A preparation method of a low-temperature and rapid-curing solder

Abstract

The present invention discloses a preparation method of a low-temperature and rapid-curing solder, specifically relating to the technical field of welding materials, and relates to a preparation method of a low-temperature and rapid-curing solder; the low-temperature and rapid-curing solder is prepared from a multi-component alloy matrix powder, a particle dopant, absolute ethanol and a soldering flux; the components and weight parts of the preparation raw materials are as follows: 55-62 parts of the multi-component alloy matrix powder, 10-15 parts of the particle dopant, 3-4 parts of absolute ethanol and 18-22 parts of the soldering flux; in the preparation process of the present invention, bismuth element is added. In the alloy system, bismuth atoms interact with other metal atoms, changing the overall crystallization behavior of the alloy, enabling the alloy to initiate the solidification process at a lower temperature, laying a foundation for low-temperature curing, being able to achieve curing at a lower temperature, effectively avoiding thermal damage to thermosensitive components, and being more suitable for welding operations in a low-temperature environment, reducing the dependence on complex heating equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of welding materials, and more specifically, to a method for preparing a low-temperature and rapid-curing solder. Background Art

[0002] In many fields such as electronic manufacturing and precision instrument assembly, welding is a key connection process; during the welding process, the solder is heated and melted to infiltrate the base material, fill the joint gap, and diffuse with the base material, thereby achieving a welded connection; it has characteristics such as high mechanical strength and good electrical conductivity, and can meet the requirements of various engineering applications; therefore, developing a new solder has important practical significance.

[0003] The solders in the related art mainly include lead and tin; among them, lead has good fluidity, which can enable the solder to better fill the weld during the welding process, help the solder spread smoothly on the surface of the welded part, thereby achieving the purpose of connecting components; and lead can lower the melting point of the solder, allowing the welding operation to be carried out at a relatively low temperature, reducing the thermal shock to the welded components; tin is also a key component of the solder, which can provide a certain mechanical strength, ensure the firmness of the welded part, enable the solder joint to withstand a certain external force, maintain the connection stability of electronic components, etc., and ensure the normal conduction of the circuit.

[0004] However, in actual use, there are still some disadvantages, such as high curing temperature. The melting point of the solder in the related art is relatively high. When welding heat-sensitive components, this relatively high curing temperature is likely to cause thermal damage to the components; low welding efficiency; during the welding process of the solder in the related art, since it needs to reach a relatively high temperature to melt, and may also require a certain amount of time to ensure good wettability and filling effect after melting, the welding time is relatively long; a relatively long residence time on the solder joint is required to ensure the quality of the solder joint, which will reduce the speed of the welding production line; poor adaptability. The wettability of the solder in the related art on some special welding surfaces is not ideal enough. This is because its composition and performance are relatively fixed and cannot well adapt to various complex welding surfaces, resulting in low solder joint quality and welding defects such as false soldering and tip pulling. Summary of the Invention

[0005] In order to improve the above problems and reduce the problems of high curing temperature and low welding efficiency of the solder in the related art, the present invention particularly provides a method for preparing a low-temperature and rapid-curing solder to solve the problems raised in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A low-temperature and rapid-curing solder, comprising a multi-element alloy matrix powder, a particle dopant, absolute ethanol, and a soldering flux; its preparation method comprises the following steps:

[0008] A1. Put the multi - element alloy matrix powder and particle dopant into a high - energy ball mill, then add absolute ethanol, and ball - mill at a speed of 350 - 450 r / min for 3 - 5 h to obtain a mixed material;

[0009] A2. Transfer the mixed material obtained in A1 into a vacuum mixer, and mix at a vacuum degree of 10 - 3 Pa and a stirring speed

[0010] of 200 - 300 r / min for 2 - 3 h, and during this period, add a soldering flux at a dropping rate of 2 - 4 mL / min; obtain a low - temperature and rapid - curing solder.

[0011] Preferably, the components and weight parts of the raw materials for preparing the low - temperature and rapid - curing solder are as follows: 55 - 62 parts of multi - element alloy matrix powder, 10 - 15 parts of particle dopant, 3 - 4 parts of absolute ethanol, and 18 - 22 parts of soldering flux.

[0012] Preferably, the multi - element alloy matrix powder is prepared from tin, bismuth, indium, and gallium.

[0013] Preferably, the preparation method of the multi - element alloy matrix powder includes the following steps:

[0014] C1. Place tin, bismuth, indium, and gallium metal blocks with a purity of 99% into a vacuum induction melting furnace, and melt at a vacuum degree of 10 -5 -10 -4 Pa and a temperature of 1100 - 1300 °C for 30 - 45 min to obtain a multi - element alloy liquid;

[0015] C2. Place the multi - element alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device, and atomize the alloy liquid into tiny droplets at an ultrasonic frequency of 20 - 30 kHz and an argon gas flow rate of the atomizing gas of 12 - 18 L / min. During the falling process, cool and solidify the droplets through circulating water with a temperature of 10 °C and a flow rate of 0.5 L / min to obtain multi - element alloy powder;

[0016] C3. Transfer the multi - element alloy powder obtained in C2 to an air classifier, and perform air classification at a classifier wheel speed of 1500 - 2000 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain a multi - element alloy matrix powder.

[0017] Preferably, the components and weight parts of the raw materials for preparing the multi - element alloy matrix powder are as follows: 3.5 - 5.5 parts of tin, 2.5 - 4 parts of bismuth, 0.8 - 1.5 parts of indium, and 0.8 - 1.5 parts of gallium.

[0018] Preferably, the particle dopant is prepared from cerium - doped particles, silver - doped particles, and a carbon - doped dispersion liquid.

[0019] Preferably, the preparation method of the particle dopant comprises the following steps:

[0020] B1. Dissolve cerium nitrate in an ethylene glycol solution with a volume four times that of cerium nitrate, then add polyvinylpyrrolidone and continue stirring for 30 min. Then place it in a high-pressure reaction kettle and react at a temperature of 180 - 200 °C for 4 - 6 h. After the reaction, wait for the high-pressure reaction kettle to cool naturally to room temperature. Transfer the generated precipitate to a centrifuge tube, centrifuge at a speed of 8000 r / min for 15 min, take the precipitate, then add absolute ethanol to the precipitate, oscillate with an oscillator for 5 min, then centrifuge again under the same conditions, repeat 3 times, and then dry at a temperature of 60 °C and a vacuum of 10 -4 Pa for 12 h to obtain cerium-doped particles;

[0021] B2. Add a glucose solution with a volume five times that of silver nitrate solution, react at a stirring speed of 300 - 400 r / min and a temperature of 80 - 100 °C for 2 - 3 h. Then transfer the product to a centrifuge tube, add absolute ethanol with a volume five times that of the product, oscillate with an oscillator for 5 min, then centrifuge at 8000 r / min for 10 min, remove the supernatant, repeat 3 times, and then dry at a temperature of 60 °C and a vacuum of 10 - 4 Pa for 12 h to obtain silver-doped particles;

[0022] B3. Add carbon nanotubes to sodium dodecyl sulfate, then place it in water with a volume ten times that of the mixture, and ultrasonically oscillate at an ultrasonic frequency of 40 - 60 Hz for 30 - 45 min. Take out the dispersion to obtain a carbon-doped dispersion;

[0023] B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion obtained in B3, then place it in absolute ethanol with a volume one time that of the mixture, then ultrasonically clean at an ultrasonic frequency of 30 Hz for 10 min, and then dry at a vacuum of 10 -4 Pa and a temperature of 60 °C for 6 h to obtain the particle dopant.

