Nickel-based amorphous brazing filler metal suitable for dissimilar material connection in high-temperature service environment and preparation method and brazing method of nickel-based amorphous brazing filler metal

Abstract

The invention relates to the technical field of amorphous alloy brazing filler metal, in particular to nickel-based amorphous brazing filler metal suitable for dissimilar material connection in a high-temperature service environment and a preparation method and a brazing method of the nickel-based amorphous brazing filler metal. The nickel-based amorphous brazing filler metal comprises the following components in percentage by mass: 8.5%-9.5% of Cr, 1.8%-2.2% of B, 3.2%-3.8% of Si, 2.2%-2.8% of Mo, 1.2%-1.8% of Co, 0.6%-0.9% of W, 0.05%-3% of rare earth elements and the balance of Ni. The preparation method comprises the steps of material preparation, smelting in a vacuum induction smelting furnace and vacuum melt-spinning treatment. The brazing method is vacuum brazing, and the brazing temperature ranges from 960 DEG C to 1120 DEG C. Compared with the prior art, the nickel-based amorphous brazing filler metal provided by the invention is high in tensile strength, stable in structure and good in oxidation resistance and corrosion resistance in a high-temperature service environment, and in addition, the nickel-based amorphous brazing filler metal also has good interface characteristics and a wider brazing temperature window.

Description

Technical Field

[0001] This invention relates to the field of amorphous alloy brazing technology, specifically to a nickel-based amorphous brazing filler metal suitable for joining dissimilar materials under high-temperature service environments, and its preparation and brazing methods. Background Technology

[0002] Nickel-based amorphous brazing filler metals are a type of amorphous brazing filler metal alloy formed by adding appropriate amounts of alloying elements such as chromium, boron, silicon, tungsten, phosphorus, and carbon to nickel as the base element. With its high amorphous forming ability, excellent high-temperature strength and precision forming characteristics, it has become a key material for reliable connection of dissimilar materials in high-temperature service environments such as aerospace and nuclear energy.

[0003] Compared to conventional nickel-based amorphous brazing filler metals, nickel-based amorphous brazing filler metals used for joining dissimilar materials in high-temperature service environments have higher requirements for high-temperature performance, such as high-temperature structural stability, oxidation resistance, corrosion resistance, and strength. Furthermore, the matching of the coefficient of thermal expansion, wettability, and interface quality of the nickel-based amorphous brazing filler metal are also crucial for improving its reliability and stability in high-temperature service environments.

[0004] In the existing technology, nickel-based amorphous brazing fillers have defects in structural stability, oxidation resistance, corrosion resistance and strength at high temperatures, and cannot well meet the requirements for long-term stable operation in high-temperature service environments. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a nickel-based amorphous brazing filler metal suitable for joining dissimilar materials in high-temperature service environments, as well as its preparation method and brazing method, to solve the problems of poor structural stability, oxidation resistance, corrosion resistance and strength of existing nickel-based amorphous brazing filler metals at high temperatures, and their inability to operate stably for a long period of time in high-temperature service environments.

[0006] To achieve the above objectives, the main technical solutions adopted by the present invention include: Firstly, this invention proposes a nickel-based amorphous brazing filler metal suitable for joining dissimilar materials under high-temperature service environments, comprising the following components by mass percentage: Cr 8.5%-9.5%, B 1.8%-2.2%, Si 3.2%-3.8%, Mo 2.2%-2.8%, Co 1.2%-1.8%, W 0.6%-0.9%, rare earth elements 0.05%-3%, with the balance being Ni.

[0007] In the aforementioned nickel-based amorphous brazing filler metal, Ni, Cr, Co, Mo, and W serve as matrix strengthening elements. Ni forms a face-centered cubic γ-Ni solid solution, while Cr and Co strengthen the filler metal through substitutional solid solution inducing lattice distortion, thus providing a solid strength foundation. Furthermore, at high temperatures, Cr oxidizes to form a continuous matrix film Cr2O3. The addition of Mo enhances the anti-stripping properties of the matrix film and improves the corrosion resistance of the nickel-based amorphous brazing filler metal in complex corrosive environments containing sulfur and chlorine. The addition of W strengthens the matrix film at ultra-high temperatures, making it more stable. Moreover, the expansion coefficient of the composite film Cr2O3-MoO3-WO3 formed after the addition of Mo and W is close to that of the matrix material, and this good matching reduces thermal stress cracking, further suppressing high-temperature spalling. In addition, the simultaneous addition of Mo and W can refine grain boundaries and inhibit the formation of brittle borides. In summary, controlling the content of Ni, Cr, Co, Mo, and W within the aforementioned range helps improve the long-term stability of the brazed joint at temperatures above 900℃.

