A method for producing a ni3sn4 alloy

Abstract

The application discloses a preparation method of a Ni3Sn4 alloy, and comprises the following steps: weighing: nickel powder and tin powder are weighed as metal powder according to the material quantity ratio of 3:4, and then water is weighed according to the mass ratio of the metal powder and water of (4-6):1; first ball milling: one-third of the mass of the metal powder and water are put into a ball milling tank for mixing and stirring, and first ball milling is carried out; second ball milling: the remaining metal powder and water are put into the ball milling tank for second ball milling, the ball milling is stopped when the slurry reaches a certain viscosity, and stirring is continuously carried out for a certain time, so that alloy slurry is obtained; drying; and sintering. The application adopts the stirring and ball milling mechanical alloying mode, the metal powder and water are added in batches for ball milling, the metal powder is prevented from agglomerating and caking, the nickel powder and the tin powder are subjected to repeated extrusion, cold welding and fracture refinement, become dispersed ultrafine particles, the block making process is reduced, alloying is realized at low temperature, the process is simple, and the method is safe and effective.

Description

Technical Field

[0001] This invention belongs to the field of electronic welding materials technology, specifically relating to a method for preparing Ni3Sn4 alloy. Background Technology

[0002] In recent years, with the increasing demand for low-temperature soldering processes in electronic packaging, and the need for low-temperature soldering processes in emerging fields such as flexible electronics, bioelectronics, and wearable electronics micro-interconnects, SnBi-based solders, with their low melting point and low-temperature soldering characteristics, have been widely used in low-temperature soldering, emerging electronics, and third-generation semiconductor fields. Although SnBi solder dominates the field of low-temperature brazing, it still faces technical challenges such as high brittleness, dendrite segregation during solidification, and uneven composition.

[0003] Ni3Sn4 is an intermetallic compound formed at the interface between solder and chip. Adding Ni3Sn4 nanoparticles to the solder can achieve dispersion-enhancing and toughening modifications, resulting in a refined solder microstructure, improved toughness, increased strength, significantly reduced phase segregation, and enhanced electromigration resistance. Currently, no researchers have attempted to systematically solve the three technical challenges of SnBi solder by adding Ni3Sn4 as an additive phase, nor have any studies employed new preparation processes to produce SnBi-based composite solders with the aforementioned dispersion-enhancing and toughening modifications and commercialize them. Therefore, the preparation of Ni3Sn4 alloys could provide a new solution to the technical challenges of SnBi solder.

[0004] 1. Patent No. CN201610657203.7 discloses a SnBiSb-based low-temperature lead-free solder and its preparation method. The method involves first preparing a Bi-Sb master alloy, then adding different master alloys according to the alloy ratio, heating to 250-500℃, holding at that temperature for 10-20 minutes, and then casting the alloy ingot into a mold. Due to differences in metal melting points, this method is prone to segregation and compositional inhomogeneity during the melting process.

[0005] 2. Patent No. CN201811352707.3 discloses a method for preparing SnZn-based lead-free solder. This method employs an intermediate alloy process, enabling the preparation of alloys with precise elemental content (on the order of 0.1%). The method also designs the melting temperature, melting time, and environmental control for different metal properties to ensure smelting speed and quality. This method requires heating to 600-700℃ under vacuum or an inert atmosphere and necessitates the preparation of multiple intermediate alloys, resulting in high energy consumption and demanding preparation conditions.