[0024] Preferably, the components and weight parts of the raw materials for preparing the particle dopant are as follows: 2 - 4 parts of cerium-doped particles, 2 - 5 parts of silver-doped particles, and 3 - 4 parts of carbon-doped dispersion.

[0025] Preferably, the soldering flux is composed of a thermosensitive polymer, an amphiphilic surfactant, a radical scavenger, and a bio-based lubricant in a weight ratio of (8 - 10):(4 - 6):(2 - 3):(1 - 2).

[0026] Preferably, the mass ratio of cerium nitrate to polyvinylpyrrolidone in B1 is (5 - 10):1;

[0027] The molar ratio of silver nitrate to glucose in B2 is 1:(1 - 1.5);

[0028] The mass ratio of carbon nanotubes to sodium dodecyl sulfate in B3 is 1:(0.08 - 0.12).

[0029] The technical effects and advantages of the present invention:

[0030] During the preparation process of the present invention, bismuth element is added. In the alloy system, bismuth atoms interact with other metal atoms, changing the overall crystallization behavior of the alloy, enabling the alloy to initiate the solidification process at a lower temperature, laying a foundation for low-temperature curing, being able to achieve curing at a lower temperature, effectively avoiding thermal damage to heat-sensitive components, and being more suitable for welding operations in a low-temperature environment, reducing the dependence on complex heating equipment;

[0031] During the preparation process of the present invention, cerium-doped particles are added, enabling the invention to complete the curing process within seconds at a lower temperature. This rapid curing characteristic greatly improves the welding efficiency, can improve production efficiency, and reduce the production cycle;

[0032] The present invention contains various functional components, which can enable the solder to spread better on the welding surface, adapt to more types of welding surfaces, including some new materials with higher requirements for wettability, thereby improving the solder joint quality and ensuring the reliability of welding. Specific embodiments

[0033] The following further elaborates on the present invention in combination with the embodiments of the present invention. The raw materials used in each example and embodiment of the present invention are all common commercially available materials except as otherwise specifically stated below;

[0034] Preparation Examples 1 - 5

[0035] A multi-component alloy matrix powder, the preparation components and their corresponding proportions are shown in the following table, and it is prepared by the following preparation method:

[0036] C1. Place tin, bismuth, indium, and gallium metal blocks with a purity of 99% into a vacuum induction melting furnace, and melt for 30 min under a vacuum degree of 10 -5 Pa and a temperature of 1100 °C to obtain a multi-component alloy liquid;

[0037] C2. Place the multi-component alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device, and atomize the alloy liquid into tiny droplets at an ultrasonic frequency of 20 kHz and an argon gas flow rate of the atomizing gas of 12 L / min. During the falling process, the droplets are cooled and solidified by circulating water at a temperature of 10 °C and a flow rate of 0.5 L / min to obtain a multi-component alloy powder;

[0038] C3. Transfer the multi - element alloy powder obtained in C2 to an air classifier, and perform air classification under the conditions of a classifier wheel speed of 1500 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain the multi - element alloy matrix powder.

[0039] Table: Components and their mass ratios (kg) of the raw materials in Preparation Examples 1 - 5

[0040]

[0041] Preparation Example 6

[0042] A multi - element alloy matrix powder, which is different from that of Preparation Example 1, and the preparation method is as follows:

[0043] C1. Place the tin, bismuth, indium, and gallium metal blocks with 99% purity into a vacuum induction melting furnace, and melt at a vacuum degree of 10 -5 Pa and a temperature of 1200 °C for 35 min to obtain a multi - element alloy liquid;

[0044] C2. Place the multi - element alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device, and atomize the alloy liquid into tiny droplets under the conditions of an ultrasonic frequency of 20 kHz and an argon gas flow rate of the atomizing gas of 12 L / min. During the falling process, the droplets are cooled and solidified by circulating water at a temperature of 10 °C and a flow rate of 0.5 L / min to obtain a multi - element alloy powder;

[0045] C3. Transfer the multi - element alloy powder obtained in C2 to an air classifier, and perform air classification under the conditions of a classifier wheel speed of 1500 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain the multi - element alloy matrix powder.

[0046] Preparation Example 7

[0047] A multi - element alloy matrix powder, which is different from that of Preparation Example 1, and the preparation method is as follows:

[0048] C1. Place the tin, bismuth, indium, and gallium metal blocks with 99% purity into a vacuum induction melting furnace, and melt at a vacuum degree of 10 -4 Pa and a temperature of 1200 °C for 40 min to obtain a multi - element alloy liquid;

[0049] C2. Place the multi - element alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device, and atomize the alloy liquid into tiny droplets under the conditions of an ultrasonic frequency of 20 kHz and an argon gas flow rate of the atomizing gas of 12 L / min. During the falling process, the droplets are cooled and solidified by circulating water at a temperature of 10 °C and a flow rate of 0.5 L / min to obtain a multi - element alloy powder;

[0050] C3. Transfer the multi - element alloy powder obtained in C2 to an air classifier, and perform air classification under the conditions of a classifier wheel speed of 1500 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain the multi - element alloy matrix powder.

[0051] Preparation Example 8

[0052] A multi - element alloy matrix powder, which is different from that of Preparation Example 1, and the preparation method is as follows:

[0053] C1. Place tin, bismuth, indium, and gallium metal blocks with a purity of 99% into a vacuum induction melting furnace, and melt at a vacuum degree of 10 -4 Pa and a temperature of 1300 °C for 45 min to obtain a multi - element alloy liquid;

[0054] C2. Place the multi - element alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device, and atomize the alloy liquid into tiny droplets under the conditions of an ultrasonic frequency of 20 kHz and an argon gas flow rate of the atomizing gas of 12 L / min. During the fall, the droplets are cooled and solidified by circulating water at a temperature of 10 °C and a flow rate of 0.5 L / min to obtain the multi - element alloy powder;

[0055] C3. Transfer the multi - element alloy powder obtained in C2 to an air classifier, and perform air classification under the conditions of a classifier wheel speed of 1500 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain the multi - element alloy matrix powder.

[0056] Preparation Example 9

[0057] A multi - element alloy matrix powder, which is different from that of Preparation Example 1, and the preparation method is as follows:

[0058] C1. Place tin, bismuth, indium, and gallium metal blocks with a purity of 99% into a vacuum induction melting furnace, and melt at a vacuum degree of 10 -5 Pa and a temperature of 1100 °C for 30 min to obtain a multi - element alloy liquid;

[0059] C2. Place the multi - element alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device, and atomize the alloy liquid into tiny droplets under the conditions of an ultrasonic frequency of 25 kHz and an argon gas flow rate of the atomizing gas of 15 L / min. During the fall, the droplets are cooled and solidified by circulating water at a temperature of 10 °C and a flow rate of 0.5 L / min to obtain the multi - element alloy powder;

[0060] C3. Transfer the multi - element alloy powder obtained in C2 to an air classifier, and perform air classification under the conditions of a classifier wheel speed of 1500 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain the multi - element alloy matrix powder.

[0061] Preparation Example 10

[0062] A multi - element alloy matrix powder, which is different from that of Preparation Example 1, and the preparation method is as follows:

[0063] C1. Place tin, bismuth, indium, and gallium metal blocks with 99% purity into a vacuum induction melting furnace, and melt them at a vacuum degree of 10 -5 Pa and a temperature of 1100 °C for 30 min to obtain a multi - element alloy liquid;

[0064] C2. Place the multi - element alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device, and atomize the alloy liquid into tiny droplets at an ultrasonic frequency of 30 kHz and an argon gas flow rate of the atomizing gas of 18 L / min. During the falling process, the droplets are cooled and solidified by circulating water at a temperature of 10 °C and a flow rate of 0.5 L / min to obtain multi - element alloy powder;

[0065] C3. Transfer the multi - element alloy powder obtained in C2 to an air classifier, and perform air classification at a classifier wheel rotation speed of 1500 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain a multi - element alloy matrix powder.

