanoparticles with different shapes and sizes, and can coat substrates with unconventional shapes, making it widely used in the production of metal coatings.

[0004] The FeCoNiCu high-entropy alloy coating possesses a variety of superior properties due to its unique composition design: the introduction of Cu endows the coating with good electrical conductivity and self-lubricating properties, while the synergistic effect of Fe, Co, and Ni provides high hardness and mechanical strength. Based on these advantages, the FeCoNiCu high-entropy alloy coating shows broad application prospects in the field of wear-resistant protection, and is expected to be used in mold surface strengthening, wear-resistant coatings for mechanical parts, and other applications.

[0005] However, the electrodeposition of FeCoNiCu high-entropy alloys faces a core challenge: the standard electrode potentials of the four metal ions differ significantly. 2+ The reduction potential of Cu is significantly more positive than that of the other three ions, resulting in a higher reduction potential during conventional electrodeposition processes. 2+ Preferential reduction leads to a Cu content in the coating that is much higher than the proportion of other elements in the plating bath, forming a Cu-rich phase or even pure Cu precipitation. This disrupts the single-phase solid solution structure of the high-entropy alloy, causing the coating composition to deviate from the target ratio and resulting in unstable performance. Therefore, how to suppress the preferential precipitation of Cu and achieve the simultaneous co-deposition of Fe, Co, Ni, and Cu ions is the core technical challenge in preparing high-quality FeCoNiCu high-entropy alloy coatings.

[0006] To control cathodic polarization behavior during electrodeposition, organic additives are often added to the plating bath in existing technologies. Existing additives, such as saccharin, are mainly used in Ni or Ni-Fe alloy systems to relieve stress and refine grains, but their application to Cu... 2+ The inhibitory effect is limited; vanillin acts as a leveling agent in Ni-Co alloys, but it has not been optimized for quaternary co-deposition systems; sodium dodecyl sulfate mainly acts as a wetting agent to reduce pinholes and does not directly regulate polarization behavior. In summary, the research on additive screening and polarization control specifically for FeCoNiCu high-entropy alloy electrodeposition is still a technological gap, lacking a dedicated additive scheme that can simultaneously inhibit Cu precipitation, refine grains, and maintain a reasonable deposition rate. Summary of the Invention

[0007] To address the shortcomings of the existing technologies mentioned above, specifically: traditional preparation methods such as magnetron sputtering and laser cladding suffer from drawbacks such as expensive equipment, low efficiency, and difficulty in large-scale production; the deposition potentials of various metal ions differ significantly, especially for Cu. 2+ The deposition potential is more positive, while Fe 2+ Co 2+ Ni 2+The negative deposition potential of FeCoNiCu leads to preferential Cu precipitation, resulting in uneven composition of the prepared coating and easy compositional segregation. There is a lack of effective cathode polarization control methods; existing additives are mainly for single metal or binary alloy systems, and their polarization control ability for FeCoNiCu quaternary co-deposition systems is limited, making it difficult to simultaneously achieve grain refinement, compositional uniformity, and deposition rate optimization. The coating lacks density, has coarse grains, a loose structure, and poor performance. This invention provides an electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings and its application. By adding specific additives to regulate cathode polarization behavior and suppress preferential Cu precipitation, a dense coating with uniform composition and refined grains is obtained, further improving the wear resistance of the coating.

[0008] The specific plan is as follows:

[0009] An electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings comprises FeSO4·7H2O, CoSO4·7H2O, NiSO4·6H2O, CuSO4·5H2O, H3BO3, sodium citrate, citric acid, NaCl, and additives.

[0010] The additive is selected from at least one of o-phenanthroline, o-chlorobenzaldehyde, potassium thiocyanate, sodium 3-mercapto-1-propanesulfonate (MPS), and 4-(2-pyridineazo)resorcinol (PAR).

[0011] Specifically, the concentrations of FeSO4·7H2O are 10-30 g / L, CoSO4·7H2O are 10-30 g / L, NiSO4·6H2O are 20-80 g / L, CuSO4·5H2O are 0.5-5 g / L, H3BO3 are 20-40 g / L, sodium citrate is 60-120 g / L, citric acid is 10-30 g / L, and NaCl is 0.1-1 g / L.

