A copper-based active brazing alloy powder, its preparation method and application

Abstract

This invention provides a copper-based active brazing alloy powder, its preparation method, and its application. The alloy powder comprises: 55.0%–68.0% copper, 6.0%–17.0% tin, 5.0%–20.0% silver, 1.0%–10.0% titanium, 0.1%–2.0% aluminum, and a total impurity element content of less than 0.3%. The preparation method includes preparing raw materials according to the alloy composition, preparing the alloy powder by melting and vacuum atomization, and then performing surface modification and debinding to obtain the final product. The alloy powder prepared by this invention exhibits more than double the oxidation resistance, a reduction of more than 20% in powder Hall flow rate, an increase of more than 15% in powder bulk density, and significantly improved particle dispersion, which is beneficial for the homogenization of metal powder dispersion and reduces sedimentation rate. By introducing silver and aluminum as reinforcing elements, the solderability of copper-based brazing filler metal is improved, and the bonding between copper and the active element titanium is effectively inhibited, thereby enhancing the activity of titanium.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a copper-based active brazing alloy powder, its preparation method, and its application. Background Technology

[0002] Brazing has become an important method for joining dissimilar materials such as metals and non-metals because its welding temperature is lower than that of the base material, which keeps the microstructure of the base material uniform, allows for more precise assembly and connection, maintains the overall structure, shape and size of the workpiece, is simple in process, can easily join different materials, can weld complex and special workpieces, and can even join multiple seams and parts at once.

[0003] In ceramic-metal bonding, ordinary brazing filler metals cannot directly wet the ceramic. Therefore, active brazing filler metals are needed to promote the bonding between ceramic and metal. Commonly used brazing materials include silver-copper-titanium (AgCuTi) and copper-tin-titanium (CuSnTi). Silver-copper-titanium active brazing filler metals are universal brazing filler metals for ceramics, capable of wetting almost all ceramics, including carbon materials, carbon composites, and glass. However, their high production cost limits their large-scale application. Furthermore, for electronic device applications requiring etching, such as copper-clad ceramic substrates, silver-copper-titanium active brazing filler metals suffer from low etching efficiency and easy migration of silver ions. Therefore, low-cost copper-tin-titanium active brazing filler metals have become a potential option. Currently, researchers have explored copper-based active brazing filler metal models such as CuSnTi, CuZnTi, and CuTi. However, problems such as insufficient brazing bond strength of copper-based active brazing filler metals and high sintering void ratio in copper-clad ceramic substrates still need to be addressed.

[0004] Solder paste is currently the main industrial application form of active brazing filler metal. Traditional powder mixing methods suffer from problems such as insufficient powder uniformity, potential powder oxidation due to prolonged mixing, increased impurity content, and stratification during transportation and storage caused by differences in different powder types. Therefore, formulating solder paste using multi-element alloy powders is an ideal choice. However, active brazing alloy powders present problems during production, including element segregation, high impurity content, easy oxidation of active elements, and powder agglomeration. These issues lead to deactivation of active elements, poor solder paste dispersion, and uneven solder distribution, ultimately affecting the volatilization of organic matter in the solder paste.

[0005] Therefore, in order to address the problems of insufficient brazing bond strength, easy oxidation of powder, easy agglomeration leading to poor dispersibility, which in turn leads to deactivation of active elements, poor solder paste dispersion, and uneven solder distribution in copper-based active brazing powder, it is necessary to develop a new type of copper-based active brazing alloy powder. Summary of the Invention

[0006] This invention provides a copper-based active brazing alloy powder, its preparation method, and its application, with the aim of solving the aforementioned problems in the background art.

[0007] To achieve the above objectives, embodiments of the present invention provide a copper-based active brazing alloy powder, its preparation method, and its application. The present invention, through surface modification treatment of the alloy powder, increases the oxidation resistance of the alloy powder by more than 100%, reduces the Hall flow rate by more than 20%, increases the loose packing density of the powder by more than 15%, and significantly improves the dispersibility between powder particles. This facilitates the homogenization of the active brazing alloy powder during subsequent paste preparation and reduces the settling rate of the metal powder. Furthermore, compared with commercial copper-tin-titanium active brazing alloy powders, the copper-based active brazing alloy powder prepared by the present invention, by introducing two reinforcing elements, silver and aluminum, improves the solderability of the copper-based brazing filler metal, effectively inhibits the bonding between copper and the active element titanium, and thus enhances the activity of titanium. Compared with commercial silver-copper-titanium active brazing alloy powders, the lower silver content significantly reduces the material cost of the brazing filler metal, while the reinforcing effect of tin and aluminum on the copper matrix weakens the impact of reduced silver content on brazing strength.

