High-strength corrosion-resistant tin-based bearing alloy and method for producing same

Abstract

The application discloses a high-strength corrosion-resistant tin-based bearing alloy and a preparation method thereof, relates to the technical field of sliding bearing materials, and comprises the following steps: Ni powder and Co powder are pressed into sheets according to a mass ratio of 0.9:(0.3-2), and the sheets are broken to obtain Ni-Co composite pressing block fragments; a binary eutectic molten salt prepared by mixing LiCl and KCl according to a ratio of 1:1.3 is used as a covering agent; a graphite crucible is placed in an induction melting furnace, Sn-11Sb-6Cu alloy blocks and the covering agent are added, the temperature is raised to 670 DEG C, and the temperature is kept until the covering agent is completely melted; the Ni-Co composite pressing block fragments are put into the furnace, and stirring, casting, air cooling and demolding are carried out to obtain the finished product. The alloy prepared by the method realizes the synergistic optimization of strength and plasticity, solves the problem of plasticity reduction caused by single Ni addition, shows a greater capacitive arc radius and a higher total polarization resistance, and indicates that the Ni-Co composite addition can effectively improve the electrochemical corrosion impedance of the alloy in a chlorine-containing medium.

Description

Technical Field

[0001] This application relates to the field of sliding bearing materials technology, and in particular to a high-strength, corrosion-resistant tin-based bearing alloy and its preparation method. Background Technology

[0002] Traditional Sn-11Sb-6Cu tin-based Babbitt alloys possess excellent anti-friction, embedding, compliance, and anti-galling properties, and are widely used in the sliding bearing linings of marine power equipment, heavy machinery, large generator sets, and low-speed diesel engines. The typical microstructure of this type of alloy consists of a soft Sn matrix with dispersed hard intermetallic compounds, achieving a balance between anti-friction and load-bearing capacity to a certain extent. Therefore, it has long been one of the important bearing alloy materials.

[0003] However, as modern equipment develops towards higher loads, higher temperatures, longer cycles, and more complex environments, the traditional Sn-11Sb-6Cu tin-based Babbitt alloy has gradually revealed the following shortcomings: First, the hard phase in the alloy tends to be distributed in coarse blocky or needle-like shapes, resulting in poor microstructure uniformity and affecting service stability.

[0004] Secondly, the as-cast structure is prone to intergranular porosity, compositional segregation, and local discontinuities, resulting in insufficient tensile strength of the material, making it difficult to meet the requirements of high-load conditions.

[0005] Third, in chlorine-containing or weakly corrosive media, the potential difference between multiphase structures can easily induce localized electrochemical corrosion and intergranular corrosion, causing surface instability and accelerating failure of the material.

[0006] While current technologies can improve some properties by increasing Sb and Cu content or adjusting casting parameters, it is difficult to simultaneously achieve uniform microstructure, strength, and corrosion resistance. This is especially true for high-melting-point strengthening elements such as Ni and Co, which often face challenges in traditional direct powder addition or direct smelting processes, including difficulties in melting, significant oxidation losses, uneven dispersion, and easy segregation and agglomeration, thus limiting their strengthening effect.

[0007] Therefore, developing a tin-based bearing alloy with a dense and uniform structure, high strength, and high corrosion resistance, and its stable and feasible preparation method, has important engineering application value. Summary of the Invention

[0008] The purpose of this application is to provide a high-strength, corrosion-resistant tin-based bearing alloy and its preparation method, so as to solve the technical problems of insufficient strength, poor corrosion resistance, and difficulty in uniformly dispersing high-melting-point elements in the current Sn-11Sb-6Cu tin-based Babbitt alloy.

[0009] To achieve the above objectives, this application provides a method for preparing a high-strength, corrosion-resistant tin-based bearing alloy, comprising the following steps: S1. Mix Ni powder and Co powder at a mass ratio of 0.9:(0.3~2), press them into sheets at a pressure of 20MPa and a holding pressure of 1g per part for 2min, and break them into irregular fragments after demolding to obtain Ni-Co composite compressed fragments. S2. Prepare a binary eutectic molten salt of LiCl and KCl as a covering agent at a mass ratio of 1:1.3; S3. Place the graphite crucible in an induction melting furnace, add Sn-11Sb-6Cu alloy blocks and covering agent, heat to 670℃ and hold until the covering agent is completely melted, then add Ni-Co composite briquettes and intermittently stir with a preheated quartz stirring rod until completely melted to obtain the melt. S4. The melt is poured into a low-carbon steel mold, air-cooled to room temperature, and then demolded to obtain a cast alloy sample, namely a high-strength corrosion-resistant tin-based bearing alloy. The mass ratio of the Sn-11Sb-6Cu alloy block to the Ni-Co composite briquettes is (97.1~98.8):(1.2~2.9).

