Low-cost high-entropy alloy and coating preparation method for offshore engineering equipment

Abstract

The application discloses a low-cost high-entropy alloy and a coating preparation method for marine engineering equipment, designs a Co high-entropy alloy system without noble metals, and a specific expression is FeCrNiCu 0.5‑y Mo x Si y , wherein x is in a range of 0.2-1, and y is in a range of 0-0.5.The coating prepared by the application has the advantages of good friction and wear resistance and corrosion resistance, is composed of face-centered cubic structure (FCC), body-centered cubic structure (BCC) and ordered phases thereof, can produce good metallurgical bonding with a base body, and has no obvious defects such as pores and cracks.

Description

Technical Field

[0001] This invention relates to the field of high-entropy alloys, and more particularly to a low-cost high-entropy alloy and coating preparation method for marine engineering equipment. Background Technology

[0002] Structural steel, such as Q235 steel, is widely used in marine engineering equipment such as offshore platforms and ships operating in extreme environments. During use, these marine engineering equipment, such as offshore drilling platforms, cranes, and bridges, often suffer from both corrosion and wear, severely impacting their service life and even causing serious casualties. Therefore, improving their corrosion resistance and friction and wear resistance becomes extremely important.

[0003] To address the aforementioned issues, introducing protective coatings with excellent wear and corrosion resistance is a crucial approach in marine engineering. Laser cladding, with its rapid solidification and excellent metallurgical bonding capabilities, has emerged as an important green remediation method. Titanium alloys and ceramics are the primary coating materials; however, their relatively low tribological and corrosion properties under extreme environments hinder further development and application.

[0004] In contrast, high-entropy alloys, as a newly developed alloy system, are widely known for their unique characteristics (high-entropy effect, lattice distortion, hysteresis diffusion, and cocktail effect), and have become a research hotspot in recent years. Among them, the FeCoCrNiCu system has become one of the mainstream high-entropy alloy systems due to its good dislocation storage capacity, ductility, toughness, and ease of forming ordered solid solution phases. However, the reported high-entropy alloy coatings of this system are prone to cracking during material preparation due to the characteristics of laser cladding and thermophysical parameters, resulting in low hardness and poor wear and corrosion resistance. Furthermore, the high proportion of the noble metal Co in this system is not conducive to large-scale engineering applications, thus limiting the development of high-entropy alloys.

[0005] Studies have found that high-entropy alloys with the FCC phase often have good corrosion resistance but low hardness, while BCC and its ordered phase have advantages in high hardness and wear resistance. Based on this, this invention designs a marine engineering protective high-entropy alloy with FCC, BCC and its ordered phase through thermodynamic calculations. The powdered material to be melted is pre-covered on the surface of the structural steel substrate using a binder and alcohol as a medium. Then, the surface of the pre-placed layer is irradiated by a laser beam, which causes the pre-placed layer and the substrate surface to melt and solidify rapidly, thereby forming a highly wear-resistant and highly corrosion-resistant coating. Compared with synchronous powder feeding, the pre-placement method has the advantages of easy forming and uniform structure. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned technical problems by providing a low-cost high-entropy alloy and coating preparation method for marine engineering equipment.

[0007] In this invention, from the perspective of large-scale engineering applications, the precious metal Co is discarded. In order to improve the corrosion resistance of high-entropy alloys, Mo is added. Considering wear resistance, the self-fluxing element Si is added to solve the problem of large-area porosity and cracks.

[0008] In view of this, the present invention provides a low-cost, high-entropy alloy coating for marine engineering equipment, characterized in that: the expression is FeCrNiCu 0.5-y Mo x Si y , where x ranges from 0.2 to 1 and y ranges from 0 to 0.5.

[0009] Preferred values: x = 0.4-1, y = 0.25-0.5.