[0008] Botanicals (B), silicon (Si), and rare earth elements are amorphous forming and strengthening elements. The addition of B and Si elements can improve the wettability and flowability of nickel-based amorphous brazing filler metals. However, excessive or insufficient addition can lead to brittleness of the brazed joint, resulting in lower shear strength. When the content of B and Si elements is controlled within the above-mentioned range, the nickel-based amorphous brazing filler metal has both good wettability and flowability, as well as very low brittleness, resulting in a low brazing temperature and high shear strength of the brazed joint. The addition of rare earth elements can significantly improve the amorphous forming ability of nickel-based amorphous brazing filler metals, further reduce the brazing temperature and reduce thermal damage to the base material. It can also generate rare earth compounds that help improve the hardness and wear resistance of the base material. In addition, some rare earth elements, such as La, can refine the grains, improve the interfacial bonding strength between the brazing filler metal and the base material, and enhance the reliability of the brazed joint.

[0009] This invention has demonstrated through several experiments that nickel-based amorphous brazing filler metal prepared by the above-mentioned components in the indicated mass percentages exhibits structural stability, good oxidation and corrosion resistance, and high strength under high-temperature conditions. When used for joining dissimilar materials under high-temperature service conditions, it can well meet the requirements for long-term stable operation under high-temperature service conditions.

[0010] Furthermore, the rare earth element is selected from at least one of La, Nd, Ce, Er, Eu, Dy, and Tb. Different rare earth elements have different suitable addition amounts. Through creative effort, this invention confirms that when La is selected as the rare earth element, the mass percentage of La is 0.1%-0.25%; when Nd is selected as the rare earth element, the mass percentage of Nd is 0.05%-1.5%; and when Ce is selected as the rare earth element, the mass percentage of Ce is 0.01%-1%.

[0011] Furthermore, the mass percentages of Cr, Mo, and W within the composite film are a, b, and c, respectively, where a, b, and c satisfy the following requirement: 2.6 < a / (b+c) < 3.1. Under this constraint, the Cr2O3-MoO3-WO3 composite film is dense and continuous, exhibiting strong anti-stripping properties, high high-temperature stability, excellent resistance to sulfur / chlorine corrosion, and good mechanical properties. It remains long-lasting and stable under high-temperature service conditions, with particularly good performance when 2.7 ≤ a / (b+c) ≤ 3. Preferably, based on the above-mentioned constraint condition that a / (b+c) satisfies, the mass percentage ratio of W to Mo, c / b, satisfies 0. When c / b ≤ 0.33, nickel-based amorphous brazing filler metals exhibit excellent high-temperature oxidation resistance and corrosion resistance. MoO3, formed by the oxidation of Mo, is unstable at high temperatures and has poor protective properties when it exists alone. However, when combined with Cr2O3, it can improve the density of the oxide film and inhibit crack propagation. WO3, formed by the oxidation of W, is stable at high temperatures and can improve oxidation resistance when combined with Cr2O3. Furthermore, the solid solution of W in the nickel matrix can also improve the high-temperature strength of the brazing filler metal. When c / b satisfies 0.30 ≤ c / b ≤ 0.33, the resulting nickel-based amorphous brazing filler metal can well meet the requirements for long-term, stable, and reliable use in harsh environments.

[0012] Furthermore, the sum of the mass percentages d of B, Si, Co, and W within it must satisfy the following requirement: 7.3% ≤ d ≤ 8.5%.

[0013] While B and Si play positive roles, excessive amounts can form intermetallic compounds with Ni. For example, B and Ni can form hard and brittle Ni2B and Ni3B, inducing local crystallization and reducing the amorphous ratio. During high-temperature brazing, the diffusion of B is accelerated, leading to the formation of more brittle phases such as Ni-B-Si at the brazed joint interface. Similarly, Si and Ni can form intermetallic compounds such as Ni3Si and Ni5Si2, which disrupt the homogeneity of amorphous materials, increase the brittleness of amorphous brazing filler metal, and result in poor toughness of the brazed joint. Excessive amounts of Co and W are detrimental to the amorphous formation ability of the brazing filler metal.

[0014] This invention discovers that by controlling the individual addition amounts of B, Si, Co, and W, and further limiting their total addition amount to 7.3%-8.5%, the stability of the amorphous structure can be effectively guaranteed, phase transformation can be avoided, and nickel-based amorphous brazing filler metal can maintain good toughness, hardness, and thermal stability, while also achieving effective control over production costs.

[0015] Furthermore, in order to achieve a balance between the amorphous forming ability and hardness of nickel-based amorphous solder, the mass percentage ratio e of B to Co within it must satisfy the following requirement: 1.2 < e ≤ 1.43.

[0016] Boron (B) is a typical melting point reducing element, which can lower the liquidus temperature of the alloy, promote amorphous formation, and form a short-range ordered Ni-B coordination structure with Ni, inhibiting crystal nucleation growth. Co can partially replace Ni solid solution, inducing lattice distortion and thus improving the strength of the brazing filler metal. This invention has found that when the mass percentage ratio of B to Co is controlled at 1.2 < e ≤ 1.43, the brazing filler metal can form a good amorphous structure while also possessing sufficient strength, ensuring the stability and reliability of the brazed joint.

[0017] Furthermore, within this context, the mass percentage ratio f of B to Si satisfies the following requirement: 0.56 ≤ f ≤ 0.61.

