Conductive paste containing ruthenium oxide and method for preparing the same
By leveraging the synergistic effect of nanoscale ruthenium oxide powder, carbon nanotubes, and specific solvents, the problems of ruthenium oxide powder agglomeration and uneven mixing were solved, resulting in a conductive paste with high conductivity and good stability, suitable for the manufacture of high-precision electronic devices.
Patent Information
- Application Number
- CN202511113334.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-11
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2045-08-11
AI Technical Summary
Existing ruthenium oxide powder is prone to agglomeration during preparation, resulting in uneven particle size distribution and difficulty in forming a uniform and dense conductive network. Furthermore, existing conductive pastes are unevenly mixed and dispersed, have poor rheological properties, and are difficult to meet the requirements of printing processes. Improper addition of auxiliary conductive agents also affects the performance of the paste.
A conductive slurry with uniform dispersion and high stability was prepared by using nano-scale ruthenium oxide powder and carbon nanotubes as the conductive phase, combined with glass powder PbO-B2O3-SiO2 as the binder phase, and using a specific ratio of terpineol and butyl carbitol mixed solvent and ethyl cellulose as dispersant through vacuum drying, ultrasonic dispersion, ball milling and other processes.
It achieves high conductivity (resistivity as low as 85.5 mΩ/sq@20μm), excellent dispersibility (stability > 5 months), low temperature adaptability and process compatibility, making it suitable for the manufacture of high-precision electronic devices.
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Figure CN120613173B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of conductive paste preparation, and particularly relates to a conductive paste containing ruthenium oxide and a preparation method thereof. BACKGROUND
[0002] As a key functional material in the field of electronic materials, conductive paste is widely used in the manufacture of many electronic components such as thick film circuits, resistors, capacitors, solar cells, etc. Its performance directly affects the electrical performance, reliability and stability of electronic components. With the rapid development of electronic technology, the performance requirements of conductive paste are also increasing, especially under the demand of high-precision and high-performance electronic components, developing conductive paste with excellent conductivity, good dispersibility and stable rheological properties has become an important direction of industry research.
[0003] Ruthenium oxide (RuO2) as an important conductive phase material has attracted much attention in the field of conductive paste due to its unique physical and chemical properties. Ruthenium oxide has high electrical conductivity, good chemical stability and thermal stability, and can maintain stable electrical properties in a wide temperature range, which makes it an ideal choice for preparing high-performance conductive paste, especially for resistive paste with high resistance stability requirements.
[0004] However, the current preparation technology of conductive paste based on ruthenium oxide still faces many challenges. On the one hand, the preparation process of ruthenium oxide powder has a significant impact on its final performance. In the traditional preparation method, ruthenium oxide powder is prone to agglomeration during synthesis, resulting in uneven particle size distribution. This agglomerated powder is difficult to form a uniform and dense conductive network after being added to the conductive paste, which affects the conductivity and stability of the conductive paste.
[0005] On the other hand, the preparation process of conductive paste is also crucial. The existing preparation method of conductive paste often fails to achieve the uniform mixing of ruthenium oxide powder and other components in the mixing and dispersion stage. Especially when mixing ruthenium oxide powder with binder phase, solvent and other components, due to the large difference in physical and chemical properties of each component, problems such as stratification and agglomeration are likely to occur, resulting in poor rheological properties of the paste and difficulty in meeting the requirements of printing and coating processes.
[0006] In addition, in order to reduce costs and further improve the performance of conductive paste, auxiliary conductive agents are usually added. However, how to choose the appropriate auxiliary conductive agent and control its addition amount so that it forms a good synergistic conductive effect with ruthenium oxide while not affecting the overall performance of the paste is also a problem that needs to be solved in current preparation technology. Although carbon nanotube auxiliary conductive agent can effectively improve the conductive performance, too much addition may cause the viscosity of the paste to be too large, affecting its processing performance; too little addition cannot fully play its auxiliary conductive role.