[0066] Preparation Example 11

[0067] A multi - element alloy matrix powder, which is different from that of Preparation Example 1, and the preparation method is as follows:

[0068] C1. Place tin, bismuth, indium, and gallium metal blocks with 99% purity into a vacuum induction melting furnace, and melt them at a vacuum degree of 10 -5 Pa and a temperature of 1100 °C for 30 min to obtain a multi - element alloy liquid;

[0069] C2. Place the multi - element alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device, and atomize the alloy liquid into tiny droplets at an ultrasonic frequency of 20 kHz and an argon gas flow rate of the atomizing gas of 12 L / min. During the falling process, the droplets are cooled and solidified by circulating water at a temperature of 10 °C and a flow rate of 0.5 L / min to obtain multi - element alloy powder;

[0070] C3. Transfer the multi - element alloy powder obtained in C2 to an air classifier, and perform air classification at a classifier wheel rotation speed of 1750 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain a multi - element alloy matrix powder.

[0071] Preparation Example 12

[0072] A multi - element alloy matrix powder, which is different from that of Preparation Example 1, and the preparation method is as follows:

[0073] C1. Place tin, bismuth, indium, and gallium metal blocks with 99% purity into a vacuum induction melting furnace, and melt them at a vacuum degree of 10 -5Pa, melt for 30 min at 1100 °C to obtain a multi-component alloy liquid;

[0074] C2. Place the multi-component alloy liquid obtained in C1 into the atomization chamber of an ultrasonic atomization device. Atomize the alloy liquid into tiny droplets at an ultrasonic frequency of 20 kHz and an atomizing gas argon flow rate of 12 L / min. During the fall, cool and solidify the droplets with circulating water at a temperature of 10 °C and a flow rate of 0.5 L / min to obtain multi-component alloy powder;

[0075] C3. Transfer the multi-component alloy powder obtained in C2 to an air classifier. Perform air classification at a classifier wheel speed of 2000 r / min, an air flow rate of 8 m³ / h, and an air pressure maintained at 0.2 MPa to obtain multi-component alloy matrix powder.

[0076] Preparation Examples 13 - 17

[0077] A particle dopant, its preparation components and their corresponding ratios are shown in the following table, and it is prepared by the following preparation method:

[0078] B1. Dissolve cerium nitrate in an ethylene glycol solution with 4 times the volume, then add polyvinylpyrrolidone and continue stirring for 30 min. Then place it in a high-pressure reaction kettle and react at a temperature of 180 °C for 4 h. After the reaction is completed, wait for the high-pressure reaction kettle to cool naturally to room temperature. Transfer the generated precipitate to a centrifuge tube and centrifuge at a centrifuge speed of 8000 r / min for 15 min. Take the precipitate, then add absolute ethanol to the precipitate, use an oscillator to oscillate for 5 min, and then centrifuge again under the same conditions. Repeat 3 times and then dry at a temperature of 60 °C and a vacuum of 10 -4 Pa for 12 h to obtain cerium-doped particles;

[0079] Among them, the mass ratio of cerium nitrate to polyvinylpyrrolidone is 10:1;

[0080] B2. Add a glucose solution with 5 times the volume to the silver nitrate solution, react at a stirring speed of 300 r / min and a temperature of 80 °C for 2 h. Then transfer the product to a centrifuge tube, add absolute ethanol with 5 times the volume, use an oscillator to oscillate for 5 min, and then centrifuge at 8000 r / min for 10 min. Remove the supernatant. Repeat 3 times and then dry at a temperature of 60 °C and a vacuum of 10 -4 Pa for 12 h to obtain silver-doped particles;

[0081] Among them, the molar ratio of silver nitrate to glucose is 1:1;

[0082] B3. Add carbon nanotubes to sodium dodecyl sulfate, then place it in water with 10 times the volume, and ultrasonically oscillate for 30 min at an ultrasonic frequency of 40 Hz. Take out the dispersion to obtain a carbon-doped dispersion;

[0083] The mass ratio of carbon nanotubes to sodium dodecyl sulfate is 1:0.08;

[0084] B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion obtained in B3, then place them in 1 volume of absolute ethanol, and then ultrasonically clean for 10 min at an ultrasonic frequency of 30 Hz, and then the vacuum degree is 10 -4 Pa, and dry for 6 h at a temperature of 60 °C to obtain a particle dopant.

[0085] Table: Each component of the preparation raw materials and their mass ratios (kg) in Preparation Examples 13-17

[0086]

[0087] Preparation Example 18

[0088] A particle dopant, which is different from that in Preparation Example 13, and the preparation method is as follows:

[0089] B1. Dissolve cerium nitrate in 4 volumes of ethylene glycol solution, then add polyvinylpyrrolidone and continue stirring for 30 min, then place it in a high-pressure reaction kettle, and react at a temperature of 190 °C for 5 h. After the reaction is completed, wait for the high-pressure reaction kettle to cool naturally to room temperature, transfer the generated precipitate to a centrifuge tube, centrifuge at a centrifuge speed of 8000 r / min for 15 min, take the precipitate, then add absolute ethanol to the precipitate, oscillate with an oscillator for 5 min, and then centrifuge under the same conditions again. After repeating 3 times, dry at a temperature of 60 °C and a vacuum degree of 10 -4 Pa for 12 h to obtain cerium-doped particles;

[0090] B2. Add 5 volumes of glucose solution to the silver nitrate solution, react at a stirring speed of 300 r / min and a temperature of 80 °C for 2 h, then transfer the product to a centrifuge tube, add 5 volumes of absolute ethanol, oscillate with an oscillator for 5 min, and then centrifuge at 8000 r / min for 10 min to remove the supernatant. After repeating 3 times, dry at a temperature of 60 °C and a vacuum degree of 10-4 Pa for 12 h to obtain silver-doped particles;

[0091] B3. Add carbon nanotubes to sodium dodecyl sulfate, then place them in 10 volumes of water, and ultrasonically oscillate for 30 min at an ultrasonic frequency of 40 Hz, take out the dispersion to obtain a carbon-doped dispersion;

[0092] B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion obtained in B3, then place them in 1 volume of absolute ethanol, and then ultrasonically clean for 10 min at an ultrasonic frequency of 30 Hz, and then the vacuum degree is 10 -4Pa, dry for 6 h at 60 °C to obtain the particle dopant.