[0018] Within the aforementioned limits for the addition of B and Si elements, this invention has discovered that when the mass percentage ratio f of B to Si is controlled between 0.56 and 0.61, a eutectic Ni-B-Si phase can be formed. This phase results in an atomic packing density of 0.72 while simultaneously reducing the critical cooling rate to 1 × 10⁻⁶. 6 At approximately ℃ / s, while ensuring good wettability and flowability of the solder, the brittleness tendency is minimized and the shear strength is improved. Furthermore, this invention unexpectedly discovered that when the mass percentage ratio f of B to Si is controlled at 0.56-0.61 and the ratio of the mass percentage of Cr to the sum of the mass percentages of Mo and W is controlled at 2.7-3, the compositional uniformity of the nickel-based amorphous solder can be significantly improved, and component segregation can be reduced.

[0019] Secondly, this invention proposes a method for preparing nickel-based amorphous solder, comprising the following steps: S1. Prepare the materials according to the mass percentage of each element in the nickel-based amorphous brazing filler metal, and the purity of the raw materials corresponding to each element shall not be less than 99.95%; S2. The alloy ingot is obtained by melting in a vacuum induction furnace under inert gas protection and then cooling after melting. S3. By vacuum spinning the obtained alloy ingot, nickel-based amorphous brazing wire strip is obtained.

[0020] It should be noted that in step S1, during material preparation, all raw materials need to be dried at 100-160℃ for 24 hours to completely remove moisture and impurities; during weighing, a high-precision weighing device with an accuracy of 0.0001g is used, and the operating environment temperature is controlled within 20-25℃ and the relative humidity is within 30%-50%; the above requirements are mainly to ensure the accuracy and stability of the brazing filler metal composition.

[0021] Furthermore, in step S2, the melting temperature is 1250-1520℃, and the melting time is 30-50 minutes; preferably, in step S2, the pressure inside the vacuum induction melting furnace is below 1×10⁻⁶ throughout the entire melting process. -3Pa; Preferably, in step S2, high-purity argon gas is filled into the vacuum induction melting furnace as a protective atmosphere; the vacuum environment and argon gas protection can effectively prevent the oxidation reaction of each element at high temperature and ensure the accuracy of the composition; Preferably, in step S2, electromagnetic stirring is continuously performed at a frequency of 50-60Hz throughout the melting process; electromagnetic stirring promotes the full diffusion and uniform distribution of various elements, avoids the phenomenon of composition segregation, so that the final alloy ingot has a uniform and consistent composition; Preferably, the vacuum induction melting furnace is heated to the melting temperature at a heating rate of 10-15℃ / min to ensure that the raw materials are completely melted and mixed uniformly, and after the melting is completed, it is cooled to room temperature at a cooling rate of no more than 5℃ / min. The low cooling rate helps to reduce the internal stress of the alloy and reduce defects, thereby obtaining an alloy ingot with uniform composition and stable quality.

[0022] Furthermore, in step S3, the obtained alloy ingot is placed in a quartz tube equipped with a nozzle, a vacuum is drawn, and the ingot is heated under inert gas protection to turn it into a liquid alloy. Then, the liquid alloy is extruded from the nozzle using inert gas and continuously dripped onto a rotating water-cooled copper roller for rapid cooling to form a nickel-based amorphous brazing filler metal strip. Preferably, in step S3, the pressure inside the quartz tube is below 1×10⁻⁶. -3 Pa reduces melt oxidation and gas entrainment, ensuring efficient interfacial heat transfer. The inert gas, high-purity argon at 0.3-0.33 MPa, suppresses alloy component volatilization. The alloy melt temperature is 1200-1500℃, at which point the viscosity is between 0.3-0.5 Pa·s with good fluidity, meeting the requirements for spray forming. Temperatures exceeding 1500℃ lead to boron volatilization and rare earth oxide particle coarsening; temperatures below 1200℃ result in excessive viscosity, poor fluidity, difficulty in forming uniform thin strips, and a decreased cooling rate. The water-cooled copper roller has an inlet at one end and an outlet at the other. Cooling water enters the water-cooled copper roller through the inlet and flows out through the outlet. The inlet temperature is 30-35℃, the outlet temperature is 55-75℃, and the cooling water flow rate is 2.5-3.5 m / s. Under these parameters, the surface temperature gradient of the copper roller is moderate, which can suppress crystallization, ensure the purity and integrity of the amorphous structure, without increasing energy consumption or causing strip thickness fluctuations. The distance between the nozzle and the surface of the water-cooled copper roller is 14-16 cm, and the rotation speed of the water-cooled copper roller is 3800-4200 r / min. By precisely controlling the above technical parameters, the surface temperature of the water-cooled copper roller is uniform, and the cooling rate is controlled at 1.1 × 10⁻⁶ during vacuum strip spinning. 6 -1.6×10 6 At ℃ / s, a uniform and stable alloy liquid can be rapidly cooled to form a uniform, stable nickel-based amorphous brazing wire strip with an amorphous phase content of >98% and a thickness of 40-50μm.

[0023] Thirdly, this invention proposes a brazing method for nickel-based amorphous brazing filler metal, wherein the brazing method is vacuum brazing and the brazing temperature is 960-1120℃.

