Gradient rare earth reinforced iron-based amorphous composite coating as well as preparation method and application thereof

Abstract

The invention discloses a gradient rare earth reinforced iron-based amorphous composite coating as well as a preparation method and application thereof. The gradient rare earth reinforced iron-based amorphous composite coating comprises the following components in percentage by atom: 45.5 to 46.5 percent of Fe, 15.5 to 16.5 percent of Cr, 10.3 to 10.7 percent of Mo, 1.4 to 1.6 percent of Nb, 2.9 to 3.1 percent of Y, 8.8 to 9.2 percent of B, 11.8 to 12.2 percent of C and 1.9 to 2.1 percent of Si. Wherein the coating comprises a nanocrystalline surface layer and an amorphous transition layer, the concentration of Y in the nanocrystalline surface layer is 1.8-2.2 times that of Y in the amorphous transition layer, and the concentration of Nb in the amorphous transition layer is 1.8-2.2 times that of Nb in the nanocrystalline surface layer. According to the gradient rare earth reinforced iron-based amorphous composite coating, all parameters of component optimization, spraying process innovation and a multi-stage heat treatment process have important influences on the coating performance, the gradient rare earth reinforced iron-based amorphous composite coating with excellent performance can be obtained by reasonably adjusting the parameters, and the requirements for component surface protection under different working conditions are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material science, in particular to a gradient rare earth strengthened iron-based amorphous composite coating and a preparation method and application thereof. BACKGROUND

[0002] In harsh environments such as marine engineering, the surface of the component is subjected to combined damage of erosion, corrosion and wear for a long time, which seriously threatens the service life and performance of the component.

[0003] After conventional uniform heat treatment, the traditional iron-based amorphous coating often falls into the dilemma of imbalance between hardness and corrosion resistance. Although the general treatment method can increase the hardness, the corrosion resistance is greatly reduced, which greatly weakens the comprehensive protection ability of the coating. Moreover, the single temperature crystallization process easily causes the coarsening of carbides, which causes the poor anti-erosion performance and is difficult to effectively protect the component in actual working conditions. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a gradient rare earth strengthened iron-based amorphous composite coating and a preparation method and application thereof, aiming to solve the above-mentioned problems recorded in the prior art.

[0005] The first aspect of the present application provides a gradient rare earth strengthened iron-based amorphous composite coating, which comprises, in atomic percentage: Fe 45.5-46.5%, Cr 15.5-16.5%, Mo 10.3-10.7%, Nb 1.4-1.6%, Y 2.9-3.1%, B 8.8-9.2%, C 11.8-12.2%, Si 1.9-2.1%; The coating comprises a nanocrystalline surface layer and an amorphous transition layer, the Y concentration in the nanocrystalline surface layer is 1.8-2.2 times the Y concentration in the amorphous transition layer, and the Nb concentration in the amorphous transition layer is 1.8-2.2 times the Nb concentration in the nanocrystalline surface layer.

[0006] According to one aspect of the above technical solution, the iron-based amorphous composite coating is a composite structure of the nanocrystalline surface layer, the amorphous transition layer, and the dense sealing layer.

[0007] According to one aspect of the above technical solution, the thicknesses of the nanocrystalline surface layer, the amorphous transition layer and the dense sealing layer are 50±5 μm, 150±10 μm and 50±5 μm, respectively.

[0008] The second aspect of the present application provides a preparation method of a gradient rare earth strengthened iron-based amorphous composite coating, which is used for preparing the iron-based amorphous composite coating in the above technical solution, and the method comprises: The raw material powders of iron trioxide, chromium trioxide, molybdenum trioxide, yttrium oxide, borax and silicon carbide are respectively taken, the taken raw material powders are pretreated, and a target powder is obtained; The super-high-speed flame spraying equipment is debugged according to preset condition parameters, the target powder is sprayed by the super-high-speed flame spraying equipment according to the condition parameters, and the target powder is sprayed on the surface of a target component; The target component after spraying is placed into a heat treatment furnace, three-stage heat treatment is performed on the target component, and an iron-based amorphous composite coating is formed on the surface of the target component.

[0009] According to an aspect of the above technical solution, the process of performing three-stage heat treatment on the target component includes a first heat treatment stage, a second heat treatment stage and a third heat treatment stage.

[0010] According to an aspect of the above technical solution, in the first heat treatment stage, after the target component is placed into a heat treatment furnace, the furnace temperature is controlled to rise to 750 DEG C at a rising rate of 10-15 DEG C / min. When the furnace temperature reaches 750 DEG C, the temperature is kept for 1 h, and a mixed atmosphere of argon and hydrogen is introduced at a flow rate of 5-8 L / min. After the first heat treatment stage ends, the furnace temperature is controlled to cool to 500 DEG C at a cooling rate of 8-10 DEG C / min, and the target component is taken out.