[0012] Specifically, the concentration of the additive is 0.01-0.05 g / L.

[0013] Preferably, the electrolyte also includes sodium dodecyl sulfonate (SDS) at a concentration of 0.01-0.05 g / L. Sodium dodecyl sulfonate acts as a lubricant, used in combination with additives to regulate the elemental content of the coating.

[0014] An application of an electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings; wherein the synthesized FeCoNiCu high-entropy alloy coatings, by atomic percentage (at%), are 15-35% Fe, 15-30% Co, 15-25% Ni, and 10-35% Cu.

[0015] Preferably, the deposition conditions are: direct current, with a current density of 0.1-0.5 A / cm³. 2 The temperature is 25-60℃, the pH value is 2.0-5.0, and the deposition time is 30min-1h.

[0016] Compared with existing technologies, the beneficial effects are as follows:

[0017] The electrolyte of this invention can be used to prepare a FeCoNiCu high-entropy alloy coating with close atomic ratios of metal elements in one step by electrodeposition, achieving co-deposition of four elements; after adding additives, the cathode polarization can be improved, the grains can be refined, and a dense coating can be prepared, exhibiting excellent wear resistance; at the same time, the process is simple, low-cost, environmentally friendly, non-toxic and green and safe. Attached Figure Description

[0018] Figure 1 a is a comparison curve of the total LSV of the electroplating solutions of Examples 1-5 and Comparative Example 1; Figure 1 b is a comparison curve of LSV of the electroplating solutions of Example 2 and Comparative Example 1; Figure 1 c is a comparison curve of LSV of the electroplating solutions of Example 4 and Comparative Example 1. Figure 1 d is a comparison curve of LSV of the electroplating solutions of Example 5 and Comparative Example 1; Figure 1 e is a comparison curve of LSV of the electroplating solutions of Example 1 and Comparative Example 1; Figure 1 f is a comparison curve of LSV of the electroplating solutions of Example 3 and Comparative Example 1;

[0019] Figure 2 a~f are SEM images of the high-entropy alloy coatings obtained in Comparative Example 1, Example 2, Example 4, Example 5, Example 1 and Example 3, respectively;

[0020] Figure 3 a~e are SEM images of the coating in Comparative Example 1 and EDS elemental distribution diagrams of Ni, Cu, Fe, and Co, respectively.

[0021] Figure 4 The friction coefficient curves of the coatings in Example 1 and Comparative Example 1 are shown.

[0022] Figure 5 The images show the XRD patterns of the coatings in Example 1 and Comparative Example 1. Detailed Implementation

[0023] The embodiments of the present invention will be described in further detail below. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0024] Example 1

[0025] An electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings comprises FeSO4·7H2O 27.801 g / L, CoSO4·7H2O 14.055 g / L, NiSO4·6H2O 78.855 g / L, CuSO4·5H2O 0.7491 g / L, H3BO3 24.732 g / L, sodium citrate 77.4207 g / L, citric acid 19.212 g / L, NaCl 0.5844 g / L, sodium dodecyl sulfate (SDS) 0.05 g / L, and additive 4-(2-pyridinium azo)resorcinol (PAR) 0.05 g / L.

[0026] Electrodeposition conditions for preparing FeCoNiCu high-entropy alloy coatings: Direct current, current density 0.4 A / cm² 2 The temperature was 40℃, the pH was 3, and the deposition time was 30 min.

[0027] Example 2

[0028] An electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings comprises 27.801 g / L FeSO4·7H2O, 14.055 g / L CoSO4·7H2O, 78.855 g / L NiSO4·6H2O, 0.7491 g / L CuSO4·5H2O, 24.732 g / L H3BO3, 77.4207 g / L sodium citrate, 19.212 g / L citric acid, 0.5844 g / L NaCl, 0.05 g / L sodium dodecyl sulfonate (SDS), and 0.05 g / L o-chlorobenzaldehyde as an additive.

[0029] Electrodeposition conditions for preparing FeCoNiCu high-entropy alloy coatings: Direct current, current density 0.4 A / cm² 2 The temperature was 40℃, the pH was 3, and the deposition time was 30 min.

