Iron-based material nickel / tungsten alloy composite coating and preparation process

Abstract

The invention relates to the technical field of coatings, and particularly discloses a preparation process of an iron-based material nickel / tungsten alloy composite coating. The preparation process of the iron-based material nickel / tungsten alloy composite coating comprises the following steps: preparing a cold-rolled steel plate into a coordination modified steel plate; preparing the coordination modified steel plate into a roughened steel plate; preparing a plating solution; taking the roughened steel plate as a cathode and graphite as an anode, immersing in a plating solution, electroplating, taking out, immersing in a sulfuric acid solution, standing, washing and drying to obtain a plated steel plate; and immersing the coated steel plate in constant-temperature water, standing, taking out, purging with nitrogen, and curing to obtain the iron-based material nickel / tungsten alloy composite coating. The prepared iron-based material nickel / tungsten alloy composite coating is high in interface bonding force, high-temperature oxidation resistance and corrosion resistance, low in cost and suitable for large-scale application and popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a process for preparing a nickel / tungsten alloy composite coating of an iron-based material. Background Art

[0002] With the continuous development of industrial technology, the requirements for material performance are becoming increasingly higher. Among the many materials, iron-based materials are widely used in various fields due to their excellent mechanical properties and cost-effectiveness. However, the performance of iron-based materials in harsh environments such as high temperature and corrosion limits their scope of application. To overcome these limitations, nickel / tungsten alloy composite coating technology has emerged as one of the important means of material surface modification. However, existing technologies still have some limitations in terms of interfacial bonding, high-temperature oxidation resistance, and corrosion resistance.

[0003] Interfacial bonding is a key performance characteristic of nickel / tungsten alloy composite coatings. Good interfacial bonding ensures the stability and reliability of the coating on the substrate surface. However, in existing technologies, many coatings lack sufficient bonding strength to the substrate, resulting in the coating being susceptible to flaking during practical applications. For example, traditional silane coupling agents primarily rely on physical adsorption, resulting in weak interfacial bonding that cannot meet the requirements of high-temperature and complex operating conditions. Furthermore, some coatings are prone to interfacial cracking at high temperatures, further reducing the coating's service life.

[0004] High-temperature oxidation resistance is another important property of nickel / tungsten alloy composite coatings. In high-temperature environments, materials are prone to oxidation reactions, resulting in performance degradation. In existing technologies, many coatings have poor oxidation resistance at high temperatures. For example, after oxidizing GH907 high-temperature alloy at 750°C for 500 hours, the oxide layer increases significantly, indicating that its high-temperature oxidation resistance is insufficient. In addition, the oxide layer formed by some coatings at high temperatures is not dense enough to effectively prevent further penetration of oxygen, resulting in rapid oxidation of the base material.

[0005] Corrosion resistance is also an important indicator for measuring coating performance. In corrosive environments, the surface of the material is susceptible to chemical attack, resulting in performance degradation. In existing technologies, the corrosion resistance of many nickel / tungsten alloy composite coatings still needs to be improved. For example, although amorphous NiP-WC composite coatings exhibit certain corrosion resistance in 3.5% NaCl solution, their self-corrosion current density is still high, and the corrosion resistance is less than ideal. In addition, some coatings have poor corrosion resistance in acidic environments and cannot meet the needs of practical applications.

[0006] In summary, existing technologies for nickel / tungsten alloy composite coatings have limitations in terms of interfacial bonding, high-temperature oxidation resistance, and corrosion resistance. These limitations restrict their application in harsh environments such as high temperatures and corrosion. Therefore, developing a nickel / tungsten alloy composite coating with high interfacial bonding, excellent high-temperature oxidation resistance, and good corrosion resistance, as well as a preparation process, is of great practical significance. Summary of the Invention

[0007] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a preparation process for a nickel / tungsten alloy composite coating of an iron-based material.

[0008] A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse the cold-rolled steel plate in ethanol and water, perform ultrasonic cleaning, remove it, immerse it in a sulfuric acid solution, stir it in a constant temperature water bath, wash it with water, and dry it to obtain a pretreated steel plate; S2. 3,4-dihydroxyphenylphosphonic acid, hydrogen peroxide solution, ethanol, and water are mixed and stirred, and the pretreated steel plate is immersed in the mixture, allowed to stand in a constant temperature water bath, taken out, washed with water, and dried to obtain a coordination-modified steel plate; S3. Mix peroxytungstic acid, hydrogen peroxide solution, and water, immerse the coordinated modified steel plate in the mixture, let it stand in a constant temperature water bath, take it out, wash it with water, and dry it to obtain a roughened steel plate; S4, dispersing nickel sulfamate, sodium tungstate, β-cyclodextrin, and citric acid in water, stirring, and adjusting the pH of the solution to obtain a plating solution; S5, immersing the roughened steel plate as a cathode and the graphite as an anode in a plating solution, electroplating, removing the plate, immersing the plate in a sulfuric acid solution, allowing the plate to stand, washing the plate with water, and drying the plate to obtain a coated steel plate; S6. Immerse the coated steel plate in constant temperature water, let it stand, take it out, purge it with nitrogen, and solidify it to obtain an iron-based material nickel / tungsten alloy composite coating.