[0008] One object of the embodiments of the present invention is to provide a copper-based active brazing alloy powder comprising, by mass percentage: 55.0% to 68.0% copper, 6.0% to 17.0% tin, 5.0% to 20.0% silver, 1.0% to 10.0% titanium, 0.1% to 2.0% aluminum, and a total impurity element content of less than 0.3%.

[0009] Adding 6.0%–17.0% tin can effectively reduce the soldering temperature of the solder. When the tin content is 6%–17%, the microstructure of the as-cast solder is mainly composed of α-Cu solid solution with a small amount of titanium dissolved in it, with a relatively small proportion of low-melting-point eutectic structure. As the tin content gradually increases, the α-Cu solid solution in the as-cast solder decreases, the low-melting-point eutectic structure increases and becomes significantly coarsened, reducing the solder's performance. Therefore, solders with 6.0%–17.0% tin have better overall performance in terms of melting temperature, wettability, shear strength, and microhardness. If the tin content is too low, the solder's melting temperature is high, the soldering wettability is significantly reduced, and the solid solution strengthening effect is poor. If the tin content is too high, the high vapor pressure tin element is easily volatilized during use, which can contaminate the device, and the material's microhardness is low, reducing the solder's thermal conductivity. Adding 5.0% to 20.0% silver can form a β-Ag+α-Cu network structure in the copper matrix, which is beneficial to improving the strength and other properties of the material. If the silver content is too low, the strengthening effect of silver is weak; if the silver content is too high, the production cost of the material will increase. In addition, the addition of silver can reduce defects such as solder voids and enhance the wettability of the solder. When the titanium content of the as-cast solder increases from 1% to 10%, Cu... 41 Sn 11The reduction of isomorphous phases and the decrease in tin content in the α-Cu solid solution, while the increase in titanium content, are beneficial to improving the shear strength of the as-cast solder. However, with further increases in titanium content, the number and size of bulk CuSn3Ti5 intermetallic compounds in the as-cast solder increase, leading to increased brittleness and deterioration of its shear resistance. The addition of 0.1%–2.0% aluminum refines the dendritic β-Sn region, expands the interdendritic eutectic region, and inhibits the formation of Ag3Sn and Cu6Sn5 compounds. Ag3Al, CuAl2, and aluminum-rich phases appear in the solder. The fine Ag3Al compound particles, approximately 3 μm in size, are neatly distributed in the interdendritic region, and their size decreases with increasing Al content. Ag3Al particles can effectively inhibit crack initiation as barriers to dislocation propagation, resulting in higher strength and greater tensile stress in the solder. Furthermore, when molten aluminum is added to the solder, aluminum atoms tend to preferentially combine with copper atoms to form aluminum-copper phase compounds, weakening the bonding between copper and titanium, and thus enhancing the activity of titanium to some extent. If the aluminum content is too low, there will be fewer fine Ag3Al and other reinforcing phases, and the reinforcing effect will be insignificant; if the content is too high, there will be more coarse CuAl2 and aluminum-rich phases, reducing the solder performance.

[0010] Preferably, the composition comprises, by mass percentage, the following components: 55.0%–68.0% copper, 6.0%–17.0% tin, 5.0%–19.0% silver, 1.0%–10.0% titanium, 0.1%–2.0% aluminum, and a total impurity element content of less than 0.3%.

[0011] Preferably, the composition comprises, by mass percentage, the following components: 55.0%–68.0% copper, 6.0%–17.0% tin, 5.0%–19.0% silver, 2.0%–10.0% titanium, 0.1%–2.0% aluminum, and a total impurity element content of less than 0.3%.

[0012] Another objective of the embodiments of the present invention is to provide a method for preparing the above-mentioned copper-based active brazing alloy powder, comprising the following steps:

[0013] S1. Copper, tin, silver, aluminum and titanium are placed in a vacuum medium frequency induction furnace for melting. After the raw materials are melted, they are stirred to obtain an alloy melt.

