Phosphorus copper ball and preparation method thereof

Abstract

The invention relates to the technical field of metallurgy, and provides a phosphor copper ball and a preparation method thereof.The preparation raw materials of the phosphor copper ball comprise the following components: 0.040-0.065 wt% of P, 0.040-0.065 wt% of S, 0.010-0.020 wt% of P, 0.010- The Cu accounts for 99.935 wt% to 99.960 wt%. According to the preparation method, a very good deoxidation effect can be achieved through 0.040-0.065 wt% of P, so that less oxide is generated during preparation of the phosphor copper ball, and meanwhile, formation of brittle phases can be reduced, so that the conductivity of the phosphor copper ball is improved. When 0.040-0.065 wt% of P and 99.935-99.960 wt% of Cu are smelted, the generated Cu3P can be uniformly dispersed in a copper matrix, so that the continuity of the copper matrix is improved, and a foundation can be laid for a subsequent preparation process.

Description

Technical Field

[0001] The present application belongs to the field of metallurgy technology, and in particular relates to a phosphor bronze ball and a preparation method thereof. Background Art

[0002] With the rapid development of electronic technology, the electronics industry's demand for the production of various circuit boards has increased significantly. Copper, a key raw material for electroplating anodes, has seen a significant increase in demand. Phosphor copper balls, essential anode materials for precision PCBs, are widely used in electronic circuit boards, particularly high-precision multilayer circuit boards. They are an essential component of electronic products and rely on phosphor copper balls as a fundamental raw material for circuit board manufacturing. The addition of phosphorus effectively slows the precipitation rate of copper atoms and reduces the formation of cuprous ions. Therefore, compared to other copper alloys, phosphor copper balls exhibit a significant catalytic effect during electrolysis, significantly accelerating the oxidation of cuprous ions and forming a black phosphorus film. This accelerates slow reactions and significantly reduces the accumulation of cuprous ions in the bath. Furthermore, the phosphorus film on the anode surface prevents cuprous ions from entering the bath, promoting their oxidation and reducing the amount of cuprous ions entering the bath, thereby significantly improving anode utilization.

[0003] In the related art, conventional cast phosphor copper balls are particularly popular as electroplating anodes. These conventional cast phosphor copper anodes exhibit numerous macroscopic defects, while their microscopic grain morphology exhibits typical cast microstructure, characterized by coarse columnar or dendritic grains. These numerous macroscopic and microscopic defects in cast phosphor copper balls lead to numerous problems during the electroplating process. These include the generation of a small amount of copper powder on the anode surface, the formation of an uneven, thick, and easily detached black film on the anode surface, and poor adhesion to the anode surface. Furthermore, after prolonged electroplating, a significant amount of black anode mud appears in the bath solution, and the phosphor copper anode surface develops a large, uneven, and rough surface, further impacting the quality of the electroplated layer. Statistics indicate that my country currently ranks second in the world in printed circuit board production, paving the way for the growing demand for phosphor copper balls. Therefore, finding the optimal production process to meet the current demand for high-end PCBs holds great promise. Summary of the Invention

[0004] The purpose of this application is to provide a phosphor copper ball and a preparation method thereof, which can improve the electroplating quality of the phosphor copper ball.

[0005] To achieve the above application objectives, the technical solutions adopted in this application are as follows: In a first aspect, the present application provides a phosphor copper ball, wherein the raw materials for preparing the phosphor copper ball include the following components: P, 0.040~0.065wt%; Cu, 99.935~99.960wt%.

[0006] The phosphor-copper spheres provided herein, with 0.040-0.065 wt% P, offer a strong deoxidizing effect, reducing oxide production during sphere preparation and reducing the formation of brittle phases, thereby improving their electrical conductivity. During smelting, the 0.040-0.065 wt% P and 99.935-99.960 wt% Cu allow the generated Cu3P to be evenly dispersed within the copper matrix, improving the matrix's continuity and paving the way for subsequent fabrication processes.

[0007] In a second aspect, the present application provides a method for preparing a phosphor copper ball, the method comprising: Providing the components of the phosphor-copper ball according to any one of the first aspects, and smelting the components to obtain a phosphor-copper melt; Drawing the phosphor copper melt to obtain a phosphor copper cast rod; extruding the phosphor bronze cast rod to obtain a phosphor bronze extruded rod; annealing the phosphor copper extruded rod to obtain a phosphor copper annealed rod; Upsetting the phosphor copper annealed rod to obtain a semi-finished phosphor copper ball; polishing the semi-finished phosphor bronze balls to obtain polished phosphor bronze balls; The polished phosphor bronze balls are electroplated to obtain phosphor bronze balls.

[0008] The present application provides a method for preparing phosphor copper balls, which prepares phosphor copper balls by adopting a casting-extrusion-annealing-upsetting-polishing-electroplating process. The smelting and pulling processes reduce the oxygen content in phosphor copper and accurately control the P content; the annealing process can refine the grains and restore plasticity; the phosphor copper balls produced by the upsetting process have a smooth surface, refined grains, a tighter grain distribution, and the grains are mainly equiaxed crystals with a small number of columnar crystals. The structure is fine, the composition is evenly distributed, and the hardness is higher. The black film after phosphor copper anode electroplating is uniform, the formed black film is thin and dense, the copper ball has a smooth appearance, and the yield of anode mud generated during the electroplating process is low. As a result, the prepared phosphor copper balls can meet the demand for high-precision and high-reliability conductive materials in high-end fields.