[0010] Preferably, the raw materials used in the Sn-11Sb-6Cu alloy block, by weight percentage, include: Sb 11 wt.%, Cu 6 wt.%, with the balance being Sn. Before adding the Sn-11Sb-6Cu alloy block, it is mechanically polished with 600-grit sandpaper and ultrasonically cleaned with anhydrous ethanol. This mechanical polishing with 600-grit sandpaper and ultrasonic cleaning with anhydrous ethanol before adding the Sn-11Sb-6Cu alloy block removes the oxide layer and grease from the Sn block surface.

[0011] Preferably, the particle size range of the Ni powder and Co powder is 0.5 μm to 3 μm.

[0012] Preferably, the covering agent completely submerges the Sn-11Sb-6Cu alloy block and the Ni-Co composite briquettes.

[0013] Preferably, the intermittent stirring frequency is 15 min / time, and the duration of each stirring is 15 s.

[0014] Preferably, the temperature of the preheated quartz stirring rod is 250°C.

[0015] Preferably, the low-carbon steel mold is preheated in a constant temperature environment of 250°C for 1 hour before casting.

[0016] This application successfully solves the technical problem of the difficulty in uniformly dispersing high-melting-point elements such as Ni and Co through pre-pressed block preparation and molten salt protected smelting process. It avoids the oxidation, segregation and agglomeration phenomena that are easy to occur when directly adding powder. The as-cast structure has finer grains and more uniform composition distribution. Moreover, it adopts conventional induction melting equipment, combined with LiCl-KCl molten salt protection and intermittent mechanical stirring, which has a wide process window and good repeatability, making it suitable for industrial mass production.

[0017] This application provides a high-strength, corrosion-resistant tin-based bearing alloy, which is prepared by the above-described method for preparing high-strength, corrosion-resistant tin-based bearing alloys.

[0018] In summary, the high-strength, corrosion-resistant tin-based bearing alloy and its preparation method provided in this application have the following advantages compared to traditional technologies: (1) This application combines Ni and Co with traditional Sn-11Sb-6Cu alloy. When the Co content is 0.7 wt.% (i.e. Sn-11Sb-6Cu-0.9Ni-0.7Co), the tensile strength reaches 76.8 MPa, while the elongation after fracture remains at 8.44%, achieving synergistic optimization of strength and plasticity. Compared with the alloy with only Ni added (Sn-11Sb-6Cu-1Ni), the plasticity is significantly improved after adding an appropriate amount of Co, solving the problem of decreased plasticity caused by adding only Ni.

[0019] (2) The electrochemical test results of the high-strength corrosion-resistant tin-based bearing alloy of this application in 3.5wt.% NaCl solution show that the alloy with appropriate amount of Co added exhibits a larger capacitive arc radius and higher charge transfer resistance. In particular, Sn-11Sb-6Cu-0.9Ni-0.3Co has the best corrosion resistance, indicating that the Ni-Co composite addition can effectively improve the electrochemical corrosion resistance of the alloy in chlorine-containing media.

[0020] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the preparation process of the high-strength, corrosion-resistant tin-based bearing alloy in this application. Figure 2 The images show the microstructures of the high-strength, corrosion-resistant tin-based bearing alloys and tin-based bearing alloys prepared in the embodiments and comparative examples of this application. Figure 2 (a) in the figure is a microstructure of the ZCHSn-11Sb-6Cu alloy prepared in Comparative Example 1. Figure 2 (b) in the figure is a microstructure of the Sn-11Sb-6Cu-0.9Ni alloy prepared in Comparative Example 2; Figure 2(c) is a microstructure diagram of the Sn-11Sb-6Cu-0.9Ni-0.3Co alloy prepared in Example 1; Figure 2 (d) in the figure is a microstructure of the Sn-11Sb-6Cu-0.9Ni-0.7Co alloy prepared in Example 2; Figure 2 (e) in the figure is a microstructure of the Sn-11Sb-6Cu-0.9Ni-1Co alloy prepared in Example 3; Figure 2 (f) in the figure is a microstructure of the Sn-11Sb-6Cu-0.9Ni-2Co alloy prepared in Example 4; Figure 3 This is a schematic diagram of tensile specimens of high-strength corrosion-resistant tin-based bearing alloys and tin-based bearing alloys prepared in the embodiments and comparative examples of this application. Figure 4 Stress-strain curves of high-strength corrosion-resistant tin-based bearing alloys and tin-based bearing alloys prepared in the embodiments and comparative examples of this application are shown. Figure 5 The electrochemical impedance spectroscopy results of the high-strength corrosion-resistant tin-based bearing alloy and tin-based bearing alloy prepared in the embodiments and comparative examples of this application in 3.5 wt.% NaCl solution are shown. Figure 5 (a) in the diagram is the Nyquist plot; Figure 5 (b) in the figure is the phase angle-frequency Bode plot; Figure 5 (c) in the figure represents the impedance magnitude-frequency Bode plot; Figure 5 (d) in the figure represents the equivalent circuit diagram used for fitting the electrochemical impedance spectroscopy. Detailed Implementation