[0030] Example 3

[0031] An electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings comprises 27.801 g / L FeSO4·7H2O, 14.055 g / L CoSO4·7H2O, 78.855 g / L NiSO4·6H2O, 0.7491 g / L CuSO4·5H2O, 24.732 g / L H3BO3, 77.4207 g / L sodium citrate, 19.212 g / L citric acid, 0.5844 g / L NaCl, 0.05 g / L sodium dodecyl sulfonate (SDS), and 0.05 g / L potassium thiocyanate as an additive.

[0032] Electrodeposition conditions for preparing FeCoNiCu high-entropy alloy coatings: Direct current, current density 0.4 A / cm² 2 The temperature was 40℃, the pH was 3, and the deposition time was 30 min.

[0033] Example 4

[0034] An electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings comprises 27.801 g / L FeSO4·7H2O, 14.055 g / L CoSO4·7H2O, 78.855 g / L NiSO4·6H2O, 0.7491 g / L CuSO4·5H2O, 24.732 g / L H3BO3, 77.4207 g / L sodium citrate, 19.212 g / L citric acid, 0.5844 g / L NaCl, 0.05 g / L sodium dodecyl sulfonate (SDS), and 0.05 g / L sodium 3-mercapto-1 propanesulfonate (MPS) additive.

[0035] Electrodeposition conditions for preparing FeCoNiCu high-entropy alloy coatings: Direct current, current density 0.4 A / cm² 2 The temperature was 40℃, the pH was 3, and the deposition time was 30 min.

[0036] Example 5

[0037] An electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings comprises 27.801 g / L FeSO4·7H2O, 14.055 g / L CoSO4·7H2O, 78.855 g / L NiSO4·6H2O, 0.7491 g / L CuSO4·5H2O, 24.732 g / L H3BO3, 77.4207 g / L sodium citrate, 19.212 g / L citric acid, 0.5844 g / L NaCl, 0.05 g / L sodium dodecyl sulfate (SDS), and 0.05 g / L o-phenanthroline as an additive.

[0038] Electrodeposition conditions for preparing FeCoNiCu high-entropy alloy coatings: Direct current, current density 0.4 A / cm² 2 The temperature was 40℃, the pH was 3, and the deposition time was 30 min.

[0039] Comparative Example 1

[0040] Referring to Example 1, the difference is that the electrolyte does not contain additives.

[0041] test

[0042] like Figure 1 a is a comparison curve of the total LSV of the electroplating solutions of Examples 1-5 and Comparative Example 1; Figure 1 b is a comparison curve of LSV of the electroplating solutions of Example 2 and Comparative Example 1; Figure 1 c is a comparison curve of LSV of the electroplating solutions of Example 4 and Comparative Example 1. Figure 1 d is a comparison curve of LSV of the electroplating solutions of Example 5 and Comparative Example 1; Figure 1 e is a comparison curve of LSV of the electroplating solutions of Example 1 and Comparative Example 1; Figure 1 f is a comparison curve of LSV of the electroplating solutions of Example 3 and Comparative Example 1. In this invention, different additives were added to the FeCoNiCu electroplating solution, and the solutions were characterized using an electrochemical workstation. The test results show that, compared with Comparative Example 1 (without additives), the deposition potentials changed after the addition of additives, and all deposition potentials shifted negatively to varying degrees. Specifically: after adding PAR, the deposition potential shifted significantly negatively, and the current density at the same potential was also significantly lower than that of Comparative Example 1, indicating that PAR has the strongest cathodic polarization effect, and the cathodic polarization effect was significantly enhanced; after adding o-chlorobenzaldehyde, the curve also showed a significant negative shift, and the deposition potential shifted negatively, showing a moderately strong polarization effect, which increased the cathodic polarization effect; after adding o-phenanthroline, the deposition potential shifted significantly negatively, which inhibited the deposition of metal elements and could be used as an inhibitor; after adding MPS, the deposition potential shifted negatively, and the polarization effect was enhanced; after adding potassium thiocyanate, the deposition potential shifted slightly negatively, which increased the cathodic polarization to a certain extent. In summary, the electroplating solution of the present invention significantly improved the deposition characteristics of FeCoNiCu high-entropy alloy coatings by adding different additives. In particular, the addition of PAR significantly increased the deposition overpotential, which is beneficial for obtaining high-quality alloy coatings with fine grains and dense structure, and is suitable for the preparation of high-performance coatings.