[0009] In some embodiments, smelting the components to obtain a phosphorus copper melt comprises: P and part of Cu are mixed to form a Cu-P intermediate master alloy; wherein the P content in the Cu-P intermediate master alloy is 5%; The remaining Cu is placed in a smelting device and heated to obtain a copper melt; The Cu-P intermediate master alloy is added to the copper melt and heated and smelted, and then the heat is kept after smelting to obtain a phosphorus copper melt.

[0010] In some embodiments, the step of placing the remaining Cu into a smelting device for heating and smelting to obtain a copper melt comprises: Put the remaining copper into the smelting device and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 -1 Pa, filled with argon to a pressure of 6×10 4 Pa~8×10 4 Pa and then heated to 1100 ° C for smelting to obtain copper melt.

[0011] In some embodiments, the step of adding a Cu-P intermediate master alloy to the copper melt, heating and smelting the copper melt, and then keeping the melt warm to obtain a phosphorus copper melt comprises: A Cu-P intermediate master alloy is added to the copper melt, and the temperature is continuously raised to 1200-1250° C. and kept warm for 5 minutes. The melt is introduced into a heat preservation device and the temperature is adjusted to 1100-1150° C. to obtain a phosphorus copper melt.

[0012] In some embodiments, in the pulling of the phosphor copper melt to obtain a phosphor copper cast rod, the pulling speed is 0.20-0.30 m / min, the stop time is 100-300 ms, the reverse push distance is 0.05-0.2 mm, the pulling frequency is 20-40 Hz, and the diameter of the obtained phosphor copper cast rod is 20 mm.

[0013] In some embodiments, in the step of extruding the phosphor copper cast rod to obtain the phosphor copper extruded rod, the extrusion rate is 10 mm / s, and the diameter of the phosphor copper extruded rod is 12 mm.

[0014] In some embodiments, in the step of annealing the phosphor copper extruded rod to obtain the phosphor copper annealed rod, the annealing temperature is 450-550° C., and the annealing time is 1-2 hours.

[0015] In some embodiments, in the process of upsetting the phosphor copper annealing rod to obtain a semi-finished phosphor copper ball, the upsetting slider stroke is 146 mm, the upsetting diameter is 350 mm, the pressure is 6 MPa, and the diameter of the semi-finished phosphor copper ball is 25 mm.

[0016] In some embodiments, in polishing the semi-finished phosphor copper ball to obtain the polished phosphor copper ball, the surface roughness of the polished phosphor copper ball is ≤0.8 μm; And / or, electroplating the polished phosphor bronze balls to obtain phosphor bronze balls comprises: The polished phosphor copper balls were electroplated using a sulfate copper plating solution at a current density of 1.3 A / dm 2 , the electroplating time is 4h, and the electroplating temperature is 40℃.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a schematic flow chart of the method for preparing phosphorus copper balls provided in an embodiment of the present application; Figure 2 1 is a schematic flow chart of step S100 of the method for preparing phosphorus copper balls provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0021] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0022] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or plural.

[0023] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0024] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0025] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally increased or decreased according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the masses described in the examples of this application may be mass units known in the chemical industry, such as μg, mg, g, and kg.

[0026] The terms "first" and "second" are used solely for descriptive purposes, to distinguish objects, such as substances, from one another. They should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. For example, a first XX could also be referred to as a second XX, and similarly, a second XX could also be referred to as a first XX, without departing from the scope of the embodiments of this application. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0027] In the related art, conventional cast phosphor copper balls are particularly popular as electroplating anodes. These conventional cast phosphor copper anodes exhibit numerous macroscopic defects, while their microscopic grain morphology exhibits typical cast microstructure, characterized by coarse columnar or dendritic grains. These numerous macroscopic and microscopic defects in cast phosphor copper balls lead to numerous problems during the electroplating process. These include the generation of a small amount of copper powder on the anode surface, the formation of an uneven, thick, and easily detached black film on the anode surface, and poor adhesion to the anode surface. Furthermore, after prolonged electroplating, a significant amount of black anode mud appears in the bath solution, and the phosphor copper anode surface develops a large, uneven, and rough surface, further impacting the quality of the electroplated layer. Statistics indicate that my country currently ranks second in the world in printed circuit board production, paving the way for the growing demand for phosphor copper balls. Therefore, finding the optimal production process to meet the current demand for high-end PCBs holds great promise.

[0028] Based on this, in order to improve the problem of low strength and wear resistance of brass alloys in related technologies, the embodiments of the present application provide the following solutions.

[0029] A first aspect of an embodiment of the present application provides a phosphor bronze ball, wherein raw materials for preparing the phosphor bronze ball include the following components: P 0.040-0.065 wt %; Cu 99.935-99.960 wt %.

[0030] It can be understood that P0.040-0.065wt% means that when the total weight of the raw materials is 100, the P content is between 0.040 and 0.065, for example, 0.040, 0.055, 0.065, etc., but not limited to these. Similarly, Cu99.935-99.960wt% represents the Cu content range when the total weight is 100.

[0031] As can be seen from the above, the phosphor copper balls provided in the embodiments of the present application, with 0.040-0.065wt% P, can have a good deoxidation effect, resulting in less oxide production during the preparation of the phosphor copper balls. At the same time, it can reduce the formation of brittle phases, thereby improving the conductivity of the phosphor copper balls and helping to further enhance the adhesion of the black film formed during the electroplating process of the microcrystalline phosphor copper balls. When smelting, 0.040-0.065wt% P and 99.935-99.960wt% Cu can evenly disperse the generated Cu3P in the copper matrix, improving the continuity of the copper matrix, thus laying the foundation for subsequent preparation processes.