[0024] Traditional nickel-based amorphous brazing filler metals are mostly limited to temperatures below 1000°C. The nickel-based amorphous brazing filler metal proposed in this invention has a wide temperature window, reducing the dependence on temperature control precision.

[0025] Compared with existing technologies, this invention optimizes the composition and proportion of nickel-based amorphous brazing filler metal and improves the preparation process to obtain a nickel-based amorphous brazing filler metal that can well meet the requirements of dissimilar material joining under high-temperature service conditions. It exhibits good structural stability, oxidation resistance, corrosion resistance, and strength at high temperatures. At 950℃, the tensile strength of the brazed joint is ≥220MPa and the shear strength is ≥310MPa. After 1000 hours of continuous service at 900℃, the tensile strength retention rate is 85% or higher. Simultaneously, it significantly improves interfacial wettability, with the wetting angle significantly reduced to 11°-26°. Furthermore, the difference in thermal expansion coefficient between the filler metal and the nickel-based base material is ≤±0.8×10⁻⁶. -6 / ℃, reducing thermal stress cracks by more than 90%; the brazing temperature window has been widened from ≤1000℃ of traditional brazing filler metal to 960-1120℃, greatly improving process adaptability. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The image shows the XRD pattern of the nickel-based amorphous solder obtained in Example 1 of this invention. Figure 2 This is a photograph of the nickel-based amorphous solder obtained in Example 1 of the present invention; Figure 3 This is a photograph of the nickel-based amorphous solder obtained in Example 5 of the present invention; Figure 4 This is a photograph of the nickel-based amorphous solder obtained in Example 8 of the present invention. Figure 5 Here is a photograph of the nickel-based amorphous solder obtained in Example 16 of this invention; Figure 6 The image shows the XRD pattern of the nickel-based amorphous solder obtained in Example 8 of this invention. Figure 7 The image shows the XRD pattern of the nickel-based amorphous solder obtained in Comparative Example 3 of this invention. Figure 8 The image shows the XRD pattern of the nickel-based amorphous solder obtained in Comparative Example 4 of this invention. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0029] Example 1

[0030] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.0%, B 2.0%, Si 3.4%, Mo 2.6%, Co 1.4%, W 0.8%, La 0.2%, and Ni 0.6%.

[0031] The specific preparation method is as follows: S1. Prepare materials according to the mass percentage of each element in the nickel-based amorphous brazing filler metal. The purity of each element in the raw material shall not be less than 99.95%. Before use, all materials shall be subjected to necessary treatments such as impurity removal and drying. The weighing environment shall be 24℃ and 35% humidity. The balance used for weighing shall have an accuracy of 0.0001g. S2. Place the prepared raw materials in a vacuum induction melting furnace, and first evacuate it until the pressure is below 1×10⁻⁶. -3 Pa, then high-purity argon gas (99.999%) is introduced, and then the furnace temperature is raised to 1400℃ at a heating rate of 12℃ / min and maintained for 45min for melting. After melting, the vacuum induction melting furnace is cooled to room temperature at a cooling rate of 5℃ / min to obtain alloy ingots. S3. Place the obtained alloy ingot into a quartz tube equipped with a nozzle, with the pressure inside the quartz tube below 1×10⁻⁶. -3 The process involves evacuating the vacuum and filling the ingot with high-purity argon gas at a pressure of 0.32 MPa. Medium-frequency induction heating transforms the alloy ingot into a molten alloy at 1385°C. The molten alloy is then extruded through a nozzle using high-purity argon gas and continuously dripped onto a rotating water-cooled copper roller for rapid cooling, forming a 45 μm thick nickel-based amorphous brazing filler metal strip (appearance as shown). Figure 2 As shown in the figure, the water-cooled copper roller has an inlet at one end and an outlet at the other end. Cooling water enters the water-cooled copper roller through the inlet and flows out through the outlet. The inlet temperature is 32℃, the outlet temperature is 65℃, and the cooling water flow rate is 3m / s. The distance between the nozzle and the surface of the water-cooled copper roller is 15cm. The rotation speed of the water-cooled copper roller is 4000r / min.

[0032] Example 2

[0033] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 8.5%, B 1.8%, Si 3.2%, Mo 2.2%, Co 1.2%, W 0.6%, La 0.2%, and Ni 82.3%.

[0034] The preparation method differs from Example 1 in the following ways: melting temperature 1520℃, time 30 min, alloy liquid temperature 1509℃, inlet temperature 30℃, outlet temperature 55℃, cooling water flow rate 3.5 m / s, distance between nozzle and water-cooled copper roller surface 14 cm, and water-cooled copper roller rotation speed 3800 r / min. A nickel-based amorphous brazing filler metal strip with a thickness of 40 μm is finally obtained.

[0035] Example 3

[0036] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.5%, B 2.2%, Si 3.8%, Mo 2.8%, Co 1.8%, W 0.9%, La 0.2%, and Ni 78.8%.

[0037] The preparation method differs from Example 1 in the following ways: melting temperature 1250℃, time 50min, alloy liquid temperature 1232℃, inlet temperature 35℃, outlet temperature 75℃, cooling water flow rate 2.5m / s, distance between nozzle and water-cooled copper roller surface 16cm, and water-cooled copper roller rotation speed 4200r / min. A nickel-based amorphous brazing filler metal strip with a thickness of 50μm is finally obtained.