[0010] Preferred: When x = 1 and y = 0.5, the wear rate of the high-entropy alloy coating is 2.2 x 10⁻⁶. -5 mm 3 .N -1 m -1 The corrosion current density is an order of magnitude higher than that of the substrate, and its main wear mechanism is abrasive wear, with a corrosion current density of 1.69 x 10⁻⁶. -7 A / cm 2 It exhibits typical characteristics of active dissolved materials, accounting for 20.17% of the matrix.

[0011] Or x = 0.4, y = 0.5. The corrosion current density of the high-entropy alloy coating is 3.09 x 10⁻⁶. -8 A / cm 2 It is approximately 37.5% of the FeCoCrNiMo0.3 coatings currently reported.

[0012] A method for preparing a low-cost, high-entropy alloy coating for marine engineering equipment, comprising the following steps:

[0013] (1) Weigh Fe, Cr, Ni, Cu, Mo and Si powders and ball mill them in a protective gas environment to make them evenly mixed. Then, vacuum dry them to obtain powder with high entropy alloy coating.

[0014] (2) Grind and polish the surface of the Q235 steel substrate, then clean and dry it with anhydrous ethanol;

[0015] (3) The mixed powder is pre-placed on the substrate with a pre-placed powder thickness of about 2 mm. A fiber laser is used for single-pass laser cladding with a laser power of 1400-2200W, a spot diameter of 4 mm, a laser scanning speed of 3-7 mm / s, and a pre-placed powder thickness of 2 mm.

[0016] In the above scheme, the alloy powders selected are all elemental powders with a particle size of 46-108 μm.

[0017] In the above scheme: the ball mill speed is 180-200 r / min, and the ball milling time is 2-3 h.

[0018] In the above scheme: the vacuum drying temperature is 95-110℃, and the drying time is 2-3 hours.

[0019] In the above scheme, the protective gas in steps (1) and (3) is argon.

[0020] The coating prepared by this invention has advantages such as good friction and wear resistance and corrosion resistance. It is composed of face-centered cubic (FCC) and body-centered cubic (BCC) structures and their ordered phases, enabling it to form a good metallurgical bond with the substrate. It is free from obvious defects such as porosity and cracks. The wear rate of this high-entropy alloy coating can reach 2.2 x 10⁻⁶. -5 mm 3 .N -1 m -1 This represents an order of magnitude improvement over the substrate, with a corrosion current density reaching 1.69 x 10⁻⁶. -7 A / cm 2 It exhibits typical characteristics of active dissolving materials, with a content of 20.17% of the Q235 steel substrate, and can play a good protective role for the substrate. It realizes the low-cost preparation of high-entropy alloy coatings for the protection of marine engineering equipment, and provides a reference for system design. Attached Figure Description

[0021] Figure 1 This is a morphology diagram of the prepared high-entropy alloy coating.

[0022] Figure 2 These are microhardness diagrams of Embodiments 1 and 3 and Comparative Examples 1-2 of the present invention.

[0023] Figure 3 This is a friction coefficient diagram of Embodiment 1 of the present invention.

[0024] Figure 4 This is a friction coefficient diagram of Embodiment 2 of the present invention.

[0025] Figure 5 This is the XRD pattern of Embodiment 3 of the present invention.

[0026] Figure 6 This is a friction coefficient diagram of Embodiment 3 of the present invention.

[0027] Figure 7 This is a specific wear rate diagram of Embodiment 3 of the present invention.

[0028] Figure 8 These are polarization curves from embodiments 3-5 of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Example 1

[0031] According to the molar ratio of high-entropy alloy powder FeCrNiCu 0.5-y Mo x Si y The proportions were calculated using the formula (x = 0.7, y = 0.25). All alloy powders used were elemental powders with a particle size of 48–106 μm.

[0032] Fe, Cr, Ni, Cu, Mo, and Si powders were weighed and ball-milled under a protective gas environment (Ar) using a YXQM-4L planetary ball mill at a speed of 180-200 r / min for 2 hours. The mixture was then vacuum-dried at 95-110℃ for 2 hours to obtain the high-entropy alloy coating powder.

[0033] After removing the oxides from the surface of the Q235 steel (60x20x8mm) with a grinding wheel, it was ultrasonically cleaned in anhydrous ethanol for 20 minutes, and then dried with a hair dryer for later use.

