High-temperature-resistant conductive connection brazing filler metal and preparation method and application thereof

Abstract

The invention belongs to the technical field of composite materials, and particularly relates to high-temperature-resistant conductive connection brazing filler metal and a preparation method and application thereof. The high-temperature-resistant conductive connection brazing filler metal comprises the following raw materials in percentage by mass: 60%-70% of silver powder, 5%-13% of titanium powder, 10%-20% of copper powder and 5%-17% of a precursor solution. According to the method, the Ag-Cu-Ti solder and the silicon-based precursor are mixed, the fluidity and wettability of the solder can be guaranteed at the same time, and metal-ceramic-based composite material connection under the non-pressure condition is achieved. By using the metal and ceramic mixed brazing filler metal, the thermal matching property of the metal and the ceramic matrix composite material can be improved, the obtained connection effect is remarkable, and meanwhile the high-temperature-resistant characteristic, the high-temperature connection characteristic and the high-temperature conductive characteristic are guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a high temperature resistant conductive connecting solder and a preparation method and application thereof. Background Art

[0002] Ceramic matrix composites have become the main candidate materials for aerospace thermal structural materials due to their high temperature resistance, oxidation resistance and excellent high temperature mechanical properties. Due to the complexity of the microstructure of ceramic matrix composites and the intrinsic brittleness of ceramics, damage will continue to occur during the service of ceramic matrix composites. The resistance method is a simple damage detection method that can be observed in real time, but there is still a lack of reliable electrode connection methods.

[0003] At present, the conventional high-temperature conductive connection method between metal and ceramic-based composite materials is to sinter and connect them through high-conductivity graphite or high-temperature metals such as platinum and rhodium. However, this method is usually connected by physical methods, and the thermal matching effect with ceramics is poor when used at high temperatures, the reliability is poor, and the temperature resistance is not high. Conventional brazing processes usually require the help of pressure, but their high-temperature conductive effects are rarely considered. The precursor conversion connection technology is a simple operation and novel process connection technology, which is currently mainly used for high-temperature connection of ceramics and ceramic-based composite materials.

[0004] For example, Chinese patent CN107322187A provides a silver-copper-titanium active solder paste, which includes: solder powder and binder; the mass percentages of the solder powder and the binder are: solder powder 85-90%, binder 10-15%; the solder powder is a mixed powder of silver powder, copper powder, and titanium hydride powder; in the mixed powder, the mass percentages of silver, copper, and titanium are: silver 65-93%, copper 5-35%, and titanium 1-4%; the binder includes the following materials in mass percentages: paste 20%-30%; solvent 50%-70%; thixotropic agent 2-5%. The invention uses titanium hydride to add to the metal mixed powder in the solder powder, which releases hydrogen during the brazing process and plays a role in reducing and protecting the welding. At the same time, titanium activates the ceramic surface, so that the metal can be brazed with the ceramic, and the brazing temperature is reduced to 850°C, reducing the impact of high temperature on metal properties and also reducing process costs. However, this invention cannot effectively solve the problem of thermal expansion coefficient mismatch at high temperatures, and does not take its conductivity at high temperatures into consideration.

[0005] For example, U.S. Patent No. 4,678,720A discloses a silver-copper-titanium alloy solder foil, which is made by a rapid solidification process. The alloy composition is 10-50 weight percent copper, 0.1-9.5 weight percent titanium, and the rest is silver. The rapid solidification of this invention provides an extremely high cooling rate (at least 10,000°C / second), resulting in a unique structure and properties. The produced foil can be used as a cast, or it can be rolled into a thinner size with a more uniform surface or processed into a preform. In modern industrial applications, such as the aerospace field or electronic packaging technology, materials with excellent thermal and electrical conductivity and good stability are usually required. This type of alloy solder foil may be selected in these fields due to its unique properties. However, this invention also has the above-mentioned problems.

[0006] Another example is Chinese patent CN112063300A, which discloses a polysilazane high temperature resistant coating and a preparation method thereof. The polysilazane high temperature resistant coating is composed of the following raw materials in parts by weight: 25-40 parts of polysilazane resin, 6-12 parts of mica powder, 6-11 parts of talc, 5-10 parts of kaolin, 8-15 parts of xylene, 2-4 parts of butyl acetate, 12-18 parts of high temperature resistant black pigment, 1-2 parts of fumed silica and 1-2 parts of dispersant. The polysilazane high temperature resistant coating in the invention has a normal paint film at a high temperature of 1200°C and has good high temperature resistance. The silazane high temperature resistant coating prepared by the inventive method does not change color, crack or fall off under the conditions of 700-1200°C, and has very good high temperature resistance. However, the invention has complex ingredients and its conductivity has not been verified.