[0006] 3. Application No.: 202211004376.0 discloses a Ni-Sn intermetallic compound, its preparation method, and its application. The preparation method of this Ni-Sn intermetallic compound includes: ball-milling a mixture of Ni powder and Sn powder, pressing it into a mold, and then vacuum melting it to obtain the Ni-Sn intermetallic compound. This invention uses ball milling to thoroughly and uniformly mix Ni powder and Sn powder, and then presses the Ni powder and Sn powder to fix their relative positions. Therefore, during vacuum melting, the Ni and Sn in the pressed, fixed form can melt in situ, allowing the Ni and Sn in the pressed, fixed-form blank to fully react and form the Ni-Sn intermetallic compound. This compound has high purity, with minimal residual Ni or Sn powder, essentially achieving complete reaction of the Ni and Sn powders. However, the ball milling process of this method can easily cause the nickel and tin powders to be oxidized, and the vacuum melting temperature after pressing and molding is 1450-1550℃, which requires a lot of energy and the preparation conditions are relatively harsh.

[0007] 4. Application No.: 201210570318.4 discloses a method for preparing an intermediate alloy for lead-free solder. First, Nd powder, Ni powder, and Sn powder are mixed in a specific ratio and then ball-milled for 4-12 hours at a speed of 200-350 rpm to ensure homogeneity. The protective gas during ball milling is pure argon, or the ball milling can be carried out in a vacuum ball mill with a vacuum degree of 1*10⁻⁶. - 5 After ball milling, the milling jar should be allowed to stand for 1-4 hours until the temperature drops to room temperature. Then, open the jar, pour out the uniformly mixed powder, and store it under vacuum. Place the uniformly mixed powder into a special mold and apply a pressure of 500-700 MPa to form a preform. Then, place the preform into a sintering furnace at 180℃-220℃ for sintering. The protective gas is pure argon or vacuum sintering, with a vacuum degree of 1*10⁻⁶. -5 Pa. Holding time is 2-4 hours. This invention uses a protective gas or vacuum state to avoid oxidation of the metal powder, which requires a high-quality ball milling environment. Although the sintering temperature is not high, thus reducing energy consumption, it still requires sintering into blocks, resulting in multiple steps. Summary of the Invention

[0008] The purpose of this invention is to solve the above-mentioned technical problems and provide a simple method for preparing Ni3Sn4 alloy that can achieve metal alloying at low temperatures.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows:

[0010] A method for preparing a Ni3Sn4 alloy includes the following steps:

[0011] (1) Weighing: Weigh nickel powder and tin powder as metal powder according to a mass ratio of 3:4, and then weigh water according to a mass ratio of metal powder to water of (4-6):1;

[0012] (2) First ball milling: Take 1 / 3 of the mass of the metal powder and water and put them into the ball mill jar to mix and stir, and then perform a first ball milling;

[0013] (3) Secondary ball milling: Take the remaining metal powder and water into the ball milling jar and perform secondary ball milling. Stop ball milling when the slurry reaches a certain viscosity and continue stirring for a certain time to obtain alloy slurry;

[0014] (4) Drying: The alloy slurry is dried under vacuum to obtain pre-alloyed powder;

[0015] (5) Sintering: The pre-alloyed powder is sintered to obtain Ni3Sn4 alloy.

[0016] As a further technical solution, in step (2) above, the mixing time is 20-30 min, the ball milling time is 30-60 min, and the ball milling rate is 25-30 r / min.

[0017] As a further technical solution, in step (3) above, the time for secondary ball milling is 24 to 30 hours, and the rate of secondary ball milling is 45 to 55 r / min.

[0018] As a further technical solution, in step (3) above, ball milling is stopped when the slurry viscosity is greater than 1000 Pa·s, and stirring is continued for 10 to 20 minutes at a stirring rate of 150 to 200 r / min.

[0019] As a further technical solution, in step (4) above, the vacuum degree is 0~-0.1MPa and the drying temperature is 60~80℃.

[0020] As a further technical solution, the sintering in step (5) above is to heat the pre-alloyed powder to 250-300℃ at a heating rate of 80-100℃ / h and hold it for 10-30 min, and then cool it down to obtain Ni3Sn4 alloy.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. This invention employs a mechanical alloying method involving stirring and ball milling. By adding metal powder and water in stages for ball milling, not only is the agglomeration of metal powder prevented, but the nickel and tin powders also undergo repeated extrusion, cold welding, and fracture refinement to become dispersed ultrafine particles. This reduces the block-making process, achieves alloying at low temperatures, and is a simple, safe, and effective process.