[0038] Example 4

[0039] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.2%, B 1.9%, Si 3.3%, Mo 2.5%, Co 1.3%, W 0.8%, La 0.2%, and Ni 0.8%.

[0040] The preparation method differs from Example 1 in the following ways: melting temperature 1300℃, time 35min, alloy liquid temperature 1285℃, inlet temperature 30℃, outlet temperature 55℃, cooling water flow rate 2.8m / s, distance between nozzle and water-cooled copper roller surface 14cm, and water-cooled copper roller rotation speed 4100r / min. A nickel-based amorphous brazing filler metal strip with a thickness of 42μm was finally obtained.

[0041] Example 5

[0042] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.5%, B 2.2%, Si 3.7%, Mo 2.8%, Co 1.7%, W 0.9%, La 0.2%, and Ni 79.0%.

[0043] The preparation method is the same as in Example 1, and the appearance of the resulting product is as follows. Figure 3 As shown.

[0044] Example 6

[0045] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 8.6%, B 1.8%, Si 3.2%, Mo 2.3%, Co 1.2%, W 0.7%, La 0.2%, and Ni 82.0%.

[0046] The preparation method is the same as in Example 1.

[0047] Example 7

[0048] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.0%, B 2.1%, Si 3.6%, Mo 2.4%, Co 1.6%, W 0.8%, La 0.2%, and Ni 0.3%.

[0049] The preparation method is the same as in Example 1.

[0050] Example 8

[0051] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.5%, B 2.2%, Si 3.8%, Mo 2.8%, Co 1.8%, W 0.9%, La 0.2%, and Ni 78.8%.

[0052] The preparation method is the same as in Example 1, and the appearance of the resulting product is as follows. Figure 4 As shown.

[0053] Example 9

[0054] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 8.8%, B 1.9%, Si 3.4%, Mo 2.4%, Co 1.4%, W 0.8%, La 0.2%, and Ni 81.1%.

[0055] The preparation method is the same as in Example 1.

[0056] Example 10

[0057] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 8.5%, B 1.8%, Si 3.2%, Mo 2.2%, Co 1.2%, W 0.6%, La 0.2%, and Ni 82.3%.

[0058] The preparation method is the same as in Example 1.

[0059] Example 11

[0060] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.2%, B 2.1%, Si 3.5%, Mo 2.6%, Co 1.5%, W 0.8%, La 0.2%, and Ni 0.1%.

[0061] The preparation method is the same as in Example 1.

[0062] Example 12

[0063] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.0%, B 2.0%, Si 3.4%, Mo 2.5%, Co 1.4%, W 0.8%, La 0.2%, and Ni 0.7%.

[0064] The preparation method is the same as in Example 1.

[0065] Example 13

[0066] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.4%, B 2.2%, Si 3.7%, Mo 2.7%, Co 1.7%, W 0.9%, La 0.2%, and Ni 79.2%.

[0067] The preparation method is the same as in Example 1.

[0068] Example 14

[0069] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 8.7%, B 1.9%, Si 3.3%, Mo 2.3%, Co 1.3%, W 0.7%, La 0.2%, and Ni 81.6%.

[0070] The preparation method is the same as in Example 1.

[0071] Example 15

[0072] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.3%, B 2.2%, Si 3.6%, Mo 2.7%, Co 1.6%, W 0.9%, La 0.2%, and Ni 79.5%.

[0073] The preparation method is the same as in Example 1.

[0074] Example 16

[0075] Compared with Example 1, the mass percentage of component La was adjusted to 0.15%, Ni was adjusted to 80.65%, and the rest remained the same as in Example 1.

[0076] The preparation method is the same as in Example 1, and the appearance of the resulting product is as follows. Figure 5 As shown.

[0077] Example 17

[0078] Compared with Example 1, the mass percentage of component La was adjusted to 0.25%, Ni was adjusted to 80.55%, and the rest remained the same as in Example 1.

[0079] The preparation method is the same as in Example 1.

[0080] Example 18

[0081] Compared with Example 1, the component La was adjusted to 0.5% Nd by mass, Ni was adjusted to 80.3%, and the rest remained the same as in Example 1.

[0082] The preparation method is the same as in Example 1.

[0083] Example 19

[0084] Compared with Example 1, the component La was adjusted to 1.5% Nd by mass, Ni was adjusted to 79.3%, and the rest remained the same as in Example 1.

[0085] The preparation method is the same as in Example 1.

[0086] Example 20

[0087] Compared to Example 1, component La was adjusted to an equal amount of Ce, while all other aspects remained the same as in Example 1.

[0088] The preparation method is the same as in Example 1.

[0089] Example 21

[0090] Compared with Example 1, component La was adjusted to 1% by mass of Ce, Ni was adjusted to 79.8%, and the rest remained the same as in Example 1.

[0091] The preparation method is the same as in Example 1.