[0032] The second aspect of the present invention provides a method for preparing phosphorus copper balls. Figure 1 The method for preparing phosphor bronze balls includes: S100, providing the components of the phosphor-copper ball as described in any of the above embodiments, and smelting the components to obtain a phosphor-copper melt.

[0033] S200, drawing the phosphor copper melt to obtain a phosphor copper casting rod.

[0034] S300, extruding the phosphor bronze cast rod to obtain a phosphor bronze extruded rod.

[0035] S400, annealing the phosphor copper extruded rod to obtain a phosphor copper annealed rod.

[0036] S500, upsetting the phosphor copper annealed rod to obtain a semi-finished phosphor copper ball.

[0037] S600: polishing the semi-finished phosphor bronze balls to obtain polished phosphor bronze balls.

[0038] S700, electroplating the polished phosphor copper ball to obtain a phosphor copper ball.

[0039] From the above, it can be seen that the method for preparing phosphor copper balls provided in the embodiment of the present application prepares phosphor copper balls by adopting a casting-extrusion-annealing-upsetting-polishing-electroplating process. The smelting and pulling process reduces the oxygen content in phosphor copper and accurately controls the P content; the annealing process can refine the grains and restore plasticity; the phosphor copper balls produced by the upsetting process have a smooth surface, refined grains, a tighter grain distribution, and the grains are mainly equiaxed crystals with a small number of columnar crystals, a fine structure, a uniform distribution of components, and a higher hardness. The black film after phosphor copper anode electroplating is uniform, the formed black film is thin and dense, the copper ball has a smooth appearance, and the yield of anode mud generated during the electroplating process is low. As a result, the prepared phosphor copper balls can meet the demand for high-precision and high-reliability conductive materials in high-end fields.

[0040] In some embodiments, see Figure 2 In step S100, the components are smelted to obtain a phosphorus copper melt, including: S110, preparing a Cu-P intermediate master alloy by mixing P with a portion of Cu; wherein the P content in the Cu-P intermediate master alloy is 5%; S120, placing the remaining Cu into a smelting device for heating and smelting to obtain a copper melt; S130, adding a Cu-P intermediate master alloy into a copper melt and heating and smelting, and then keeping the temperature after smelting to obtain a phosphorus copper melt.

[0041] It is understood that a Cu-P intermediate master alloy is an alloy intermediate formed by pre-melting Cu and P, which serves as a P carrier for subsequent smelting. Due to P's low density and volatility, directly adding elemental P to the copper melt can result in large weighing errors and a high burnout rate. The melting apparatus can be, but is not limited to, a medium-frequency induction furnace, an electric arc furnace, or a melting crucible.

[0042] This setup allows the preparation of a master alloy containing 5% P to improve P addition accuracy to ±0.002wt%, while also minimizing volatilization losses through the master alloy's massive structure. Furthermore, through the phased process of "master alloy preparation → pure copper smelting → eutectic holding," the purity and uniformity of the phosphorus copper melt are enhanced.

[0043] Optionally, in some embodiments, in step S120, the remaining Cu is placed in a smelting device and heated and smelted to obtain a copper melt, comprising: Put the remaining copper into the smelting device and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 -1 Pa, filled with argon to a pressure of 6×10 4 Pa~8×10 4 Pa and then heated to 1100 ° C for smelting to obtain copper melt.

[0044] It is understandable that the pressure is 6×104 Pa~8×10 4 Pa, for example, can be 6×10 4 Pa, 7×10 4 Pa, 8×10 4 Pa, etc., but not limited thereto.

[0045] With this setup, the oxygen content in the smelting device can be significantly reduced through the two-stage vacuum pumping-argon replacement process. At the same time, the inertness of argon gas can be used to block the contact between copper and oxygen, thus inhibiting the oxidation of the copper melt. 4 Pa~8×10 4 The slightly positive pressure environment of Pa can prevent the infiltration of external air, and at the same time form a stable argon protective layer on the surface of the copper melt, reducing gas absorption during the smelting process to improve the purity of the copper melt, provide a clean matrix environment for subsequent alloying reactions, and ultimately improve the density and mechanical properties of phosphorus copper.

[0046] Optionally, in some embodiments, in step S130, a Cu-P intermediate master alloy is added to a copper melt and heated and smelted, and then kept warm after smelting to obtain a phosphorus copper melt, including: adding the Cu-P intermediate master alloy to the copper melt, continuing to heat up to 1200~1250℃ and keeping warm for 5 minutes, introducing the melt into a heat preservation device, adjusting the temperature to 1100~1150℃, and obtaining a phosphorus copper melt.

[0047] It is understood that the temperature raised to 1200-1250°C may be, for example, 1200°C, 1225°C, 1250°C, etc., but is not limited thereto. The temperature adjusted to 1100-1150°C may be, for example, 1100°C, 1125°C, 1150°C, etc., but is not limited thereto. The holding device may be, for example, a resistance holding furnace, an induction holding furnace, etc., but is not limited thereto.