[0022] The technical methods of this application will be further described below with reference to the accompanying drawings and embodiments.

[0023] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0024] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. All materials and reagents used in this application are commercially available products.

[0025] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning as understood by a person of ordinary skill in the art to which this application pertains.

[0026] This application provides a method for preparing a high-strength, corrosion-resistant tin-based bearing alloy, such as... Figure 1 As shown, it includes: cold pressing, crushing, induction melting and alloy ingot casting.

[0027] The specific embodiments provided in this application are as follows.

[0028] Example 1 A method for preparing a high-strength, corrosion-resistant tin-based bearing alloy (Sn-11Sb-6Cu-0.9Ni-0.3Co) includes the following steps: S1. Mix 0.9g Ni powder (particle size range 1-3μm) and 0.3g Co powder (particle size range 0.5-1μm), then compress the mixture into sheets at a pressure of 20MPa and a holding pressure of 1g per portion for 2min. After demolding, break the sheets into irregular fragments to obtain Ni-Co composite compressed fragments.

[0029] S2. Prepare a binary eutectic molten salt of LiCl and KCl as a covering agent at a mass ratio of 1:1.3.

[0030] S3. Place the graphite crucible in an induction melting furnace, add the Sn-11Sb-6Cu alloy block and covering agent, heat to 670℃ and hold until the covering agent is completely melted, then add Ni-Co composite briquettes and fragments, so that the covering agent completely submerges the Sn-11Sb-6Cu alloy block and Ni-Co composite briquettes and fragments. Then use a quartz stirring rod with a preheated temperature of 250℃ to perform intermittent stirring at a frequency of 15min / time, with each stirring lasting for 15s, until the Sn-11Sb-6Cu alloy block and Ni-Co composite briquettes and fragments are completely melted to obtain the melt. The raw materials used in the Sn-11Sb-6Cu alloy block, by weight percentage, include: Sb 11wt.%, Cu 6wt.%, with the balance being Sn. Before being added to the Sn-11Sb-6Cu alloy block, the Sn-11Sb-6Cu alloy block is mechanically polished with 600-grit sandpaper and ultrasonically cleaned with anhydrous ethanol. The mass ratio of the Sn-11Sb-6Cu alloy block to the Ni-Co composite briquettes is 98.8:1.2.

[0031] S4. The melt is poured into a low-carbon steel mold that has been preheated at a constant temperature of 250°C for 1 hour. After air cooling to room temperature, the mold is demolded to obtain a high-strength corrosion-resistant tin-based bearing alloy, namely Sn-11Sb-6Cu-0.9Ni-0.3Co.

[0032] Example 2 A method for preparing a high-strength, corrosion-resistant tin-based bearing alloy (Sn-11Sb-6Cu-0.9Ni-0.7Co) includes the following steps: S1. Mix 0.9g Ni powder (particle size range 1-3μm) and 0.7g Co powder (particle size range 0.5-1μm), compress the mixture into sheets at a pressure of 20MPa per 1g and a holding pressure of 2min. After demolding, break the sheets into irregular fragments to obtain Ni-Co composite compressed fragments.

[0033] S2. Prepare a binary eutectic molten salt of LiCl and KCl as a covering agent at a mass ratio of 1:1.3.

[0034] S3. Place the graphite crucible in an induction melting furnace, add the Sn-11Sb-6Cu alloy block and covering agent, heat to 670℃ and hold until the covering agent is completely melted, then add Ni-Co composite briquettes and fragments, so that the covering agent completely submerges the Sn-11Sb-6Cu alloy block and Ni-Co composite briquettes and fragments. Then use a quartz stirring rod with a preheated temperature of 250℃ to perform intermittent stirring at a frequency of 15min / time, with each stirring lasting for 15s, until the Sn-11Sb-6Cu alloy block and Ni-Co composite briquettes and fragments are completely melted to obtain the melt. The raw materials used in the Sn-11Sb-6Cu alloy block, by weight percentage, include: Sb 11wt.%, Cu 6wt.%, with the balance being Sn. Before being added to the Sn-11Sb-6Cu alloy block, the Sn-11Sb-6Cu alloy block is mechanically polished with 600-grit sandpaper and ultrasonically cleaned with anhydrous ethanol. The mass ratio of the Sn-11Sb-6Cu alloy block to the Ni-Co composite briquettes is 98.4:1.6.