[0009] Preferably, in step S1, the weight ratio of the cold-rolled steel sheet, ethanol, water, and sulfuric acid solution is 900-1100:400-600:400-600:950-1050.

[0010] Preferably, in step S1, ultrasonic cleaning is performed, the ultrasonic cleaning time is 10-30 minutes, and the ultrasonic frequency is 40-60 kHz.

[0011] Preferably, in step S1, the mass fraction of the sulfuric acid solution is 5%.

[0012] Preferably, in step S1, stirring is performed in a constant temperature water bath, the water bath temperature is 23-27° C., the constant temperature water bath stirring time is 1-3 min, and the stirring speed is 300-400 rpm.

[0013] Preferably, in step S2, the weight ratio of 3,4-dihydroxyphenylphosphonic acid, hydrogen peroxide solution, ethanol and water is 40-60:15-25:200-300:200-300.

[0014] Preferably, in step S2, the mass fraction of the hydrogen peroxide solution is 25-35%.

[0015] Preferably, in step S2, the stirring is performed with a stirring time of 0.5-1 h and a stirring speed of 400-500 rpm.

[0016] Preferably, in step S2, the mixture is placed in a constant temperature water bath, the water bath temperature is 78-82° C., and the constant temperature water bath placement time is 1-2 hours.

[0017] Preferably, in step S3, the weight ratio of peroxytungstic acid, hydrogen peroxide solution, and water is 25-35:5-15:450-550.

[0018] Preferably, in step S3, the mass fraction of the hydrogen peroxide solution is 25-35%.

[0019] Preferably, in step S3, the mixture is placed in a constant temperature water bath, the water bath temperature is 78-82° C., and the constant temperature water bath placement time is 0.5-1 h.

[0020] Preferably, in step S4, the weight ratios of nickel sulfamate, sodium tungstate, β-cyclodextrin, citric acid and water are 180-220:40-60:5-15:35-45 and 700-900.

[0021] Preferably, in step S4, the pH of the solution is adjusted to 3.8-4.2 using 10% ammonia water by mass.

[0022] Preferably, in step S4, stirring is performed with a stirring time of 1-2 hours and a stirring speed of 500-600 rpm.

[0023] Preferably, in step S5, the roughened steel plate is used as the cathode and the graphite is used as the anode, and the plates are immersed in the plating solution. A DC power supply is used for electroplating for 0.5-1 h, the constant temperature bath temperature is 43-47° C., and the current density is 5-7 A / dm².

[0024] Preferably, in step S5, the mass fraction of the sulfuric acid solution is 5%.

[0025] Preferably, in step S5, the mixture is allowed to stand for 1-2 minutes.

[0026] Preferably, in step S6, the coated steel plate is immersed in constant temperature water, and the temperature of the constant temperature water is 55-65°C.

[0027] Preferably, in step S6, the mixture is allowed to stand for 2-3 hours.

[0028] Preferably, in step S6, nitrogen is used for purging, the purging time is 8-12 minutes, and the nitrogen flow rate is 8-12 L / min.

[0029] Preferably, in step S6, during curing, the oven temperature is 115-125° C., and the curing time is 0.5-1 h.

[0030] A nickel / tungsten alloy composite coating of an iron-based material is produced by any of the above methods for producing a nickel / tungsten alloy composite coating of an iron-based material. Beneficial effects

[0031] This invention overcomes the technical bottlenecks of traditional iron-based nickel / tungsten alloy coatings, such as low interfacial bonding strength, compositional segregation, and poor high-temperature stability, through the collaborative innovation of molecular-level chemical bonding design, in-situ nucleation guidance, and dynamic coordination deposition. Compared with existing technologies that rely on single coupling agents or external field-assisted processes, this invention constructs a synergistic mechanism of bidentate coordination anchoring-directional nucleation of tungsten oxygen clusters-gradient dynamic deposition-self-filling closed-loop repair from the perspectives of molecular group functionalization and microstructural regulation, achieving improved coating performance from the perspectives of chemical bonding and microstructural regulation.

[0032] Specifically, by introducing the bifunctional molecule 3,4-dihydroxyphenylphosphonic acid, its catechol group forms a high-energy chemical bond with the iron matrix Fe³⁺, and the phosphonic acid group guides tungsten deposition through the WOP bond, solving the problem of insufficient interface bonding caused by traditional silane coupling agents relying on physical adsorption, greatly improving the bonding strength of the coating, and eliminating the risk of interface cracking at high temperatures, providing reliable protection for the long-term service of the coating. Furthermore, traditional homogeneous coatings are prone to oxidation and peeling due to thermal expansion mismatch. The present invention generates W6O in situ. 19 The ²⁻ clusters guide the preferential deposition of tungsten, and the nickel / tungsten gradient distribution (high tungsten in the inner layer and high nickel in the outer layer) is controlled by a β-cyclodextrin / citric acid dynamic coordination system, forming a thermal stress buffer structure. Simultaneously, the decomposition products of citric acid react with residual metal ions to form NiWO4 nanoparticles, which fill the pores and form an antioxidant barrier, significantly extending the service life in high-temperature environments. Traditional coatings are easily penetrated by corrosive media due to their high porosity (>0.8%). This invention uses oxygen microbubble etching to increase surface roughness and enhance the mechanical bite of the coating. Dynamic gradient deposition reduces lattice distortion and lowers internal stress. A self-filling mechanism closes pores and forms a NiWO4 ceramic phase to block corrosion diffusion. Salt spray tests show that the coating's corrosion resistance life exceeds 1800 hours, a significant performance improvement compared to traditional processes.