[0092] Example 22

[0093] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.2%, B 2.0%, Si 3.4%, Mo 2.2%, Co 1.4%, W 0.6%, La 0.2%, and Ni 81.0%. The preparation conditions are consistent with those of Example 1.

[0094] Example 23

[0095] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.0%, B 2.0%, Si 3.4%, Mo 2.4%, Co 1.4%, W 0.84%, La 0.2%, and Ni 0.76%. The preparation conditions are consistent with those of Example 1.

[0096] Example 24

[0097] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.0%, B 1.98%, Si 3.4%, Mo 2.6%, Co 1.8%, W 0.8%, La 0.2%, and Ni 0.22%. The preparation conditions are consistent with those of Example 1.

[0098] Example 25

[0099] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.0%, B 1.8%, Si 3.6%, Mo 2.6%, Co 1.4%, W 0.8%, La 0.2%, and Ni 0.6%. The preparation conditions are consistent with those of Example 1.

[0100] Example 26

[0101] A nickel-based amorphous solder comprises the following components in the indicated mass percentages: Cr 9.0%, B 2.05%, Si 3.2%, Mo 2.6%, Co 1.4%, W 0.8%, La 0.2%, and Ni 0.75%. The preparation conditions are consistent with those of Example 1.

[0102] Comparative Example 1 Compared with Example 1, the nickel-based amorphous solder does not contain La, and the mass percentage of Ni is adjusted from 80.6% to 80.8%, while the rest remains the same as in Example 1.

[0103] Comparative Example 2 Compared with Example 1, the content of La in the nickel-based amorphous solder was adjusted from 0.2% to 0.4%, and the mass percentage of Ni was adjusted from 80.6% to 80.4%, while the rest remained the same as in Example 1.

[0104] Comparative Example 3 Compared with Example 1, the content of B in the nickel-based amorphous solder was adjusted from 2.0% to 1.5%, and the mass percentage of Ni was adjusted from 80.6% to 81.1%, while the rest remained the same as in Example 1.

[0105] Comparative Example 4 Compared with Example 1, the content of B in the nickel-based amorphous solder was adjusted from 2.0% to 2.5%, and the mass percentage of Ni was adjusted from 80.6% to 80.1%, while the rest remained the same as in Example 1.

[0106] Comparative Example 5 Compared with Example 1, the Si content in the nickel-based amorphous solder was adjusted from 3.4% to 3.0%, and the Ni mass percentage was adjusted from 80.6% to 81.0%, while the rest remained the same as in Example 1.

[0107] Comparative Example 6 Compared with Example 1, the Si content in the nickel-based amorphous solder was adjusted from 3.4% to 4.0%, and the Ni mass percentage was adjusted from 80.6% to 80.0%, while the rest remained the same as in Example 1.

[0108] Comparative Example 7 Compared with Example 1, the Co content in the nickel-based amorphous solder was adjusted from 1.4% to 1%, and the Ni mass percentage was adjusted from 80.6% to 81%, while the rest remained the same as in Example 1.

[0109] Comparative Example 8 Compared with Example 1, the Co content in the nickel-based amorphous solder was adjusted from 1.4% to 2%, and the Ni mass percentage was adjusted from 80.6% to 80%, while the rest remained the same as in Example 1.

[0110] Comparative Example 9 Compared with Example 1, in step S3 of the preparation process, the inlet temperature was 25°C, the outlet temperature was 80°C, the distance between the nozzle and the surface of the water-cooled copper roller was 12cm, and the rotation speed of the water-cooled copper roller was 4500r / min. All other aspects remained the same as in Example 1.

[0111] Comparative Example 10 Compared with Example 1, in step S3 of the preparation process, the inlet temperature was 40°C, the outlet temperature was 50°C, the distance between the nozzle and the surface of the water-cooled copper roller was 18cm, and the rotation speed of the water-cooled copper roller was 3600r / min. All other aspects remained the same as in Example 1.

[0112] The mass percentage of each component and the key technical parameters of preparation in the above embodiments and comparative examples are shown in Table 1 (for ease of description, Example 1 is represented by S1, Comparative Example 1 by D1, and so on; the distance between the nozzle and the surface of the water-cooled copper roller is simply referred to as "gap", and the rotational speed of the water-cooled copper roller is simply referred to as "rotational speed").

[0113]

[0114] from Figures 1 to 8 As can be seen from the results shown in Tables 1 and 2: (1) Compared with traditional BNi-2 brazing filler metal (shear strength ≤180MPa, wetting angle ≥30°), the nickel-based amorphous brazing filler metal prepared in this invention exhibits improved shear strength of the brazed joint to 310-445MPa and reduced wetting angle to 11°-26° under vacuum brazing conditions at 950℃. This indicates that through the rational proportioning and scientific design of components such as Cr, B, Si, Mo, Co, W, rare earth elements, and Ni, the elements exert a synergistic effect, significantly improving the structural stability, oxidation resistance, corrosion resistance, and mechanical strength of the brazing filler metal under high-temperature conditions. Further testing shows that the difference between the thermal expansion coefficient of this brazing filler metal and the nickel-based base material does not exceed ±0.8×10⁻⁶. -6 / ℃, thermal stress cracks are reduced by more than 90%, and the brazing temperature window is widened from ≤1000℃ of traditional brazing filler metal to 960-1120℃, significantly enhancing process adaptability.

