Dispersion strengthened copper-tin alloy and preparation method and application thereof

Abstract

The invention belongs to the field of metallurgy, and particularly relates to a dispersion strengthened copper-tin alloy and a preparation method and application thereof. The method comprises the following steps: 1) preparing an aluminum-containing aqueous solution, putting copper oxide into the aluminum-containing aqueous solution, mixing, and continuously stirring until the mixture is pasty to obtain a pasty material; 2) oxidizing and calcining the pasty material to obtain a copper aluminum oxide mixture; and (3) the copper-aluminum oxide mixture is subjected to reduction calcination, aluminum oxide dispersion copper alloy powder is obtained, the aluminum oxide dispersion copper alloy powder and tin powder are mixed and then subjected to diffusion alloying treatment, and the dispersion strengthened copper-tin alloy is obtained. Micro-level combination of copper and aluminum is achieved through a special process, the copper-tin alloy can be effectively and flexibly constructed on the basis, and it is ensured that the copper-tin alloy has good physical and chemical properties.

Description

Technical Field

[0001] The present invention belongs to the field of metallurgy, and in particular relates to a dispersion-strengthened copper-tin alloy and a preparation method and application thereof. Background Art

[0002] Alumina dispersion-strengthened copper-tin alloy is a composite material that utilizes the incorporation of aluminum oxide (Al2O3) particles to enhance the performance of the copper-tin alloy. This dispersion-strengthening strategy is widely used in various engineering fields to optimize the alloy's key properties, including mechanical properties, hardness, wear resistance, and high-temperature resistance. The addition of aluminum oxide particles significantly increases the alloy's tensile strength and hardness, effectively enhancing its load-bearing capacity. Furthermore, the presence of dispersed aluminum oxide particles significantly enhances the alloy's wear resistance, reducing friction and wear, thereby extending the material's service life. Of particular note, aluminum oxide particles have a high melting point and excellent high-temperature resistance, improving the alloy's stability and overall performance in high-temperature environments. Alumina exhibits certain antioxidant properties, helping to inhibit oxidative corrosion in high-temperature environments. By adjusting the size and content of the aluminum oxide particles, the alloy's properties can be customized to meet diverse application requirements. Alumina dispersion-strengthened copper-tin alloys have broad potential for application in high-performance bearings, conductive materials, wear-resistant parts, and other fields. The alloy holds significant application prospects in the automotive, aerospace, machinery manufacturing, and electronics industries. In summary, alumina dispersion-strengthened copper-tin alloys significantly enhance their performance under high-load, high-temperature, and high-wear environments by fully utilizing the excellent properties of alumina. Copper-tin alloys themselves also have a wide range of applications in engineering fields such as electronics, aerospace, and mechanical manufacturing, demonstrating their unique characteristics and value in bearings, connectors, wires, and electronic components.

[0003] Conventional methods for preparing alumina dispersion-strengthened copper-tin alloys are divided into two categories: mechanical mixing method and internal oxidation method.

[0004] The mechanical mixing method involves mechanically mixing alumina particles with copper-tin powder. Ball milling, or other mechanical processes, are typically used to uniformly mix the two powders, dispersing the alumina particles within the copper-tin matrix. A major advantage of this method is its simplicity and relatively low cost. The preparation process does not require complex equipment or high-temperature treatment, making it suitable for small-batch production and laboratory research. Furthermore, composition control is relatively precise. However, a disadvantage of this method is that the alloy composition and relative content can be adjusted, resulting in a relatively weak dispersion effect. This can lead to a weak bond between the alumina particles and the copper-tin powder, which can affect the final alloy properties. Furthermore, the interface between the reinforcing phase and the matrix may be weak, limiting the alloy's mechanical properties and wear resistance. The internal oxidation method involves introducing aluminum / alumina particles into a copper-tin alloy and then heat-treating them at high temperatures. This allows the aluminum / alumina particles to undergo an internal oxidation reaction within the alloy matrix, forming a dispersed phase. This method excels in terms of dispersion. Because the alumina particles are uniformly distributed throughout the alloy, it can achieve excellent strengthening. Furthermore, the size and distribution of the alumina particles can be adjusted by controlling process parameters to meet diverse performance requirements. However, this method is complex, requiring multiple heat treatment steps at high temperatures, making it difficult to control process parameters. The production cycle is long, potentially increasing production costs. Furthermore, impurities may be introduced during the preparation process, affecting the purity and performance of the alloy. Summary of the Invention

[0005] In order to solve the problems of poor dispersion effect of existing alumina dispersion strengthened copper-tin powder, complicated process flow, long preparation cycle, and uncontrollable amount of alumina addition, the present invention provides a dispersion strengthened copper-tin alloy, as well as a preparation method and application of the copper-tin alloy.