[0011] According to an aspect of the above technical solution, in the second heat treatment stage, the target component after the first heat treatment stage is placed into a heat treatment furnace again, the furnace temperature is controlled to rise to 600 DEG C at a rising rate of 8-12 DEG C / min. When the furnace temperature reaches 600 DEG C, the temperature is kept for 2 h. After the temperature keeping ends, the target component is taken out, and a cooling device is used to cool the target component to room temperature at a cooling rate of 50 DEG C / min.

[0012] According to an aspect of the above technical solution, in the third heat treatment stage, the target component after the second heat treatment stage and rapid cooling is placed into another heat treatment furnace, the furnace temperature is controlled to rise to 400 DEG C at a rising rate of 5-8 DEG C / min. When the furnace temperature reaches 400 DEG C, the temperature is kept for 1 h. After the temperature keeping ends, the target component is taken out, and the target component is immersed in a pre-configured aluminum phosphate solution, so that the aluminum phosphate solution penetrates into pores of the coating. The target component is placed into the heat treatment furnace again, and the temperature is kept at 400 DEG C for 1 h, so that the aluminum phosphate solution in the pores reacts to form an AlPO4 sealing layer. The AlPO4 sealing layer is a compact sealing hole layer in the iron-based amorphous composite coating.

[0013] According to an aspect of the above technical solution, the mass fraction of the aluminum phosphate solution is 10%-15%, and the immersion time of the target component is 30-60 min.

[0014] The third aspect of the present application provides an application of the gradient rare earth strengthened iron-based amorphous composite coating in the surface strengthening treatment of metal components.

[0015] Compared with the prior art, the gradient rare earth strengthened iron-based amorphous composite coating, the preparation method and the application thereof have the following beneficial effects: The iron-based amorphous composite coating comprises, in atomic percentage, Fe 45.5-46.5%, Cr 15.5-16.5%, Mo 10.3-10.7%, Nb 1.4-1.6%, Y 2.9-3.1%, B 8.8-9.2%, C 11.8-12.2%, and Si 1.9-2.1%. The coating comprises a nanocrystalline surface layer and an amorphous transition layer. The Y concentration in the nanocrystalline surface layer is 1.8-2.2 times that in the amorphous transition layer, and the Nb concentration in the amorphous transition layer is 1.8-2.2 times that in the nanocrystalline surface layer. The composition optimization, spraying process innovation and various parameters of the multi-stage heat treatment process of the present application have important influences on the coating performance. By reasonably adjusting these parameters, a gradient rare earth strengthened iron-based amorphous composite coating with excellent performance can be obtained, which meets the requirements of component surface protection under different working conditions. At the same time, it provides a reference for further research and optimization of coating performance, and helps to promote the wide application of the technology in practical engineering. In actual production and research, appropriate process parameter combinations can be selected according to the specific component material, use environment and performance requirements to achieve the best coating performance and economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings, in which: Figure 1 The flowchart of the preparation method of the gradient rare earth strengthened iron-based amorphous composite coating in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0017] In order to make the objects, features and advantages of the present application more clear, the following will be a detailed description of the embodiments of the present application with reference to the accompanying drawings. The embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present application is more thorough and comprehensive.

[0018] It should be noted that when an element is referred to as being "fixed" to another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "left", "right", and similar expressions used herein are for illustrative purposes only.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0020] A first aspect of the present application provides a gradient rare earth strengthened iron-based amorphous composite coating, the iron-based amorphous composite coating comprises, in atomic percentage: Fe 45.5-46.5%, Cr 15.5-16.5%, Mo 10.3-10.7%, Nb 1.4-1.6%, Y 2.9-3.1%, B 8.8-9.2%, C 11.8-12.2%, Si 1.9-2.1%; The coating comprises a nanocrystalline surface layer and an amorphous transition layer, the Y concentration in the nanocrystalline surface layer is 1.8-2.2 times the Y concentration in the amorphous transition layer, and the Nb concentration in the amorphous transition layer is 1.8-2.2 times the Nb concentration in the nanocrystalline surface layer.

[0021] According to an aspect of the above technical solution, the iron-based amorphous composite coating is a composite structure of the nanocrystalline surface layer, the amorphous transition layer, and the dense sealing layer.

[0022] According to an aspect of the above technical solution, the thicknesses of the nanocrystalline surface layer, the amorphous transition layer, and the dense sealing layer are 50±5 μm, 150±10 μm, and 50±5 μm, respectively.

[0023] Please refer to Figure 1The second aspect of the present application provides a preparation method of a gradient rare earth strengthened iron-based amorphous composite coating. In step S10, the raw material powders of iron trioxide, chromium trioxide, molybdenum trioxide, yttrium oxide, borax and silicon carbide are weighed respectively, and the weighed raw material powders are pretreated to obtain target powders. In step S20, the ultra-high-speed flame spraying equipment is debugged according to the preset condition parameters, and the target powders are sprayed on the surface of the target component by the ultra-high-speed flame spraying equipment according to the condition parameters. In step S30, the target component after spraying is placed in a heat treatment furnace, and the target component is subjected to three-stage heat treatment, so that the surface of the target surface forms an iron-based amorphous composite coating.