[0007] Therefore, there is an urgent need to study a composite material that can ensure high-temperature connectivity and high-temperature conductivity while ensuring high-temperature resistance. Summary of the invention

[0008] Based on the problems existing in the prior art, the present invention aims to provide a high-temperature resistant conductive connection solder and its preparation method and application. The titanium element in the solder, the nitrogen element in the ceramic and the carbon in the ceramic-based composite material react to generate conductive ceramics at the composite material boundary; at the molybdenum boundary, the polysilazane precursor provides a silicon source, and during the reaction, it forms a chemical connection with the metal, which greatly improves the connection strength of the two interfaces, so that the connection can maintain a high bonding strength and tensile strength at room temperature; at the same time, since the new phases formed are all high-temperature resistant conductive phases, their high-temperature mechanical properties and conductive properties can be guaranteed at the same time.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] On the one hand, the present invention provides a high temperature resistant conductive connection solder, comprising the following raw materials: silver powder, titanium powder, copper powder and a precursor solution.

[0011] Preferably, the precursor solution is one or more of a polysilazane precursor solution, a polycarbosilane precursor solution, and a polyborosilane precursor solution.

[0012] Preferably, the polysilazane precursor solution is purchased from the Institute of Chemistry, Chinese Academy of Sciences, with the model number KH-PSN2.

[0013] Preferably, the high temperature resistant conductive connection solder comprises the following raw materials by mass fraction: 60%-70% silver powder, 5%-13% titanium powder, 10%-20% copper powder, and 5%-17% polysilazane precursor solution.

[0014] Preferably, the high temperature resistant conductive connection solder comprises the following raw materials by mass fraction: 62%-68% silver powder, 7%-12% titanium powder, 12%-17% copper powder, and 8%-14% polysilazane precursor solution.

[0015] More preferably, the high temperature resistant conductive connecting solder comprises the following raw materials by mass fraction: 64%-66% silver powder, 8%-11% titanium powder, 14%-16% copper powder, and 9%-12% polysilazane precursor solution.

[0016] Further preferably, the high temperature resistant conductive connection solder comprises the following raw materials by mass fraction: 65% silver powder, 10% titanium powder, 15% copper powder, and 10% polysilazane precursor solution.

[0017] In addition, the present invention also provides a method for preparing a high temperature resistant conductive connection solder, which specifically comprises the following steps:

[0018] (1) fully mixing the silver powder, copper powder and titanium powder in the prescribed amount to obtain a mixture; ball milling and drying the mixture to obtain a mixed powder;

[0019] (2) Adding the mixed powder obtained in step (1) into the polysilazane precursor solution, stirring and mixing uniformly, to obtain a mixed solder.

[0020] Preferably, the ball milling in step (1) is: ball milling the mixture to particles of 20-50 nm.

[0021] Preferably, the drying in step (1) needs to be carried out under the protection of an inert gas; the inert gas is at least one of argon, nitrogen and helium, preferably argon.

[0022] Preferably, the drying temperature in step (1) is 80°C.

[0023] The invention also provides application of high temperature resistant conductive connection solder in preparing a connector.

[0024] The present invention also provides a method for preparing a connector made of the above-mentioned high temperature resistant conductive connecting solder, and the specific operating steps are as follows:

[0025] The ceramic matrix composite material is punched, and the high temperature resistant conductive connection solder prepared by the above preparation method is placed between the metal wire and the ceramic to be connected. After sintering and cooling, a high temperature resistant conductive connection body is obtained.

[0026] Preferably, the metal wire is a Mo metal wire or a Mo alloy wire.

[0027] Preferably, the diameter of the punched holes is 1 mm.

[0028] Preferably, the sintering is carried out at 800-1200° C. for 2-4 hours in a protective gas atmosphere.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The present invention mixes Ag-Cu-Ti solder with a silicon-based precursor, which can ensure the fluidity of the solder while ensuring the wetting effect, thereby achieving the connection of metal-ceramic-based composite materials under pressure-free conditions.

[0031] (2) The present invention improves the thermal matching of metal and ceramic-based composite materials by mixing metal and ceramic, and the obtained connection effect is significant, while ensuring high temperature resistance, high temperature connection characteristics and high temperature conductivity characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The room temperature shear stress curve of the high temperature resistant conductive connector prepared in Example 1;

[0033] Figure 2 After the high temperature resistant conductive connector prepared in Example 1 is connected, the conductive stability between two metal wires is tested;

[0034] Figure 3 The interface morphology and EDS spectrum of the high temperature resistant conductive connector prepared in Application Example 1. DETAILED DESCRIPTION

[0035] The technical scheme of the present invention is clearly and completely described below with specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The materials, reagents, etc. used, if not otherwise specified, are reagents and materials available from commercial sources.