[0006] The main objectives of the present invention are:

[0007] 1. Achieve better dispersion effect, so that the alumina particles and the copper-tin matrix are closely combined with each other;

[0008] 2. Obtain alloys with higher strength and wear resistance;

[0009] 3. Flexibly control the content of alumina.

[0010] A method for preparing a dispersion-strengthened copper-tin alloy.

[0011] The method comprises:

[0012] 1) preparing an aluminum-containing aqueous solution, and placing copper oxide in the aluminum-containing aqueous solution, mixing and continuously stirring until a paste is formed; 2) oxidizing and calcining the paste to obtain a copper oxide-aluminum mixture;

[0013] 3) The copper oxide and aluminum mixture is subjected to reduction calcination to obtain aluminum oxide dispersed copper alloy powder, and the aluminum oxide dispersed copper alloy powder is mixed with tin powder and then subjected to diffusion alloying treatment to obtain a dispersion strengthened copper-tin alloy.

[0014] As a preference,

[0015] The aluminum-containing aqueous solution in step 1) is an aluminum nitrate aqueous solution;

[0016] Step 1) the copper oxide has a purity of ≥99.9 wt %;

[0017] In step 1), the atomic ratio of aluminum in the aluminum-containing aqueous solution to copper in copper oxide is (0.016-0.048):1.

[0018] As a preference,

[0019] In step 2), the oxidation calcination process controls the calcination temperature to be 900-1000° C. and the calcination time to be 2-4 hours.

[0020] As a preference,

[0021] Step 3) The reduction calcination is carried out in a hydrogen atmosphere at a calcination temperature of 650-700° C. for 3-6 hours.

[0022] As a preference,

[0023] The atomic ratio of tin in the tin powder in step 3) to copper in the copper oxide used in step 1) is (0.5-1.8):(8.2-9.5).

[0024] As a preference,

[0025] Step 3) The diffusion alloying treatment is carried out in a hydrogen atmosphere at a treatment temperature of 450-500° C. for 3-6 hours.

[0026] A dispersion strengthened copper-tin alloy.

[0027] Application of a dispersion-strengthened copper-tin alloy,

[0028] The dispersion-strengthened copper-tin alloy is used for preparing oil-containing bearings.

[0029] The present invention uses alumina dispersion-strengthened copper particles prepared by a chemical decomposition method as raw material, achieving highly uniform dispersion: by performing a decomposition reaction at high temperature, aluminum nitrate nonahydrate solution can form a thin layer of aluminum oxide on the surface of the copper oxide particles, thereby achieving dispersion strengthening of the aluminum oxide. This method can evenly disperse the aluminum oxide in the copper matrix, improving the strength and hardness of the material. Alumina is a ceramic material with high hardness and good strengthening effects. The aluminum oxide prepared by the decomposition reaction is dispersed in the copper matrix, which can significantly improve the mechanical properties and wear resistance of the copper. The preparation process using aluminum nitrate nonahydrate solution and copper oxide to carry out a decomposition reaction at high temperature is relatively simple, does not require complex equipment and process conditions, and can be completed under conventional preparation conditions. Compared with other strengthening methods, the cost of preparing aluminum oxide dispersion-strengthened copper by decomposing aluminum nitrate nonahydrate solution and copper oxide is relatively low and can be produced on a large scale. By adjusting parameters such as the ratio of aluminum nitrate nonahydrate solution and copper oxide, reaction temperature, and time, the aluminum oxide content and dispersion can be controlled, thereby adjusting the material's properties to meet the needs of different applications.

[0030] As for the three-stage heat treatment process:

[0031] The decomposition temperature will affect the morphology of alumina in alumina dispersion strengthened copper particles. If the decomposition temperature is too high, the alumina dispersion strengthened copper particles will become compacted, increasing the difficulty of crushing and reducing the yield of fine powder. If the decomposition temperature is too low, α-Al2O3 will not be generated, thereby reducing the wear resistance of the alumina dispersion strengthened copper-tin alloy.