[0014] S2. High-purity argon gas is used to atomize the alloy melt in a vacuum to obtain alloy powder;

[0015] S3. The surface modifier obtained by mixing organic solvent and modifier is mixed with alloy powder in a vacuum mixer to obtain modified alloy powder;

[0016] S4. Remove the organic solvent from the modified alloy powder to obtain copper-based active brazing alloy powder.

[0017] Preferably, in step S1, the melting temperature is 1100-1200℃, the vacuum degree is ≤40Pa, and the stirring time after the raw material is melted is 5-30min.

[0018] Preferably, in step S2, the purity of the high-purity argon gas is ≥99.999%; the spray angle of the atomizer is 30°~50°, the atomizing pressure is 3~7MPa, the atomizing temperature is 900~1150℃, and the atomizing rate is 4~6kg / min.

[0019] Preferably, in step S3, the organic solvent includes one or more of methyl ethyl ketone, methyl ketone, ethanol, acetone, and diethyl ether, and the modifier includes one or more of hexadecanoate, methyl palmitate, and palmitic acid; the volume ratio of the organic solvent to the mass of the modifier is 50–1100:1; and the mass ratio of the alloy powder to the volume of the organic solvent is 6–20:1. Preferably, the volume ratio of the organic solvent to the mass of the modifier is 700:1, 800:1, 900:1, or 1000:1.

[0020] Preferably, in step S3, the temperature is 30–45°C; the mixing time of the organic solvent and the modifier is 2–10 min; and the mixing time of the surface modifier and the alloy powder is 15–30 min.

[0021] Preferably, in step S4, the removal temperature is 40–65°C, the vacuum degree is 50–100 Pa, and the removal time is 5–20 min.

[0022] The embodiments of the present invention also provide the application of the copper-based active brazing alloy powder described above or the copper-based active brazing alloy powder obtained by the above preparation method in the brazing field, the brazing field including the fields of ceramic copper-clad substrates, diamond tools, ceramics and Kovar alloys.

[0023] The above-described solution of the present invention has the following beneficial effects:

[0024] (1) Compared with the unmodified alloy powder, the modified alloy powder of the present invention has more than doubled the oxidation resistance, reduced the powder Hall flow rate by more than 20%, increased the loose packing density of the powder by more than 15%, and significantly improved the dispersibility between powder particles. This is beneficial to the dispersion and homogenization of active brazing alloy powder in the subsequent paste preparation process and reduces the settling rate of metal powder.

[0025] (2) Compared with commercial copper-tin-titanium active brazing alloy powder, the copper-based active brazing alloy powder prepared in this invention improves the solderability of copper-based brazing filler metal by introducing two reinforcing elements, silver and aluminum, effectively inhibiting the combination of copper and active element titanium, thereby enhancing the activity of titanium. Compared with commercial silver-copper-titanium active brazing alloy powder, the lower silver content significantly reduces the material cost of brazing filler metal, while the reinforcing effect of tin and aluminum on the copper matrix can weaken the impact of reduced silver content on brazing strength.

[0026] (3) The copper-based active brazing alloy powder of the present invention is suitable for brazing in the fields of ceramic copper-clad substrates, diamond tools, ceramics and Kovar alloys. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The microstructure of a copper-based active brazing alloy powder is shown in Example 3 of the present invention.

[0029] Figure 2 The microstructure of a copper-based active brazing alloy powder is shown in Comparative Example 1 of the present invention.

[0030] Figure 3 The microstructure of a copper-based active brazing alloy powder is shown in Comparative Example 2 of the present invention.

[0031] Figure 4 The void ratio test results are for a copper-based active brazing alloy powder brazed silicon nitride ceramic copper-clad substrate prepared in Example 3 of this invention. Detailed Implementation

[0032] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0033] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0034] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0035] The raw materials mentioned in the text, such as "copper, tin, silver, aluminum, and titanium," are all elemental metals. The unit of mass is "g," and the unit of volume is "mL." The "B" mentioned in the comparative example represents brazing filler metal; see relevant national standards such as "GBT6418-2008-Copper-based Brazing Filler Metals," which is also the commonly used terminology in the industry.

[0036] The core problems to be solved by this invention are: (1) Copper-based active powder prepared by direct vacuum atomization has poor dispersibility, no flowability, and small bulk ratio, which is detrimental to the preparation and performance of subsequent pastes; (2) When commercial copper-tin-titanium active brazing filler metal is used to braze ceramic copper-clad substrates and other materials, the materials have poor wettability, high void ratio, and insufficient bonding strength. The addition of silver content can improve the above properties, but will greatly increase the cost, etc. Therefore, a copper-based active brazing alloy powder, its preparation method and application are provided.