[0036] Example 1 A high temperature resistant conductive connection solder

[0037] Including the following ingredients:

[0038] 65% silver powder, 10% titanium powder, 15% copper powder, 10% polysilazane precursor solution.

[0039] The preparation method of the high temperature resistant conductive link solder comprises the following steps:

[0040] (1) mixing the silver powder, copper powder and titanium powder in the prescribed amount to obtain a mixture; ball-milling the mixture to a particle size of 20-50 nm, and drying at 80° C. under argon protection to obtain a mixed powder;

[0041] (2) Add the mixed powder obtained in step (1) into a corresponding amount of polysilazane precursor solution, stir and mix evenly to obtain a mixed solder.

[0042] Example 2 A high temperature resistant conductive connection solder

[0043] The only difference from Example 1 is that 65% silver powder, 10% titanium powder, 15% copper powder, and 10% polysilazane precursor solution is replaced with 60% silver powder, 13% titanium powder, 10% copper powder, and 17% polysilazane precursor solution. The remaining steps are the same as in Example 1.

[0044] Example 3 A high temperature resistant conductive connection solder

[0045] The only difference from Example 1 is that 65% silver powder, 10% titanium powder, 15% copper powder, 10% polysilazane precursor solution is substituted for 70% silver powder, 5% titanium powder, 20% copper powder, 5% polysilazane precursor solution. The remaining steps are the same as Example 1.

[0046] Example 4 A high temperature resistant conductive connection solder

[0047] The only difference from Example 1 is that 65% silver powder, 10% titanium powder, 15% copper powder, and 10% polysilazane precursor solution are replaced with 64% silver powder, 8% titanium powder, 16% copper powder, and 12% polysilazane precursor solution. The remaining steps are the same as in Example 1.

[0048] Example 5 A high temperature resistant conductive connection solder

[0049] The only difference from Example 1 is that 65% silver powder, 10% titanium powder, 15% copper powder, and 10% polysilazane precursor solution are replaced with 66% silver powder, 11% titanium powder, 14% copper powder, and 9% polysilazane precursor solution. The remaining steps are the same as in Example 1.

[0050] Comparative Example 1

[0051] According to the method described in Example 2 of patent CN107322187A, a high temperature resistant conductive connection solder is prepared, including the following raw materials:

[0052] 70% silver powder, 4% titanium hydride, 26% copper powder, 30% acrylic resin, 20% tert-butyl alcohol, 18% polyvinyl alcohol, 17% N,N-dimethylformamide, 11% nonylphenol polyglycol ether and 4% polyamide wax.

[0053] The preparation method of the high temperature resistant conductive connection solder is as follows:

[0054] (1) mixing the silver powder, copper powder and titanium powder in the prescribed amount to obtain a mixture; ball-milling the mixture to a particle size of 20-50 nm, and drying at 80° C. under argon protection to obtain a mixed powder;

[0055] (2) Add 30% acrylic resin, 20% tert-butyl alcohol, 18% polyvinyl alcohol, 17% N,N-dimethylformamide, 11% nonylphenol polyglycol ether and 4% polyamide wax to the mixed powder obtained in step (1), stir and mix evenly to obtain a mixed solder.

[0056] Comparative Example 2: A high temperature resistant conductive solder

[0057] The only difference from Example 1 is that 65% silver powder, 10% titanium powder, 15% copper powder, and 10% KH-PSN2 polysilazane precursor solution are replaced with 40% silver powder, 15% titanium powder, 25% copper powder, and 20% KH-PSN2 polysilazane precursor solution. The remaining steps are the same as in Example 1.

[0058] Comparative Example 3: A high temperature resistant conductive solder

[0059] The only difference from Example 1 is that 65% silver powder, 10% titanium powder, 15% copper powder, and 10% KH-PSN2 polysilazane precursor solution are replaced with 86% silver powder, 3% titanium powder, 7% copper powder, and 4% KH-PSN2 polysilazane precursor solution. The remaining steps are the same as in Example 1.

[0060] Application Examples 1-5 and Application Comparative Examples 1-3 are used to prepare a high temperature resistant conductive connector according to the following steps:

[0061] The specific operations are as follows:

[0062] The ceramic-based composite material is punched, and the high-temperature resistant conductive connecting solder prepared in the above Examples 1-5 and Comparative Examples 1-3 is placed between the metal wire to be connected and the ceramic-based composite material, sintered at 1000°C under argon protection for 2 hours, and cooled to obtain the corresponding high-temperature resistant conductive connectors.