[0032] The reduction temperature will affect the performance of alumina dispersion strengthened copper-tin alloy powder. If the reduction temperature is too high, the fine powder will agglomerate severely during the reduction process, resulting in larger particle size and increased bulk density of the alumina dispersion strengthened copper-tin alloy powder. If the reduction temperature is too low, the degree of reduction of the fine powder will be low, and tin will be easily oxidized during the alloying process, which will lead to an increase in the final oxygen content of the powder. On the other hand, if the reduction temperature is too low, the fine powder will have poor agglomeration effect, be too active, and be easily oxidized in the air.

[0033] The temperature of the diffusion alloying treatment will affect the performance of the alumina dispersion-strengthened copper-tin alloy powder. If the reduction temperature is too high, the deagglomeration effect of tin in the diffusion alloying process will be weakened, and the particle size of the alumina dispersion-strengthened copper-tin alloy powder will become larger, failing to achieve the technical effect of the present invention. If the temperature of the diffusion alloying treatment is too low, the reduction effect at this stage will be reduced, and the oxygen content of the powder will increase. In addition to the above key cores, many operational details of the present invention will also have a significant impact on the performance of the product. Such as the concentration of the aluminum-containing aqueous solution, and the preliminary mixing method of the aluminum salt and copper oxide. Although the essence of the two is mixing, for the doping and dispersion strengthening of aluminum oxide in the copper-tin alloy, it is necessary to construct a specific micro-coordination and microstructure to eliminate the performance impact caused by the ambient temperature during its working process due to the difference in thermal expansion coefficients between the copper-tin alloy and alumina. Among them, the first is the concentration of the aluminum-containing aqueous solution. The present invention needs to relatively strictly control the mass concentration of aluminum elements in the aluminum-containing aqueous solution, thereby controlling the aluminum ion concentration. The present invention requires that the aluminum concentration in the aluminum-containing aqueous solution is 0.5-1.5wt%, because the aluminum-containing aqueous solution tends to be acidic due to the presence of hydrolysis. In this case, the copper oxide surface is positively charged. When the aluminum concentration is too low, effective adsorption cannot be formed, because the copper oxide surface will expose oxygen vacancies, hydroxyl groups and other sites due to the acidic conditions. Aluminum ions may react with these sites or undergo chemical adsorption to form coordination bonds or chemical bonds, thereby fixing aluminum ions on the copper oxide surface. If the concentration is too low, the adsorption rate will drop significantly, and local enrichment and uneven distribution will occur. At the same time, under appropriate low concentration conditions, aluminum ions are hydrated in the solution to form hydrated aluminum ions, such as Al(H2O)6 3+ The presence of water molecules will affect the electrostatic interaction between aluminum ions and the copper oxide surface, reducing the effect of electrostatic repulsion. At the same time, water molecules can also act as bridging ligands to participate in the coordination reaction between aluminum ions and the copper oxide surface, and achieve the distribution and coordination of copper oxide and aluminum ions under multiple effects. When the aluminum concentration is too high, it is easy for aluminum ions to produce aluminum hydroxide precipitation due to hydrolysis, which destroys or shields the active adsorption sites. At the same time, precipitation leads to the formation of physical mixing, and the tightness of the mixing is significantly reduced, which ultimately leads to a sharp increase in the unevenness of the copper-aluminum distribution. In addition, due to the increase in the viscosity of the solution system under high concentrations, copper oxide is prone to sedimentation or agglomeration before stirring and removing water. In addition, copper and aluminum are only simply physically mixed, which further increases the uneven distribution of copper and aluminum, and the performance and controllability of the target product are significantly reduced. Therefore, appropriate viscosity is very important.