[0037] One object of the embodiments of the present invention is to provide a copper-based active brazing alloy powder comprising, by mass percentage: 55.0% to 68.0% copper, 6.0% to 17.0% tin, 5.0% to 20.0% silver, 1.0% to 10.0% titanium, 0.1% to 2.0% aluminum, and a total impurity element content of less than 0.3%.

[0038] Adding 6.0%–17.0% tin can effectively reduce the soldering temperature of the solder. When the tin content is 6%–17%, the microstructure of the as-cast solder is mainly composed of α-Cu solid solution with a small amount of titanium dissolved in it, with a relatively small proportion of low-melting-point eutectic structure. As the tin content gradually increases, the α-Cu solid solution in the as-cast solder decreases, the low-melting-point eutectic structure increases and becomes significantly coarsened, reducing the solder's performance. Therefore, solders with 6.0%–17.0% tin have better overall performance in terms of melting temperature, wettability, shear strength, and microhardness. If the tin content is too low, the solder's melting temperature is high, the soldering wettability is significantly reduced, and the solid solution strengthening effect is poor. If the tin content is too high, the high vapor pressure tin element is easily volatilized during use, which can contaminate the device, and the material's microhardness is low, reducing the solder's thermal conductivity. Adding 5.0% to 20.0% silver can form a β-Ag+α-Cu network structure in the copper matrix, which is beneficial to improving the strength and other properties of the material. If the silver content is too low, the strengthening effect of silver is weak; if the silver content is too high, the production cost of the material will increase. In addition, the addition of silver can reduce defects such as solder voids and enhance the wettability of the solder. When the titanium content of the as-cast solder increases from 1% to 10%, Cu... 41 Sn 11The reduction of isomorphous phases and the decrease in tin content in the α-Cu solid solution, while the increase in titanium content, are beneficial to improving the shear strength of the as-cast solder. However, with further increases in titanium content, the number and size of bulk CuSn3Ti5 intermetallic compounds in the as-cast solder increase, leading to increased brittleness and deterioration of its shear resistance. The addition of 0.1%–2.0% aluminum refines the dendritic β-Sn region, expands the interdendritic eutectic region, and inhibits the formation of Ag3Sn and Cu6Sn5 compounds. Ag3Al, CuAl2, and aluminum-rich phases appear in the solder. The fine Ag3Al compound particles, approximately 3 μm in size, are neatly distributed in the interdendritic region, and their size decreases with increasing Al content. Ag3Al particles can effectively inhibit crack initiation as barriers to dislocation propagation, resulting in higher strength and greater tensile stress in the solder. Furthermore, when molten aluminum is added to the solder, aluminum atoms tend to preferentially combine with copper atoms to form aluminum-copper phase compounds, weakening the bonding between copper and titanium, and thus enhancing the activity of titanium to some extent. If the aluminum content is too low, there will be fewer fine Ag3Al and other reinforcing phases, and the reinforcing effect will be insignificant; if the content is too high, there will be more coarse CuAl2 and aluminum-rich phases, reducing the solder performance.

[0039] Preferably, the composition comprises, by mass percentage, the following components: 55.0%–68.0% copper, 6.0%–17.0% tin, 5.0%–19.0% silver, 1.0%–10.0% titanium, 0.1%–2.0% aluminum, and a total impurity element content of less than 0.3%.

[0040] Preferably, the composition comprises, by mass percentage, the following components: 55.0%–68.0% copper, 6.0%–17.0% tin, 5.0%–19.0% silver, 2.0%–10.0% titanium, 0.1%–2.0% aluminum, and a total impurity element content of less than 0.3%.

[0041] Another objective of the embodiments of the present invention is to provide a method for preparing the above-mentioned copper-based active brazing alloy powder, comprising the following steps:

[0042] S1. Copper, tin, silver, aluminum and titanium are placed in a vacuum medium frequency induction furnace for melting. After the raw materials are melted, they are stirred to obtain an alloy melt.

[0043] S2. High-purity argon gas is used to atomize the alloy melt in a vacuum to obtain alloy powder;

[0044] S3. The surface modifier obtained by mixing organic solvent and modifier is mixed with alloy powder in a vacuum mixer to obtain modified alloy powder;

[0045] S4. Remove the organic solvent from the modified alloy powder to obtain copper-based active brazing alloy powder.