[0063] Technical Effects

[0064] 1. Shear resistance test

[0065] The high temperature resistant conductive connectors prepared in Example 1-5 and Comparative Example 1-3 were subjected to tensile tests on a universal mechanical properties testing machine to test the shear strength between the metal conductor and the ceramic matrix composite material. The experimental results are as follows: Figure 1 And as shown in Table 1.

[0066] Table 1 Shear strength of high temperature resistant conductive connection interface

[0067] Shear strength(MPa) Application Example 1 18.212 Application Example 2 14.056 Application Example 3 12.662 Application Example 4 11.644 Application Example 5 9.135 Application Comparative Example 1 6.563 Application Comparative Example 2 3.157 Application Comparative Example 3 8.691

[0068] From Table 1 and Figure 1 It can be seen from the data that the shear strength of the high temperature resistant conductive connectors prepared by using Examples 1-5 is higher than that of the comparative examples 1-3, which indicates that the high temperature resistant conductive connectors prepared by the present invention have strong anti-destruction ability.

[0069] 2. Resistance stability test

[0070] The high temperature resistant conductive connector prepared in Example 1 was kept at 900 degrees Celsius, 1000 degrees Celsius, 1100 degrees Celsius, and 1200 degrees Celsius for 20 minutes in an argon atmosphere in a tube furnace, and the resistance value change between the two metal wires was measured. The experimental results are as follows: Figure 1 shown.

[0071] Figure 2 The results show that the high temperature resistant conductive connection achieved by using Example 1 has stable resistance under high temperature conditions.

[0072] 3. Scanning electron microscope test

[0073] The microstructure of the connection structure was observed by scanning electron microscopy. Figure 3 shown.

[0074] Depend on Figure 3 It can be observed that the high temperature resistant conductive connector prepared by using Example 1 forms a reliable and dense connection layer at the interface, strengthening the connection of the structure. Further, by analyzing the element distribution through EDS energy spectrum, it can be observed that a reaction layer is formed at both interfaces, providing technical support for reliable connection.

[0075] The above results indicate that the high temperature resistant conductive solder prepared by the present invention can effectively improve the temperature resistance, relieve the thermal stress of the composite material and the metal wire, and at the same time ensure the connection performance and high temperature conductivity.

Claims

1. A high temperature resistant conductive connection solder, characterized in that: The invention comprises the following raw materials: 60%-70% silver powder, 5%-13% titanium powder, 10%-20% copper powder and 5%-17% precursor solution.

2. The high temperature resistant conductive connection solder according to claim 1, characterized in that: The precursor solution is selected from one or more of a polysilazane precursor solution, a polycarbosilane precursor solution, and a polyborosilane precursor solution.

3. The high temperature resistant conductive connection solder according to claim 1, characterized in that: The raw materials include the following by mass fraction: 60%-70% silver powder, 5%-13% titanium powder, 10%-20% copper powder, and 5%-17% polysilazane precursor solution.

4. The high temperature resistant conductive connection solder according to claim 3, characterized in that: The raw materials include the following by mass fraction: 65% silver powder, 10% titanium powder, 15% copper powder, and 10% polysilazane precursor solution.

5. The method for preparing the high temperature resistant conductive connection solder according to any one of claims 1 to 4, characterized in that: The steps include: (1) fully mixing the silver powder, copper powder and titanium powder in the prescribed amount to obtain a mixture; ball milling and drying the mixture to obtain a mixed powder; (2) Adding the mixed powder obtained in step (1) into the polysilazane precursor solution, stirring and mixing uniformly, to obtain a mixed solder.

6. The preparation method according to claim 5, characterized in that: The ball milling in step (1) is as follows: the mixed material is ball milled until the particles are 20-50 nm.

7. The preparation method according to claim 5, characterized in that: The drying in step (1) needs to be carried out under the protection of an inert gas; the inert gas is at least one of argon, nitrogen and helium; and the drying temperature is 80°C.

8. Use of the high temperature resistant conductive connecting solder according to any one of claims 1 to 4 or the high temperature resistant conductive connecting solder prepared by the preparation method according to any one of claims 5 to 7 in preparing a connector.

9. The use according to claim 8, characterized in that: The method for preparing the connector is specifically performed as follows: punch holes in the ceramic-based composite material, place the high-temperature resistant conductive connecting solder described in any one of claims 1 to 4 or the high-temperature resistant conductive connecting solder prepared by the preparation method of any one of claims 5 to 7 between the metal and ceramic to be connected, sinter, and cool to obtain a high-temperature resistant conductive connector.

10. The use according to claim 9, characterized in that: The sintering is carried out at a temperature of 800-1200° C. in an argon atmosphere for 2-4 hours.

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