[0007] There is an urgent need to develop more preparation methods to solve the problems in the prior art, and to prepare conductive paste containing ruthenium oxide with excellent performance, high stability and suitable for industrial production. SUMMARY
[0008] To solve the above technical problems, the present application uses nanoscale ruthenium oxide powder and carbon nanotubes as the conductive phase, uses glass powder PbO-B2O3-SiO2 (softening temperature matching the sintering temperature of the substrate) and ethyl cellulose as the binder phase, uses a mixture of terpineol and butyl carbitol mixed in a specific ratio as the mixed solvent, uses polyacrylamide as the dispersant, and uses dibutyl phthalate as the plasticizer. Through formulation research and process optimization, a conductive paste containing ruthenium oxide with uniform dispersion, good stability and excellent conductive performance is obtained.
[0009] In one aspect, the present application provides a conductive paste containing ruthenium oxide, which is composed of the following components in mass percentage: 40%-50% of ruthenium oxide, 3.8%-5% of carbon nanotubes, 5%-10% of PbO-B2O3-SiO2, 3%-8% of ethyl cellulose, 21%-28% of terpineol, 9%-12% of butyl carbitol, 0.7%-1% of polyacrylamide, and 1%-2% of dibutyl phthalate.
[0010] Further, in the conductive paste, the conductive paste is composed of the following components in mass percentage: 50% of ruthenium oxide, 5% of carbon nanotubes, 10% of PbO-B2O3-SiO2, 3% of ethyl cellulose, 21% of terpineol, 9% of butyl carbitol, 1% of polyacrylamide, and 1% of dibutyl phthalate.
[0011] In a second aspect, a method for preparing the conductive paste of the present application is also provided, which comprises the following steps:
[0012] S1, vacuum drying the ruthenium oxide powder at 180-210℃ for 2-3 hours to obtain activated ruthenium oxide;
[0013] S2, mixing the activated ruthenium oxide obtained in S1 with polyacrylamide after cooling to room temperature, and ultrasonically dispersing for 30-35 minutes at 42-45 kHz to obtain a ruthenium oxide-polyacrylamide composite dispersion system;
[0014] S3, mixing terpineol and butyl carbitol to obtain a mixed solvent;
[0015] S4, adding PbO-B2O3-SiO2, carbon nanotubes and the ruthenium oxide-polyacrylamide composite dispersion system into the mixed solvent, and ball milling for 4-5 hours to obtain a ball-milled mixture;
[0016] S5, ultrasonic dispersion of the ball-milling mixture prepared in S4 to obtain a fine dispersion mixture;
[0017] S6, adding ethyl cellulose and dibutyl phthalate into the fine dispersion mixture prepared in S5, stirring, sieving, to obtain a conductive paste containing ruthenium oxide.
[0018] Further, in the method, the particle size of the ruthenium oxide powder in S1 is 50-100 nm.
[0019] Further, in the method, the mass ratio of terpineol to butyl carbitol in S3 is 7:3.
[0020] Further, in the method, the tube diameter of the carbon nanotube in S4 is 10-20 nm, and the aspect ratio is 50-100.
[0021] Further, in the method, the ball-milling in S4 is ball-milling using zirconia balls, and the rotation speed is 300-350 rpm.
[0022] Further, in the method, the ultrasonic power of the ultrasonic dispersion in S5 is 500 W, and the ultrasonic dispersion time is 20-30 min.
[0023] Further, in the method, in S6, the stirring is magnetic stirring, and the stirring temperature is 60-65℃.
[0024] Finally, the application also provides the use of the conductive paste in the preparation of electronic components.
[0025] Compared with the prior art, the technical scheme provided by the application has at least the following beneficial effects or advantages:
[0026] (1) High conductivity: through the synergistic effect of RuO2 and CNT, the paste resistivity is as low as 85.5 mΩ / sq@20 μm, which is reduced by 30%-50% compared with the comparative examples.
[0027] (2) Excellent dispersibility: vacuum-activated RuO2 combined with two-step dispersion process of ball-milling and ultrasonic dispersion avoids filler agglomeration, and the paste stability is >5 months.