[0024] According to one aspect of the above technical solution, the process of three-stage heat treatment of the target component includes a first heat treatment stage, a second heat treatment stage and a third heat treatment stage.

[0025] According to one aspect of the above technical solution, in the first heat treatment stage, after the target component is placed in the heat treatment furnace, the furnace temperature is controlled to rise to 750℃ at a rate of 10-15℃ / min. When the furnace temperature reaches 750℃, the temperature is kept for 1h, and a mixed atmosphere of argon and hydrogen is introduced at a flow rate of 5-8L / min. After the first heat treatment stage, the furnace temperature is controlled to cool to 500℃ at a rate of 8-10℃ / min, and the target component is taken out.

[0026] According to one aspect of the above technical solution, in the second heat treatment stage, the target component after the first heat treatment stage is placed again in the heat treatment furnace, and the furnace temperature is controlled to rise to 600℃ at a rate of 8-12℃ / min. When the furnace temperature reaches 600℃, the temperature is kept for 2h. After the temperature keeping is finished, the target component is taken out, and a cooling device is used to cool the target component to room temperature at a cooling rate of 50℃ / min.

[0027] According to one aspect of the above technical solution, in the third heat treatment stage, the target component after the second heat treatment stage and rapid cooling is placed in another heat treatment furnace, and the furnace temperature is controlled to rise to 400℃ at a rate of 5-8℃ / min. When the furnace temperature reaches 400℃, the temperature is kept for 1h. After the heat preservation is finished, the target component is taken out and immersed in a pre-configured aluminum phosphate solution, so that the aluminum phosphate solution penetrates into the coating pores; The target component is again placed in a heat treatment furnace, and the aluminum phosphate solution in the pores is allowed to react to form an AlPO4 sealing layer at 400 DEG C for 1 hour; The AlPO4 sealing layer is a dense sealing layer in the iron-based amorphous composite coating.

[0028] According to one aspect of the above technical solution, the mass fraction of the aluminum phosphate solution is 10%-15%, and the immersion time of the target component is 30-60 min.

[0029] The third aspect of the application provides an application of the gradient rare earth reinforced iron-based amorphous composite coating in the surface strengthening treatment of metal components.

[0030] Example 1 This embodiment prepares a gradient rare earth reinforced iron-based amorphous composite coating, and the preparation method comprises the following steps: Raw material preparation: according to Fe 46 Cr 16 Mo 12 Y3B9C 12 Si2 (at.%) accurately, and the raw material powders such as iron trioxide (Fe2O3), chromium trioxide (Cr2O3), molybdenum trioxide (MoO3), yttrium oxide (Y2O3), borax (Na2B4O7•10H2O), and silicon carbide (SiC) are weighed, especially to ensure that the content of rare earth element Y is increased by 50% compared with previous studies, and the operation is carried out in a dry and clean environment to avoid moisture or impurities in the raw materials.

[0031] (1) Powder pretreatment: the weighed raw material powders are placed in a vacuum drying box and dried at 100-120 DEG C for 2-4 h to remove water, and then a ball mill is used to mix and refine the powders, the ball milling time is 4-6 h, the ball-to-material ratio is 5:1-8:1, the rotation speed is 200-300 r / min, and an appropriate amount of anhydrous ethanol is added to prevent agglomeration and ensure uniform powder particle size.

[0032] (2) Spray process parameter setting: an ultra-high velocity air fuel spray (HVAF) device is selected, the propane flow is set to 75 psi, the hydrogen flow is adjusted to 15 L / min, the spray distance is adjusted to 200 mm using a laser range finder, and the powder feeding rate is controlled at 70 g / min through an electronic speed regulating device, and the spray gun, powder feeding system, heating system, etc. of the equipment are checked and preheated to ensure that the equipment is in the best working state.

[0033] (3) Spraying operation: The pretreated raw material powder is loaded into the powder feeder, the HVAF equipment is turned on, the spraying gun moving speed is kept at 10-15 cm / s, the reciprocating spraying mode is adopted, the powder is uniformly sprayed on the surface of the pretreated target component, and the flame temperature, particle speed, spraying pressure and other parameters are closely monitored during the process to make them stable within the set range, and the operation is ensured to be carried out in a clean, dry and well-ventilated environment.

[0034] (4) First stage heat treatment: the sprayed target component is placed into a heat treatment furnace, heated to 750°C at a heating rate of 10-15°C / min, and held for 1 hour while argon-5% H2 mixed gas is introduced, the gas flow is controlled at 5-8 L / min, the temperature and gas composition are monitored in real time by using a temperature sensor and a gas analyzer, after the heat treatment is completed, the furnace is cooled to 500°C at a cooling rate of 8-10°C / min, and then the target component is taken out.