[0033] The present invention abandons the conventional path of physical coarsening or external field regulation, and forms a closed-loop logic chain of "interface bonding-nucleation guidance-gradient deposition-self-repair" through molecular structure design and dynamic reaction control: the bidentate coordination of 3,4-dihydroxyphenylphosphonic acid lays a strong interface foundation, the tungsten oxygen clusters and the dynamic coordination system synergistically optimize the deposition dynamics, and the self-filling mechanism eliminates defects from the terminal. The three are progressive and mutually supportive, providing a new technical paradigm for the industrial application of high-performance nickel / tungsten alloy coatings. DETAILED DESCRIPTION

[0034] The present invention will be further explained below with reference to specific embodiments.

[0035] The cold-rolled steel sheets used in the present invention are all of SPCC type with a thickness of 1.5 mm.

[0036] Example 1 A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 900 g of cold-rolled steel plate in 400 g of ethanol and 400 g of water, ultrasonically clean for 10 min at an ultrasonic frequency of 40 kHz, remove the plate, immerse the plate in 950 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 23°C for 1 min at a stirring speed of 300 rpm, rinse with water, and dry the plate to obtain a pretreated steel plate; S2. Mix 40 g of 3,4-dihydroxyphenylphosphonic acid, 15 g of 25% hydrogen peroxide solution, 200 g of ethanol, and 200 g of water, stir for 0.5 h at a stirring speed of 400 rpm, immerse the pretreated steel plate in the mixture, and place it in a constant temperature water bath at 78°C for 1 h. Then, remove it, wash it with water, and dry it to obtain a coordination-modified steel plate; S3. Mix 25 g of peroxytungstic acid, 5 g of 25% hydrogen peroxide solution, and 450 g of water, immerse the coordinated modified steel plate in the mixture, and place it in a constant temperature water bath at 78°C for 0.5 h. Then, take it out, wash it with water, and dry it to obtain a roughened steel plate. S4, 180g nickel sulfamate, 40g sodium tungstate, 5g β-cyclodextrin, and 35g citric acid were dispersed in 700g water, stirred for 1h at a stirring speed of 500rpm, and the pH of the solution was adjusted to 3.8 with 10% ammonia water to obtain a plating solution; S5. The roughened steel plate was used as the cathode and the graphite was used as the anode. The plates were immersed in the plating solution and electroplated using a DC power supply for 0.5 h. The constant temperature bath temperature was 43 ° C and the current density was 5 A / dm². The plates were taken out and immersed in 950 g of 5% sulfuric acid solution by mass. The plates were allowed to stand for 1 min, washed with water and dried to obtain a coated steel plate. S6. Immerse the coated steel plate in 950g of constant temperature water at 55°C, let it stand for 2 hours, take it out, purge it with nitrogen for 8 minutes at a nitrogen flow rate of 8L / min, and cure it in an oven at 115°C for 0.5 hours to obtain an iron-based material nickel / tungsten alloy composite coating.

[0037] Example 2 A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 1100 g of cold-rolled steel plate in 600 g of ethanol and 600 g of water, ultrasonically clean for 30 min at an ultrasonic frequency of 60 kHz, remove the plate, immerse the plate in 1050 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 27° C. for 3 min at a stirring speed of 400 rpm, rinse with water, and dry the plate to obtain a pretreated steel plate; S2. Mix 60 g of 3,4-dihydroxyphenylphosphonic acid, 25 g of 35% hydrogen peroxide solution, 300 g of ethanol, and 300 g of water, stir for 1 h at a stirring speed of 500 rpm, immerse the pretreated steel plate in the mixture, and place it in a constant temperature water bath at 82°C for 2 h. Then, remove it, wash it with water, and dry it to obtain a coordination-modified steel plate; S3. Mix 35g of peroxytungstic acid, 15g of 35% hydrogen peroxide solution, and 550g of water, immerse the coordinated modified steel plate in the mixture, and place it in a constant temperature water bath at 82°C for 1 hour. Remove the plate, wash it with water, and dry it to obtain a roughened steel plate. S4, 220g nickel sulfamate, 60g sodium tungstate, 15g β-cyclodextrin, 45g citric acid were dispersed in 900g water, stirred for 2h at a stirring speed of 600rpm, and the pH of the solution was adjusted to 4.2 with 10% ammonia water to obtain a plating solution; S5. The roughened steel plate was used as the cathode and the graphite was used as the anode. The plates were immersed in the plating solution and electroplated using a DC power supply for 1 hour. The constant temperature bath temperature was 47°C and the current density was 7A / dm². The plates were taken out and immersed in 1050g of 5% sulfuric acid solution by mass. The plates were allowed to stand for 2 minutes, washed with water, and dried to obtain a coated steel plate. S6. Immerse the coated steel plate in 1050 g of constant temperature water at 65° C., let it stand for 3 hours, take it out, purge it with nitrogen for 12 minutes at a nitrogen flow rate of 12 L / min, and cure it in an oven at 125° C. for 1 hour to obtain an iron-based material nickel / tungsten alloy composite coating.