[0043] like Figure 2a~f are SEM images of the high-entropy alloy coatings obtained in Comparative Examples 1, 2, 4, 5, 1, and 3, respectively. It can be seen that: before the addition of additives, the coating grain size is large and the structure is relatively loose; after the addition of additives, the morphology of the coating is improved, the grain size is reduced, and the structure is dense; the coating grains in Examples 1 and 2 are refined and more dense; the coating in Example 3 is dense, and the grains are refined to the nanometer level; the coating structure in Example 4 is more dense, with almost no voids; the coating grains in Example 5 are refined and the structure is dense.

[0044] like Figure 3 a~e are SEM images of the coating in Comparative Example 1 and EDS elemental distribution diagrams of Ni, Cu, Fe, and Co, respectively. As shown in the figure, the coating surface is dense and free of cracks. According to the EDS surface scan analysis, the four elements Fe, Co, Ni, and Cu are evenly distributed without obvious segregation. This indicates that without the aid of any additives, the electrolyte and deposition process parameters used in this invention can still produce a high-quality alloy coating.

[0045] like Figure 4 The graphs show the friction coefficients of the coatings in Example 1 and Comparative Example 1; the average friction coefficient of the coating in Comparative Example 1 is 0.85169, and the wear rate is 3.25 × 10⁻⁶. -5 mm 3 / Nm, the average coefficient of friction of the coating in Example 1 was 0.69854, and the wear rate was 3.13×10. -5 mm 3 / Nm, the decrease in friction coefficient and wear rate indicates that the addition of additive PAR improves the friction performance of the coating and demonstrates excellent wear resistance.

[0046] like Figure 5 The XRD patterns of the coatings in Example 1 and Comparative Example 1 show that the prepared coatings all exhibit three diffraction peaks, corresponding to the (111), (200), and (220) crystal planes of the FCC phase, respectively. This indicates that the prepared coatings are all single FCC phases, and no independent diffraction peaks of elements such as Fe, Co, Ni, and Cu were detected. In addition, after the addition of PAR additive, the diffraction peaks of the coatings became wider, indicating that the grains were refined, which is consistent with the results observed in the SEM images.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electrolyte for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings, characterized in that, Including FeSO4·7H2O, CoSO4·7H2O, NiSO4·6H2O, CuSO4·5H2O, H3BO3, sodium citrate, citric acid, NaCl, and additives; The additive is selected from at least one of o-phenanthroline, o-chlorobenzaldehyde, potassium thiocyanate, sodium 3-mercapto-1-propanesulfonate (MPS), and 4-(2-pyridineazo)resorcinol (PAR).

2. The electrolyte according to claim 1, characterized in that, The concentration of the additive is 0.01-0.05 g / L.

3. The electrolyte according to claim 1, characterized in that, The concentrations of FeSO4·7H2O are 10-30 g / L, CoSO4·7H2O is 10-30 g / L, NiSO4·6H2O is 20-80 g / L, CuSO4·5H2O is 0.5-5 g / L, H3BO3 is 20-40 g / L, sodium citrate is 60-120 g / L, citric acid is 10-30 g / L, and NaCl is 0.1-1 g / L.

4. The electrolyte according to claim 1, characterized in that, The electrolyte also includes sodium dodecyl sulfonate (SDS).

5. The electrolyte according to claim 4, characterized in that, The concentration of sodium dodecyl sulfonate is 0.01-0.05 g / L.

6. The application of the electrolyte according to claim 1 for electrodeposition preparation of FeCoNiCu high-entropy alloy coatings, characterized in that, Used for electrodeposition to prepare FeCoNiCu high-entropy alloy coatings.

7. The application according to claim 6, characterized in that, The deposition conditions were: current density of 0.1-0.5 A / cm³. 2 The temperature is 25-60℃, the pH value is 2.0-5.0, and the deposition time is 30min-1h.

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