[0048] This setup, through a staged temperature control process of high-temperature diffusion followed by medium-temperature insulation, ensures uniform distribution of phosphorus in the copper melt, while keeping the total phosphorus burnout rate below 3%. A high temperature environment of 1200-1250°C allows the Cu3P phase to fully dissolve and diffuse throughout the melt, forming a homogeneous solid solution. Adjusting the temperature in the insulation device to 1100-1150°C reduces the copper melt's aspiration (such as nitrogen formation) caused by prolonged high temperatures, while also controlling the melt's viscosity, facilitating continuous forming during subsequent drawing into rods. Ultimately, a phosphorus copper melt with a dense structure and uniform composition is obtained, laying the foundation for the preparation of high-performance phosphorus copper balls.

[0049] In some embodiments, in step S200, the phosphor copper melt is pulled to obtain a phosphor copper cast rod, with a pulling speed of 0.20-0.30 m / min, a stop time of 100-300 ms, a reverse push distance of 0.05-0.2 mm, and a pulling frequency of 20-40 Hz. The diameter of the obtained phosphor copper cast rod is 20 mm.

[0050] It is understood that the drawing speed is 0.20-0.30 m / min, for example, 0.20 m / min, 0.25 m / min, 0.30 m / min, etc., but not limited thereto. The stopping time is 100-300 ms, for example, 100 ms, 200 ms, 300 ms, etc., but not limited thereto. The reverse thrust stroke is 0.05-0.2 mm, for example, 0.05 mm, 0.1 mm, 0.2 mm, etc., but not limited thereto. The pulling frequency is 20-40 Hz, for example, 20 Hz, 30 Hz, 40 Hz, etc., but not limited thereto. The pulling equipment can be an upcasting machine or a continuous casting and rolling mill, etc., but not limited thereto.

[0051] Such an arrangement, through the above-mentioned pulling parameters, helps to improve the quality of the ingot and obtain a high-quality phosphor copper cast rod with uniform Cu-P phase distribution.

[0052] In some embodiments, in step S300 , the phosphor copper cast rod is extruded to obtain a phosphor copper extruded rod, the extrusion rate is 10 mm / s, and the diameter of the phosphor copper extruded rod is 12 mm.

[0053] It is understood that extrusion is performed continuously, and the continuous extrusion equipment can be, but is not limited to, a horizontal continuous extruder or a vertical continuous extruder. The extrusion ratio of a phosphor bronze cast rod from 20 mm in diameter to 12 mm is (20 / 12)²≈2.78:1, which is considered a moderate deformation.

[0054] This low extrusion speed of 10 mm / s allows the alloy ample time for dynamic recrystallization within the die, breaking down the coarse equiaxed grains in the cast state and forming a finer grain structure in the extruded state. This also closes the micropores remaining from the casting process and increases the density of the phosphor bronze extruded rod. Controlling the extrusion ratio further improves density and tensile strength, while also providing a foundation for dimensional adaptation in the subsequent upsetting process.

[0055] In some embodiments, in step S400 , the phosphor copper extruded rod is annealed to obtain a phosphor copper annealed rod, and the annealing temperature is 450-550° C. and the annealing time is 1-2 hours.

[0056] It is understood that the annealing temperature is 450-550°C, for example, 450°C, 500°C, 550°C, etc., but not limited thereto. The annealing time is 1-2 hours, for example, 1 hour, 1.5 hours, 2 hours, etc., but not limited thereto. The annealing equipment used for annealing can be a box annealing furnace, a mesh belt annealing furnace, or a vacuum annealing furnace, but not limited thereto.

[0057] This setting controls the annealing temperature to 450-550°C, a temperature range above the recrystallization temperature of copper. This allows the work-hardened structure produced during extrusion to recrystallize, forming new equiaxed grains. This also preserves the dispersed Cu3P particles that pin grain boundaries and inhibit excessive grain growth. Annealing for 1-2 hours allows for full stress release and restores elongation from 8%-10% in the extruded state to 20%-25%, ensuring the hardness meets the plasticity requirements of the subsequent upsetting process.

[0058] In some embodiments, in step S500, the phosphor copper annealing rod is upset to obtain a semi-finished phosphor copper ball, the upsetting slider stroke is 146 mm, the upsetting diameter is 350 mm, the pressure is 6 MPa, and the diameter of the semi-finished phosphor copper ball is 25 mm.

[0059] It can be understood that the upsetting equipment is a ball upsetting machine.

[0060] With this setup, the 6MPa upsetting pressure falls within the low-to-medium pressure range of the cold upsetting process. Combined with a long 146mm stroke, this allows the end of a 12mm diameter annealed rod to be slowly upset within the die, preventing rod bending or sphere cracking caused by sudden pressure changes. The 350mm upsetting diameter, coupled with uniform plastic flow under 6MPa pressure, results in a sphere roundness error of ≤0.1mm. The semi-finished phosphor bronze spheres also have a smooth surface, refined grains, and a denser grain distribution. The grains are primarily equiaxed, with a small number of columnar crystals, resulting in a fine structure, uniform composition distribution, and higher hardness.

[0061] In some embodiments, in step S600, the semi-finished phosphor bronze balls are polished to obtain polished phosphor bronze balls, wherein the surface roughness of the polished phosphor bronze balls is ≤0.8 um.

[0062] It is understood that the polishing equipment may be a diamond grinding wheel or chemical mechanical polishing (CMP), etc., but is not limited thereto.

[0063] With this setting, the polishing process can remove the peaks and valleys on the surface and improve the surface flatness; controlling the surface roughness of the polished phosphor copper ball to ≤0.8um can reduce the tip discharge phenomenon during subsequent electroplating, improve the uniformity of the coating, and at the same time enhance the bonding strength between the coating and the substrate, reducing the occurrence of coating peeling or holes caused by surface defects.