[0034] A mixed powder was pre-placed on a substrate with a thickness of approximately 2 mm. Single-pass laser cladding was performed using a YSL-10000 fiber laser with the following parameters: laser power 2200 W, spot diameter 4 mm, and laser scanning speed 5 mm / s. This yielded a low-cost, high-entropy alloy coating for marine engineering equipment. Figure 1 As shown.

[0035] The coating was sampled using an electrical discharge machining (EDM) machine, and the hardness curve is shown below. Figure 2 As shown, the average hardness of the coating is 511.6 HV. 0.5 It is 2.69 times that of the matrix; the friction coefficient curve is as follows Figure 3 As shown, the average coefficient of friction is 0.388, which has a good effect on reducing friction.

[0036] Example 2

[0037] According to the molar ratio of high-entropy alloy powder FeCrNiCu 0.5-y Mo x Si y The proportions were calculated using the formula (x = 0.4, y = 0.3). All alloy powders used were elemental powders with a particle size of 48–106 μm.

[0038] Fe, Cr, Ni, Cu, Mo, and Si powders were weighed and ball-milled under a protective gas environment (Ar) using a YXQM-4L planetary ball mill at a speed of 180-200 r / min for 3 hours. The mixture was then vacuum-dried at 110℃ for 2 hours to obtain the high-entropy alloy coating powder.

[0039] After removing the oxides from the surface of the Q235 steel (60x20x8mm) with a grinding wheel, it was ultrasonically cleaned in anhydrous ethanol for 30 minutes, and then dried with a hair dryer for later use.

[0040] A mixed powder was pre-placed on a substrate with a thickness of approximately 2 mm. Single-pass laser cladding was performed using a YSL-10000 fiber laser with the following parameters: laser power 2000 W, spot diameter 4 mm, and laser scanning speed 3 mm / s. This yielded a low-cost, high-entropy alloy coating for marine engineering equipment. Figure 1 As shown.

[0041] The coating was prepared using an electrical discharge machining (EDM) machine, and the friction coefficient curve is shown below. Figure 4 As shown, the average coefficient of friction is 0.4134.

[0042] Example 3

[0043] According to the molar ratio of high-entropy alloy powder FeCrNiCu 0.5-y Mo x Si y The proportions were calculated using the formula (x=1, y=0.5). All alloy powders selected were elemental powders with a particle size of 48~106μm.

[0044] Fe, Cr, Ni, Cu, Mo, and Si powders were weighed and ball-milled under a protective gas environment (Ar) using a YXQM-4L planetary ball mill at a speed of 200 r / min for 2 hours. The mixture was then vacuum-dried at 95℃ for 3 hours to obtain the high-entropy alloy coating powder.

[0045] After removing the oxides from the surface of the Q235 steel (60x20x8mm) with a grinding wheel, it was ultrasonically cleaned in anhydrous ethanol for 10 minutes, and then dried with a hair dryer for later use.

[0046] A mixed powder was pre-placed on a substrate to a thickness of approximately 2 mm. Single-pass laser cladding was performed using a YSL-10000 fiber laser with the following parameters: laser power 1800 W, spot diameter 4 mm, and laser scanning speed 7 mm / s. This yielded a low-cost, high-entropy alloy coating for marine engineering equipment. Figure 1 As shown.

[0047] The coating was sampled using an electrical discharge machining (EDM) machine, and then XRD tests were performed. Figure 5 As shown in Figure 2, the coating mainly consists of FCC phase and BCC and its ordered phase; the hardness curve is shown in Figure 2, and the average hardness of the coating is 686.78 HV. 0.5 It is 3.6 times that of the matrix; the friction coefficient curve is as follows Figure 6 As shown, the average coefficient of friction is 0.3785; the specific wear rate is as follows: Figure 7 As shown, the wear rate is 2.2 x 10⁻⁶. -5 mm 3 .N -1 m -1 It increased by 3.2 times compared to the matrix; from Figure 8 It can be seen that the corrosion current density reaches 1.69 x 10⁻⁶. -7 A / cm 2 It is only 20.17% of the matrix.