[0046] Preferably, in step S1, the melting temperature is 1100-1200℃, the vacuum degree is ≤40Pa, and the stirring time after the raw material is melted is 5-30min.

[0047] Preferably, in step S2, the purity of the high-purity argon gas is ≥99.999%; the spray angle of the atomizer is 30°~50°, the atomizing pressure is 3~7MPa, the atomizing temperature is 900~1150℃, and the atomizing rate is 4~6kg / min.

[0048] Preferably, in step S3, the organic solvent includes one or more of methyl ethyl ketone, methyl ketone, ethanol, acetone, and diethyl ether, and the modifier includes one or more of hexadecanoate, methyl palmitate, and palmitic acid; the volume ratio of the organic solvent to the mass of the modifier is 50–1100:1; and the mass ratio of the alloy powder to the volume of the organic solvent is 6–20:1. Preferably, the volume ratio of the organic solvent to the mass of the modifier is 700:1, 800:1, 900:1, or 1000:1.

[0049] Preferably, in step S3, the temperature is 30–45°C; the mixing time of the organic solvent and the modifier is 2–10 min; and the mixing time of the surface modifier and the alloy powder is 15–30 min.

[0050] Preferably, in step S4, the removal temperature is 40–65°C, the vacuum degree is 50–100 Pa, and the removal time is 5–20 min.

[0051] The embodiments of the present invention also provide the application of the copper-based active brazing alloy powder described above or the copper-based active brazing alloy powder obtained by the above preparation method in the brazing field, the brazing field including the fields of ceramic copper-clad substrates, diamond tools, ceramics and Kovar alloys.

[0052] The following will be explained through specific embodiments.

[0053] Example 1

[0054] This embodiment provides a copper-based active brazing alloy powder, whose chemical composition by mass percentage includes: 14.0% Sn, 15.0% Ag, 1.2% Al, 5.0% Ti, total impurity elements less than 0.3%, and the remainder being copper.

[0055] The preparation method of the above-mentioned copper-based active brazing alloy powder includes the following steps:

[0056] (1) Place copper, tin, silver, aluminum and titanium in a vacuum induction furnace, and under medium frequency induction mode (80~90KW, 900~1050Hz) and vacuum degree of 20~30Pa, melt the raw materials completely and stir for 10 minutes to obtain a homogenized alloy melt.

[0057] (2) High-purity argon gas (purity ≥99.999%) was used to atomize the homogenized alloy melt in a vacuum to obtain alloy powder; the spray angle of the atomizer was 35°, the atomizing pressure was 5~5.5MPa, the atomizing temperature was 1050~1100℃, and the atomizing rate was 5~6kg / min.

[0058] (3) At a temperature of 40-45℃, the volume of methyl ethyl ketone and the mass ratio of hexadecanoic acid hexadecyl ester are mixed for 5 min to obtain a surface modifier. Then, at a temperature of 40-45℃, the alloy powder and the surface modifier are mixed in a vacuum mixer for 20 min to obtain modified alloy powder. The mass ratio of the alloy powder to the volume of the organic solvent is 12.5:1.

[0059] (4) At 50-55℃, the modified alloy powder is subjected to organic solvent removal in a vacuum mixer. The vacuum degree is 70-80 Pa and the removal time is 8 min to obtain copper-based active brazing alloy powder.

[0060] Example 2

[0061] This embodiment provides a copper-based active brazing alloy powder, whose chemical composition by mass percentage includes: 12.0% Sn, 16.0% Ag, 0.8% Al, 4.0% Ti, total impurity elements less than 0.3%, and the remainder being copper.

[0062] The difference between this embodiment and Example 1 is that the surface modifier is obtained by mixing ethanol at a volume ratio of 80:1 to hexadecanoate mass at 40-45°C for 5 minutes. Other preparation steps and parameters are the same as in Example 1.

[0063] Example 3

[0064] This embodiment provides a copper-based active brazing alloy powder, the microstructure of which is shown in the image below. Figure 1 As shown, its chemical composition, by mass percentage, includes: 17.0% Sn, 18.0% Ag, 1.0% Al, 4.5% Ti, total impurity elements less than 0.3%, and the remainder being copper.

[0065] The difference between this embodiment and Example 1 is that the surface modifier is obtained by mixing acetone at a volume ratio of 100:1 to palmitic acid at a temperature of 40-45°C for 3 minutes. Other preparation steps and parameters are the same as in Example 1.