[0035] (5) Second stage heat treatment: the target component after the first stage heat treatment is placed into a heat treatment furnace again, heated to 600°C at a heating rate of 8-12°C / min, held for 2 hours, and then cooled to room temperature at a speed of 50°C / min by using a rapid cooling device combining air cooling and water cooling, and the temperature change of the target component is continuously monitored during the cooling process.

[0036] (6) Third stage heat treatment and pore sealing treatment: the target component is placed into another heat treatment furnace, heated to 400°C at a heating rate of 5-8°C / min, held for 1 hour, then immersed in an aluminum phosphate solution with a concentration of 10%-15% (mass fraction) for 30-60 minutes to make the solution fully penetrate into the coating pores, the target component is taken out after the immersion, and then placed into the heat treatment furnace again for continuous holding at 400°C for 1 hour to form an AlPO4 sealing layer, and the parameters are strictly controlled to ensure the sealing effect.

[0037] The iron-based amorphous composite coating prepared by the method shown in the embodiment is subjected to: (1) Corrosion resistance test: the coating sample is placed in a 3.5% NaCl solution, the corrosion current density is measured by using an electrochemical workstation, the immersion time is 72 h, and the corrosion of the coating surface is observed in detail; (2) Wear resistance test: a pin-on-disc wear tester is used, a load of 5N is applied, the rotation speed is 200 r / min, the mass loss of the coating before and after wear is accurately measured, and the wear rate is accurately calculated; (3) Erosion resistance test: a slurry erosion tester is used, a pH=11 slurry environment is simulated, the coating sample is impacted at a flow rate of 10 m / s for 4 h, and the weight loss rate of the sample is accurately measured.

[0038] The above results are shown in Tables 1, 2 and 3 respectively.

[0039] Example Two This example also prepared a gradient rare earth strengthened iron-based amorphous composite coating, the difference between the preparation method and example one is that the Y content is adjusted to 1%, and the remaining steps are the same as example one. The iron-based amorphous composite coating prepared by the method shown in this example was tested in multiple ways, and the results are shown in Table 1.

[0040] Example Three This example also prepared a gradient rare earth strengthened iron-based amorphous composite coating, the difference between the preparation method and example one is that the Y content is adjusted to 2%, and the remaining steps are the same as example one.

[0041] The iron-based amorphous composite coating prepared by the method shown in this example was tested in multiple ways, and the results are shown in Table 1.

[0042] Example Four This example also prepared a gradient rare earth strengthened iron-based amorphous composite coating, the difference between the preparation method and example one is that the Y content is adjusted to 4%, and the remaining steps are the same as example one.

[0043] The iron-based amorphous composite coating prepared by the method shown in this example was tested in multiple ways, and the results are shown in Table 1.

[0044] Table 1: Effect of Y content of rare earth elements on corrosion resistance and erosion resistance of coating

[0045] This experiment focuses on the effect of Y content of rare earth elements on the performance of the coating. In the composition design, the change of Y content will change the chemical reaction and microstructure inside the coating. Y has high chemical activity and can react with O2, Cr and other elements to form Y2O3 / Cr2O3 composite film. In example one, the Y content is 3%, at this time the composite film formation effect is best, which can tightly cover the surface of the coating, effectively block the corrosion medium such as Cl - , inhibit the grain boundary segregation, and the corrosion current density is as low as 1.2×10 -7 A / cm 2 , the weight loss rate is only 0.08mg / h, and the corrosion resistance and erosion resistance are excellent. In example two, the Y content is adjusted to 1%, and due to the insufficient Y content, the amount of composite film generated is small, which cannot fully inhibit the grain boundary segregation, resulting in an increase in corrosion current density to 2.5×10 -7 A / cm 2 , the weight loss rate increases to 0.12mg / h, and the corrosion resistance and erosion resistance decrease significantly. In example four, the Y content is increased to 4%, although the corrosion resistance is improved, the corrosion current density is 1.5×10 -7 A / cm 2However, excessive Y content may cause element segregation, which poses a potential risk to the overall performance of the coating. Comprehensive comparison shows that the 3% Y content in Example 1 achieves the best balance in promoting the formation of the composite film and improving the corrosion resistance and erosion resistance of the coating.

[0046] Example 5 This embodiment also prepares a gradient rare earth-reinforced iron-based amorphous composite coating. The difference between its preparation method and that of Example 1 is that the Nb content is adjusted to 1%, and the remaining steps are the same as those of Example 1.

[0047] The iron-based amorphous composite coating prepared by the method shown in this embodiment was subjected to multiple tests, and the results are shown in Table 2.

[0048] Example 6 This embodiment also prepares a gradient rare earth-reinforced iron-based amorphous composite coating. The difference between its preparation method and that of Example 1 is that the Nb content is adjusted to 2%, and the remaining steps are the same as those of Example 1.

[0049] The iron-based amorphous composite coating prepared by the method shown in this embodiment was subjected to multiple tests, and the results are shown in Table 2.