[0048] Example 4

[0049] According to the molar ratio of high-entropy alloy powder FeCrNiCu 0.5-y Mo x Si y The proportions were calculated using the formula (x = 0.4, y = 0.5). All alloy powders used were elemental powders with a particle size of 48–106 μm.

[0050] Fe, Cr, Ni, Cu, Mo, and Si powders were weighed and ball-milled under a protective gas environment (Ar) using a YXQM-4L planetary ball mill at a speed of 180 r / min for 2 hours. The mixture was then vacuum-dried at 100℃ for 2 hours to obtain the high-entropy alloy coating powder.

[0051] After removing the oxides from the surface of the Q235 steel (60x20x8mm) with a grinding wheel, it was ultrasonically cleaned in anhydrous ethanol for 20 minutes, and then dried with a hair dryer for later use.

[0052] A mixed powder was pre-placed on a substrate to a thickness of approximately 2 mm. Single-pass laser cladding was performed using a YSL-10000 fiber laser with the following parameters: laser power 1400 W, spot diameter 4 mm, and laser scanning speed 5 mm / s. This yielded a low-cost, high-entropy alloy coating for marine engineering equipment. Figure 1 As shown.

[0053] The coating was prepared using an electrical discharge machining (EDM) machine, and electrochemical experiments were conducted. Polarization curves were measured using the potentiodynamic method, with the test range set to -0.5–1.5 V (vsOCP). Figure 8 It can be seen that the corrosion current density reaches 3.09 x 10⁻⁶.- 8 A / cm 2 Approximately the FeCoCrNiMo reported so far. 0.3 The coating has a 37.5% coverage, resulting in a significant improvement in corrosion resistance.

[0054] Example 5

[0055] According to the molar ratio of high-entropy alloy powder FeCrNiCu 0.5-y Mo x Si y The proportions were calculated using the formula (x = 0.7, y = 0.5). All alloy powders used were elemental powders with a particle size of 48–106 μm.

[0056] Fe, Cr, Ni, Cu, Mo, and Si powders were weighed and ball-milled under a protective gas environment (Ar) using a YXQM-4L planetary ball mill at a speed of 180 r / min for 2 hours. The mixture was then vacuum-dried at 100℃ for 2 hours to obtain the high-entropy alloy coating powder.

[0057] After removing the oxides from the surface of the Q235 steel (60x20x8mm) with a grinding wheel, it was ultrasonically cleaned in anhydrous ethanol for 20 minutes, and then dried with a hair dryer for later use.

[0058] A mixed powder was pre-placed on a substrate to a thickness of approximately 2 mm. Single-pass laser cladding was performed using a YSL-10000 fiber laser with the following parameters: laser power 1800 W, spot diameter 4 mm, and laser scanning speed 5 mm / s. This yielded a low-cost, high-entropy alloy coating for marine engineering equipment. Figure 1 As shown.

[0059] The coating was prepared using an electrical discharge machining (EDM) machine, and electrochemical experiments were conducted. Polarization curves were measured using the potentiodynamic method, with the test range set to -0.5–1.5 V (vsOCP). Figure 8 It can be seen that the corrosion current density reaches 3.54 x 10⁻⁶. - 8 A / cm 2 Its corrosion resistance has been significantly improved.

[0060] Comparative Example 1

[0061] According to the molar ratio of high-entropy alloy powder FeCrNiCu 0.5-y Mo x Si y B 0.05 The proportions were calculated using the formula (x = 0.7, y = 0.5). All alloy powders used were elemental powders with a particle size of 48–106 μm.

[0062] Fe, Cr, Ni, Cu, Mo, Si, and B powders were weighed and ball-milled under a protective gas environment (Ar) using a YXQM-4L planetary ball mill at a speed of 180 r / min for 2 hours. The mixture was then vacuum-dried at 100℃ for 2 hours to obtain the high-entropy alloy coating powder.