[0038] Example 3 A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 1000 g of cold-rolled steel plate in 500 g of ethanol and 500 g of water, ultrasonically clean for 20 min at an ultrasonic frequency of 50 kHz, remove the plate, immerse the plate in 1000 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 25° C. for 2 min at a stirring speed of 350 rpm, wash the plate with water, and dry the plate to obtain a pretreated steel plate; S2. 50 g of 3,4-dihydroxyphenylphosphonic acid, 20 g of a 30% hydrogen peroxide solution, 250 g of ethanol, and 250 g of water were mixed and stirred for 0.7 h at a stirring speed of 4500 rpm. The pretreated steel plate was immersed in the mixture and allowed to stand in a constant temperature water bath at 80° C. for 1.5 h. The pretreated steel plate was removed, washed with water, and dried to obtain a coordination-modified steel plate. S3. Mix 30 g of peroxytungstic acid, 10 g of 30% hydrogen peroxide solution, and 500 g of water, immerse the coordinated modified steel plate in the mixture, and place the mixture in a constant temperature water bath at 80°C for 0.7 h. Then, remove the mixture, rinse it with water, and dry it to obtain a roughened steel plate. S4, 200g nickel sulfamate, 50g sodium tungstate, 10g β-cyclodextrin, 40g citric acid were dispersed in 800g water, stirred for 1.5h at a stirring speed of 550rpm, and the pH of the solution was adjusted to 4 with 10% ammonia water to obtain a plating solution; S5. The roughened steel plate was used as the cathode and the graphite was used as the anode. The plates were immersed in the plating solution and electroplated using a DC power supply for 0.7 h. The constant temperature bath temperature was 45°C and the current density was 6 A / dm². The plates were taken out and immersed in 1000 g of a 5% sulfuric acid solution. The plates were allowed to stand for 1.5 min, washed with water and dried to obtain a coated steel plate. S6. Immerse the coated steel plate in 1000g of constant temperature water at 60°C, let it stand for 2.5 hours, take it out, purge it with nitrogen for 10 minutes at a nitrogen flow rate of 10L / min, and cure it in a 120°C oven for 0.7 hours to obtain an iron-based material nickel / tungsten alloy composite coating.

[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 3 is that the 3,4-dihydroxyphenylphosphonic acid in step S2 is replaced by 3-aminopropyltriethoxysilane.

[0040] A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 1000 g of cold-rolled steel plate in 500 g of ethanol and 500 g of water, ultrasonically clean for 20 min at an ultrasonic frequency of 50 kHz, remove the plate, immerse the plate in 1000 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 25° C. for 2 min at a stirring speed of 350 rpm, wash the plate with water, and dry the plate to obtain a pretreated steel plate; S2. 50 g of 3-aminopropyltriethoxysilane, 20 g of a 30% hydrogen peroxide solution, 250 g of ethanol, and 250 g of water were mixed and stirred for 0.7 h at a stirring speed of 4500 rpm. The pretreated steel plate was immersed in the mixture and allowed to stand in a constant temperature water bath at 80°C for 1.5 h. The pretreated steel plate was removed, washed with water, and dried to obtain a coordination-modified steel plate. S3. Mix 30 g of peroxytungstic acid, 10 g of 30% hydrogen peroxide solution, and 500 g of water, immerse the coordinated modified steel plate in the mixture, and place the mixture in a constant temperature water bath at 80°C for 0.7 h. Then, remove the mixture, rinse it with water, and dry it to obtain a roughened steel plate. S4, 200g nickel sulfamate, 50g sodium tungstate, 10g β-cyclodextrin, 40g citric acid were dispersed in 800g water, stirred for 1.5h at a stirring speed of 550rpm, and the pH of the solution was adjusted to 4 with 10% ammonia water to obtain a plating solution; S5. The roughened steel plate was used as the cathode and the graphite was used as the anode. The plates were immersed in the plating solution and electroplated using a DC power supply for 0.7 h. The constant temperature bath temperature was 45°C and the current density was 6 A / dm². The plates were taken out and immersed in 1000 g of a 5% sulfuric acid solution. The plates were allowed to stand for 1.5 min, washed with water and dried to obtain a coated steel plate. S6. Immerse the coated steel plate in 1000g of constant temperature water at 60°C, let it stand for 2.5 hours, take it out, purge it with nitrogen for 10 minutes at a nitrogen flow rate of 10L / min, and cure it in a 120°C oven for 0.7 hours to obtain an iron-based material nickel / tungsten alloy composite coating.

[0041] Comparative Example 2 The difference between Comparative Example 2 and Example 3 is that the 3,4-dihydroxyphenylphosphonic acid in step S2 is replaced by an equal amount of catechol to remove the phosphonic acid group function.