[0064] In some embodiments, in step S700, electroplating the polished phosphor bronze balls to obtain phosphor bronze balls includes: The polished phosphor copper balls were electroplated using sulfate copper plating solution at a current density of 1.3A / dm 2 , the electroplating time is 4h, and the electroplating temperature is 40℃.

[0065] It can be understood that the sulfate copper plating solution is prepared from CuSO4∙5H2O, concentrated H2SO4 and concentrated HCl.

[0066] This setup allows for a low current density of 1.3A / dm² to uniformly deposit copper ions on the sphere surface, preventing dendrite growth or scorching that can occur at higher current densities, resulting in minimal variation in coating thickness. The low temperature of 40°C inhibits excessive dissolution of the phosphorus copper spheres, while the weakly acidic sulfate solution stabilizes the anodic dissolution rate at 0.5-0.8g / (A·h), reducing anode slime production. A 4-hour electroplating time ensures a coating thickness that meets the requirements for electronic-grade applications.

[0067] The following describes the details in conjunction with specific embodiments.

[0068] Example 1 1) Prepare 0.05wt% P and 99.95wt% Cu in a proportioning ratio, with P added in the form of a Cu-P intermediate master alloy; place Cu in a melting crucible and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 -1 Pa, filled with argon to a pressure of 7×10 4 Pa, the temperature is raised to 1100°C for heating and melting to obtain a copper melt; heating is stopped and Cu-P intermediate master alloy is added, the temperature is continued to be raised to 1220°C and kept warm for 5 minutes; the melt is then introduced into a holding furnace and the temperature is adjusted to 1130°C to obtain a phosphorus copper melt.

[0069] 2) A phosphor copper casting rod with a diameter of 20 mm was obtained by using an upward continuous casting machine with the working parameters of a pulling speed of 0.25 m / min, a stop time of 200 ms, a reverse thrust stroke of 0.13 mm, and a pulling frequency of 30 Hz.

[0070] 3) The phosphor bronze cast rod is extruded through a continuous extruder at an extrusion rate of 10 mm / s to form a phosphor bronze extruded rod with a diameter of 12 mm.

[0071] 4) After heating the annealing furnace to 500°C, place the phosphor copper extruded rod in the furnace, keep it warm for 1.5 hours, take it out, and air cool it to room temperature to obtain the phosphor copper annealed rod.

[0072] 5) The phosphor copper annealed rod is processed into a semi-finished phosphor copper ball with a diameter of 25 mm by a ball upsetting machine with a forging slide stroke of 146 mm, an upsetting diameter of 350 mm, and a pressure of 6 MPa.

[0073] 6) Use a diamond grinding wheel to polish the surface of the semi-finished phosphor bronze ball to obtain a polished phosphor bronze ball with a surface roughness of ≤0.8um.

[0074] 7) A sulfate copper plating solution was prepared using 200 g / L CuSO₄∙5H₂O + 60 g concentrated H₂SO₄ + 120 mg concentrated HCl. Electroplating was performed using a BH-Hastelloy cell tester (20 A) and a 267 ml Hastelloy cell at a current density of 1.3 A / dm₂, a plating time of 4 h, and a plating temperature of 40°C to obtain phosphorus copper balls.

[0075] Example 2 1) Prepare 0.04wt% P and 99.96wt% Cu, P is added in the form of Cu-P intermediate master alloy; put Cu into the melting crucible and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 -1 Pa, filled with argon to a pressure of 6×10 4 Pa, then heat to 1100 ° C and melt to obtain copper melt; stop heating and add Cu-P intermediate master alloy, continue to heat to 1200 ° C and keep warm for 5 minutes; then introduce the melt into a holding furnace and adjust the temperature to 1100 ° C to obtain phosphorus copper melt.

[0076] 2) A phosphor copper casting rod with a diameter of 20 mm was obtained by using an upward continuous casting machine with the working parameters of a pulling speed of 0.20 m / min, a stop time of 100 ms, a reverse thrust stroke of 0.05 mm, and a pulling frequency of 20 Hz.

[0077] 3) The phosphor bronze cast rod is extruded through a continuous extruder at an extrusion rate of 10 mm / s to form a phosphor bronze extruded rod with a diameter of 12 mm.

[0078] 4) After heating the annealing furnace to 450°C, place the phosphor copper extruded rod in it, keep it warm for 1 hour, then take it out and air cool it to room temperature to obtain the phosphor copper annealed rod.

[0079] 5) The phosphor copper annealed rod is processed into a semi-finished phosphor copper ball with a diameter of 25 mm by a ball upsetting machine with a forging slide stroke of 146 mm, an upsetting diameter of 350 mm, and a pressure of 6 MPa.

[0080] 6) Use a diamond grinding wheel to polish the surface of the semi-finished phosphor bronze ball to obtain a polished phosphor bronze ball with a surface roughness of ≤0.8um.

[0081] 7) A sulfate copper plating solution was prepared using 200 g / L CuSO₄∙5H₂O + 60 g concentrated H₂SO₄ + 120 mg concentrated HCl. Electroplating was performed using a BH-Hastelloy cell tester (20 A) and a 267 ml Hastelloy cell at a current density of 1.3 A / dm₂, a plating time of 4 h, and a plating temperature of 40°C to obtain phosphorus copper balls.