[0034] The present invention adopts a solid-liquid mixing and pasting method. As mentioned above, the purpose is to achieve non-physical mixing and ensure the uniformity of copper and aluminum distribution, so that aluminum is effectively distributed in the form of a lattice on the surface of copper oxide particles rather than covered or enriched and deposited. Compared with conventional mechanical mixing methods, although mechanical mixing such as ball milling can also effectively break up agglomerations, so that the two powders can be highly uniformly mixed at the particle scale and uniform distribution of copper and aluminum can be achieved, the difference is that the mixing uniformity limit of the mechanical ball milling mixing method is the size of a single particle. For example, if one particle is Al salt and the adjacent particle is pure CuO, the aluminum and copper elements are separated at the sub-particle scale (i.e., inside the particle). Even if ball milling may refine the particles and increase the contact area, it is still difficult to achieve the atomic / molecular level lattice deposition and attachment effect on the surface of a single particle as in the solution method. At the same time, when the solution method of the present invention is mixed and sintered, the aluminum oxide nanoparticles generated by the decomposition of aluminum nitrate directly contact the surface of the single particle. The surface contact of copper oxide particles, or the intertwined growth of aluminum oxide and copper oxide grains at the nanoscale, greatly shortens the material diffusion path, making it easier to form a two-phase nanocomposite or fine dispersion structure with small and evenly distributed grains and a large phase interface area. Traditional mechanical mixing methods require diffusion from one particle through the interface to the interior of the adjacent particle in order to react or to cause the grains to grow and intertwine. The path length is at least on the order of the particle radius, making it difficult to obtain a nanocomposite structure. Even if the initial powder is very fine, the grains tend to grow during sintering, making it even more difficult to maintain the nanoscale structure. At the sub-particle scale, the two phases are separated, easily forming larger single-phase regions, which leads to microscopic separation of copper and aluminum. Under normal circumstances, the impact may not be significant, but when encountering high temperatures or large temperature fluctuations, it will lead to polarized changes in performance.

[0035] In addition, due to the particularity of the copper-aluminum composite of the present invention, it is also crucial to finally stir it to a paste-like state. The paste referred to in the present invention is a paste product with a viscosity of about 25,000 to 50,000 cP obtained by stirring at a speed of 50 to 70 rpm. In this case, the product obtained is essentially similar to a high-solid content, high-viscosity non-Newtonian fluid. During this process, the CuO particles form a three-dimensional network structure, which hinders flow. The high viscosity prevents the denser CuO particles from settling, maintaining a uniform distribution of aluminum / copper elements. At the same time, during the continuous evaporation of water, the paste structure locks the Al 3+ The lattice is evenly distributed on the surface of CuO particles, and the shear stirring forces the CuO particles to fully contact with the aluminum salt solution, strengthening ion adsorption and facilitating subsequent sintering mass transfer. If the stirring is stopped too early and sintering is carried out, the CuO particles may settle and stratify, resulting in a macroscopic phase separation of CuO-rich at the bottom and Al-rich at the top, destroying the uniformity and the unabsorbed Al 3+As water molecules migrate, they accumulate and crystallize in the upper layer during drying, resulting in Al2O3-rich and CuO-rich regions in the sintered product. However, excessive stirring can damage the adsorption layer on the surface of the CuO particles due to high shear forces, causing some aluminum ions to desorb. Local oversaturation triggers in-situ crystallization of aluminum salts, forming hard agglomerates. After sintering, the aluminum salt agglomerate areas form large sintered agglomerates, hindering densification and causing severe compositional segregation. Furthermore, local density differences lead to inconsistent sintering shrinkage, causing warping and severely affecting performance. Therefore, in multiple horizontal comparison tests, a paste product with a viscosity of 800-1200 cP at a rotational speed of approximately 60 rpm achieved the best results. Secondly, due to the particularity and strict control of the copper-aluminum mixing method of the present invention, the copper-tin ratio in the copper-tin alloy of the present invention can be further expanded. In addition to being used for the common Cu90Sn10 copper-tin alloy, it can also be extremely specially used for special ratio copper-tin alloy systems such as CuSn15 with a tin content of 12% or even more than 15%. This is because the thermal expansion coefficient of the common Cu90Sn10 copper-tin alloy is relatively small compared with that of alumina, but the thermal expansion coefficient of high-tin copper-tin alloys such as the CuSn15 series (such as CuSn15Zn3) and alumina is greatly different, which makes the existing methods unsuitable for alumina dispersion strengthening of high-tin copper-tin alloys such as CuSn15. However, high-tin copper-tin alloys such as CuSn15 are a basic system with generally excellent comprehensive performance. Therefore, by constructing a unique copper-aluminum combination fixation, the subsequent sintering process can make the aluminum oxide more effectively distributed in the interior and surface of the copper-tin alloy in the form of a woven mesh, forming an anti-oxidation protective film layer on the outside while forming a woven mesh skeleton on the inside, greatly enhancing the performance while reducing the defects of poor heat resistance (and thermal shock) due to the difference in thermal expansion coefficient.