[0035] S4. The melt is poured into a low-carbon steel mold that has been preheated at a constant temperature of 250℃ for 1 hour. After air cooling to room temperature, the mold is demolded to obtain a high-strength corrosion-resistant tin-based bearing alloy, namely Sn-11Sb-6Cu-0.9Ni-0.7Co.

[0036] Example 3 A method for preparing a high-strength, corrosion-resistant tin-based bearing alloy (Sn-11Sb-6Cu-0.9Ni-1Co) includes the following steps: S1. Mix 0.9g of Ni powder (particle size range 1-3μm) and 1g of Co powder (particle size range 0.5-1μm), and compress them into sheets at a pressure of 20MPa and a holding pressure of 1g per portion for 2min. After demolding, break them into irregular fragments to obtain Ni-Co composite compressed fragments.

[0037] S2. Prepare a binary eutectic molten salt of LiCl and KCl as a covering agent at a mass ratio of 1:1.3.

[0038] S3. Place the graphite crucible in an induction melting furnace, add the Sn-11Sb-6Cu alloy block and covering agent, heat to 670℃ and hold until the covering agent is completely melted, then add Ni-Co composite briquettes and fragments, so that the covering agent completely submerges the Sn-11Sb-6Cu alloy block and Ni-Co composite briquettes and fragments. Then use a quartz stirring rod with a preheated temperature of 250℃ to perform intermittent stirring at a frequency of 15min / time, with each stirring lasting for 15s, until the Sn-11Sb-6Cu alloy block and Ni-Co composite briquettes and fragments are completely melted to obtain the melt. The raw materials used in the Sn-11Sb-6Cu alloy block, by weight percentage, include: Sb 11wt.%, Cu 6wt.%, with the balance being Sn. Before being added to the Sn-11Sb-6Cu alloy block, the Sn-11Sb-6Cu alloy block is mechanically polished with 600-grit sandpaper and ultrasonically cleaned with anhydrous ethanol. The mass ratio of the Sn-11Sb-6Cu alloy block to the Ni-Co composite briquettes is 98.1:1.9.

[0039] S4. The melt is poured into a low-carbon steel mold that has been preheated at a constant temperature of 250°C for 1 hour. After air cooling to room temperature, the mold is demolded to obtain a high-strength, corrosion-resistant tin-based bearing alloy, namely Sn-11Sb-6Cu-0.9Ni-1Co.

[0040] Example 4 A method for preparing a high-strength, corrosion-resistant tin-based bearing alloy (Sn-11Sb-6Cu-0.9Ni-2Co) includes the following steps: S1. Mix 0.9g Ni powder (particle size range 1-3μm) and 2g Co powder (particle size range 0.5-1μm), compress the mixture into sheets at a pressure of 20MPa and a holding pressure of 1g per portion for 2min. After demolding, break the sheets into irregular fragments to obtain Ni-Co composite compressed fragments.

[0041] S2. Prepare a binary eutectic molten salt of LiCl and KCl as a covering agent at a mass ratio of 1:1.3.

[0042] S3. Place the graphite crucible in an induction melting furnace, add the Sn-11Sb-6Cu alloy block and covering agent, heat to 670℃ and hold until the covering agent is completely melted, then add Ni-Co composite briquettes and fragments, so that the covering agent completely submerges the Sn-11Sb-6Cu alloy block and Ni-Co composite briquettes and fragments. Then use a quartz stirring rod with a preheated temperature of 250℃ to perform intermittent stirring at a frequency of 15min / time, with each stirring lasting for 15s, until the Sn-11Sb-6Cu alloy block and Ni-Co composite briquettes and fragments are completely melted to obtain the melt. The raw materials used in the Sn-11Sb-6Cu alloy block, by weight percentage, include: Sb 11wt.%, Cu 6wt.%, with the balance being Sn. Before being added to the Sn-11Sb-6Cu alloy block, the Sn-11Sb-6Cu alloy block is mechanically polished with 600-grit sandpaper and ultrasonically cleaned with anhydrous ethanol. The mass ratio of the Sn-11Sb-6Cu alloy block to the Ni-Co composite briquettes is 97.1:2.9.