[0082] Example 3 1) Prepare 0.065wt% P and 99.945wt% Cu, P is added in the form of Cu-P intermediate master alloy; put Cu into the melting crucible and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 -1 Pa, filled with argon to a pressure of 8×10 4 Pa, then heat to 1100 ° C and melt to obtain copper melt; stop heating and add Cu-P intermediate master alloy, continue to heat to 1250 ° C and keep warm for 5 minutes; then introduce the melt into a holding furnace and adjust the temperature to 1150 ° C to obtain phosphorus copper melt.

[0083] 2) A phosphor copper casting rod with a diameter of 20 mm was obtained by using an upward continuous casting machine with the working parameters of a pulling speed of 0.30 m / min, a stop time of 300 ms, a reverse thrust stroke of 0.2 mm, and a pulling frequency of 40 Hz.

[0084] 3) The phosphor bronze cast rod is extruded through a continuous extruder at an extrusion rate of 10 mm / s to form a phosphor bronze extruded rod with a diameter of 12 mm.

[0085] 4) After heating the annealing furnace to 550°C, place the phosphor copper extruded rod in the furnace, keep it warm for 2 hours, take it out, and air cool it to room temperature to obtain the phosphor copper annealed rod.

[0086] 5) The phosphor copper annealed rod is processed into a semi-finished phosphor copper ball with a diameter of 25 mm by a ball upsetting machine with a forging slide stroke of 146 mm, an upsetting diameter of 350 mm, and a pressure of 6 MPa.

[0087] 6) Use a diamond grinding wheel to polish the surface of the semi-finished phosphor bronze ball to obtain a polished phosphor bronze ball with a surface roughness of ≤0.8um.

[0088] 7) A sulfate copper plating solution was prepared using 200 g / L CuSO₄∙5H₂O + 60 g concentrated H₂SO₄ + 120 mg concentrated HCl. Electroplating was performed using a BH-Hastelloy cell tester (20 A) and a 267 ml Hastelloy cell at a current density of 1.3 A / dm₂, a plating time of 4 h, and a plating temperature of 40°C to obtain phosphorus copper balls.

[0089] Comparative Example 1 1) Prepare 0.05wt% P and 99.95wt% Cu in a proportioning ratio, with P added in the form of a Cu-P intermediate master alloy; place Cu in a melting crucible and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 -1 Pa, filled with argon to a pressure of 7×10 4 Pa, the temperature is raised to 1100°C for heating and melting to obtain a copper melt; heating is stopped and Cu-P intermediate master alloy is added, the temperature is continued to be raised to 1220°C and kept warm for 5 minutes; the melt is then introduced into a holding furnace and the temperature is adjusted to 1130°C to obtain a phosphorus copper melt.

[0090] 2) A phosphor copper casting rod with a diameter of 20 mm was obtained by using an upward continuous casting machine with the working parameters of a pulling speed of 0.25 m / min, a stop time of 200 ms, a reverse thrust stroke of 0.13 mm, and a pulling frequency of 30 Hz.

[0091] 3) The phosphor bronze cast rod is extruded through a continuous extruder at an extrusion rate of 10 mm / s to form a phosphor bronze extruded rod with a diameter of 12 mm.

[0092] 4) After heating the annealing furnace to 500°C, place the phosphor copper extruded rod in the furnace, keep it warm for 1.5 hours, take it out, and air cool it to room temperature to obtain the phosphor copper annealed rod.

[0093] 5) The phosphor copper annealed rod is passed through a phosphor copper ball rolling mill at a rolling temperature of 1100°C, a roller diameter of 250 mm, a cutting cylinder diameter of 150 mm, and a pressure of 8 MPa to be processed into semi-finished phosphor copper balls with a diameter of 25 mm.

[0094] 6) Use a diamond grinding wheel to polish the surface of the semi-finished phosphor bronze ball to obtain a polished phosphor bronze ball with a surface roughness of ≤0.8um.

[0095] 7) A sulfate copper plating solution was prepared using 200 g / L CuSO₄∙5H₂O + 60 g concentrated H₂SO₄ + 120 mg concentrated HCl. Electroplating was performed using a BH-Hastelloy cell tester (20 A) and a 267 ml Hastelloy cell at a current density of 1.3 A / dm₂, a plating time of 4 h, and a plating temperature of 40°C to obtain phosphorus copper balls.

[0096] Comparative Example 2 1) Prepare 0.03wt% P and 99.97wt% Cu in a proportioning ratio, with P added in the form of a Cu-P intermediate master alloy; place Cu in a melting crucible and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 -1 Pa, filled with argon to a pressure of 7×10 4Pa, the temperature is raised to 1100°C for heating and melting to obtain a copper melt; heating is stopped and Cu-P intermediate master alloy is added, the temperature is continued to be raised to 1220°C and kept warm for 5 minutes; the melt is then introduced into a holding furnace and the temperature is adjusted to 1130°C to obtain a phosphorus copper melt.

[0097] 2) A phosphor copper casting rod with a diameter of 20 mm was obtained by using an upward continuous casting machine with the working parameters of a pulling speed of 0.25 m / min, a stop time of 200 ms, a reverse thrust stroke of 0.13 mm, and a pulling frequency of 30 Hz.

[0098] 3) The phosphor bronze cast rod is extruded through a continuous extruder at an extrusion rate of 10 mm / s to form a phosphor bronze extruded rod with a diameter of 12 mm.