[0093] Preparation Example 19

[0094] A particle dopant, different from that of Preparation Example 13, the preparation method is as follows:

[0095] B1. Dissolve cerium nitrate in 4 times the volume of ethylene glycol solution, then add polyvinylpyrrolidone and continue stirring for 30 min. Then place it in a high-pressure reactor and react at 1000 °C for 6 h. After the reaction is completed, wait for the high-pressure reactor to cool naturally to room temperature. Transfer the generated precipitate to a centrifuge tube and centrifuge at a centrifuge speed of 8000 r / min for 15 min. Take the precipitate, then add absolute ethanol to the precipitate, oscillate with an oscillator for 5 min, and then centrifuge again under the same conditions. Repeat 3 times and then dry at 60 °C under a vacuum of 10 -4 Pa for 12 h to obtain cerium-doped particles;

[0096] B2. Add 5 times the volume of glucose solution to the silver nitrate solution, react at a stirring speed of 300 r / min and a temperature of 80 °C for 2 h. Then transfer the product to a centrifuge tube, add 5 times the volume of absolute ethanol, oscillate with an oscillator for 5 min, and then centrifuge at 8000 r / min for 10 min. Remove the supernatant. Repeat 3 times and then dry at 60 °C under a vacuum of 10 -4 Pa for 12 h to obtain silver-doped particles;

[0097] B3. Add carbon nanotubes to sodium dodecyl sulfate, then place it in 10 times the volume of water and ultrasonically oscillate for 30 min at an ultrasonic frequency of 40 Hz. Take out the dispersion to obtain a carbon-doped dispersion;

[0098] B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion obtained in B3, then place it in 1 times the volume of absolute ethanol, and then ultrasonically clean for 10 min at an ultrasonic frequency of 30 Hz, and then under a vacuum of 10 -4 Pa, dry for 6 h at 60 °C to obtain the particle dopant.

[0099] Preparation Example 20

[0100] A particle dopant, different from that of Preparation Example 13, the preparation method is as follows:

[0101] B1. Dissolve cerium nitrate in an ethylene glycol solution with a volume four times that of cerium nitrate, then add polyvinylpyrrolidone and continue stirring for 30 min. Next, place it in a high-pressure reaction kettle and react at 180 °C for 4 h. After the reaction is completed, wait for the high-pressure reaction kettle to cool naturally to room temperature. Transfer the generated precipitate to a centrifuge tube, centrifuge at a centrifuge speed of 8000 r / min for 15 min, take the precipitate, then add absolute ethanol to the precipitate, shake it with an oscillator for 5 min, and then centrifuge again under the same conditions. After repeating 3 times, dry it at 60 °C under a vacuum of 10 -4 Pa for 12 h to obtain cerium-doped particles;

[0102] B2. Add a glucose solution with a volume five times that of silver nitrate solution to the silver nitrate solution, react at a stirring speed of 350 r / min and a temperature of 90 °C for 2.5 h. Then transfer the product to a centrifuge tube, add absolute ethanol with a volume five times that of the product, shake it with an oscillator for 5 min, and then centrifuge at 8000 r / min for 10 min to remove the supernatant. After repeating 3 times, dry it at 60 °C under a vacuum of 10 -4 Pa for 12 h to obtain silver-doped particles;

[0103] B3. Add carbon nanotubes to sodium dodecyl sulfate, then place it in water with a volume ten times that of carbon nanotubes, and ultrasonically oscillate it for 30 min at an ultrasonic frequency of 40 Hz. Take out the dispersion to obtain a carbon-doped dispersion;

[0104] B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion obtained in B3, then place it in absolute ethanol with a volume one time that of the mixture, and then ultrasonically clean it at an ultrasonic frequency of 30 Hz for 10 min. Then dry it at 60 °C under a vacuum of 10 -4 Pa for 6 h to obtain a particle dopant.

[0105] Preparation Example 21

[0106] A particle dopant, which is different from that in Preparation Example 13, and the preparation method is as follows:

[0107] B1. Dissolve cerium nitrate in an ethylene glycol solution with a volume four times that of cerium nitrate, then add polyvinylpyrrolidone and continue stirring for 30 min. Next, place it in a high-pressure reaction kettle and react at 180 °C for 4 h. After the reaction is completed, wait for the high-pressure reaction kettle to cool naturally to room temperature. Transfer the generated precipitate to a centrifuge tube, centrifuge at a centrifuge speed of 8000 r / min for 15 min, take the precipitate, then add absolute ethanol to the precipitate, shake it with an oscillator for 5 min, and then centrifuge again under the same conditions. After repeating 3 times, dry it at 60 °C under a vacuum of 10 -4 Pa for 12 h to obtain cerium-doped particles;

[0108] B2. Add a glucose solution with a volume 5 times that of the silver nitrate solution, react at a stirring speed of 400 r / min and a temperature of 100 °C for 3 h. Then transfer the product to a centrifuge tube, add an anhydrous ethanol with a volume 5 times that of the product, oscillate for 5 min using an oscillator, then centrifuge at 8000 r / min for 10 min, remove the supernatant. Repeat this process 3 times and then dry at a temperature of 60 °C and a vacuum of 10 -4 Pa for 12 h to obtain silver-doped particles;

[0109] B3. Add carbon nanotubes to sodium dodecyl sulfate, then place it in water with a volume 10 times that of the mixture, and ultrasonically oscillate for 30 min at an ultrasonic frequency of 40 Hz. Take out the dispersion to obtain a carbon-doped dispersion;

[0110] B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion obtained in B3, then place it in anhydrous ethanol with a volume 1 times that of the mixture, then ultrasonically clean for 10 min at an ultrasonic frequency of 30 Hz, and then dry at a vacuum of 10 -4 Pa and a temperature of 60 °C for 6 h to obtain a particle dopant.

[0111] Preparation Example 22

[0112] A particle dopant, which is different from that in Preparation Example 13, and the preparation method is as follows:

[0113] B1. Dissolve cerium nitrate in an ethylene glycol solution with a volume 4 times that of the cerium nitrate, then add polyvinylpyrrolidone and continue stirring for 30 min. Then place it in a high-pressure reaction kettle and react at a temperature of 180 °C for 4 h. After the reaction ends, wait for the high-pressure reaction kettle to cool naturally to room temperature. Transfer the generated precipitate to a centrifuge tube and centrifuge at a centrifuge speed of 8000 r / min for 15 min. Take the precipitate, then add anhydrous ethanol to the precipitate, oscillate for 5 min using an oscillator, and then centrifuge again under the same conditions. Repeat this process 3 times and then dry at a temperature of 60 °C and a vacuum of 10 -4 Pa for 12 h to obtain cerium-doped particles;

[0114] B2. Add a glucose solution with a volume 5 times that of the silver nitrate solution, react at a stirring speed of 300 r / min and a temperature of 80 °C for 2 h. Then transfer the product to a centrifuge tube, add an anhydrous ethanol with a volume 5 times that of the product, oscillate for 5 min using an oscillator, then centrifuge at 8000 r / min for 10 min, remove the supernatant. Repeat this process 3 times and then dry at a temperature of 60 °C and a vacuum of 10 -4 Pa for 12 h to obtain silver-doped particles;

[0115] B3. Add carbon nanotubes to sodium dodecyl sulfate, then place it in water with a volume 10 times that of the above mixture, and ultrasonically oscillate for 40 min under the condition of an ultrasonic frequency of 50 Hz. Take out the dispersion liquid to obtain a carbon-doped dispersion liquid;

[0116] B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion liquid obtained in B3, then place it in absolute ethanol with a volume 1 times that of the above mixture, then ultrasonically clean for 10 min at an ultrasonic frequency of 30 Hz, and then dry for 6 h under the conditions of a vacuum degree of 10 -4 Pa and a temperature of 60 °C to obtain a particle dopant.