[0043] S4. The melt is poured into a low-carbon steel mold that has been preheated at a constant temperature of 250℃ for 1 hour. After air cooling to room temperature, the mold is demolded to obtain a high-strength corrosion-resistant tin-based bearing alloy, namely Sn-11Sb-6Cu-0.9Ni-2Co.

[0044] Comparative Example 1 A method for preparing a tin-based bearing alloy (ZCHSn-11Sb-6Cu) includes the following steps: S1. Prepare a binary eutectic molten salt of LiCl and KCl as a covering agent at a mass ratio of 1:1.3.

[0045] S3. Place the graphite crucible in an induction melting furnace, add the Sn-11Sb-6Cu alloy block and covering agent, heat to 670℃ and hold until the covering agent is completely melted, ensuring the covering agent completely submerges the Sn-11Sb-6Cu alloy block. Then, use a quartz stirring rod preheated to 250℃ for intermittent stirring at a frequency of 15 min / time, with each stirring lasting 15 s, until the Sn-11Sb-6Cu alloy block is completely melted, obtaining a melt. The raw materials used in the Sn-11Sb-6Cu alloy block, by weight percentage, include: Sb 11 wt.%, Cu 6 wt.%, with the balance being Sn. Before adding the Sn-11Sb-6Cu alloy block, mechanically polish it with 600-grit sandpaper and ultrasonically clean it with anhydrous ethanol.

[0046] S4. The melt is poured into a low-carbon steel mold that has been preheated at a constant temperature of 250°C for 1 hour. After air cooling to room temperature, the mold is demolded to obtain a tin-based bearing alloy, namely ZCHSn-11Sb-6Cu.

[0047] Comparative Example 2 A method for preparing a tin-based bearing alloy (Sn-11Sb-6Cu-0.9Ni) includes the following steps: S1. 0.9g of Ni powder (particle size range of 1-3μm) is compressed into sheets at a pressure of 20MPa per 1g and a holding pressure of 2min. After demolding, the sheets are broken into irregular fragments to obtain Ni compressed fragments.

[0048] S2. Prepare a binary eutectic molten salt of LiCl and KCl as a covering agent at a mass ratio of 1:1.3.

[0049] S3. Place the graphite crucible in an induction melting furnace, add the Sn-11Sb-6Cu alloy block and covering agent, heat to 670℃ and hold until the covering agent is completely melted, then add Ni briquettes and fragments, ensuring the covering agent completely submerges the Sn-11Sb-6Cu alloy block and Ni briquettes and fragments. Then, use a quartz stirring rod preheated to 250℃ for intermittent stirring at a frequency of 15 min / time, with each stirring lasting 15 s, until the added Sn-11Sb-6Cu alloy block and Ni briquettes and fragments are completely melted, obtaining a melt. The raw materials used for the Sn-11Sb-6Cu alloy block, by weight percentage, include: Sb 11 wt.%, Cu 6 wt.%, with the balance being Sn. Before adding the Sn-11Sb-6Cu alloy block, mechanically polish it with 600-grit sandpaper and ultrasonically clean it with anhydrous ethanol. The mass ratio of Sn-11Sb-6Cu alloy blocks to Ni briquettes is 99.1:0.9.

[0050] S4. The melt is poured into a low-carbon steel mold that has been preheated at a constant temperature of 250°C for 1 hour. After air cooling to room temperature, the mold is removed to obtain a tin-based bearing alloy, denoted as Sn-11Sb-6Cu-0.9Ni.

[0051] Microstructure analysis of alloy Microstructural observations were performed on the high-strength, corrosion-resistant tin-based bearing alloys (Sn-11Sb-6Cu-0.9Ni-0.3Co, Sn-11Sb-6Cu-0.9Ni-0.7Co, Sn-11Sb-6Cu-0.9Ni-1Co, Sn-11Sb-6Cu-0.9Ni-2Co) prepared in Examples 1 to 4, as well as the tin-based bearing alloys (ZCHSn-11Sb-6Cu and Sn-11Sb-6Cu-0.9Ni) prepared in Comparative Examples 1 and 2. The results are as follows: Figure 2 As shown. Figure 2 The light gray area represents the Sn matrix, while the dark gray phase mainly consists of intermetallic compounds such as SnSb and Cu6Sn5. Figure 2 (a) Figure 2 (b) Figure 2 (c) Figure 2 (d) Figure 2 (e) and Figure 2 As shown in (f), the second phase in the ZCHSn-11Sb-6Cu alloy prepared in Comparative Example 1 is relatively large, mostly appearing as coarse flakes, rods, or locally continuous distributions, resulting in poor microstructure uniformity. In Comparative Example 2, the size of the intermetallic compounds decreased after the addition of 0.9 wt.% Ni, but local aggregation still existed. After further adding 0.3 wt.% Co, the second phase in the alloy was significantly refined, and the SnSb and Cu6Sn5 phases were more dispersed in the Sn matrix, indicating that the Ni-Co composite addition can promote the uniform dispersion of high-melting-point elements in the tin matrix and inhibit the formation of coarse intermetallic compounds. When the Co content is appropriate, the fine and dispersed second phase can strengthen the matrix and reduce local stress concentration, which is beneficial to improving the strength and plasticity matching of the alloy. When the Co content exceeds 1 wt.%, the Cu6Sn5-based intermetallic compounds coarsen and locally agglomerate, the microstructure uniformity decreases, and the mechanical stability and corrosion resistance of the alloy are easily weakened.