[0099] 4) After heating the annealing furnace to 500°C, place the phosphor copper extruded rod in the furnace, keep it warm for 1.5 hours, take it out, and air cool it to room temperature to obtain the phosphor copper annealed rod.

[0100] 5) The phosphor copper annealed rod is processed into a semi-finished phosphor copper ball with a diameter of 25 mm by a ball upsetting machine with a forging slide stroke of 146 mm, an upsetting diameter of 350 mm, and a pressure of 6 MPa.

[0101] 6) Use a diamond grinding wheel to polish the surface of the semi-finished phosphor bronze ball to obtain a polished phosphor bronze ball with a surface roughness of ≤0.8um.

[0102] 7) A sulfate copper plating solution was prepared using 200 g / L CuSO₄∙5H₂O + 60 g concentrated H₂SO₄ + 120 mg concentrated HCl. Electroplating was performed using a BH-Hastelloy cell tester (20 A) and a 267 ml Hastelloy cell at a current density of 1.3 A / dm₂, a plating time of 4 h, and a plating temperature of 40°C to obtain phosphorus copper balls.

[0103] Comparative Example 3 1) Prepare 0.07wt% P and 99.93wt% Cu, P is added in the form of Cu-P intermediate master alloy; put Cu into the melting crucible and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 -1 Pa, filled with argon to a pressure of 7×10 4 Pa, the temperature is raised to 1100°C for heating and melting to obtain a copper melt; heating is stopped and Cu-P intermediate master alloy is added, the temperature is continued to be raised to 1220°C and kept warm for 5 minutes; the melt is then introduced into a holding furnace and the temperature is adjusted to 1130°C to obtain a phosphorus copper melt.

[0104] 2) A phosphor copper casting rod with a diameter of 20 mm was obtained by using an upward continuous casting machine with the working parameters of a pulling speed of 0.25 m / min, a stop time of 200 ms, a reverse thrust stroke of 0.13 mm, and a pulling frequency of 30 Hz.

[0105] 3) The phosphor bronze cast rod is extruded through a continuous extruder at an extrusion rate of 10 mm / s to form a phosphor bronze extruded rod with a diameter of 12 mm.

[0106] 4) After heating the annealing furnace to 500°C, place the phosphor copper extruded rod in the furnace, keep it warm for 1.5 hours, take it out, and air cool it to room temperature to obtain the phosphor copper annealed rod.

[0107] 5) The phosphor copper annealed rod is processed into a semi-finished phosphor copper ball with a diameter of 25 mm by a ball upsetting machine with a forging slide stroke of 146 mm, an upsetting diameter of 350 mm, and a pressure of 6 MPa.

[0108] 6) Use a diamond grinding wheel to polish the surface of the semi-finished phosphor bronze ball to obtain a polished phosphor bronze ball with a surface roughness of ≤0.8um.

[0109] 7) A sulfate copper plating solution was prepared using 200 g / L CuSO₄∙5H₂O + 60 g concentrated H₂SO₄ + 120 mg concentrated HCl. Electroplating was performed using a BH-Hastelloy cell tester (20 A) and a 267 ml Hastelloy cell at a current density of 1.3 A / dm₂, a plating time of 4 h, and a plating temperature of 40°C to obtain phosphorus copper balls.

[0110] Comparative Example 4 1) Prepare a ratio of 0.05 wt% P and 99.95 wt% Cu, with P added in the form of a Cu-P master alloy. Place Cu in a melting crucible, heat to 1100°C, and melt to obtain a copper melt. Stop heating and add the Cu-P master alloy. Continue heating to 1220°C and hold for 5 minutes. Then, introduce the melt into a holding furnace and adjust the temperature to 1130°C to obtain a phosphorus copper melt.

[0111] 2) A phosphor copper casting rod with a diameter of 20 mm was obtained by using an upward continuous casting machine with the working parameters of a pulling speed of 0.25 m / min, a stop time of 200 ms, a reverse thrust stroke of 0.13 mm, and a pulling frequency of 30 Hz.

[0112] 3) The phosphor bronze cast rod is extruded through a continuous extruder at an extrusion rate of 10 mm / s to form a phosphor bronze extruded rod with a diameter of 12 mm.

[0113] 4) After heating the annealing furnace to 500°C, place the phosphor copper extruded rod in the furnace, keep it warm for 1.5 hours, take it out, and air cool it to room temperature to obtain the phosphor copper annealed rod.

[0114] 5) The phosphor copper annealed rod is processed into a semi-finished phosphor copper ball with a diameter of 25 mm by a ball upsetting machine with a forging slide stroke of 146 mm, an upsetting diameter of 350 mm, and a pressure of 6 MPa.

[0115] 6) Use a diamond grinding wheel to polish the surface of the semi-finished phosphor bronze ball to obtain a polished phosphor bronze ball with a surface roughness of ≤0.8um.

[0116] 7) A sulfate copper plating solution was prepared using 200 g / L CuSO₄∙5H₂O + 60 g concentrated H₂SO₄ + 120 mg concentrated HCl. Electroplating was performed using a BH-Hastelloy cell tester (20 A) and a 267 ml Hastelloy cell at a current density of 1.3 A / dm₂, a plating time of 4 h, and a plating temperature of 40°C to obtain phosphorus copper balls.

[0117] The phosphor copper balls prepared in all the above examples and comparative examples were tested for hardness, coating roughness, coating thickness, and anode mud quality after electroplating. The testing method is as follows: 1. Hardness: Use WILSON VH1102 fully automatic micro Vickers hardness tester.