[0042] A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 1000 g of cold-rolled steel plate in 500 g of ethanol and 500 g of water, ultrasonically clean for 20 min at an ultrasonic frequency of 50 kHz, remove the plate, immerse the plate in 1000 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 25° C. for 2 min at a stirring speed of 350 rpm, wash the plate with water, and dry the plate to obtain a pretreated steel plate; S2. 50 g of catechol, 20 g of 30% hydrogen peroxide solution, 250 g of ethanol, and 250 g of water were mixed and stirred for 0.7 h at a stirring speed of 4500 rpm. The pretreated steel plate was immersed in the mixture and allowed to stand in a constant temperature water bath at 80°C for 1.5 h. The pretreated steel plate was removed, washed with water, and dried to obtain a coordination-modified steel plate. S3. Mix 30 g of peroxytungstic acid, 10 g of 30% hydrogen peroxide solution, and 500 g of water, immerse the coordinated modified steel plate in the mixture, and place the mixture in a constant temperature water bath at 80°C for 0.7 h. Then, remove the mixture, rinse it with water, and dry it to obtain a roughened steel plate. S4, 200g nickel sulfamate, 50g sodium tungstate, 10g β-cyclodextrin, 40g citric acid were dispersed in 800g water, stirred for 1.5h at a stirring speed of 550rpm, and the pH of the solution was adjusted to 4 with 10% ammonia water to obtain a plating solution; S5. The roughened steel plate was used as the cathode and the graphite was used as the anode. The plates were immersed in the plating solution and electroplated using a DC power supply for 0.7 h. The constant temperature bath temperature was 45°C and the current density was 6 A / dm². The plates were taken out and immersed in 1000 g of a 5% sulfuric acid solution. The plates were allowed to stand for 1.5 min, washed with water and dried to obtain a coated steel plate. S6. Immerse the coated steel plate in 1000g of constant temperature water at 60°C, let it stand for 2.5 hours, take it out, purge it with nitrogen for 10 minutes at a nitrogen flow rate of 10L / min, and cure it in a 120°C oven for 0.7 hours to obtain an iron-based material nickel / tungsten alloy composite coating.

[0043] Comparative Example 3 The difference between Comparative Example 3 and Example 3 is that peroxytungstic acid and hydrogen peroxide in step S3 are deleted, and sodium tungstate is directly added instead.

[0044] A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 1000 g of cold-rolled steel plate in 500 g of ethanol and 500 g of water, ultrasonically clean for 20 min at an ultrasonic frequency of 50 kHz, remove the plate, immerse the plate in 1000 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 25° C. for 2 min at a stirring speed of 350 rpm, wash the plate with water, and dry the plate to obtain a pretreated steel plate; S2. 50 g of 3,4-dihydroxyphenylphosphonic acid, 20 g of a 30% hydrogen peroxide solution, 250 g of ethanol, and 250 g of water were mixed and stirred for 0.7 h at a stirring speed of 4500 rpm. The pretreated steel plate was immersed in the mixture and allowed to stand in a constant temperature water bath at 80° C. for 1.5 h. The pretreated steel plate was removed, washed with water, and dried to obtain a coordination-modified steel plate. S3. Dissolve 30 g of sodium tungstate in 500 g of water, immerse the coordinated modified steel plate in the solution, place it in a constant temperature water bath at 80°C for 0.7 h, take it out, wash it with water, and dry it to obtain a roughened steel plate; S4, 200g nickel sulfamate, 50g sodium tungstate, 10g β-cyclodextrin, 40g citric acid were dispersed in 800g water, stirred for 1.5h at a stirring speed of 550rpm, and the pH of the solution was adjusted to 4 with 10% ammonia water to obtain a plating solution; S5. The roughened steel plate was used as the cathode and the graphite was used as the anode. The plates were immersed in the plating solution and electroplated using a DC power supply for 0.7 h. The constant temperature bath temperature was 45°C and the current density was 6 A / dm². The plates were taken out and immersed in 1000 g of a 5% sulfuric acid solution. The plates were allowed to stand for 1.5 min, washed with water and dried to obtain a coated steel plate. S6. Immerse the coated steel plate in 1000g of constant temperature water at 60°C, let it stand for 2.5 hours, take it out, purge it with nitrogen for 10 minutes at a nitrogen flow rate of 10L / min, and cure it in a 120°C oven for 0.7 hours to obtain an iron-based material nickel / tungsten alloy composite coating.

[0045] Comparative Example 4 The difference between Comparative Example 4 and Example 3 is that the β-cyclodextrin in step S4 is deleted.

[0046] A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 1000 g of cold-rolled steel plate in 500 g of ethanol and 500 g of water, ultrasonically clean for 20 min at an ultrasonic frequency of 50 kHz, remove the plate, immerse the plate in 1000 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 25° C. for 2 min at a stirring speed of 350 rpm, wash the plate with water, and dry the plate to obtain a pretreated steel plate; S2. 50 g of 3,4-dihydroxyphenylphosphonic acid, 20 g of a 30% hydrogen peroxide solution, 250 g of ethanol, and 250 g of water were mixed and stirred for 0.7 h at a stirring speed of 4500 rpm. The pretreated steel plate was immersed in the mixture and allowed to stand in a constant temperature water bath at 80° C. for 1.5 h. The pretreated steel plate was removed, washed with water, and dried to obtain a coordination-modified steel plate. S3. Mix 30 g of peroxytungstic acid, 10 g of 30% hydrogen peroxide solution, and 500 g of water, immerse the coordinated modified steel plate in the mixture, and place the mixture in a constant temperature water bath at 80°C for 0.7 h. Then, remove the mixture, rinse it with water, and dry it to obtain a roughened steel plate. S4, 200g nickel sulfamate, 50g sodium tungstate, and 40g citric acid were dispersed in 800g water, stirred for 1.5h at a stirring speed of 550rpm, and the pH of the solution was adjusted to 4 with 10% ammonia water to obtain a plating solution; S5. The roughened steel plate was used as the cathode and the graphite was used as the anode. The plates were immersed in the plating solution and electroplated using a DC power supply for 0.7 h. The constant temperature bath temperature was 45°C and the current density was 6 A / dm². The plates were taken out and immersed in 1000 g of a 5% sulfuric acid solution. The plates were allowed to stand for 1.5 min, washed with water and dried to obtain a coated steel plate. S6. Immerse the coated steel plate in 1000g of constant temperature water at 60°C, let it stand for 2.5 hours, take it out, purge it with nitrogen for 10 minutes at a nitrogen flow rate of 10L / min, and cure it in a 120°C oven for 0.7 hours to obtain an iron-based material nickel / tungsten alloy composite coating.