[0115] Taking the product obtained in Example 1 as an example, its amorphous phase content exceeds 98%, and its glass transition temperature is 525°C. During vacuum brazing at 950°C, the shear strength of the brazed joint reaches 390 MPa, which is 117% higher than that of traditional BNi-2 brazing filler metal (≤180 MPa); the wetting angle is 16°, which is 47% lower than that of BNi-2 brazing filler metal (≥30°); and the tensile strength is 250 MPa, which is 39% higher than that of BNi-2 brazing filler metal (≤180 MPa).

[0116] (2) B, Si, and rare earth elements, as amorphous forming and strengthening elements, have a significant impact on the performance of brazing filler metals. Comparison of the results of Example 1 and Comparative Examples 3-6 shows that when the B or Si content is below or above the range defined in this invention, it leads to increased brittleness and decreased wetting performance of the brazed joint, manifested as reduced shear strength and increased wetting angle. Specifically, when the mass fraction ratio f of B to Si is controlled between 0.56 and 0.61, it helps to form a eutectic Ni-B-Si phase, increasing the atomic packing density and reducing the critical cooling rate, effectively suppressing the precipitation of brittle phases while maintaining good wettability and fluidity. As shown in Examples 25 (f=0.50) and 26 (f=0.64), when f deviates from this range, the shear strength of the brazed joint is only 340 MPa and 345 MPa, respectively, and the wetting angle increases to 26° and 25°, respectively, resulting in a significant decrease in overall performance.

[0117] From the comparison between Examples 1, 16 - 21 and Comparative Examples 1, 2, it can be seen that the appropriate addition of rare earth elements significantly improves the properties of the filler metal. In Example 1, when 0.2% La was added, the amorphous content exceeded 98%, and the shear strength of the brazed joint reached 390 MPa; when La was not added (Comparative Example 1), the amorphous content decreased to 95%, and the shear strength decreased sharply to 285 MPa; when La was in excess (Comparative Example 2), it caused a crystallization tendency, which also led to the deterioration of the properties of the brazed joint. The present invention determines that the addition amount of La does not exceed 0.25%, Nd is between 0.05% - 1.5%, and Ce does not exceed 1%, all of which contribute to optimizing the product performance.

[0118] As a matrix strengthening element, when the content of Co is too low, it will affect the stability of the amorphous structure, and when it is too high, it is not conducive to the formation of amorphous. As a melting point reducing element, B can reduce the liquidus temperature of the alloy and promote the formation of amorphous. The present invention finds that when the mass fraction ratio e of B to Co satisfies 1.2 < e ≤ 1.43, a good balance between the amorphous forming ability and hardness can be achieved. As shown in Comparative Examples 7 and 8, when the Co content is too low or too high, resulting in e deviating from this range, it is difficult to form a good amorphous structure, thereby reducing the strength of the filler metal and the stability of the brazed joint.

[0119] (3) Through the systematic analysis of Examples 1 - 15, 22 - 26 and Comparative Examples 3 - 6, it is found that the combined control of parameters a / (b + c) and f helps to alleviate the phenomenon of compositional segregation. For the examples where both a / (b + c) and f are within the defined ranges (such as Examples 1, 2, 4, 6, 7, 9, 10 - 14, 23, 24), the amorphous phase content of their products all exceeds 98%; while when any one of the parameters exceeds the defined range (such as Examples 3, 5, 8, 15, 22, 25, 26 and Comparative Examples 3 - 6), the amorphous phase content is lower than 98%.

[0120] (4) The vacuum melt spinning process parameters have an important influence on the microstructure and properties of the product. On the basis of ensuring the full melting of raw materials and the uniform diffusion of components, by precisely controlling the inlet temperature, outlet temperature, cooling water flow rate, nozzle - copper roller distance and copper roller speed, the present invention achieves a cooling rate of 1.1×10 6 / ℃ - 1.6×10 6 ℃ / s, and successfully prepares a uniform strip with an amorphous phase content exceeding 98% and a thickness of 40 - 50 μm. In Comparative Example 9, due to the low inlet temperature (25℃), high outlet temperature (80℃), small nozzle - copper roller distance (1,2 cm) and high roller speed (4,500 r / min), the cooling rate abnormally increased to 1.8×10 6The temperature drop of ℃ / s is outside the reasonable range; excessively rapid cooling will cause internal stress concentration and atomic arrangement disorder, thus the glass transition temperature drops to 460℃, the shear strength of the brazed joint is only 220MPa, and the wetting angle increases to 38°. In Comparative Example 10, the cooling rate drops to 0.9×10⁻⁶ due to the low outlet temperature (50℃), the excessive nozzle-copper roller distance (18cm), and the excessively low roller speed (3600r / min). 6 The temperature of ℃ / s is insufficient to suppress crystallization. Some amorphous phases transform into crystalline phases, and the glass transition temperature remains at 510℃. However, the brazed joint becomes more brittle, the shear strength drops to 250MPa, and the wetting angle increases to 32°, which fails to meet the requirements for high-temperature service.