[0050] Example 7 This embodiment also prepares a gradient rare earth-reinforced iron-based amorphous composite coating. The difference between its preparation method and that of Example 1 is that the Nb content is adjusted to 2.5%, and the remaining steps are the same as those of Example 1.

[0051] The iron-based amorphous composite coating prepared by the method shown in this embodiment was subjected to multiple tests, and the results are shown in Table 2.

[0052] Table 2: Effect of Nb content on the glass forming ability and wear resistance of the alloy

[0053] This group of experiments mainly explored the mechanism of the effect of Nb content on coating performance. Nb has a similar atomic radius to Mo but a different electronic structure. During the solidification process of the alloy, Nb can change the interaction between atoms and the diffusion rate. In Example 1, the Nb content was 1.5%, at which point the critical cooling rate of the alloy dropped to 8×10 4 K / s, the amorphous forming ability is enhanced, the proportion of amorphous phase is increased, the grain boundary defects are reduced, the nanocrystalline structure is refined, and the coating uniformity is improved by 30%, and the wear rate is as low as 2.5×10 -6 mm 3 / (N·m), good wear resistance. In Example 5, the Nb content was adjusted to 1%, the amorphous forming ability decreased, the amorphous phase decreased, and the carbides were easily coarsened, resulting in reduced coating uniformity and an increase in the wear rate to 2.7×10 -6 mm 3(N-m), and the wear resistance deteriorated. Example Seven increased the Nb content to 2.5%, which improved some properties to some extent, but possibly introduced brittle phases, and the overall performance was not further optimized. Thus, the 1.5% Nb content of Example One is optimal in enhancing the amorphous forming ability and improving the wear resistance of the coating.

[0054] Example Eight This example also prepared a gradient rare earth strengthened iron-based amorphous composite coating, and the difference between the preparation method and Example One is that the propane flow is adjusted to 65 psi, and the hydrogen flow is adjusted to 12 L / min, and the remaining steps are the same as Example One.

[0055] The iron-based amorphous composite coating prepared by the method shown in this example was tested for multiple tests, and the results are shown in Table 3.

[0056] Example Nine This example also prepared a gradient rare earth strengthened iron-based amorphous composite coating, and the difference between the preparation method and Example One is that the propane flow is adjusted to 80 psi, and the hydrogen flow is adjusted to 10 L / min, and the remaining steps are the same as Example One.

[0057] The iron-based amorphous composite coating prepared by the method shown in this example was tested for multiple tests, and the results are shown in Table 3.

[0058] Example Ten This example also prepared a gradient rare earth strengthened iron-based amorphous composite coating, and the difference between the preparation method and Example One is that the propane flow is adjusted to 70 psi, and the hydrogen flow is adjusted to 18 L / min, and the remaining steps are the same as Example One. The iron-based amorphous composite coating prepared by the method shown in this example was tested for multiple tests, and the results are shown in Table 3.

[0059] Table 3: Effect of fuel gas flow on coating density and corrosion resistance

[0060] This group of experiments focuses on the effect of fuel gas flow on coating performance during high velocity oxygen fuel spraying. Changes in fuel gas flow will change the flame characteristics and heat input. In Example One, the propane flow is 75 psi, and the hydrogen flow is 15 L / min. Reducing the propane flow reduces the heat input, and increasing the hydrogen flow increases the flame temperature and stability, allowing the sprayed particles to uniformly melt and deposit at high speed (speed up to 550 m / s), the oxygen content of the coating is <800 ppm, and the porosity is <1.5%, effectively inhibiting the oxidation reaction and improving the coating density, thereby reducing the corrosion current density to 1.2 x 10 -7 A / cm 2, the corrosion resistance was significantly reduced. In Example Ten, the propane flow rate was adjusted to 70 psi, resulting in insufficient heat input and a decrease in particle bonding strength, which also affected the performance of the coating. Therefore, the gas flow rate combination in Example One has a significant advantage in optimizing the density and corrosion resistance of the coating. -7 A / cm 2 , the corrosion resistance was significantly reduced. In Example Ten, the propane flow rate was adjusted to 70 psi, resulting in insufficient heat input and a decrease in particle bonding strength, which also affected the performance of the coating. Therefore, the gas flow rate combination in Example One has a significant advantage in optimizing the density and corrosion resistance of the coating.

[0061] Example Eleven In this example, a gradient rare earth strengthened iron-based amorphous composite coating was also prepared. The difference between this example and Example One is that the spraying distance was adjusted to 180 mm and the powder feeding rate was adjusted to 60 g / min, and the remaining steps were the same as in Example One. The iron-based amorphous composite coating prepared by the method shown in this example was tested, and the results are shown in Table 4.

[0062] Example Twelve In this example, a gradient rare earth strengthened iron-based amorphous composite coating was also prepared. The difference between this example and Example One is that the spraying distance was adjusted to 220 mm and the powder feeding rate was adjusted to 80 g / min, and the remaining steps were the same as in Example One. The iron-based amorphous composite coating prepared by the method shown in this example was tested, and the results are shown in Table 4.