[0047] Comparative Example 5 The difference between Comparative Example 5 and Example 3 is that β-cyclodextrin and citric acid are deleted in step S4, and no coordination regulator is used.

[0048] A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 1000 g of cold-rolled steel plate in 500 g of ethanol and 500 g of water, ultrasonically clean for 20 min at an ultrasonic frequency of 50 kHz, remove the plate, immerse the plate in 1000 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 25° C. for 2 min at a stirring speed of 350 rpm, wash the plate with water, and dry the plate to obtain a pretreated steel plate; S2. 50 g of 3,4-dihydroxyphenylphosphonic acid, 20 g of a 30% hydrogen peroxide solution, 250 g of ethanol, and 250 g of water were mixed and stirred for 0.7 h at a stirring speed of 4500 rpm. The pretreated steel plate was immersed in the mixture and allowed to stand in a constant temperature water bath at 80° C. for 1.5 h. The pretreated steel plate was removed, washed with water, and dried to obtain a coordination-modified steel plate. S3. Mix 30 g of peroxytungstic acid, 10 g of 30% hydrogen peroxide solution, and 500 g of water, immerse the coordinated modified steel plate in the mixture, and place the mixture in a constant temperature water bath at 80°C for 0.7 h. Then, remove the mixture, rinse it with water, and dry it to obtain a roughened steel plate. S4, dispersing 200g of nickel sulfamate and 50g of sodium tungstate in 800g of water, stirring for 1.5h at a stirring speed of 550rpm, and adjusting the pH of the solution to 4 with 10% ammonia water to obtain a plating solution; S5. The roughened steel plate was used as the cathode and the graphite was used as the anode. The plates were immersed in the plating solution and electroplated using a DC power supply for 0.7 h. The constant temperature bath temperature was 45°C and the current density was 6 A / dm². The plates were taken out and immersed in 1000 g of a 5% sulfuric acid solution. The plates were allowed to stand for 1.5 min, washed with water and dried to obtain a coated steel plate. S6. Immerse the coated steel plate in 1000g of constant temperature water at 60°C, let it stand for 2.5 hours, take it out, purge it with nitrogen for 10 minutes at a nitrogen flow rate of 10L / min, and cure it in a 120°C oven for 0.7 hours to obtain an iron-based material nickel / tungsten alloy composite coating.

[0049] Comparative Example 6 The difference between Comparative Example 6 and Example 3 is that step S6 is deleted, and only nitrogen purging and drying are used after electroplating.

[0050] A process for preparing a nickel / tungsten alloy composite coating of an iron-based material comprises the following steps: S1. Immerse 1000 g of cold-rolled steel plate in 500 g of ethanol and 500 g of water, ultrasonically clean for 20 min at an ultrasonic frequency of 50 kHz, remove the plate, immerse the plate in 1000 g of 5% sulfuric acid solution, stir the plate in a constant temperature water bath at 25° C. for 2 min at a stirring speed of 350 rpm, wash the plate with water, and dry the plate to obtain a pretreated steel plate; S2. 50 g of 3,4-dihydroxyphenylphosphonic acid, 20 g of a 30% hydrogen peroxide solution, 250 g of ethanol, and 250 g of water were mixed and stirred for 0.7 h at a stirring speed of 4500 rpm. The pretreated steel plate was immersed in the mixture and allowed to stand in a constant temperature water bath at 80° C. for 1.5 h. The pretreated steel plate was removed, washed with water, and dried to obtain a coordination-modified steel plate. S3. Mix 30 g of peroxytungstic acid, 10 g of 30% hydrogen peroxide solution, and 500 g of water, immerse the coordinated modified steel plate in the mixture, and place the mixture in a constant temperature water bath at 80°C for 0.7 h. Then, remove the mixture, rinse it with water, and dry it to obtain a roughened steel plate. S4, 200g nickel sulfamate, 50g sodium tungstate, 10g β-cyclodextrin, 40g citric acid were dispersed in 800g water, stirred for 1.5h at a stirring speed of 550rpm, and the pH of the solution was adjusted to 4 with 10% ammonia water to obtain a plating solution; S5. Use the roughened steel plate as the cathode and the graphite as the anode, immerse them in the plating solution, use a DC power supply to electroplate for 0.7h, the constant temperature bath temperature is 45℃, the current density is 6A / dm², take it out, immerse it in 1000g of 5% sulfuric acid solution, let it stand for 1.5min, wash it with water and dry it, and purge it with nitrogen for 10min at a nitrogen flow rate of 10L / min to obtain an iron-based material nickel / tungsten alloy composite coating.