[0117] Preparation Example 23

[0118] A particle dopant, which is different from that in Preparation Example 13, and the preparation method is as follows:

[0119] B1. Dissolve cerium nitrate in ethylene glycol solution with a volume 4 times that of the above mixture, then add polyvinylpyrrolidone and continue stirring for 30 min. Then place it in a high-pressure reaction kettle and react for 4 h under the condition of a temperature of 180 °C. After the reaction is completed, wait for the high-pressure reaction kettle to cool naturally to room temperature. Transfer the generated precipitate to a centrifuge tube, centrifuge at a centrifuge speed of 8000 r / min for 15 min, take the precipitate, then add absolute ethanol to the precipitate, oscillate with an oscillator for 5 min, and then centrifuge under the same conditions again. Repeat 3 times and then dry at a temperature of 60 °C and a vacuum degree of 10 -4 Pa for 12 h to obtain cerium-doped particles;

[0120] B2. Add glucose solution with a volume 5 times that of the above mixture to the silver nitrate solution, react at a stirring speed of 300 r / min and a temperature of 80 °C for 2 h. Then transfer the product to a centrifuge tube, add absolute ethanol with a volume 5 times that of the above mixture, oscillate with an oscillator for 5 min, and then centrifuge at 8000 r / min for 10 min to remove the supernatant. Repeat 3 times and then dry at a temperature of 60 °C and a vacuum degree of 10 -4 Pa for 12 h to obtain silver-doped particles;

[0121] B3. Add carbon nanotubes to sodium dodecyl sulfate, then place it in water with a volume 10 times that of the above mixture, and ultrasonically oscillate for 45 min under the condition of an ultrasonic frequency of 60 Hz. Take out the dispersion liquid to obtain a carbon-doped dispersion liquid;

[0122] B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion liquid obtained in B3, then place it in absolute ethanol with a volume 1 times that of the above mixture, then ultrasonically clean for 10 min at an ultrasonic frequency of 30 Hz, and then dry for 6 h under the conditions of a vacuum degree of 10 -4 Pa and a temperature of 60 °C to obtain a particle dopant.

[0123] Preparation Example 24

[0124] A particle dopant, different from Preparation Example 13, in that the mass ratio of cerium nitrate to polyvinylpyrrolidone in B1 is 5:1.

[0125] Preparation Example 25

[0126] A particle dopant, different from Preparation Example 13, in that the molar ratio of silver nitrate to glucose in B2 is 1:1.5.

[0127] Preparation Example 26

[0128] A particle dopant, different from Preparation Example 13, in that the mass ratio of carbon nanotubes to sodium dodecyl sulfate in B3 is 1:0.12.

[0129] Preparation Examples 27 - 31

[0130] A low-temperature rapid-curing solder, the preparation components and their corresponding ratios are shown in the following table, and it is prepared by the following preparation method:

[0131] A1. Put the multi-alloy matrix powder and the particle dopant into a high-energy ball mill, then add absolute ethanol, and ball mill at a speed of 350 r / min for 3 h to obtain a mixed material;

[0132] The multi-alloy matrix powder is prepared from Preparation Example 1;

[0133] The particle dopant is prepared from Preparation Example 13;

[0134] A2. Transfer the mixed material obtained in A1 into a vacuum mixer, and mix at a vacuum degree of 10 -3 Pa and a stirring speed of 200 r / min for 2 h, and during this period, add the soldering flux at a dropping rate of 2 mL / min; to obtain a low-temperature rapid-curing solder.

[0135] Among them, the soldering flux is composed of a thermosensitive polymer, an amphiphilic surfactant, a radical scavenger, and a bio-based lubricant in a weight ratio of 9:5:2:1;

[0136] Table: Each component of the preparation raw materials and their mass ratios (kg) in Preparation Examples 27 - 31

[0137]

[0138] Preparation Example 32

[0139] A low-temperature rapid-curing solder, different from Preparation Example 27, in that the preparation method is as follows:

[0140] A1. Put the multi - element alloy matrix powder and particle dopant into a high - energy ball mill, then add absolute ethanol, and ball - mill at a speed of 400 r / min for 4 h to obtain a mixed material;

[0141] A2. Transfer the mixed material obtained in A1 into a vacuum mixer, and mix it for 2 h under a vacuum degree of 10 -3 Pa and a stirring speed of 200 r / min, and add a soldering flux at a dropping rate of 2 mL / min during the mixing process; obtain a low - temperature and rapid - curing solder.

[0142] Preparation Example 33

[0143] A low - temperature and rapid - curing solder, which is different from Preparation Example 27, and the preparation method is as follows:

[0144] A1. Put the multi - element alloy matrix powder and particle dopant into a high - energy ball mill, then add absolute ethanol, and ball - mill at a speed of 450 r / min for 5 h to obtain a mixed material;

[0145] A2. Transfer the mixed material obtained in A1 into a vacuum mixer, and mix it for 2 h under a vacuum degree of 10 -3 Pa and a stirring speed of 200 r / min, and add a soldering flux at a dropping rate of 2 mL / min during the mixing process; obtain a low - temperature and rapid - curing solder.

[0146] Preparation Example 34

[0147] A low - temperature and rapid - curing solder, which is different from Preparation Example 27, and the preparation method is as follows:

[0148] A1. Put the multi - element alloy matrix powder and particle dopant into a high - energy ball mill, then add absolute ethanol, and ball - mill at a speed of 350 r / min for 3 h to obtain a mixed material;

[0149] A2. Transfer the mixed material obtained in A1 into a vacuum mixer, and mix it for 2.5 h under a vacuum degree of 10 -3 Pa and a stirring speed of 250 r / min, and add a soldering flux at a dropping rate of 3 mL / min during the mixing process; obtain a low - temperature and rapid - curing solder.

[0150] Preparation Example 35

[0151] A low - temperature and rapid - curing solder, which is different from Preparation Example 27, and the preparation method is as follows:

[0152] A1. Put the multi - element alloy matrix powder and particle dopant into a high - energy ball mill, then add absolute ethanol, and ball - mill at a speed of 350 r / min for 3 h to obtain a mixed material;

[0153] A2. Transfer the mixed materials obtained in A1 into a vacuum mixer, and mix them for 3 h under a vacuum degree of 10 -2 Pa and a stirring speed of 300 r / min. During this period, add the soldering flux at a dropping rate of 4 mL / min to obtain a low-temperature and rapid-curing solder.

[0154] Preparation Example 36

[0155] A low-temperature and rapid-curing solder, which is different from Preparation Example 27 in that the soldering flux is composed of a thermosensitive polymer, an amphiphilic surfactant, a radical scavenger, and a bio-based lubricant in a weight ratio of 8:6:3:2.

[0156] Preparation Example 37

[0157] A low-temperature and rapid-curing solder, which is different from Preparation Example 27 in that the soldering flux is composed of a thermosensitive polymer, an amphiphilic surfactant, a radical scavenger, and a bio-based lubricant in a weight ratio of 10:4:2:1.

[0158] Preparation Examples 38 - 48

[0159] A low-temperature and rapid-curing solder, which is different from Preparation Example 27 in that the usage of the multi-alloy matrix powder used in its components is different, and the specific corresponding relationship is shown in the following table.

[0160] Table: Comparison Table of the Usage of the Multi-Alloy Matrix Powder in Preparation Examples 38 - 48

[0161]

[0162] Preparation Examples 49 - 61

[0163] A low-temperature and rapid-curing solder, which is different from Preparation Example 27 in that the usage of the multi-alloy matrix powder used in its components is different, and the specific corresponding relationship is shown in the following table.

[0164] Table: Comparison Table of the Usage of the Multi-Alloy Matrix Powder in Preparation Examples 49 - 61

[0165]

[0166] Performance Detection Test

[0167] Select the low-temperature and rapid-curing solders prepared in each example for inspection. The test subjects are 700 portions of low-temperature and rapid-curing solders, with 20 portions in each group. Detect their curing temperature and curing speed, and the specific detection steps are as follows:

[0168] Curing Temperature:

[0169] Samples were first taken from the low-temperature rapid-curing solder obtained in the examples. Using differential scanning calorimetry, the solder samples were placed in a DSC instrument and heated at a heating rate of 5 °C / min, and the change curve of the heat flow with temperature was recorded. The temperature corresponding to the endothermic peak on the curve was the curing temperature. The test results and evaluation criteria are as follows:

[0170] Curing temperature < 140 °C (regarded as low curing temperature);

[0171] 140 °C < curing temperature < 180 °C (regarded as medium curing temperature)

[0172] Curing temperature > 180 °C (regarded as high curing temperature).