[0063] Example Thirteen In this example, a gradient rare earth strengthened iron-based amorphous composite coating was also prepared. The difference between this example and Example One is that the spraying distance was adjusted to 190 mm and the powder feeding rate was adjusted to 75 g / min, and the remaining steps were the same as in Example One. The iron-based amorphous composite coating prepared by the method shown in this example was tested, and the results are shown in Table 4.

[0064] Table 4: Effect of spraying distance and powder feeding rate on coating bonding strength

[0065] This group of experiments focuses on the effect of spraying distance and powder feeding rate on the performance of the coating. The spraying distance and powder feeding rate affect the flight behavior and deposition effect of the particles. In Example One, the spraying distance was 200 mm and the powder feeding rate was 70 g / min. The 200 mm distance allowed the particles to accelerate sufficiently, and the 70 g / min powder feeding rate ensured that the particles were fully melted. The combined effect of the two resulted in a particle bonding strength of 85 MPa, reducing particle agglomeration and uneven deposition, and the wear rate was as low as 2.5 x 10 -6 mm 3(N-m). Example eleven adjusts the spray distance to 180 mm, which is too close and results in insufficient kinetic energy of particles, decreased bonding strength, and increased wear rate to 3.0 x 10 -6 mm 3 (N-m). Example twelve adjusts the powder feed rate to 80 g / min, which is too high and causes incomplete melting of particles, increased porosity, and thus affects the coating performance. Therefore, the spray distance and powder feed rate parameter combination of example one is optimal in terms of optimizing the coating bonding strength and reducing the wear rate.

[0066] Example fourteen This example also prepares a gradient rare earth strengthened iron-based amorphous composite coating, the difference between the preparation method and example one is that the first stage heat treatment temperature is adjusted to 700℃, the time is adjusted to 0.5h, and the remaining steps are the same as example one.

[0067] The iron-based amorphous composite coating prepared by the method of this example is tested in multiple tests, and the results are shown in Table 5.

[0068] Example fifteen This example also prepares a gradient rare earth strengthened iron-based amorphous composite coating, the difference between the preparation method and example one is that the first stage heat treatment temperature is adjusted to 800℃, the time is adjusted to 1.5h, and the remaining steps are the same as example one.

[0069] The iron-based amorphous composite coating prepared by the method of this example is tested in multiple tests, and the results are shown in Table 5.

[0070] Example sixteen This example also prepares a gradient rare earth strengthened iron-based amorphous composite coating, the difference between the preparation method and example one is that the first stage heat treatment temperature is adjusted to 720℃, the time is adjusted to 1.2h, and the remaining steps are the same as example one.

[0071] The iron-based amorphous composite coating prepared by the method of this example is tested in multiple tests, and the results are shown in Table 5.

[0072] Table 5: Effect of first stage heat treatment parameters on nanocrystallization

[0073] The present experiment mainly studies the influence of the first stage heat treatment parameters in the multistage heat treatment process on the coating performance. The temperature and time of the first stage heat treatment will affect the microstructure of the coating. In Example One, the first stage heat treatment temperature is 750℃, and the time is 1h, under the hydrogen reduction atmosphere, which inhibits the atomic migration ability, promotes the formation of 20-50nm nanocrystalline dispersed phase in the surface layer of the coating, and the grain boundary strengthening effect is obvious, so that the hardness of the coating reaches 1250HV0.3, the wear rate is reduced by 40%, and the wear resistance of the coating is effectively improved. In Example Fifteen, the temperature is increased to 800℃, and the time is extended to 1.5h, and the high temperature leads to grain coarsening (60-80nm), the hardness decreases by 8%, and the wear rate increases to 2.8×10 -6 mm 3 / (N•m). In Example Fourteen, the temperature is reduced to 700℃, and the time is shortened to 0.5h, the number of nanocrystals is insufficient, the strengthening effect is weakened, and the wear rate is 3.0×10 -6 mm 3 / (N•m). Therefore, the first stage heat treatment parameters of Example One are the most suitable for controlling the formation of nanocrystals and improving the wear resistance of the coating.

[0074] Example Seventeen In this embodiment, a gradient rare earth strengthened iron-based amorphous composite coating is also prepared, and the difference between the preparation method and Example One is that the second stage heat treatment temperature is adjusted to 550℃, the time is adjusted to 1.5h, and the cooling rate is adjusted to 40℃ / min, and the remaining steps are the same as those of Example One.

[0075] The iron-based amorphous composite coating prepared by the method shown in this embodiment is subjected to a plurality of tests, and the results are shown in Table 6.

[0076] Example Eighteen In this embodiment, a gradient rare earth strengthened iron-based amorphous composite coating is also prepared, and the difference between the preparation method and Example One is that the second stage heat treatment temperature is adjusted to 620℃, the time is adjusted to 2.5h, and the cooling rate is adjusted to 60℃ / min, and the remaining steps are the same as those of Example One.