[0023] 2. The ball milling environment of the present invention is simple, and water is used as a medium to achieve more uniform powder mixing, while avoiding the oxidation of nickel powder and tin powder during the ball milling process. Attached Figure Description

[0024] Figure 1 This is the XRD pattern of the Ni3Sn4 alloy in Example 1 of the present invention. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited to the scope shown in the embodiments.

[0026] Example 1

[0027] A method for preparing a Ni3Sn4 alloy, comprising:

[0028] (1) Weighing: Weigh 2435 g of nickel powder, 6565 g of tin powder and 1500 ml of water;

[0029] (2) First ball milling: Turn on the cooling water, add 811 g of nickel powder, 2188 g of tin powder and 500 ml of water to the ball milling jar in sequence, stir for 30 min and then ball mill at a rate of 25 r / min for 30 min.

[0030] (3) Secondary ball milling: The remaining nickel powder, tin powder and water are added to the ball milling jar in sequence, and ball milling is carried out at a rate of 50 r / min for 30 h; when the viscosity of the alloy slurry is measured to be 1021 Pa·s, ball milling is stopped and the mixture is stirred at 200 r / min for 15 min.

[0031] (4) Drying: Transfer the alloy slurry to a vacuum drying oven, evacuate to -0.1MPa, and dry at 80℃ for 12h to obtain pre-alloyed powder;

[0032] (5) Sintering: Under a nitrogen protective atmosphere, the pre-alloyed powder was heated to 250℃ at a heating rate of 100℃ / h and held for 30 min. After cooling, Ni3Sn4 alloy was obtained. The results were tested as follows: Figure 1 As shown.

[0033] Example 2

[0034] (1) Weighing: Weigh 2435 g of nickel powder, 6565 g of tin powder and 1500 ml of water;

[0035] (2) First ball milling: Turn on the cooling water, add 811 g of nickel powder, 2188 g of tin powder and 500 ml of water to the ball milling jar in sequence, stir for 30 min and then ball mill at a rate of 30 r / min for 60 min.

[0036] (3) Secondary ball milling: The remaining nickel powder, tin powder and water are added to the ball milling jar in sequence, and ball milling is carried out at a rate of 55 r / min for 28 h; when the viscosity of the alloy slurry is measured to be 1009 Pa·s, ball milling is stopped and the mixture is stirred at 200 r / min for 20 min.

[0037] (4) Drying: Transfer the alloy slurry to a vacuum drying oven, evacuate to -0.1MPa, and dry at 70℃ for 12h to obtain pre-alloyed powder;

[0038] (5) Sintering: In a nitrogen protective atmosphere, the pre-alloyed powder is heated to 300℃ at a heating rate of 80℃ / h and held for 10min. After cooling, Ni3Sn4 alloy is obtained.

[0039] Example 3

[0040] (1) Weighing: Weigh 2435 g of nickel powder, 6565 g of tin powder and 2250 ml of water;

[0041] (2) First ball milling: Turn on the cooling water, add 811 g of nickel powder, 2188 g of tin powder and 750 ml of water to the ball milling jar in sequence, stir for 30 min and then ball mill at a rate of 30 r / min for 45 min.

[0042] (3) Secondary ball milling: The remaining nickel powder, tin powder and water are added to the ball milling jar in sequence, and ball milling is carried out at a rate of 45 r / min for 24 h; when the viscosity of the alloy slurry is detected to be 1002 Pa.S, the ball milling is stopped and stirred at 200 r / min for 20 min.