[0036] The beneficial effects of the present invention are:

[0037] The present invention realizes the microscopic level bonding of copper and aluminum through a special process, and based on this, can effectively and flexibly construct a copper-tin alloy, ensuring that the copper-tin alloy has good physical and chemical properties. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only a portion of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0039] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0040] Unless otherwise specified, the aluminum-containing aqueous solutions prepared in the embodiments of the present invention are all aluminum nitrate nonahydrate aqueous solutions with an aluminum concentration of 1.0 wt %. Unless otherwise specified, the copper oxide used in the embodiments of the present invention are all electronic-grade copper oxide with a purity of ≥99.9 wt %.

[0041] Example 1

[0042] A dispersion-strengthened copper-tin alloy, the specific preparation method of which is as follows:

[0043] 1) preparing an aluminum-containing aqueous solution, and placing copper oxide in the aluminum-containing aqueous solution and mixing, wherein the atomic ratio of aluminum in the aluminum-containing aqueous solution to copper in the copper oxide is 0.032:1, and continuously stirring at 60 rpm until the viscosity reaches approximately 37,500 cP to obtain a paste;

[0044] 2) oxidatively calcining the paste at 950° C. for 3 h in an air atmosphere to obtain a copper-aluminum oxide mixture;

[0045] 3) The copper oxide and aluminum mixture is subjected to reduction calcination at 680° C. for 4.5 hours in a hydrogen atmosphere, crushed to 80 mesh to obtain an aluminum oxide dispersed copper alloy powder, and the aluminum oxide dispersed copper alloy powder is mixed with tin powder. During the mixing, the atomic ratio of tin in the tin powder in step 3) to copper in the copper oxide used in step 1) is controlled to be 1:9. Diffusion alloying treatment is performed at 470° C. for 4.5 hours in a hydrogen atmosphere to obtain a dispersion-strengthened copper-tin alloy.

[0046] The performance of the product in this example was characterized. The obtained product was crushed into 120 mesh fine powder and prepared into alloy bearings by conventional powder metallurgy. The performance of the alloy bearings was characterized. The characterization specifically includes tensile strength characterization, surface hardness characterization and wear resistance characterization. The characterization environment is divided into room temperature environment (22°C), high temperature environment (160°C) and thermal shock environment (-10~160°C cycle, temperature change rate is ±10°C / min, with 20°C as the starting temperature, first heating to 160°C and then cooling to -10°C, then heating to 160°C for cycling, reaching 160°C and -10°C 50 times respectively before returning to room temperature 22°C). After the sample completes the thermal shock cycle in the thermal shock environment, the performance is characterized at room temperature (22°C).

[0047] The characterization results are shown in the following table.

[0048]

[0049]

[0050] It can be clearly seen from the above characterization results that the dispersion-strengthened copper-tin alloy of the present invention has very excellent performance. When used to prepare bearings, it can enable the bearings to have excellent basic mechanical properties, and have very excellent high temperature resistance and thermal shock resistance, and improved resistance to changes in ambient temperature.

[0051] The same performance characterization results of bearings prepared by powder metallurgy using conventional Cu90Sn10 alloy powder (120 mesh) are as follows.

[0052] Tensile strength (MPa) Surface hardness (HB) <![CDATA[Wear rate (mm 3 / N·m)]]> Room temperature environment 312 98 <![CDATA[≤5×10 -6 ]]> High temperature environment 237 73 <![CDATA[6.2×10 -6 ]]> Thermal shock environment 261 81 <![CDATA[5.9×10 -6 ]]>

[0053] It can be clearly seen from the comparison that the dispersion-strengthened copper-tin alloy of the present invention has significantly optimized mechanical properties in all aspects compared to copper-tin alloys of similar systems, and has an absolute advantage in heat resistance and thermal shock resistance.