[0063] After removing the oxides from the surface of the Q235 steel (60x20x8mm) with a grinding wheel, it was ultrasonically cleaned in anhydrous ethanol for 20 minutes, and then dried with a hair dryer for later use.

[0064] The mixed powder was pre-placed on the substrate with a thickness of about 2 mm. A YSL-10000 fiber laser was used for single-pass laser cladding with the following process parameters: laser power 1800W, spot diameter 4 mm, and laser scanning speed 5 mm / s.

[0065] The coating was sampled using an electrical discharge machining (EDM) machine, and the hardness curve is shown below. Figure 2 As shown, the average hardness of the coating is 534.9V. 0.5 Compared to high-entropy alloy coatings without B, the performance was not improved.

[0066] Comparative Example 2

[0067] According to the molar ratio of high-entropy alloy powder FeCrNiCu 0.5-y Mo x Si y B 0.05 The proportions were calculated using the formula (x=1, y=0.5). All alloy powders selected were elemental powders with a particle size of 48~106μm.

[0068] Fe, Cr, Ni, Cu, Mo, Si, and B powders were weighed and ball-milled under a protective gas environment (Ar) using a YXQM-4L planetary ball mill at a speed of 180 r / min for 2 hours. The mixture was then vacuum-dried at 100℃ for 2 hours to obtain the high-entropy alloy coating powder.

[0069] After removing the oxides from the surface of the Q235 steel (60x20x8mm) with a grinding wheel, it was ultrasonically cleaned in anhydrous ethanol for 20 minutes, and then dried with a hair dryer for later use.

[0070] The mixed powder was pre-placed on the substrate with a thickness of about 2 mm. Laser cladding was performed using a YSL-10000 fiber laser with the following process parameters: laser power 2000W, spot diameter 4 mm, and laser scanning speed 5 mm / s. Single-pass laser cladding scanning was performed.

[0071] The coating was sampled using an electrical discharge machining (EDM) machine, and the hardness curve is shown below. Figure 2 As shown, the average hardness of the coating is 607.39 HV. 0.5 Compared to the coating in Example 3, the addition of element B reduced performance and decreased coating thickness, which is not conducive to engineering applications.

[0072] High-entropy alloy coatings prepared by laser cladding are superior to Q235 steel substrates. They are composed of FCC+BCC phase structures and can improve the service life of marine engineering equipment. However, doping with boron is not conducive to performance improvement.

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A low-cost, high-entropy alloy coating for marine engineering equipment, characterized in that: The expression is FeCrNiMo x Si y Where x=1, y=0.5; composed of face-centered cubic (FCC) and body-centered cubic (BCC) structures and their ordered phases, prepared according to the following steps: (1) Weigh Fe, Cr, Ni, Mo and Si powders and ball mill them in a protective gas environment to make them evenly mixed. Then, vacuum dry them to obtain powder with high entropy alloy coating. (2) Grind and polish the surface of the Q235 steel substrate, then clean and dry it with anhydrous ethanol; (3) The mixed powder is pre-placed on the substrate with a thickness of 2 mm. A fiber laser is used for single-pass laser cladding with a laser power of 1400-2200W, a spot diameter of 4 mm, and a laser scanning speed of 3-7 mm / s.

2. The low-cost, high-entropy alloy coating for marine engineering equipment according to claim 1, characterized in that: The alloy powders selected were all elemental powders with a particle size of 46~108µm.

3. The low-cost, high-entropy alloy coating for marine engineering equipment according to claim 1 or 2, characterized in that: The ball milling speed is 180-200 r / min, and the ball milling time is 2-3 h.

4. The low-cost, high-entropy alloy coating for marine engineering equipment according to claim 3, characterized in that: The vacuum drying temperature is 95-110℃, and the drying time is 2-3 hours.

5. The low-cost, high-entropy alloy coating for marine engineering equipment according to claim 4, characterized in that: In steps (1) and (3), the protective gas is argon.

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