[0028] (3) Low-temperature adaptability: the synergistic effect of the specific glass frit (PbO-B2O3-SiO2) and the mixed solvent formed by mixing terpineol and butyl carbitol at a specific mass ratio matches the low-temperature sintering process of 500-600℃.
[0029] (4) Process compatibility: the rheological properties of the conductive paste of the application are optimized by ethyl cellulose and plasticizer, making it suitable for precision devices such as thick film circuits and solar cells.
[0030] The application solves the problems of insufficient conductivity and easy agglomeration of traditional slurry by using the ternary synergistic system of ruthenium oxide-carbon nanotube-glass frit and specific solvent ratio and the specific conductive slurry preparation process, and is suitable for high-precision electronic device manufacturing. BRIEF DESCRIPTION OF DRAWINGS
[0031] Figure 1 The process flow chart of the application is shown in the following. DETAILED DESCRIPTION
[0032] The technical solutions of the application will be described below in combination with examples, but the application is not limited to the following examples.
[0033] In order to enable those skilled in the art to better understand the technical solutions of the application and implement them, the application will be further described below in combination with specific examples and drawings, but the examples are not limiting to the application.
[0034] The experimental methods and detection methods described in the following examples are all conventional methods unless otherwise specified, and the reagents and materials can be purchased on the market unless otherwise specified.
[0035] Example 1
[0036] This example is for preparing a conductive slurry containing ruthenium oxide.
[0037] In this example, the carbon nanotubes are multi-walled carbon nanotubes with a tube diameter of 10 nm and an aspect ratio of 50; the particle size of ruthenium oxide (RuO2) is 50 nm; in PbO-B2O3-SiO2, PbO is 60 wt%, B2O3 is 20 wt%, and SiO2 is 20 wt%; and the process flow chart is shown in Figure 1
[0038] The conductive slurry containing ruthenium oxide is composed of the following components in mass percentage: 40% of ruthenium oxide (RuO2), 4% of carbon nanotubes (CNT), 5% of PbO-B2O3-SiO2, 8% of ethyl cellulose, 28% of terpineol, 12% of butyl carbitol, 1% of ammonium polyacrylate, and 2% of dibutyl phthalate.
[0039] According to the above composition, each component is weighed, and the conductive slurry containing ruthenium oxide is prepared according to the following steps:
[0040] S1, RuO2 powder is vacuum dried at 200℃ for 2.5 hours to reduce surface adsorbed water, and activated RuO2 is prepared;
[0041] S2, the activated ruthenium oxide prepared in S1 is cooled to room temperature and mixed with ammonium polyacrylate, and a ruthenium oxide-ammonium polyacrylate composite dispersion system is prepared by ultrasonic dispersion at 42 kHz for 30 minutes;
[0042] S3, mixing terpineol with butyl carbitol, stirring and mixing uniformly to prepare a mixed solvent;
[0043] S4, adding PbO-B2O3-SiO2, carbon nanotubes and RuO2-ammonium polyacrylate composite dispersion system into the mixed solvent, using zirconium oxide balls for ball milling at a speed of 300 rpm for 4 h to prepare a ball-milled mixture;
[0044] S5, preparing a finely dispersed mixture by using 500 W ultrasonic dispersion for 20 min on the ball-milled mixture prepared in S4;
[0045] S6, adding ethyl cellulose and dibutyl phthalate into the finely dispersed mixture prepared in S5, magnetic stirring at 60°C for 2 h, and then passing through a 400-mesh sieve to obtain a conductive paste containing RuO2, which is marked as 1# conductive paste.
[0046] Example 2
[0047] This example is to prepare a conductive paste containing RuO2.
[0048] In this example, the carbon nanotubes are multi-walled carbon nanotubes with a tube diameter of 15 nm and an aspect ratio of 80; the particle size of RuO2 is 70 nm; in PbO-B2O3-SiO2, PbO is 60 wt%, B2O3 is 20 wt%, and SiO2 is 20 wt%.