[0066] Example 4

[0067] This embodiment provides a copper-based active brazing alloy powder, whose chemical composition by mass percentage includes: 10.0% Sn, 19.0% Ag, 0.5% Al, 4.0% Ti, total impurity elements less than 0.3%, and the remainder being copper.

[0068] The difference between this embodiment and Example 1 is that the atomization temperature is 950-1000℃, and the surface modifier is obtained by mixing acetone at a volume ratio of 160:1 to palmitic acid at a temperature of 40-45℃ for 3 minutes. Other preparation steps and parameters are the same as in Example 1.

[0069] Example 5

[0070] This embodiment provides a copper-based active brazing alloy powder, whose chemical composition by mass percentage includes: 14% Sn, 17% Ag, 1.0% Al, 6.0% Ti, total impurity elements less than 0.3%, and the remainder being copper.

[0071] The difference between this embodiment and Example 1 is that the surface modifier is obtained by mixing acetone at a volume ratio of 120:1 to methyl palmitate at a temperature of 40-45°C for 3 minutes. Other preparation steps and parameters are the same as in Example 1.

[0072] Comparative Example 1

[0073] This comparative example provides a copper-based active brazing alloy powder, whose chemical composition by mass percentage includes: 14% Sn, 15% Ag, 1.2% Al, 5.0% Ti, total impurity elements less than 0.3%, and the remainder being copper.

[0074] The preparation method of the above-mentioned copper-based active brazing alloy powder includes the following steps:

[0075] (1) Place copper, tin, silver, aluminum and titanium in a vacuum induction furnace. Under medium frequency induction mode (80-90KW, 900-1050Hz) and vacuum degree of 20-30Pa, melt the raw materials completely and stir for 10 minutes to obtain a homogenized alloy melt.

[0076] (2) The homogenized alloy melt was vacuum-atomized with high-purity argon gas (purity ≥ 99.999%) to obtain alloy powder. The microstructure is shown in the figure below. Figure 2 As shown; the atomizer's spray angle is 35°, the atomizing pressure is 5-5.5 MPa, the atomizing temperature is 1050-1100℃, and the atomizing rate is 5-6 kg / min.

[0077] Comparative Example 2

[0078] This comparative example uses commercially available BCuSnTi active brazing alloy powder; the microstructure is shown in the image below. Figure 3 As shown, its chemical composition by mass percentage includes: 19% Sn, 10.0% Ti, total impurity elements less than 0.3%, and the remainder is copper, in accordance with the group standard T / CWAN 0085-2022.

[0079] Comparative Example 3

[0080] This comparative example uses commercially available BAgCuTi active brazing alloy powder, whose chemical composition by mass percentage includes: 28% Cu, 4.0% Ti, less than 0.3% total impurity elements, and the remainder being silver.

[0081] The melting characteristics of the copper-based active brazing alloy powders obtained in the above embodiments and comparative examples were tested, and the results are shown in Table 1. Furthermore, the copper-based active brazing alloy powders obtained in the above embodiments and comparative examples were applied to a silicon nitride ceramic copper-clad substrate (substrate size: 138mm x 190mm, copper thickness: 0.3mm, testing equipment and conditions: ultrasonic scanning microscope, resolution 50μm), and brazing void rate and peel strength were tested. The test results are shown in Table 2.

[0082] Table 1. Properties and oxidation resistance tests of brazing alloy powders with different compositions.

[0083]

[0084] Table 2. Tests of brazing silicon nitride ceramic copper-clad substrates with different brazing alloy powder compositions.

[0085]

[0086] As shown in Tables 1 and 2, compared with the copper-based active brazing alloy powder in the comparative example, the loose packing density of the copper-based active brazing alloy powder prepared in this invention is lower than 4.6 g / cm³. 3 It increased to over 5.3 g / cm³. 3 The increase exceeded 15%; the Hall flow rate was significantly reduced, and a lower Hall flow rate indicates better powder flowability. When the alloy powder was directly exposed to the same environment, the powder oxygen increase indicated a significant enhancement in the oxidation resistance of the surface-modified alloy powder; and when applied to silicon nitride ceramic copper-clad substrates, the solder void rate was significantly reduced, and the peel strength was well improved.