[0054] Example 2

[0055] A dispersion-strengthened copper-tin alloy, the specific preparation method of which is as follows:

[0056] 1) preparing an aluminum-containing aqueous solution, and placing copper oxide in the aluminum-containing aqueous solution and mixing, wherein the atomic ratio of aluminum in the aluminum-containing aqueous solution to copper in the copper oxide is 0.016:1, and continuously stirring at a speed of 60 rpm until the viscosity reaches approximately 37,500 cP to obtain a paste;

[0057] 2) oxidatively calcining the paste at 1000° C. for 2 h in an air atmosphere to obtain a copper oxide-aluminum mixture;

[0058] 3) The copper oxide and aluminum mixture is subjected to reduction calcination at 650° C. for 6 hours in a hydrogen atmosphere, crushed to 80 mesh to obtain an aluminum oxide dispersed copper alloy powder, and the aluminum oxide dispersed copper alloy powder is mixed with tin powder. During the mixing, the atomic ratio of tin in the tin powder in step 3) to copper in the copper oxide used in step 1) is controlled to be 1:9. Diffusion alloying treatment is performed at 450° C. for 6 hours in a hydrogen atmosphere to obtain a dispersion-strengthened copper-tin alloy.

[0059] The product of this example was subjected to the same performance characterization test as in Example 1, and the characterization results are shown in the following table.

[0060] Tensile strength (MPa) Surface hardness (HB) <![CDATA[Wear rate (mm 3 / N·m)]]> Room temperature environment 359 129 <![CDATA[≤2×10 -6 ]]> High temperature environment 356 129 <![CDATA[≤2×10 -6 ]]> Thermal shock environment 354 127 <![CDATA[≤3×10 -6 ]]>

[0061] Example 3

[0062] A dispersion-strengthened copper-tin alloy, the specific preparation method of which is as follows:

[0063] 1) preparing an aluminum-containing aqueous solution, and placing copper oxide in the aluminum-containing aqueous solution and mixing, wherein the atomic ratio of aluminum in the aluminum-containing aqueous solution to copper in the copper oxide is 0.048:1, and continuously stirring at a speed of 60 rpm until the viscosity reaches approximately 37,500 cP to obtain a paste;

[0064] 2) oxidatively calcining the paste at 900° C. for 4 h in an air atmosphere to obtain a copper-aluminum oxide mixture;

[0065] 3) The copper oxide and aluminum mixture is reduction-calcined at 700° C. for 3 h in a hydrogen atmosphere, crushed to 80 mesh to obtain an aluminum oxide-dispersed copper alloy powder, and the aluminum oxide-dispersed copper alloy powder is mixed with tin powder. During the mixing, the atomic ratio of tin in the tin powder in step 3) to copper in the copper oxide used in step 1) is controlled to be 1:9. Diffusion alloying treatment is performed at 500° C. for 3 h in a hydrogen atmosphere to obtain a dispersion-strengthened copper-tin alloy.

[0066] The product of this example was subjected to the same performance characterization test as in Example 1, and the characterization results are shown in the following table.

[0067] Tensile strength (MPa) Surface hardness (HB) <![CDATA[Wear rate (mm 3 / N·m)]]> Room temperature environment 374 132 <![CDATA[≤2×10 -6 ]]> High temperature environment 372 131 <![CDATA[≤2×10 -6 ]]> Thermal shock environment 371 130 <![CDATA[≤2×10 -6 ]]>

[0068] It can be seen from the characterization results of Examples 1 to 3 above that the dispersion-strengthened copper-tin alloy of the present invention has stable and excellent performance, and has significant performance advantages over conventional copper-tin alloys.

[0069] Example 4

[0070] A dispersion-strengthened copper-tin alloy, the specific preparation method of which is as follows:

[0071] 1) preparing an aluminum-containing aqueous solution, and placing copper oxide in the aluminum-containing aqueous solution and mixing, wherein the atomic ratio of aluminum in the aluminum-containing aqueous solution to copper in the copper oxide is 0.032:1, and continuously stirring at 60 rpm until the viscosity reaches approximately 37,500 cP to obtain a paste;

[0072] 2) oxidatively calcining the paste at 950° C. for 3 h in an air atmosphere to obtain a copper-aluminum oxide mixture;

[0073] 3) The copper oxide and aluminum mixture is reduction-calcined at 680° C. for 4.5 hours in a hydrogen atmosphere, crushed to 80 mesh to obtain an aluminum oxide-dispersed copper alloy powder, and the aluminum oxide-dispersed copper alloy powder is mixed with tin powder and zinc powder. During the mixing, the atomic ratio of tin in the tin powder in step 3), zinc in the zinc powder, and copper in the copper oxide used in step 1) is controlled to be 1.5:0.3:8.2. Diffusion alloying treatment is performed at 470° C. for 4.5 hours in a hydrogen atmosphere to obtain a dispersion-strengthened copper-tin alloy.

[0074] The product of this example was subjected to the same performance characterization test as in Example 1, and the characterization results are shown in the following table.