[0121] In summary, by optimizing the composition design and preparation process of nickel-based amorphous brazing filler metal, this invention has obtained a brazing filler metal suitable for joining dissimilar materials in high-temperature service environments. It exhibits excellent structural stability, oxidation resistance, corrosion resistance, and high strength under high-temperature conditions.

[0122] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions, and variations to the above embodiments within the scope of the present invention. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples.

Claims

1. A nickel-based amorphous brazing filler metal suitable for joining dissimilar materials in high-temperature service environments, characterized in that: The components include the following mass percentages: Cr 8.5%-9.5%, B 1.8%-2.2%, Si 3.2%-3.8%, Mo 2.2%-2.8%, Co 1.2%-1.8%, W 0.6%-0.9%, rare earth elements 0.05%-3%, with the balance being Ni.

2. The nickel-based amorphous solder according to claim 1, characterized in that: Rare earth elements are selected from at least one of La, Nd, Ce, Er, Eu, Dy, and Tb; Preferably, the rare earth element is La, and the mass percentage of La is 0.1%-0.25%; Preferably, the rare earth element is Nd, and the mass percentage of Nd is 0.05%-1.5%; Preferably, the rare earth element is Ce, and the mass percentage of Ce is 0.01%-1%.

3. The nickel-based amorphous solder according to claim 1, characterized in that: Within it, the mass percentages of Cr, Mo, and W are a, b, and c, respectively, and a, b, and c satisfy the following requirement: 2.6 < a / (b+c) < 3.1; Preferably, 2.7 ≤ a / (b+c) ≤ 3; Preferably, 0.30≤c / b≤0.

33.

4. The nickel-based amorphous solder according to claim 1, characterized in that: Within it, the sum of the mass percentages d of B, Si, Co, and W must satisfy the following requirement: 7.3% ≤ d ≤ 8.5%.

5. The nickel-based amorphous solder according to claim 1, characterized in that: Within this, the mass percentage ratio e of B to Co satisfies the following requirement: 1.2 < e ≤ 1.

43.

6. The nickel-based amorphous solder according to claim 3, characterized in that: Within this, the mass percentage ratio f of B to Si satisfies the following requirement: 0.56 ≤ f ≤ 0.

61.

7. A method for preparing a nickel-based amorphous solder as described in any one of claims 1-6, characterized in that: The following steps are included: S1. Prepare the materials according to the mass percentage of each element in the nickel-based amorphous brazing filler metal, and the purity of the raw materials corresponding to each element shall not be less than 99.95%; S2. The alloy ingot is obtained by melting in a vacuum induction furnace under inert gas protection and then cooling after melting. S3. By vacuum spinning the obtained alloy ingot, nickel-based amorphous brazing wire strip is obtained.

8. The preparation method according to claim 7, characterized in that: In step S2, the melting temperature is 1250-1520℃ and the melting time is 30-50min; Preferably, in step S2, the pressure inside the vacuum induction melting furnace is below 1×10⁻⁶ throughout the entire melting process. -3 Pa; Preferably, in step S2, high-purity argon gas is introduced into the vacuum induction melting furnace as a protective atmosphere. Preferably, in step S2, electromagnetic stirring is continuously performed at a frequency of 50-60Hz throughout the entire melting process; Preferably, the vacuum induction melting furnace is heated to the melting temperature at a heating rate of 10-15℃ / min, and cooled to room temperature at a cooling rate of no more than 5℃ / min after melting.

9. The preparation method according to claim 7, characterized in that: In step S3, the obtained alloy ingot is placed in a quartz tube with a nozzle, vacuumed and heated under inert gas protection to turn the alloy ingot into an alloy liquid. Then, the alloy liquid is squeezed out from the nozzle through inert gas and continuously dripped onto a rotating water-cooled copper roller for rapid cooling to form a nickel-based amorphous brazing wire strip. Preferably, in step S3, the pressure inside the quartz tube is less than 1×10⁻⁶. -3 Pa; Preferably, in step S3, the inert gas is high-purity argon gas with a pressure of 0.30-0.33 MPa; Preferably, in step S3, the temperature of the alloy liquid is 1200-1500℃; Preferably, in step S3, the water-cooled copper roller is provided with an inlet at one end and an outlet at the other end. Cooling water enters the water-cooled copper roller through the inlet and flows out through the outlet. The inlet temperature is 30-35℃, the outlet temperature is 55-75℃, and the cooling water flow rate is 2.5-3.5m / s. Preferably, in step S3, the distance between the nozzle and the surface of the water-cooled copper roller is 14-16 cm; Preferably, in step S3, the rotational speed of the water-cooled copper roller is 3800-4200 r / min; Preferably, in step S3, the thickness of the obtained nickel-based amorphous brazing filler strip is 40-50 μm.

10. A brazing method for a nickel-based amorphous brazing filler metal as described in any one of claims 1-6 or a nickel-based amorphous brazing filler metal prepared according to the preparation method described in any one of claims 7-9, characterized in that, The brazing method is vacuum brazing, and the brazing temperature is 960-1120℃.

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