[0077] The iron-based amorphous composite coating prepared by the method shown in this embodiment is subjected to a plurality of tests, and the results are shown in Table 6.

[0078] Example Nineteen In this embodiment, a gradient rare earth strengthened iron-based amorphous composite coating is also prepared, and the difference between the preparation method and Example One is that the second stage heat treatment temperature is adjusted to 580℃, the time is adjusted to 2.2h, and the cooling rate is adjusted to 55℃ / min, and the remaining steps are the same as those of Example One. The iron-based amorphous composite coating prepared by the method shown in this embodiment is subjected to a plurality of tests, and the results are shown in Table 6.

[0079] Table 6: Effect of second stage heat treatment parameters on amorphous / nanocrystalline transition layer

[0080] The present experiment adjusts the second stage heat treatment parameters (temperature, time, cooling rate) to explore its effect on the microstructure and performance of the coating. In Example One, 600°C / 2h + 50°C / min fast cooling is used. Under the synergistic effect of atomic diffusion and rapid cooling, 60% amorphous phase is retained and 20-50nm nanocrystals are formed, constructing a strong and tough transition layer (hardness 900-1000HV0.3). This structure relieves stress concentration through amorphous phase and provides strength support through nanocrystals, making the coating wear rate as low as 2.5x10 -6 mm 3 / (N•m) and erosion resistance rate 0.08mg / h. In Example Seventeen (550°C / 1.5h + 40°C / min), the temperature is too low and the cooling is too slow, reducing the amorphous phase to 55%, and the grain coarsening leads to a decrease in wear resistance (wear rate 3.1x10 -6 mm 3 / (N•m) and a deterioration in erosion resistance (weight loss rate 0.14mg / h). In Example Eighteen (620°C / 2.5h + 60°C / min), although the cooling is accelerated, the high temperature and long time treatment still cause excessive crystallization, further reducing the amorphous phase, increasing the wear rate to 2.9x10 -6 mm 3 / (N•m), and the erosion resistance is not improved (weight loss rate 0.13mg / h). Therefore, the parameter combination of Example One precisely controls atomic diffusion and cooling rate, achieving the best balance of amorphous / nanocrystalline structure, significantly improving the wear resistance and erosion resistance of the coating.

[0081] Example Twenty This example also prepares a gradient rare earth strengthened iron-based amorphous composite coating, the difference between its preparation method and Example One is that the aluminum phosphate solution concentration is adjusted to 5%, and the rest of the steps are the same as Example One. The iron-based amorphous composite coating prepared by the method shown in this example was tested, and the results are shown in Table 7.

[0082] Example Twenty-One This example also prepares a gradient rare earth strengthened iron-based amorphous composite coating, the difference between its preparation method and Example One is that epoxy resin is used instead of aluminum phosphate solution for sealing treatment, and the rest of the steps are the same as Example One. The iron-based amorphous composite coating prepared by the method shown in this example was tested, and the results are shown in Table 7.

[0083] Example Twenty-Two The embodiment also prepares a gradient rare earth strengthened iron-based amorphous composite coating, and the difference between the preparation method and that of the first embodiment is that the aluminum phosphate solution concentration is adjusted to 20%, and the remaining steps are the same as those of the first embodiment. The iron-based amorphous composite coating prepared by the method shown in the embodiment is subjected to a plurality of tests, and the results are shown in Table 7.

[0084] Table 7: Effect of sealing treatment on coating porosity

[0085] The present experiment aims to explore the effect of sealing treatment on the performance of the coating. The sealing treatment method and the aluminum phosphate solution concentration can affect the pore filling effect of the coating. In the first embodiment, 10-15% aluminum phosphate solution is used for sealing treatment, and at 400°C, the solution penetrates and thermally solidifies to form an AlPO4 sealing layer, reducing the porosity from 1.5% to 0.3%, effectively filling the coating pores and greatly reducing the penetration channel of corrosive medium, reducing the corrosion current density by 76%, and prolonging the salt spray life to >8000h, thereby significantly improving the corrosion resistance of the coating. In the twenty-first embodiment, the concentration of the aluminum phosphate solution is adjusted to 5%, and the low concentration leads to insufficient filling, and the corrosion resistance is limited, with a corrosion current density of 2.0x10 -7 A / cm 2 . In the twenty-first embodiment, epoxy resin is used instead of aluminum phosphate solution, and due to the poor thermal stability of epoxy resin, it cannot form an effective chemical sealing layer like AlPO4, and the corrosion resistance is not as good as that of the first embodiment, with a corrosion current density of 1.8x10 -7 A / cm 2 . Therefore, the sealing treatment method and solution concentration of the first embodiment have obvious advantages in reducing the porosity of the coating and improving the corrosion resistance.