[0051] Performance Testing Bonding strength: The coatings produced in Examples 1-3 and Comparative Examples 1-6 were cut into rectangular samples of uniform size and soldered to the backside with a wire. A scratch tester (CSM Revetest) was used with a diamond indenter (radius 200 μm), applying a linear load of 0-100 N at a scratching speed of 10 mm / min. The critical load (Lc) (N) was determined by the point where the acoustic emission signal spiked, and the data were recorded. The results are shown in Table 1.

[0052] High-temperature oxidation resistance: The coatings prepared in Examples 1-3 and Comparative Examples 1-6 were cut into rectangular samples of uniform size, and the initial mass m0 (mg) was weighed. The samples were then placed in a muffle furnace and oxidized at 600°C for 300 h. After cooling, the sample mass m1 (mg) was weighed and recorded. The results are shown in Table 1.

[0053] Calculation formula: ; A 样品 is the area of ​​the coating (cm 2 ).

[0054] Corrosion Resistance: The coatings prepared in Examples 1-3 and Comparative Examples 1-6 were cut into rectangular samples of uniform size and encapsulated at the edges with epoxy resin. The samples were placed in a salt spray chamber (5% NaCl, 35°C) and observed every 24 hours for the appearance of red rust. The time to the first appearance of red rust (hours) was recorded. The results are shown in Table 1.

[0055] Table 1 Performance test results

[0056] Data Analysis: From the data of Examples 1-3 in Table 1, it can be seen that the iron-based nickel / tungsten alloy composite coating prepared by the present invention has obvious advantages in interface bonding strength, high temperature oxidation resistance and corrosion resistance. The average bonding strength is 107N and the maximum can reach 108N; the weight gain per unit area ( ) The average value is 2.0mg / cm², and the lowest can reach 1.9mg / cm²; the average time for red rust to appear in the salt spray test is 1893h, and the highest can reach 1895h.

[0057] As can be seen from the data of Example 3 and Comparative Example 1 in Table 1, Example 3 significantly outperforms Comparative Example 1 in terms of interfacial bonding, corrosion resistance, and high-temperature oxidation resistance of the coating. This is primarily due to the catechol group of the 3,4-dihydroxyphenylphosphonic acid used in Example 3 forming a high-energy chemical bond with the iron matrix, while the 3-aminopropyltriethoxysilane used in Comparative Example 1 relies on physical adsorption, resulting in insufficient interfacial bonding. Furthermore, the synergistic effects of the bifunctional design and in-situ nucleation guidance in Example 3 make the coating more structurally stable and more resistant to oxidation at high temperatures, while Comparative Example 1 lacks these advantages, and its coating is prone to performance degradation in high-temperature and corrosive environments.

[0058] As can be seen from the data of Example 3 and Comparative Example 2 in Table 1, Example 3 is significantly superior to Comparative Example 2 in terms of the interfacial bonding strength, corrosion resistance, and high-temperature oxidation resistance of the coating. This is mainly because the 3,4-dihydroxyphenylphosphonic acid in Example 3 contains a phosphonic acid group, which can guide tungsten deposition, while in Comparative Example 2, the phosphonic acid group function is removed and only catechol is used, resulting in a decrease in the interfacial bonding strength and corrosion resistance of the coating. Example 3 uses synergistic innovations such as molecular-level chemical bonding design and dynamic coordination deposition to enable the coating to maintain structural stability at high temperatures and have better oxidation resistance. However, due to the lack of these synergistic effects, Comparative Example 2 performs worse than Example 3 in high temperature and corrosive environments.

[0059] From the data of Example 3 and Comparative Example 3 in Table 1, it can be seen that Example 3 is significantly better than Comparative Example 3 in terms of the interface bonding strength, corrosion resistance and high temperature oxidation resistance of the coating. This is mainly due to the fact that peroxytungstic acid and hydrogen peroxide are used to in situ generate W6O 19 ²⁻ clusters, achieving chemical anchoring of tungsten seed sources and micro-nano etching of the substrate surface, while Comparative Example 3 directly added sodium tungstate, lacking this process, resulting in the coating's interface bonding strength and corrosion resistance being inferior to Example 3. In addition, the synergistic effects of the dynamic coordination system and self-filling mechanism in Example 3 give the coating better oxidation resistance and stability at high temperatures, while Comparative Example 3, lacking these synergistic effects, has poor performance in high-temperature environments.

[0060] As can be seen from the data of Example 3 and Comparative Example 4 in Table 1, Example 3 is significantly superior to Comparative Example 4 in terms of the interfacial bonding strength, corrosion resistance, and high-temperature oxidation resistance of the coating. This is mainly due to the use of a β-cyclodextrin / citric acid dynamic coordination system in Example 3 to achieve precise decoupling control of the nickel / tungsten deposition rate, while Comparative Example 4 deletes β-cyclodextrin, resulting in increased stress within the coating and an undesirable composition gradient structure, which affects the interfacial bonding strength and corrosion resistance of the coating. In addition, the self-filling mechanism in Example 3 can close the pores in the coating in situ, improving the high-temperature oxidation resistance of the coating, while Comparative Example 4 lacks this mechanism and its performance in high-temperature environments is inferior to that of Example 3.