[0118] 2. Coating roughness: The GT-X three-dimensional profilometer is used to test the two-dimensional and three-dimensional profiles of the coating in the horizontal (X direction) and vertical (Y direction) directions to detect the roughness of the coating.

[0119] 3. Coating Thickness: Coating thickness is measured using the gravimetric method according to ISO 10111-2019, "Metallic and other inorganic coatings — Measurement of mass per unit area." The testing process is as follows: Before the test, clean the brass plate and air dry it. Weigh it with an electronic scale and record the weight, which is M1. After the test, clean and dry the coating, weigh it, and record the weight, which is M2. The surface area of the coating is the area of the brass sheet, S. The density of copper is ρ. Therefore, the coating thickness H is: H = (M1 − M2) / ρS.

[0120] 4. Quality of anode mud after electroplating: weighed using an electronic balance.

[0121] The test results are shown in Table 1 below.

[0122] Table 1 According to the test data in Table 1, the phosphor copper balls prepared using the raw materials and preparation method of the phosphor copper balls of the present application have a tighter grain distribution and relatively excellent hardness. The black film after phosphor copper anode electroplating is uniform, the formed black film is thin and dense, the copper ball has a smooth surface, and the anode mud yield generated during the electroplating process is controlled within 0.25%.

[0123] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A phosphor bronze ball, characterized in that: The raw materials for preparing the phosphor bronze ball include the following components: P, 0.040~0.065wt%; Cu, 99.935~99.960wt%.

2. A method for preparing phosphorus copper balls, characterized in that: The method for preparing the phosphorus copper ball comprises: Providing the components of the phosphor-copper ball according to claim 1, and smelting the components to obtain a phosphor-copper melt; Drawing the phosphor copper melt to obtain a phosphor copper cast rod; extruding the phosphor bronze cast rod to obtain a phosphor bronze extruded rod; annealing the phosphor copper extruded rod to obtain a phosphor copper annealed rod; Upsetting the phosphor copper annealed rod to obtain a semi-finished phosphor copper ball; polishing the semi-finished phosphor bronze balls to obtain polished phosphor bronze balls; The polished phosphor bronze balls are electroplated to obtain phosphor bronze balls.

3. The method for preparing phosphorus copper balls according to claim 2, wherein: The process of smelting the components to obtain a phosphorus copper melt comprises: P and part of Cu are mixed to form a Cu-P intermediate master alloy; wherein the P content in the Cu-P intermediate master alloy is 5%; The remaining Cu is placed in a smelting device and heated to obtain a copper melt; The Cu-P intermediate master alloy is added to the copper melt and heated and smelted, and then the heat is kept after smelting to obtain a phosphorus copper melt.

4. The method for preparing phosphorus copper balls according to claim 3, wherein: The process of placing the remaining Cu into a smelting device for heating and smelting to obtain a copper melt comprises: Put the remaining copper into the smelting device and evacuate to 10 -1 Pa, fill with argon to normal pressure, and evacuate to 10 - 1 Pa, filled with argon to a pressure of 6×10 4 Pa~8×10 4 Pa and then heated to 1100 ° C for smelting to obtain copper melt.

5. The method for preparing phosphorus copper balls according to claim 3, wherein: The process of adding the Cu-P intermediate master alloy to the copper melt, heating and smelting the copper melt, and then keeping the heat after smelting to obtain the phosphorus copper melt comprises: A Cu-P intermediate master alloy is added to the copper melt, and the temperature is continuously raised to 1200-1250° C. and kept warm for 5 minutes. The melt is introduced into a heat preservation device and the temperature is adjusted to 1100-1150° C. to obtain a phosphorus copper melt.

6. The method for preparing phosphorus copper balls according to claim 2, wherein: In the process of pulling the phosphor copper melt to obtain a phosphor copper cast rod, the pulling speed is 0.20-0.30 m / min, the stopping time is 100-300 ms, the reverse pushing distance is 0.05-0.2 mm, and the pulling frequency is 20-40 Hz. The diameter of the obtained phosphor copper cast rod is 20 mm.

7. The method for preparing phosphorus copper balls according to claim 2, characterized in that: In the process of extruding the phosphor copper cast rod to obtain the phosphor copper extruded rod, the extrusion rate is 10 mm / s and the diameter of the phosphor copper extruded rod is 12 mm.

8. The method for preparing phosphorus copper balls according to claim 2, characterized in that: In the step of annealing the phosphor copper extruded rod to obtain the phosphor copper annealed rod, the annealing temperature is 450-550° C. and the annealing time is 1-2 hours.

9. The method for preparing phosphorus copper balls according to claim 2, characterized in that: In the process of upsetting the phosphor copper annealing rod to obtain a semi-finished phosphor copper ball, the upsetting slider stroke is 146 mm, the upsetting diameter is 350 mm, the pressure is 6 MPa, and the diameter of the semi-finished phosphor copper ball is 25 mm.

10. The method for preparing phosphorus copper balls according to claim 2, wherein: In polishing the semi-finished phosphor copper ball to obtain the polished phosphor copper ball, the surface roughness of the polished phosphor copper ball is ≤0.8 μm; And / or, electroplating the polished phosphor bronze balls to obtain phosphor bronze balls comprises: The polished phosphor copper balls were electroplated using a sulfate copper plating solution at a current density of 1.3 A / dm 2 , the electroplating time is 4h, and the electroplating temperature is 40℃.

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