[0052] Tensile strength test Tensile tests were conducted on the high-strength, corrosion-resistant tin-based bearing alloys (Sn-11Sb-6Cu-0.9Ni-0.3Co, Sn-11Sb-6Cu-0.9Ni-0.7Co, Sn-11Sb-6Cu-0.9Ni-1Co, Sn-11Sb-6Cu-0.9Ni-2Co) prepared in Examples 1-4, and the tin-based bearing alloys (ZCHSn-11Sb-6Cu and Sn-11Sb-6Cu-0.9Ni) prepared in Comparative Examples 1 and 2, respectively, at a tensile rate of 0.6 mm / min using a high-precision universal testing machine at room temperature. Five tests were performed on each alloy, and the average value was taken. The specifications of the tensile specimens for the high-strength, corrosion-resistant tin-based bearing alloys and the tin-based bearing alloys are as follows: Figure 3 As shown. Figure 3 The specimen has a total length of 40 mm and a thickness of 2 mm. The width of the clamping sections at both ends is 10 mm, the width of the middle tensile section is 5 mm, the length of the parallel tensile section is 18 mm, and the length of the straight section from the end of the clamping section to the start of the transition arc is 7 mm. R5 indicates that the radius of the transition arc between the clamping and tensile sections is 5 mm, used to reduce stress concentration at abrupt changes in cross-section. Before the experiment, the surface of the high-strength corrosion-resistant tin-based bearing alloy and the tin-based bearing alloy after wire cutting was polished with 600-grit, 1000-grit, and 2000-grit sandpaper to remove residual traces and oil stains. Stress-strain curves were plotted based on the load-displacement data obtained from the tensile test, as shown below. Figure 4As shown in Table 1, the mechanical properties, such as tensile strength (UTS) and elongation after fracture (EL), are as follows.

[0053] Table 1. Tensile strength and elongation after fracture of high-strength corrosion-resistant tin-based bearing alloys and tin-based bearing alloys.

[0054] Depend on Figure 4 As shown in Table 1, the tensile strength of ZCHSn-11Sb-6Cu is 52.3 MPa, and the elongation after fracture is 9.45%. After adding 0.9 wt.% Ni (i.e., Sn-11Sb-6Cu-0.9Ni), the tensile strength increases to 61.2 MPa, but the elongation after fracture decreases to 5.74%, indicating that while adding Ni alone can improve the alloy's strength, it leads to a decrease in plasticity. Further addition of Co significantly improves the balance between the alloy's strength and plasticity. Among the alloys, when the Co content is 0.3 wt.%, i.e., Sn-11Sb-6Cu-0.9Ni-0.3Co, the tensile strength increases to 66.8 MPa, and the elongation after fracture recovers to 6.70%. When the Co content is 0.7 wt.%, i.e., Sn-11Sb-6Cu-0.9Ni-0.7Co, the alloy exhibits the best overall performance, with a tensile strength reaching 76.8 MPa, which is approximately 46.8% higher than ZCHSn-11Sb-6Cu, while the elongation after fracture remains at 8.44%, significantly better than the alloy with only Ni added. These results indicate that the introduction of an appropriate amount of Co can effectively alleviate the problem of decreased plasticity while improving the alloy's strength, achieving synergistic optimization of strength and plasticity. When the Co content continues to increase to 1.0 wt.% and 2.0 wt.%, i.e. Sn-11Sb-6Cu-0.9Ni-1Co and Sn-11Sb-6Cu-0.9Ni-2Co, the tensile strength decreases to 70.5 MPa and 60.3 MPa, respectively, and the elongation after fracture is 6.79% and 5.65%, respectively. This indicates that excessive Co content will lead to a decrease in the overall mechanical properties of the alloy. Therefore, in this application, the Co content in the high-strength corrosion-resistant tin-based bearing alloy is preferably controlled in the range of 0.3 wt.% to 1.0 wt.%, and more preferably 0.7 wt.%, to obtain a better strength-plasticity match.