[0173] Curing speed:

[0174] Samples were first taken from the low-temperature rapid-curing solder obtained in the examples. A visual welding monitoring platform was built and equipped with a high-speed camera to directly capture the whole process of solder melting and curing, and record the time until the surface of the solder joint solidified and there was no longer a liquid flow characteristic, obtaining the curing time of the prepared low-temperature rapid-curing solder, and characterizing the curing speed of the low-temperature rapid-curing solder based on this data. The test results and evaluation criteria are as follows:

[0175] Curing time < 5 s (regarded as fast curing speed);

[0176] 5 s < curing time < 15 s (regarded as medium curing speed)

[0177] Curing time > 15 s (regarded as slow curing speed).

[0178] It should be specifically noted that the above-prepared low-temperature rapid-curing solder is the low-temperature rapid-curing solder produced by maintaining the normal production method. For the defective low-temperature rapid-curing solder produced, the data of this low-temperature rapid-curing solder is discarded and not counted.

[0179] Examples 1-5

[0180] A low-temperature rapid-curing solder, and the corresponding relationships of the preparation methods used are shown in the following table.

[0181] Table: Comparison table of the usage of low-temperature rapid-curing solder in Examples 1-5

[0182]

[0183] The low-temperature rapid-curing solder in the above Examples 1-5 was extracted, and its curing temperature and curing time were tested according to the above measurement steps and measurement standards, and the test results were averaged and recorded in the following table.

[0184] Table: Performance test results of curing temperature and curing time in Examples 1-5

[0185]

[0186] As can be seen from the above table, the low-temperature fast-curing solder preparation processes in Examples 1-5 all have a good effect of improving the production effect of the low-temperature fast-curing solder. The addition of bismuth in the multi-element alloy matrix powder significantly reduces the melting point of the alloy, and forms a eutectic structure with tin, which changes the crystallization temperature range of the alloy, so that the solder can start the melting and solidification process at a lower temperature, providing a basic support for achieving low-temperature solidification; during the solidification process of the solder, the cerium-doped particles act as heterogeneous core adsorption atoms, which reduces the energy barrier required for nucleation of the alloy system, promotes grain refinement and uniform distribution, and numerous fine grains accelerate the solidification process and shorten the solidification time, thereby achieving the purpose of improving the production effect of the low-temperature fast-curing solder;

[0187] Its curing temperature is 134.7-144.6°C, which is considered to be a low curing temperature; its curing time is 3.72-4.75s, which is considered to be a fast curing speed;

[0188] It can be seen that when the production raw materials are certain, the production effect of the low-temperature fast-curing solder can be increased by adjusting the proportion of the preparation raw materials. Combined with the data in the above table, it is not difficult to see that when preparing the low-temperature fast-curing solder, 55 parts of the multi-alloy matrix powder, 15 parts of the particle dopant, 22 parts of the flux, and 4 parts of anhydrous ethanol are used, the curing temperature is the lowest. The reason for this is that the proportion of the multi-alloy matrix powder is relatively moderate, so that there are more cerium-doped particles, which act as a large number of heterogeneous cores during the solidification process, greatly reducing the energy required for alloy nucleation, so that the alloy can start crystallization at a very small degree of supercooling, significantly lowering the curing starting temperature, which is obtained from Examples 1-5.

[0189] It can be seen that when the production raw materials are certain, the production effect of the low-temperature fast-curing solder can be increased by adjusting the proportion of the prepared raw materials. Combined with the data in the above table, it is not difficult to see that when preparing the low-temperature fast-curing solder, using 60 parts of multi-alloy matrix powder, 12 parts of particle dopants, 20 parts of flux, and 3 parts of anhydrous ethanol, the curing time is the shortest. The reason for this is that 60 parts of the multi-alloy matrix powder as the main body provides sufficient metal to ensure the basic strength and conductivity required for the rapid forming of the solder joint. Its relatively simple alloy composition can flow quickly to fill the solder joint after melting, reducing the problem of slow melting due to complex components, and gaining time for subsequent rapid solidification, which is obtained from Examples 1-5.

[0190] Embodiment 6-11

[0191] A low-temperature fast-curing solder and its corresponding preparation methods are shown in the following table.

[0192] Table: Comparison of low temperature fast curing solder usage in Examples 6-11

[0193]

[0194] Extract the low-temperature rapid-curing solder in Examples 6-11 above, and test its curing temperature and curing time according to the above measurement steps and measurement standards. The average value of the test results is recorded in the following table.

[0195] Table: Performance test results of the curing temperature and curing time of Examples 1, 6-11

[0196]

[0197] As can be seen from the above table, in the preparation process of the low-temperature rapid-curing solder in Examples 6-11, it has a good effect of improving the production effect of the low-temperature rapid-curing solder. The addition of bismuth in the multi-component alloy matrix powder significantly reduces the melting point of the alloy. It forms a eutectic structure with tin, changing the crystallization temperature range of the alloy, enabling the solder to start the melting and solidification process at a lower temperature, providing a basic support for achieving low-temperature curing; during the solidification process of the solder, the cerium-doped particles, as heterogeneous nuclei adsorbing atoms, reduce the energy barrier required for nucleation in the alloy system, promoting grain refinement and uniform distribution. Numerous fine grains accelerate the solidification process and shorten the solidification time, thus achieving the purpose of improving the production effect of the low-temperature rapid-curing solder;

[0198] Its curing temperature is 136.6 - 139.1 °C, which is regarded as a low curing temperature; the curing time is 3.51 - 3.91 s, which is regarded as a fast curing speed;

[0199] It can be seen that when the production raw materials are certain, the production effect of the low-temperature rapid-curing solder can be increased by adjusting the preparation conditions. Combining the data in the above table, it is not difficult to see that when preparing the low-temperature rapid-curing solder, increasing the ball-milling speed and time in the primary mixing process; the vacuum degree, flux dropping rate, stirring speed, and mixing time in the secondary mixing process, the curing temperature decreases and the curing speed increases. The reason is that higher ball-milling speed and longer ball-milling time significantly enhance the mechanical interaction between the multi-component alloy matrix powder and the functional particle dopant; the nanoparticles can be embedded deeper and more uniformly into the alloy matrix, serving as heterogeneous nucleation sites, effectively reducing the undercooling required for alloy solidification, promoting the decrease of the curing temperature. The uniform dispersion of the nanoparticles in the alloy matrix optimizes the internal structure of the solder, and the diffusion path of atoms during solidification is regular, accelerating the solidification process; the faster flux dropping rate, higher stirring speed, and longer mixing time can make the flux wrap the alloy powder more quickly and fully, shortening the curing time, as obtained from Examples 1, 6-9.