[0075]

[0076]

[0077] Compared to the Cu90Sn10 base system, the CuSn15Zn3 base system has its own advantages and disadvantages. However, this example demonstrates that the preparation method of the present invention can also be used to strengthen copper-tin alloy systems with ultra-high tin content without causing thermal shock failure. In contrast, this example also uses mechanical ball milling to mix aluminum oxide and copper oxide. The specific preparation process is as follows:

[0078] 1) Weighing an amount of aluminum oxide equivalent to the aluminum in the aluminum-containing aqueous solution, directly mixing the aluminum oxide with copper oxide and mechanically ball milling for 3 hours to obtain a mixed powder;

[0079] 2) oxidatively calcining the mixed powder at 950° C. for 3 h in an air atmosphere to obtain a copper-aluminum oxide mixture;

[0080] 3) The copper oxide and aluminum mixture is reduction-calcined at 680° C. for 4.5 hours in a hydrogen atmosphere, crushed to 80 mesh to obtain an aluminum oxide-dispersed copper alloy powder, and the aluminum oxide-dispersed copper alloy powder is mixed with tin powder and zinc powder. During the mixing, the atomic ratio of tin in the tin powder in step 3), zinc in the zinc powder, and copper in the copper oxide used in step 1) is controlled to be 1.5:0.3:8.2. Diffusion alloying treatment is performed at 470° C. for 4.5 hours in a hydrogen atmosphere to obtain a dispersion-strengthened copper-tin alloy.

[0081] The prepared dispersion-strengthened copper-tin alloy (mechanically mixed sample) was subjected to the same performance characterization test as in Example 1. The characterization results are shown in the following table.

[0082] Tensile strength (MPa) Surface hardness (HB) <![CDATA[Wear rate (mm 3 / N·m)]]> Room temperature environment 381 126 <![CDATA[5.1×10 -6 ]]> High temperature environment 351 127 <![CDATA[7.2×10 -6 ]]> Thermal shock environment 319 107 <![CDATA[13.2×10 -6 ]]>

[0083] The above characterization results clearly demonstrate that mechanically adding alumina does not effectively improve the heat resistance and thermal shock resistance of copper-tin alloys, and the overall strengthening effect is far inferior to that of the dispersion-strengthened copper-tin alloy produced by the method of the present invention. In particular, the significant difference in thermal expansion coefficients between alumina and the copper-tin alloy base system can lead to a sharp decline in sample performance during thermal shock or in high-temperature environments.

[0084] Comparative Example 1

[0085] A dispersion-strengthened copper-tin alloy, the specific preparation method of which is as follows:

[0086] 1) preparing an aluminum-containing aqueous solution, and placing copper oxide in the aluminum-containing aqueous solution and mixing, wherein the atomic ratio of aluminum in the aluminum-containing aqueous solution to copper in the copper oxide is 0.032:1, and continuously stirring at 60 rpm until the viscosity reaches approximately 37,500 cP to obtain a paste;

[0087] 2) oxidatively calcining the paste at 950° C. for 3 h in an air atmosphere to obtain a copper-aluminum oxide mixture;

[0088] 3) The copper oxide and aluminum mixture is subjected to reduction calcination at 680° C. for 4.5 hours in a hydrogen atmosphere, crushed to 80 mesh to obtain an aluminum oxide dispersed copper alloy powder, and the aluminum oxide dispersed copper alloy powder is mixed with tin powder. During the mixing, the atomic ratio of tin in the tin powder in step 3) to copper in the copper oxide used in step 1) is controlled to be 1:9. Diffusion alloying treatment is performed at 470° C. for 4.5 hours in a hydrogen atmosphere to obtain a dispersion-strengthened copper-tin alloy.

[0089] In this example, samples were prepared using aluminum-containing aqueous solutions of different concentrations, and the same performance characterization tests as in Example 1 were performed. The characterization results are shown in the following table.

[0090]

[0091] The above characterization results show that aluminum-containing aqueous solutions of varying concentrations exhibit significantly different trends when mixed with copper oxide to form a paste. When the concentration of the aluminum-containing aqueous solution is too low, the performance enhancement is far less than expected, and segregation is easily produced. Segregation can lead to significant performance fluctuations in thermal shock environments. However, when the concentration of the aluminum-containing aqueous solution is too high, the performance trends of the solution at room temperature, high temperature, and thermal shock environments are similar to those of the control sample described in Example 4, indicating that high-concentration aluminum-containing aqueous solutions may lead to a tendency for the final mixing of aluminum oxide and copper oxide to shift to physical mixing. Therefore, it can be seen that the concentration of the aluminum-containing aqueous solution also needs to be relatively effectively controlled.