[0055] Corrosion performance testing Electrochemical impedance spectroscopy was used to systematically test the corrosion performance of the high-strength, corrosion-resistant tin-based bearing alloys (Sn-11Sb-6Cu-0.9Ni-0.3Co, Sn-11Sb-6Cu-0.9Ni-0.7Co, Sn-11Sb-6Cu-0.9Ni-1Co, Sn-11Sb-6Cu-0.9Ni-2Co) prepared in Examples 1-4, as well as the tin-based bearing alloys (ZCHSn-11Sb-6Cu and Sn-11Sb-6Cu-0.9Ni) prepared in Comparative Examples 1 and 2, in 3.5 wt.% NaCl solution. The results are as follows. Figure 5 As shown, where Figure 5 In Table 2, (d) represents the equivalent circuit diagram used for fitting the electrochemical impedance spectroscopy, and the relevant electrochemical parameters are shown in Table 2. R in Table 2 s The resistance of the solution in a 3.5 wt.% NaCl solution; R t R1 is the sum of R1 and R2, i.e., the total polarization resistance, used to evaluate the degree of hindrance to the overall corrosion reaction of the alloy. R1 is the corrosion product film resistance, reflecting the ability of the corrosion product layer to hinder the diffusion and ion transport of the corrosive medium. R2 is the charge transfer resistance at the corrosion product film / alloy substrate interface, reflecting the ease of anodic dissolution of the alloy substrate. CPE1 is the non-ideal capacitance response at the corresponding corrosion product film / solution interface. CPE2 is the non-ideal double-layer capacitance response at the corrosion product film / alloy substrate interface. n1 is the dispersion index of CPE1, used to characterize the degree to which the capacitance behavior of the corrosion product film / solution interface deviates from the ideal capacitance. n2 is the dispersion index of CPE2, used to characterize the degree of non-ideality of the double-layer capacitance behavior at the corrosion product film / alloy substrate interface.

[0056] Table 2. Results of electrochemical impedance spectroscopy fitting of high-strength corrosion-resistant tin-based bearing alloys using equivalent circuits.

[0057] according to Figure 5As shown in (a) and Table 2 (electrochemical impedance spectroscopy results), ZCHSn-11Sb-6Cu has the smallest capacitive arc radius, indicating a lower total polarization resistance and a greater susceptibility to corrosion. Adding 0.9 wt.% Ni (Sn-11Sb-6Cu-0.9Ni) significantly increases the capacitive arc radius, demonstrating that Ni effectively improves the electrochemical corrosion resistance of the alloy interface. Further addition of Co further improves the corrosion resistance of the alloy, with Sn-11Sb-6Cu-0.9Ni-0.3Co exhibiting the largest capacitive arc radius, indicating the highest total polarization resistance and optimal corrosion inhibition. However, as the Co content continues to increase to 1.0 wt.% and 2.0 wt.% (Sn-11Sb-6Cu-0.9Ni-1Co and Sn-11Sb-6Cu-0.9Ni-2Co), the capacitive arc radius decreases, indicating that excessive Co content weakens the corrosion resistance improvement effect.

[0058] Figure 5 (b) further demonstrates that the Ni-Co modified alloys (Sn-11Sb-6Cu-0.9Ni-0.3Co, Sn-11Sb-6Cu-0.9Ni-0.7Co, Sn-11Sb-6Cu-0.9Ni-1Co, Sn-11Sb-6Cu-0.9Ni-2Co) exhibit more significant interfacial capacitance behavior, indicating that their surface film or interfacial protective layer is more stable. The comprehensive impedance spectroscopy results show that the Sn-11Sb-6Cu-0.9Ni-0.3Co, Sn-11Sb-6Cu-0.9Ni-0.7Co, Sn-11Sb-6Cu-0.9Ni-1Co, and Sn-11Sb-6Cu-0.9Ni-2Co prepared in this application, under appropriate Co addition conditions, exhibit significantly better electrochemical corrosion resistance than ZCHSn-11Sb-6Cu, and there is an optimal range for Co content addition.