[0061] The data from Example 3 and Comparative Example 5 in Table 1 show that Example 3 significantly outperforms Comparative Example 5 in terms of interfacial adhesion, corrosion resistance, and high-temperature oxidation resistance of the coating. This is primarily due to the use of β-cyclodextrin and citric acid as coordination modifiers in Example 3, which enables precise control of the nickel / tungsten deposition rate. The omission of these two coordination modifiers in Comparative Example 5 results in increased stress within the coating and uneven composition distribution, which compromises the interfacial adhesion and corrosion resistance of the coating. Furthermore, the self-filling mechanism in Example 3 effectively reduces the porosity of the coating and improves high-temperature oxidation resistance, whereas Comparative Example 5 lacks this mechanism, resulting in poor performance in high-temperature environments.

[0062] The data from Example 3 and Comparative Example 6 in Table 1 show that Example 3 significantly outperforms Comparative Example 6 in terms of interfacial adhesion, corrosion resistance, and high-temperature oxidation resistance of the coating. This is primarily due to the fact that Step S6 in Example 3, through a self-filling mechanism involving citric acid decomposition, closes the coating pores in situ and forms a dispersion-strengthened phase. In contrast, Step S6 is omitted from Comparative Example 6, which utilizes only nitrogen purging and drying. This results in a higher porosity in the coating, which compromises its interfacial adhesion and corrosion resistance. Furthermore, the self-filling mechanism in Example 3 also enhances the coating's high-temperature oxidation resistance, while Comparative Example 6, lacking this mechanism, performs inferior to Example 3 in high-temperature environments.

[0063] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A process for preparing a nickel / tungsten alloy composite coating of an iron-based material, characterized in that: The steps include: S1. Immerse the cold-rolled steel plate in ethanol and water, perform ultrasonic cleaning, take it out, immerse it in a sulfuric acid solution, stir it in a constant temperature water bath, wash it with water and dry it to obtain a pretreated steel plate; S2, 3,4-dihydroxyphenylphosphonic acid, hydrogen peroxide solution, ethanol and water are mixed, stirred, and the pretreated steel plate is immersed in it, and allowed to stand in a constant temperature water bath, taken out, washed with water and dried to obtain a coordination-modified steel plate; S3, mixing peroxytungstic acid, hydrogen peroxide solution and water, immersing the coordinated modified steel plate, leaving it in a constant temperature water bath, taking it out, washing it with water and drying it to obtain a roughened steel plate; S4, dispersing nickel sulfamate, sodium tungstate, β-cyclodextrin, and citric acid in water, stirring, and adjusting the pH of the solution to obtain a plating solution; S5, using the roughened steel plate as a cathode and graphite as an anode, immersing the plate in a plating solution, electroplating, taking the plate out, immersing the plate in a sulfuric acid solution, standing, washing with water and drying the plate to obtain a coated steel plate; S6. Immerse the coated steel plate in constant temperature water, let it stand, take it out, purge it with nitrogen, and solidify it to obtain an iron-based material nickel / tungsten alloy composite coating.

2. The process for preparing the iron-based material nickel / tungsten alloy composite coating according to claim 1, characterized in that: In the step S1, the weight ratio of the cold-rolled steel plate, ethanol, water and sulfuric acid solution is 900-1100:400-600:400-600:950-1050.

3. The preparation process of the iron-based material nickel / tungsten alloy composite coating according to claim 1, characterized in that: In the step S2, the weight ratio of 3,4-dihydroxyphenylphosphonic acid, hydrogen peroxide solution, ethanol and water is 40-60:15-25:200-300:200-300.

4. The process for preparing the iron-based material nickel / tungsten alloy composite coating according to claim 1, characterized in that: In step S3, the weight ratio of peroxytungstic acid, hydrogen peroxide solution and water is 25-35:5-15:450-550.

5. The process for preparing the iron-based material nickel / tungsten alloy composite coating according to claim 1, characterized in that: In step S4, the weight ratio of nickel sulfamate, sodium tungstate, β-cyclodextrin, citric acid and water is 180-220:40-60:5-15:35-45, 700-900.

6. The process for preparing the iron-based material nickel / tungsten alloy composite coating according to claim 1, characterized in that: In the step S4, the pH value of the solution is adjusted to 3.8-4.2 using 10% ammonia water by mass.

7. The process for preparing the iron-based material nickel / tungsten alloy composite coating according to claim 1, characterized in that: In the step S5, the roughened steel plate is used as the cathode and the graphite is used as the anode, immersed in the plating solution, and electroplated for 0.5-1h using a DC power supply, the constant temperature bath temperature is 43-47°C, and the current density is 5-7A / dm².

8. The process for preparing the iron-based material nickel / tungsten alloy composite coating according to claim 1, characterized in that: In the step S6, nitrogen is used for purging, the purging time is 8-12 minutes, and the nitrogen flow rate is 8-12 L / min.

9. The process for preparing the iron-based material nickel / tungsten alloy composite coating according to claim 1, characterized in that: In the step S6, curing is performed with an oven temperature of 115-125° C. and a curing time of 0.5-1 h.

10. An iron-based material nickel / tungsten alloy composite coating, characterized in that: The nickel / tungsten alloy composite coating of the iron-based material is prepared by the preparation method of any one of claims 1 to 9.

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