[0043] (5) Drying: Transfer the alloy slurry to a vacuum drying oven, evacuate to -0.09MPa, and dry at 80℃ for 12h to obtain pre-alloyed powder;

[0044] (6) Sintering: In a nitrogen protective atmosphere, the pre-alloyed powder is heated to 300℃ at a heating rate of 100℃ / h and held for 20min. After cooling, Ni3Sn4 alloy is obtained.

[0045] Example 4

[0046] (1) Weighing: Weigh 2705g of nickel powder, 7295g of tin powder and 2000ml of water;

[0047] (2) First ball milling: Turn on the cooling water, add 902 g of nickel powder, 2432 g of tin powder and 667 ml of water to the ball milling jar in sequence, stir for 30 min and then ball mill at a rate of 30 r / min for 60 min;

[0048] (3) Secondary ball milling: The remaining nickel powder, tin powder and water are added to the ball milling jar in sequence, and ball milling is carried out at a rate of 55 r / min for 28 h;

[0049] (4) Testing and stirring: When the viscosity of the alloy slurry is 1004 Pa·s, stop ball milling and stir at 200 r / min for 15 min;

[0050] (5) Drying: Transfer the alloy slurry to a vacuum drying oven, evacuate to -0.1MPa, and dry at 80℃ for 12h to obtain pre-alloyed powder;

[0051] (6) Sintering: In a nitrogen protective atmosphere, the pre-alloyed powder is heated to 280℃ at a heating rate of 90℃ / h and held for 20min. After cooling, Ni3Sn4 alloy is obtained.

[0052] Comparative experiment:

[0053] Comparative Example 1: Ball milling was performed without water as the medium, according to the parameters of Example 1. The specific steps were as follows:

[0054] (1) Weighing: Weigh 2435 g of nickel powder and 6565 g of tin powder;

[0055] (2) First ball milling: Turn on the cooling water, add 811 g of nickel powder and 2188 g of tin powder to the ball milling jar in sequence, stir for 30 min, and then ball mill at a rate of 25 r / min for 30 min.

[0056] (3) Secondary ball milling: The remaining nickel powder and tin powder are added to the ball milling jar in sequence, and ball milling is carried out at a rate of 50 r / min for 30 h, and stirred at 200 r / min for 15 min.

[0057] (4) Drying: Transfer the alloy slurry to a vacuum drying oven, evacuate to -0.1MPa, and dry at 80℃ for 12h to obtain pre-alloyed powder;

[0058] (5) Sintering: Under a nitrogen protective atmosphere, the pre-alloyed powder is heated to 250℃ at a heating rate of 100℃ / h and held for 30 min. After cooling, Ni3Sn is obtained. 4、 SnO2 alloy.

[0059] As seen in Comparative Example 1, metal powder is easily oxidized in the absence of water, generating tin dioxide and reducing the purity of Ni3Sn4. The addition of water as a medium in this invention can effectively prevent the metal from being oxidized, while the ball milling environment is simple and easy to control.

[0060] Comparative Example 2: A one-time ball milling was performed according to the parameters of Example 1. The specific steps were as follows:

[0061] (1) Weighing: Weigh 2435 g of nickel powder, 6565 g of tin powder and 1500 ml of water;

[0062] (2) Ball milling: Weigh the nickel powder, tin powder and water into the ball milling jar in sequence, and ball mill at a rate of 50 r / min for 30 h; when the viscosity of the alloy slurry is 1013 Pa·s, stop ball milling and stir at 200 r / min for 15 min.

[0063] (3) Drying: Transfer the alloy slurry to a vacuum drying oven and dry it at 80°C for 12 h to obtain pre-alloyed powder;

[0064] (4) Sintering: Under a nitrogen protective atmosphere, the pre-alloyed powder is heated to 250℃ at a heating rate of 100℃ / h and held for 30 min. After cooling, Ni3Sn is obtained. 4、 Ni and Sn alloys.

[0065] As seen in Comparative Example 2, single-stage ball milling results in incomplete alloying of the product. This invention, by using multi-stage feeding, ensures complete alloying of the nickel and tin.