[0059] The trend curves of Bode impedance modulus points for each alloy are as follows: Figure 5 As shown in (c) of the figure. The trend curves of the Bode impedance modulus points of each alloy were fitted with the Nyquist curves, and the results were basically consistent. The larger the impedance modulus in the low-frequency region, the higher the total corrosion resistance of the alloy / solution interface, and the more difficult the diffusion and charge transfer processes of the corrosive medium. ZCHSn-11Sb-6Cu had the lowest impedance modulus in the low-frequency region, indicating that its surface corrosion product film had weak protective ability and that corrosion reactions were more likely to occur. After adding 0.9wt.%Ni, the low-frequency impedance modulus of Sn-11Sb-6Cu-0.9Ni increased significantly, indicating that Ni could enhance the stability of the alloy interface and improve corrosion resistance. Further addition of 0.3wt.%Co resulted in Sn-11Sb-6Cu-0.9Ni-0.3Co exhibiting the highest low-frequency impedance modulus, indicating that its surface protective film was more dense and stable, and that it was more effective against Cl.- The Sn-11Sb-6Cu-0.9Ni alloy exhibits the strongest barrier effect against corrosive media, thus possessing the best corrosion resistance. As the Co content increases to 1.0 wt.% and 2.0 wt.%, the low-frequency impedance modulus gradually decreases, indicating that excessive Co weakens the continuity and stability of the corrosion product film, leading to a decline in corrosion resistance. In summary, appropriate Co addition can significantly improve the electrochemical corrosion resistance of the Sn-11Sb-6Cu-0.9Ni alloy, with Sn-11Sb-6Cu-0.9Ni-0.3Co showing the best corrosion inhibition effect.

[0060] The high-strength, corrosion-resistant tin-based bearing alloy and its preparation method provided in this application can be directly implemented on existing industrial induction melting equipment without special modifications. The prepared high-strength, corrosion-resistant tin-based bearing alloy is suitable for sliding bearing linings in marine power equipment, heavy machinery, large generator sets, and low-speed diesel engines, and is particularly suitable for long-term service conditions under high loads and chlorine-containing corrosive environments, showing clear prospects for industrial applications.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit them. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of this application, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of this application.

Claims

1. A method for preparing a high-strength, corrosion-resistant tin-based bearing alloy, characterized in that, Includes the following steps: S1. Mix Ni powder and Co powder at a mass ratio of 0.9:(0.3~2), press them into sheets at a pressure of 20MPa and a holding pressure of 1g per part for 2min, and break them into irregular fragments after demolding to obtain Ni-Co composite compressed fragments. S2. Prepare a binary eutectic molten salt of LiCl and KCl as a covering agent at a mass ratio of 1:1.3; S3. Place the graphite crucible in an induction melting furnace, add Sn-11Sb-6Cu alloy blocks and covering agent, heat to 670℃ and hold until the covering agent is completely melted, then add Ni-Co composite briquettes and intermittently stir with a preheated quartz stirring rod until completely melted to obtain the melt. S4. The melt is poured into a low-carbon steel mold, air-cooled to room temperature, and then demolded to obtain a cast alloy sample, namely a high-strength corrosion-resistant tin-based bearing alloy. The mass ratio of the Sn-11Sb-6Cu alloy block to the Ni-Co composite briquettes is (97.1~98.8):(1.2~2.9).

2. The method for preparing the high-strength, corrosion-resistant tin-based bearing alloy according to claim 1, characterized in that, The raw materials used in the Sn-11Sb-6Cu alloy block, by weight percentage, include: Sb 11wt.%, Cu 6wt.%, with the balance being Sn; before being added to the Sn-11Sb-6Cu alloy block, the Sn-11Sb-6Cu alloy block is mechanically polished with 600-grit sandpaper and ultrasonically cleaned with anhydrous ethanol.

3. The method for preparing the high-strength, corrosion-resistant tin-based bearing alloy according to claim 1, characterized in that, The particle size range of the Ni powder and Co powder is 0.5μm to 3μm.

4. The method for preparing the high-strength, corrosion-resistant tin-based bearing alloy according to claim 1, characterized in that, The covering agent completely submerges the Sn-11Sb-6Cu alloy block and the Ni-Co composite briquettes.

5. The method for preparing the high-strength, corrosion-resistant tin-based bearing alloy according to claim 1, characterized in that, The intermittent stirring frequency is 15 min / time, and the duration of each stirring is 15 s.

6. The method for preparing the high-strength, corrosion-resistant tin-based bearing alloy according to claim 1, characterized in that, The temperature of the preheated quartz stirring rod is 250°C.

7. The method for preparing the high-strength, corrosion-resistant tin-based bearing alloy according to claim 1, characterized in that, The low-carbon steel mold was preheated in a constant temperature environment of 250°C for 1 hour before casting.

8. A high-strength, corrosion-resistant tin-based bearing alloy, characterized in that, It is prepared by the method for preparing high-strength corrosion-resistant tin-based bearing alloy according to any one of claims 1-7.

Images