[0200] It can be seen that when the production raw materials are fixed, the production effect of the low-temperature rapid-curing solder can be increased by adjusting the proportion of the flux raw materials. Combining the data in the above table, it is not difficult to see that when preparing the low-temperature rapid-curing solder, using the flux prepared from 9 parts of thermosensitive polymer, 5 parts of amphiphilic surfactant, 2 parts of radical scavenger, and 1 part of biobased lubricant, the curing temperature and curing time are the shortest. Analyzing the reason, it is because the content of the thermosensitive polymer in this flux formulation is relatively high, and its stretched molecular chains can enhance the fluidity of the solder, making heat transfer more efficient, promoting the alloy to reach the nucleation temperature faster, and facilitating the initiation of the solidification process at a lower temperature. The amphiphilic surfactant fully exerts its interface self-adaptive function, quickly wets the substrate and accelerates heat transfer, causing the solder to melt rapidly; the thermosensitive polymer precisely restricts the flow of the solder in the high-temperature welding area, ensuring the rapid formation of solder joints, obtained from Example 1 and Examples 10 - 11.

[0201] Examples 12 - 22

[0202] A low-temperature rapid-curing solder, and the corresponding relationships of its preparation methods are shown in the following table.

[0203] Table: Comparison table of the usage of low-temperature rapid-curing solder in Examples 12 - 22

[0204]

[0205] Extract the low-temperature rapid-curing solder in the above Examples 12 - 22, and test its curing temperature and curing time according to the above measurement steps and measurement standards. The test results are averaged and recorded in the following table.

[0206] Table: Performance test results of curing temperature and curing time in Examples 1, 12 - 22

[0207]

[0208] As can be seen from the above table, during the preparation of the low-temperature rapid-curing solder in Examples 12 - 22, they all have a good effect of improving the production effect of the low-temperature rapid-curing solder. The addition of bismuth in the multi-component alloy matrix powder significantly reduces the melting point of the alloy. It forms a eutectic structure with tin, changing the crystallization temperature range of the alloy, enabling the solder to initiate the melting and solidification processes at a lower temperature, providing a basic support for achieving low-temperature curing; during the solidification process of the solder, the cerium-doped particles, as heterogeneous nuclei, adsorb atoms, reducing the energy barrier required for nucleation in the alloy system, promoting the refinement and uniform distribution of grains. The numerous fine grains accelerate the solidification process and shorten the solidification time, thus achieving the purpose of improving the production effect of the low-temperature rapid-curing solder;

[0209] Its curing temperature is 136.5 - 139.4 °C, which is regarded as a low curing temperature; the curing time is 3.61 - 3.91 s, which is regarded as a fast curing speed;

[0210] It can be seen that when the production raw materials are fixed, the production effect of the low-temperature rapid-curing solder can be increased by adjusting the preparation conditions. From the data in the above table, it is not difficult to see that when preparing the multi-alloy matrix powder, the low-temperature rapid-curing solder prepared from 4 parts of tin, 4 parts of bismuth, 0.8 part of indium, and 1.2 parts of gallium has the lowest curing temperature. Analyzing the reason, the content of bismuth in this ratio is as high as 40%. As an element that can significantly reduce the melting point of the alloy, bismuth greatly lowers the melting point of the alloy in this proportion, enabling the solder to start the solidification process at a lower temperature. Obtained from Examples 1, 12 - 15.

[0211] It can be seen that when the production raw materials are fixed, the production effect of the low-temperature rapid-curing solder can be increased by adjusting the preparation conditions. From the data in the above table, it is not difficult to see that when preparing the multi-alloy matrix powder, the low-temperature rapid-curing solder prepared from 5 parts of tin, 3 parts of bismuth, 1 part of indium, and 1 part of gallium has the fastest curing speed. Analyzing the reason, 50% of tin ensures good fluidity, 30% of bismuth reduces the melting point so that the solder can melt and solidify quickly, 10% of indium is beneficial for the formation of solder joints, and 10% of gallium forms microscopic low-melting-point regions, promoting the overall solder to flow and solidify rapidly at low temperatures. Obtained from Examples 1, 12 - 15.

[0212] It can be seen that when the production raw materials are fixed, the production effect of the low-temperature rapid-curing solder can be increased by adjusting the preparation conditions. From the data in the above table, it is not difficult to see that when preparing the multi-alloy matrix powder, increasing the vacuum degree, melting temperature, and melting time during the melting process, the ultrasonic frequency and atomizing gas flow rate during the atomization process, and the rotating speed of the classification wheel during the air classification process, the curing temperature decreases and the curing speed increases. Analyzing the reason, when the melting vacuum degree is increased, during the solidification of the alloy, the atomic arrangement is more regular, and the heat transfer resistance continues to decrease, further optimizing the stability of the curing temperature. When the melting temperature is increased, the fusion of alloy elements will be more complete. High temperature promotes the full mixing of atoms of different elements, and the melting points of each part are closer during solidification, with excellent curing temperature consistency. Increasing the ultrasonic frequency makes the particle size distribution uniformity of the powder approach the extreme, almost in an ideal monodisperse state, reaching the ideal liquid temperature instantly during melting; increasing the atomizing gas flow rate, the high-speed atomizing gas causes the alloy droplets to cool rapidly, and the grain refinement degree of the powder particles is extremely high; the high-speed rotating classification wheel can accurately screen out the multi-alloy matrix powder that meets the requirements, further optimizing the powder particle size uniformity. Obtained from Examples 1, 16 - 22.

[0213] Examples 23 - 35

[0214] A low-temperature rapid-curing solder, and the corresponding relationships of its preparation methods are shown in the following table.

[0215] Table: Comparative Table of the Usage of Low-Temperature Rapid-Curing Solder in Examples 23 - 35

[0216]

[0217] Extract the low-temperature rapid-curing solder in the above Examples 23 - 35, and test its curing temperature and curing time according to the above measurement steps and measurement standards. The test results are averaged and recorded in the following table.

[0218] Table: Performance Test Results of Curing Temperature and Curing Time in Examples 1, 23 - 35

[0219]

[0220] As can be seen from the above table, during the preparation process of the low-temperature rapid-curing solder in Examples 23 - 35, it all has a good effect of improving the production effect of the low-temperature rapid-curing solder. The addition of bismuth in the multi-element alloy matrix powder significantly reduces the melting point of the alloy. It forms a eutectic structure with tin, changing the crystallization temperature range of the alloy, enabling the solder to start the melting and solidification process at a lower temperature, providing a basic support for achieving low-temperature curing; during the solidification process of the solder, cerium-doped particles, as heterogeneous nuclei, adsorb atoms, reducing the energy barrier required for nucleation in the alloy system, promoting grain refinement and uniform distribution. Numerous fine grains accelerate the solidification process and shorten the solidification time, thus achieving the purpose of improving the production effect of the low-temperature rapid-curing solder;

[0221] Its curing temperature is 136.2 - 139.1 °C, which is regarded as a low curing temperature; the curing time is 3.59 - 3.83 s, which is regarded as a fast curing speed;

[0222] It can be seen that when the production raw materials are certain, the production effect of the low-temperature rapid-curing solder can be increased by adjusting the preparation conditions. Combining the data in the above table, it is not difficult to see that when preparing the particle dopant, it is prepared from 4 parts of cerium-doped particles, 2 parts of silver-doped particles, and 4 parts of carbon-doped dispersion liquid. The low-temperature rapid-curing solder prepared by it has the lowest curing temperature and the fastest curing speed. Analyzing the reason, it is that the content of cerium-doped particles is the highest, at 40%; cerium-doped particles can act as heterogeneous nuclei to adsorb atoms during the solidification process, effectively reducing the energy barrier required for nucleation in the alloy system, promoting grain refinement and uniform distribution. Numerous fine grains accelerate the solidification process and also reduce the curing temperature; enabling the alloy to start solidification at a lower degree of supercooling. Due to the high content of cerium-doped particles, it can promote grain refinement and uniform distribution, and the solidification process starts simultaneously from numerous fine nuclei, greatly shortening the solidification time, obtained from Examples 1, 23 - 26.