[0049] The conductive paste containing RuO2 is composed of the following components in mass percentage: 44% of RuO2, 3.8% of carbon nanotubes (CNT), 8% of PbO-B2O3-SiO2, 7% of ethyl cellulose, 24.5% of terpineol, 10.5% of butyl carbitol, 0.7% of ammonium polyacrylate, and 1.5% of dibutyl phthalate.
[0050] According to the above composition, each component is weighed and the conductive paste containing RuO2 is prepared according to the following steps:
[0051] S1, drying RuO2 powder at 180°C for 3 hours in vacuum to reduce surface adsorbed water and prepare activated RuO2;
[0052] S2, mixing the activated RuO2 prepared in S1 with ammonium polyacrylate after cooling to room temperature, and using ultrasonic at 45 kHz for 32 min to prepare a RuO2-ammonium polyacrylate composite dispersion system;
[0053] S3, mixing terpineol with butyl carbitol, stirring and mixing uniformly to prepare a mixed solvent;
[0054] S4, adding PbO-B2O3-SiO2, carbon nanotubes and ruthenium oxide-ammonium polyacrylate composite dispersion system into the mixed solvent, using zirconium oxide balls for ball milling, rotating speed 320 rpm, ball milling 4.5 h, to obtain a ball-milled mixture;
[0055] S5, using 500 W ultrasonic dispersion for 25 min to obtain a finely dispersed mixture from the ball-milled mixture of S4;
[0056] S6, adding ethyl cellulose and dibutyl phthalate into the finely dispersed mixture of S5, magnetic stirring at 65℃ for 2.5 h, and then passing through a 400-mesh sieve to obtain a conductive paste containing ruthenium oxide, which is marked as 2# conductive paste.
[0057] Example 3
[0058] This example is to prepare a conductive paste containing ruthenium oxide.
[0059] In this example, the carbon nanotubes are multi-walled carbon nanotubes with a tube diameter of 20 nm and an aspect ratio of 100; the particle size of ruthenium oxide (RuO2) is 100 nm; in PbO-B2O3-SiO2, PbO is 60 wt%, B2O3 is 20 wt%, and SiO2 is 20 wt%.
[0060] The conductive paste containing ruthenium oxide is composed of the following components by mass percentage: 50% ruthenium oxide (RuO2), 5% carbon nanotubes (CNT), 10% PbO-B2O3-SiO2, 3% ethyl cellulose, 21% terpineol, 9% butyl carbitol, 1% ammonium polyacrylate, and 1% dibutyl phthalate.
[0061] According to the above composition, each component is weighed and the conductive paste containing ruthenium oxide is prepared according to the following steps:
[0062] S1, drying RuO2 powder at 210℃ for 2 hours in vacuum to reduce surface adsorbed water, to obtain activated RuO2.
[0063] S2, mixing the activated RuO2 obtained in S1 with ammonium polyacrylate after cooling to room temperature, and using 42 kHz ultrasonic for 35 min to obtain a ruthenium oxide-ammonium polyacrylate composite dispersion system;
[0064] S3, mixing terpineol and butyl carbitol, and stirring to obtain a mixed solvent;
[0065] S4, adding PbO-B2O3-SiO2, carbon nanotubes and ruthenium oxide-ammonium polyacrylate composite dispersion system into the mixed solvent, using zirconium oxide balls for ball milling, rotating speed 350 rpm, ball milling 5 h, to obtain a ball-milled mixture;
[0066] S5, the ball-milling mixture prepared in S4 was dispersed for 30 min using 500W ultrasonic dispersion to prepare a fine dispersion mixture;
[0067] S6, ethyl cellulose and dibutyl phthalate were added to the fine dispersion mixture prepared in S5, and the mixture was stirred magnetically at 62°C for 3h, and then sieved through a 400-mesh sieve to obtain a conductive paste containing ruthenium oxide, which was labeled as 3# conductive paste.