[0066] Comparative Example 3: Following the parameters of Example 1, but omitting the stirring after the second ball milling, the steps are as follows:

[0067] (1) Weighing: Weigh 2435 g of nickel powder, 6565 g of tin powder and 1500 ml of water;

[0068] (2) First ball milling: Turn on the cooling water, add 811 g of nickel powder, 2188 g of tin powder and 500 ml of water to the ball milling jar in sequence, and ball mill at a rate of 25 r / min for 30 min.

[0069] (3) Secondary ball milling: The remaining nickel powder, tin powder and water are added to the ball milling jar in sequence, and ball milling is carried out at a rate of 50 r / min for 48 h; when the viscosity of the alloy slurry is measured to be 1008 Pa·s, the ball milling is stopped;

[0070] (4) Drying: Transfer the alloy slurry to a vacuum drying oven and dry it at 80°C for 12 h to obtain pre-alloyed powder;

[0071] (5) Sintering: In a nitrogen protective atmosphere, the pre-alloyed powder is heated to 250℃ at a heating rate of 100℃ / h and held for 30min. After cooling, Ni3Sn4 alloy is obtained.

[0072] As seen in Comparative Example 3, the addition of stirring in this invention can significantly shorten the alloy preparation time.

[0073] The comparative analysis shows that water prevents oxidation, and the phased feeding method, matched with the instrument, ensures better mixing in the aqueous medium. The addition of stirring also significantly shortens the alloy preparation time. Furthermore, this invention can generate Ni3Sn4 alloys without requiring 1500℃, and the mechanical alloying process does not introduce other metallic phases. Experimental results demonstrate that the method used in this invention is simple, effective, safe, and environmentally friendly.

[0074] The above embodiments are merely specific examples to further illustrate the purpose, technical solution, and beneficial effects of the present invention, and the present invention is not limited thereto. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the disclosure of the present invention are included within the protection scope of the present invention.

Claims

1. A method for preparing a Ni3Sn4 alloy, characterized in that, Includes the following steps: (1) Weighing: Weigh nickel powder and tin powder as metal powder according to a mass ratio of 3:4, and then weigh water according to a mass ratio of metal powder to water of (4-6):1; (2) First ball milling: Take 1 / 3 of the mass of the metal powder and water and put them into the ball mill jar to mix and stir, and then perform a first ball milling; (3) Secondary ball milling: Take the remaining metal powder and water into the ball milling jar and perform secondary ball milling. Stop ball milling when the slurry reaches a certain viscosity and continue stirring for a certain time to obtain alloy slurry; (4) Drying: The alloy slurry is dried under vacuum to obtain pre-alloyed powder; (5) Sintering: The pre-alloyed powder is sintered to obtain Ni3Sn4 alloy; the sintering is carried out in a nitrogen protective atmosphere, the pre-alloyed powder is heated to 250-300℃ at a heating rate of 80-100℃ / h and held for 10-30 min, and then cooled to obtain Ni3Sn4 alloy.

2. The method for preparing a Ni3Sn4 alloy according to claim 1, characterized in that: In step (2), the mixing time is 20-30 min, the ball milling time is 30-60 min, and the ball milling rate is 25-30 r / min.

3. The method for preparing a Ni3Sn4 alloy according to claim 1, characterized in that: In step (3), the secondary ball milling time is 24 to 30 hours, and the secondary ball milling rate is 45 to 55 r / min.

4. The method for preparing a Ni3Sn4 alloy according to claim 3, characterized in that: In step (3), stop ball milling when the slurry viscosity is greater than 1000 Pa·s, and continue stirring for 10 to 20 minutes at a stirring rate of 150 to 200 r / min.

5. The method for preparing a Ni3Sn4 alloy according to claim 1, characterized in that: In step (4), the vacuum degree is 0~-0.1MPa and the drying temperature is 60~80℃.

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