[0223] It can be seen that when the production raw materials are fixed, the production effect of the low-temperature rapid-curing solder can be increased by adjusting the preparation conditions. From the data in the above table, it is not difficult to see that when preparing the multi-alloy matrix powder, increasing the reaction temperature and time during the preparation of cerium-doped particles, the heating temperature, stirring speed, and reaction time during the preparation of silver-doped particles, and the ultrasonic oscillation frequency and time during the preparation of carbon-doped dispersion liquid, the curing temperature of the prepared low-temperature rapid-curing solder decreases and the curing speed increases. The reason for this is that after the temperature is increased and the time is extended, the crystallization process of cerium-doped particles becomes more perfect, the generated particle sizes are more uniform, the particle size distribution range shrinks, and the well-crystallized cerium-doped particles can be incorporated into the multi-alloy matrix powder more quickly when mixed, activating the solidification activity of the alloy; the increase in heating temperature, acceleration of stirring, and extension of reaction time make the silver nitrate reduction reaction proceed more fully, and the generated silver-doped particles have smaller particle sizes and higher purity; when mixed with other components, the small-sized silver-doped particles can be quickly dispersed and synergistically activate the material activity; higher-frequency ultrasonic oscillation and longer-time treatment make the dispersion degree of carbon nanotubes in the dispersion liquid almost perfect, showing a single-dispersed state; after the solder melts, the extremely dispersed carbon nanotubes quickly transfer heat, stimulate atomic thermal motion, and provide strong power for solidification, as obtained from Examples 1, 27 - 32.

[0224] It can be seen that when the production raw materials are fixed, the production effect of the low-temperature rapid-curing solder can be increased by adjusting the preparation conditions. From the data in the above table, it is not difficult to see that when preparing the multi-alloy matrix powder, the mass ratio of cerium nitrate to polyvinylpyrrolidone is 5:1; the mol ratio of silver nitrate to glucose is 1:1; among them, the mass ratio of carbon nanotubes to sodium dodecyl sulfate is 1:0.08, and the prepared rapid-curing solder has the lowest curing temperature and the fastest curing speed, as obtained from Examples 1, 33 - 35.

[0225] This specific embodiment is only an explanation of the present invention and not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A method for preparing a low-temperature fast-curing solder, characterized in that: The following steps are involved: A1. Put the multi-element alloy matrix powder and the particle dopant into a high-energy ball mill, then add anhydrous ethanol, and ball mill at a speed of 350-450 r / min for 3-5 hours to obtain a mixed material; A2, transfer the mixture obtained in A1 into a vacuum mixer, mix for 2-3 hours at a vacuum degree of 10-3Pa and a stirring speed of 200-300r / min, during which time the flux is added dropwise at a dropping rate of 2-4mL / min; A low temperature fast solidifying solder is obtained; The components and weight proportions of the raw materials for preparing the low-temperature rapid curing solder are as follows: 55-62 parts of multi-element alloy matrix powder, 10-15 parts of particle dopant, 3-4 parts of anhydrous ethanol and 18-22 parts of flux; The components and weight proportions of the raw materials for preparing the multi-element alloy matrix powder are as follows: 3.5-5.5 parts of tin, 2.5-4 parts of bismuth, 0.8-1.5 parts of indium and 0.8-1.5 parts of gallium; The components and weight proportions of the raw materials for preparing the particle dopant are as follows: 2-4 parts of cerium-doped particles, 2-5 parts of silver-doped particles and 3-4 parts of carbon-doped dispersion.

2. A method for preparing a low-temperature fast-curing solder according to claim 1, characterized in that: The multi-element alloy matrix powder is prepared from tin, bismuth, indium and gallium; and the preparation method thereof comprises the following steps: C1. Place 99% pure tin, bismuth, indium and gallium metal blocks into a vacuum induction melting furnace, and melt for 30-45 minutes at a vacuum degree of 10-5-10-4Pa and 1100-1300°C to obtain a multi-element alloy liquid; C2, placing the multi-component alloy liquid obtained in C1 in the atomizing chamber of an ultrasonic atomizing device, atomizing the alloy liquid into tiny droplets at an ultrasonic frequency of 20-30kHz and an atomizing gas argon flow rate of 12-18L / min, cooling and solidifying the droplets through circulating water at a temperature of 10°C and a flow rate of 0.5L / min during the drop, to obtain a multi-component alloy powder; C3. The multi-component alloy powder obtained in C2 is transferred to an air flow classifier, and air flow classification is performed under the conditions of a classifying wheel speed of 1500-2000 r / min, an air flow rate of 8 m³ / h, and an air flow pressure maintained at 0.2 MPa to obtain a multi-component alloy matrix powder.

3. The method for preparing a low-temperature rapid solidification solder according to claim 1, characterized in that: The particle dopant is prepared from cerium-doped particles, silver-doped particles and carbon-doped dispersion; and the preparation method thereof comprises the following steps: B1. Dissolve cerium nitrate in 4 times the volume of ethylene glycol solution, then add polyvinyl pyrrolidone and continue stirring for 30 minutes, then place in a high-pressure reactor, react at a temperature of 180-200°C for 4-6 hours, after the reaction is completed, wait for the high-pressure reactor to cool naturally to room temperature, transfer the generated precipitate to a centrifuge tube, centrifuge at a speed of 8000r / min for 15 minutes, take the precipitate, then add anhydrous ethanol to the precipitate, use an oscillator to oscillate for 5 minutes, and then centrifuge again under the same conditions, repeat 3 times, and dry at a temperature of 60°C and a vacuum degree of 10-4Pa for 12 hours to obtain cerium-doped particles; B2. Add 5 times the volume of glucose solution to the silver nitrate solution, react at a stirring speed of 300-400 r / min and a temperature of 80-100°C for 2-3 hours, then transfer the product to a centrifuge tube, add 5 times the volume of anhydrous ethanol, oscillate on an oscillator for 5 minutes, and then centrifuge at 8000 r / min for 10 minutes, remove the supernatant, repeat 3 times, and dry at a temperature of 60°C and a vacuum degree of 10-4Pa for 12 hours to obtain silver-doped particles; B3, adding carbon nanotubes to sodium dodecyl sulfate, then placing in 10 times the volume of water, ultrasonically oscillating at an ultrasonic frequency of 40-60 Hz for 30-45 minutes, taking out the dispersion to obtain a carbon-doped dispersion; B4. Mix the cerium-doped particles obtained in B1, the silver-doped particles obtained in B2, and the carbon-doped dispersion obtained in B3, and then place them in 1 volume of anhydrous ethanol, followed by ultrasonic cleaning at an ultrasonic frequency of 30 Hz for 10 min, and then drying at a vacuum degree of 10-4 Pa and a temperature of 60°C for 6 h to obtain a particle dopant.

4. The method for preparing a low-temperature rapid curing solder according to claim 1, characterized in that: The soldering flux is composed of a thermosensitive polymer, an amphiphilic active agent, a free radical scavenger and a bio-based lubricant in a weight ratio of (8-10): (4-6): (2-3): (1-2).

5. The method for preparing a low-temperature rapid solidification solder according to claim 3, characterized in that: The mass ratio of cerium nitrate to polyvinyl pyrrolidone in B1 is (5-10): 1; The molar ratio of silver nitrate to glucose in B2 is 1:(1-1.5); The mass ratio of carbon nanotubes to sodium dodecyl sulfate in B3 is 1:(0.08-0.12).

6. A low-temperature fast-curing solder prepared according to the preparation method according to any one of claims 1 to 5.

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