[0086] As can be seen from the above embodiments, the component optimization, spraying process innovation and various parameters of the multi-stage heat treatment process of the present application have important effects on the performance of the coating. By reasonably adjusting these parameters, a gradient rare earth strengthened iron-based amorphous composite coating with excellent performance can be obtained to meet the needs of surface protection of parts under different working conditions. At the same time, these embodiments also provide a reference for further research and optimization of coating performance, which is helpful to promote the wide application of this technology in practical engineering. In actual production and research process, appropriate process parameter combination can be selected according to the specific part material, use environment and performance requirements to achieve the best coating performance and economic benefits.

[0087] The technical features of the above embodiments can be combined in any way. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0088] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0089] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A gradient rare earth reinforced iron-based amorphous composite coating, characterized in that: The iron-based amorphous composite coating comprises, by atomic percentage: Fe 45.5-46.5%, Cr 15.5-16.5%, Mo 10.3-10.7%, Nb 1.4-1.6%, Y 2.9-3.1%, B 8.8-9.2%, C 11.8-12.2%, Si 1.9-2.1%; The coating includes a nanocrystalline surface layer and an amorphous transition layer, the Y concentration in the nanocrystalline surface layer is 1.8-2.2 times the Y concentration in the amorphous transition layer, and the Nb concentration in the amorphous transition layer is 1.8-2.2 times the Nb concentration in the nanocrystalline surface layer.

2. The gradient rare earth reinforced iron-based amorphous composite coating according to claim 1, characterized in that: The iron-based amorphous composite coating is a composite structure of the nanocrystalline surface layer, the amorphous transition layer, and a pore-sealing layer.

3. The gradient rare earth reinforced iron-based amorphous composite coating according to claim 2, characterized in that: The thicknesses of the nanocrystalline surface layer, the amorphous transition layer and the pore-sealing layer are 50±5 μm, 150±10 μm and 50±5 μm respectively.

4. A method for preparing a gradient rare earth reinforced iron-based amorphous composite coating, characterized in that: For preparing the iron-based amorphous composite coating according to any one of claims 1 to 3, the method comprises: Weighing raw material powders of ferric oxide, chromium oxide, molybdenum oxide, yttrium oxide, borax and silicon carbide respectively, and pretreating the raw material powders to obtain target powders; Debugging the ultra-high velocity flame spraying equipment according to pre-set condition parameters, spraying the target powder through the ultra-high velocity flame spraying equipment according to the condition parameters, so that the target powder is sprayed on the surface of the target component; The sprayed target component is placed in a heat treatment furnace and subjected to a three-stage heat treatment to form an iron-based amorphous composite coating on the surface of the target component.

5. The method for preparing the gradient rare earth reinforced iron-based amorphous composite coating according to claim 4, characterized in that: The process of performing three-stage heat treatment on the target component includes a first heat treatment stage, a second heat treatment stage and a third heat treatment stage.

6. The method for preparing the gradient rare earth reinforced iron-based amorphous composite coating according to claim 5, characterized in that: In the first heat treatment stage, after placing the target component in a heat treatment furnace, the furnace temperature is controlled to rise to 750° C. at a heating rate of 10-15° C. / min; When the furnace temperature reaches 750℃, keep it warm for 1 hour and introduce a mixed atmosphere of argon and hydrogen at a flow rate of 5-8L / min; After the first heat treatment stage is completed, the furnace temperature is controlled to cool to 500° C. at a cooling rate of 8-10° C. / min, and the target component is taken out.

7. The method for preparing the gradient rare earth reinforced iron-based amorphous composite coating according to claim 5, characterized in that: In the second heat treatment stage, the target component that has undergone the first heat treatment stage is placed in the heat treatment furnace again, and the furnace temperature is controlled to rise to 600°C at a heating rate of 8-12°C / min; When the furnace temperature reaches 600℃, keep it warm for 2h; After the heat preservation is completed, the target component is taken out and cooled to room temperature at a cooling rate of 50° C. / min using a cooling device.

8. The method for preparing the gradient rare earth reinforced iron-based amorphous composite coating according to claim 5, characterized in that: In the third heat treatment stage, the target component that has undergone the second heat treatment stage and rapid cooling is placed in another heat treatment furnace, and the furnace temperature is controlled to rise to 400°C at a heating rate of 5-8°C / min; When the furnace temperature reaches 400℃, keep it warm for 1 hour; After the heat preservation is completed, the target component is taken out and immersed in a pre-configured aluminum phosphate solution to allow the aluminum phosphate solution to penetrate into the pores of the coating; The target component is placed in a heat treatment furnace again and kept at 400°C for 1 hour to allow the aluminum phosphate solution in the pores to react chemically to form an AlPO4 sealing layer; The AlPO4 sealing layer is the pore-sealing layer in the iron-based amorphous composite coating.

9. The method for preparing a gradient rare earth reinforced iron-based amorphous composite coating according to claim 8, characterized in that: The mass fraction of the aluminum phosphate solution is 10%-15%, and the immersion time of the target component is 30-60 minutes.

10. Use of the gradient rare earth reinforced iron-based amorphous composite coating according to any one of claims 1 to 3 in surface strengthening treatment of metal parts.

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