[0092] Comparative Example 2

[0093] A dispersion-strengthened copper-tin alloy, the specific preparation method of which is as follows:

[0094] 1) preparing an aluminum-containing aqueous solution, and placing copper oxide in the aluminum-containing aqueous solution and mixing, wherein the atomic ratio of aluminum in the aluminum-containing aqueous solution to copper in the copper oxide is 0.032:1, and continuously stirring the paste at a speed of 60 rpm;

[0095] 2) oxidatively calcining the paste at 950° C. for 3 h in an air atmosphere to obtain a copper-aluminum oxide mixture;

[0096] 3) The copper oxide and aluminum mixture is subjected to reduction calcination at 680° C. for 4.5 hours in a hydrogen atmosphere, crushed to 80 mesh to obtain an aluminum oxide dispersed copper alloy powder, and the aluminum oxide dispersed copper alloy powder is mixed with tin powder. During the mixing, the atomic ratio of tin in the tin powder in step 3) to copper in the copper oxide used in step 1) is controlled to be 1:9. Diffusion alloying treatment is performed at 470° C. for 4.5 hours in a hydrogen atmosphere to obtain a dispersion-strengthened copper-tin alloy.

[0097] In this example, samples were prepared using pastes of different viscosities, and the same performance characterization tests as in Example 1 were performed. The characterization results are shown in the following table.

[0098]

[0099] The above characterization results indicate that the viscosity of the paste, which effectively represents the relative distribution of the aluminum compound and copper oxide at the end of mixing, significantly impacts the product's performance. This suggests that one of the key elements of the present invention lies in strictly controlling the effective bonding and distribution of aluminum and copper within the paste, as well as their binding state, ultimately achieving molecular / atomic-level bonding and dispersion, and optimizing product performance.

Claims

1. A method for preparing a dispersion-strengthened copper-tin alloy, characterized in that: The method comprises: 1) preparing an aluminum-containing aqueous solution, and placing copper oxide in the aluminum-containing aqueous solution and mixing and continuously stirring until a paste is formed; 2) oxidizing and calcining the paste to obtain a copper oxide and aluminum oxide mixture; 3) The copper oxide and aluminum mixture is subjected to reduction calcination to obtain aluminum oxide dispersed copper alloy powder, and the aluminum oxide dispersed copper alloy powder is mixed with tin powder and then subjected to diffusion alloying treatment to obtain a dispersion strengthened copper-tin alloy.

2. The method for preparing a dispersion-strengthened copper-tin alloy according to claim 1, wherein: Step 1) the aluminum-containing aqueous solution is an aluminum nitrate aqueous solution; Step 1) the copper oxide purity is ≥99.9 wt%; In step 1), the atomic ratio of aluminum in the aluminum-containing aqueous solution to copper in copper oxide is (0.016-0.048):

1.

3. The method for preparing a dispersion-strengthened copper-tin alloy according to claim 1, wherein: In step 2), the oxidation calcination process is performed at a temperature of 900 to 1000° C. and a calcination time of 2 to 4 h.

4. The method for preparing a dispersion-strengthened copper-tin alloy according to claim 1, wherein: Step 3) The reduction calcination is carried out in a hydrogen atmosphere at a temperature of 650-700° C. for 3-6 hours.

5. The method for preparing a dispersion-strengthened copper-tin alloy according to claim 1, wherein: The atomic ratio of tin in the tin powder in step 3) to copper in the copper oxide used in step 1) is (0.5-1.8): (8.2-9.5).

6. The method for preparing a dispersion-strengthened copper-tin alloy according to claim 1 or 5, characterized in that: Step 3) The diffusion alloying treatment is carried out in a hydrogen atmosphere at a treatment temperature of 450-500° C. for 3-6 hours.

7. A dispersion strengthened copper-tin alloy prepared by the method according to any one of claims 1 to 6.

8. A use of the dispersion-strengthened copper-tin alloy according to claim 7, characterized in that: The dispersion-strengthened copper-tin alloy is used for preparing oil-containing bearings.

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