[0087] In the preparation process of copper-based active alloy powder, powder adhesion and agglomeration are prone to occur during the melting and atomization process. This is the direct reason why the commercially available powder in Comparative Example 2 and the unmodified atomized powder in Comparative Example 1 exhibit severe powder agglomeration, low powder bulk ratio, and lack of flowability, as can be seen from their microscopic morphology images. This invention, through surface modification of the powder, can significantly improve the aforementioned powder agglomeration, powder bulk ratio, flowability, and other performance indicators. This is crucial for the fineness, dispersibility, and uniformity of the powder in the subsequent powder preparation process to form a paste.

[0088] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A copper-based active brazing alloy powder characterized by, According to the mass percentage, the alloy comprises the following components: 55.0%-68.0% copper, 6.0%-17.0% tin, 5.0%-20.0% silver, 1.0%-10.0% titanium, 0.1%-2.0% aluminum, and the total amount of impurity elements is less than 0.3%. The preparation method of the copper-based active brazing alloy powder comprises the following steps: mixing a surface modifier obtained by mixing an organic solvent and a modifier with alloy powder in a vacuum mixer to obtain modified alloy powder, and removing the organic solvent from the modified alloy powder to obtain the copper-based active brazing alloy powder.

2. A copper-base active braze alloy powder according to claim 1, wherein, According to the mass percentage, the alloy comprises the following components: 55.0%-68.0% copper, 6.0%-17.0% tin, 5.0%-19.0% silver, 1.0%-10.0% titanium, 0.1%-2.0% aluminum, and the total amount of impurity elements is less than 0.3%.

3. A copper-base active braze alloy powder according to claim 1, wherein, According to the mass percentage, the alloy comprises the following components: 55.0%-68.0% copper, 6.0%-17.0% tin, 5.0%-19.0% silver, 2.0%-9.0% titanium, 0.1%-2.0% aluminum, and the total amount of impurity elements is less than 0.3%.

4. A method of producing a copper-based active braze alloy powder according to any one of claims 1 to 3, characterized in that The method comprises the following steps: S1. Melting copper, tin, silver, aluminum and titanium in a vacuum medium-frequency induction furnace, and stirring after the raw materials are melted to obtain an alloy melt; S2. The alloy melt is subjected to vacuum gas atomization using high-purity argon to obtain an alloy powder; S3. A surface modifier obtained by mixing an organic solvent and a modifier is mixed with the alloy powder in a vacuum mixer to obtain modified alloy powder; S4. The modified alloy powder is subjected to removal of the organic solvent to obtain a copper-based active brazing alloy powder.

5. The method of claim 4, wherein the copper-based active braze alloy powder is prepared by the steps of: In step S1, the melting temperature is 1100-1200 ℃, the vacuum degree is ≤40 Pa, and the stirring time after the raw materials are melted is 5-30 min.

6. The method of claim 4, wherein the copper-based active braze alloy powder is prepared by the steps of: In step S2, the purity of the high-purity argon is ≥99.999%, the spray angle of the atomizer is 30-50°, the atomization gas pressure is 3-7 MPa, the atomization temperature is 900-1150 ℃, and the atomization rate is 4-6 kg / min.

7. The method of claim 4, wherein the copper-based active braze alloy powder is prepared by the steps of: In step S3, the organic solvent includes one or more of methyl ethyl ketone, ketone, ethanol, acetone, and diethyl ether, and the modifier includes one or more of hexadecanoic acid, methyl palmitate, stearic acid, and palmitic acid; the ratio of the volume of the organic solvent to the mass of the modifier is 50-1100:1; and the ratio of the mass of the alloy powder to the volume of the organic solvent is 6-20:

1.

8. The method of claim 4, wherein the copper-based active braze alloy powder is prepared by the steps of: In step S3, the temperature is 30-45 ℃, the mixing time of the organic solvent and the modifier is 2-10 min, and the mixing time of the surface modifier and the alloy powder is 15-30 min.

9. The method of claim 4, wherein the copper-based active braze alloy powder is prepared by the steps of: In step S4, the removal temperature is 40-65 ℃, the vacuum degree is 50-100 Pa, and the removal time is 5-20 min.

10. Use of a copper-based active brazing alloy powder according to any one of claims 1 to 3 or a copper-based active brazing alloy powder obtained by the production method according to any one of claims 4 to 9 in the field of brazing, characterized in that The brazing field includes the fields of ceramic copper-clad substrates, diamond tools, and ceramics and Kovar alloys.

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