[0068] Comparative Example 1
[0069] In this comparative example, 30% of terpineol was used to replace the mixed solvent composed of 21% of terpineol and 9% of butyl carbitol, and the other components and preparation conditions were the same as those in Example 3. The prepared conductive paste was labeled as 1# comparative example.
[0070] Comparative Example 2
[0071] In this comparative example, 30% of butyl carbitol was used to replace the mixed solvent composed of 21% of terpineol and 9% of butyl carbitol, and the other components and preparation conditions were the same as those in Example 3. The prepared conductive paste was labeled as 2# comparative example.
[0072] Comparative Example 3
[0073] In this comparative example, 3% of polyvinylpyrrolidone was used to replace 3% of ethyl cellulose, and the other components and preparation conditions were the same as those in Example 3. The prepared conductive paste was labeled as 3# comparative example.
[0074] Test Example
[0075] In this test example, the conductive pastes prepared in Examples 1-3 and the conductive pastes prepared in Comparative Examples 1-3 were made into conductive films, and the resistivity of the conductive films was measured by the four-probe method to evaluate the conductive performance of different conductive pastes.
[0076] The conductive paste stability determination method was to place the conductive paste at room temperature, and observe whether the conductive paste appeared to be aggregated by naked eye, and record the time. The test results are shown in Table 1.
[0077] Table 1 Performance test results of different conductive pastes
[0078]
[0079] Note: For resistivity, 128.9 mΩ / sq@20μm means that for a square film of this material with a thickness of 20μm, the resistance between opposite sides is 128.9 mΩ; 98.7 mΩ / sq@20μm means that for a square film of this material with a thickness of 20μm, the resistance between opposite sides is 98.7 mΩ.
[0080] The results show that the resistivity of the conductive films prepared from the conductive pastes 1#-3# prepared in Examples 1-3 is 85.5-98.7 mΩ / sq@20μm, which is significantly lower than the resistivity of the conductive films prepared from the conductive pastes prepared in Comparative Examples 1-3, which is 128.9-183.4 mΩ / sq@20μm, indicating that the electronic paste prepared from the mixed solvent of terpineol and butyl carbitol has better conductive performance than the electronic paste prepared from the single solvent of terpineol, the single solvent of butyl carbitol, and the conductive paste prepared by replacing ethyl cellulose with polyvinylpyrrolidone, indicating that the components of the conductive paste containing ruthenium oxide provided in the application have a synergistic effect.
[0081] The stability of the conductive pastes prepared in Examples 1-3 (>5-6 months) is better than that of Comparative Examples 1-3 (>3 months only), indicating that the mixed solvent of terpineol and butyl carbitol in the application is compatible with ethyl cellulose, and the stability of the conductive paste is better.
[0082] The preparation method provided in the application first uses vacuum drying to activate the ruthenium oxide, removes the physically adsorbed moisture on the surface of the ruthenium oxide, reduces the surface hydroxyl groups, thereby exposing more metal active sites, further forming a bridging network with CNTs with high aspect ratio, filling the gap between the conductive paths, reducing the contact resistance, improving the conductive efficiency, and the resistivity is as low as 85.5 mΩ / sq@20μm. Terpineol improves the stability of the conductive paste, butyl carbitol improves the leveling property, and the specific ratio of the two optimizes the rheological property of the conductive paste. The uniformity of the components in the paste is improved by the synergistic effect of the dispersant and the multi-step dispersion process of ball milling and ultrasonic, and the stability of the paste is improved. The technical problems of insufficient conductivity and easy agglomeration of traditional pastes are solved.
[0083] As described above, the basic principles, main features and advantages of the application are better described. The above examples and descriptions only describe the preferred embodiments of the application, and the application is not limited by the above examples. Without departing from the spirit and scope of the application, various changes and improvements to the technical solutions of the application made by those skilled in the art shall fall within the scope of protection of the application.
Claims
1. A conductive paste containing ruthenium oxide, characterized in that, The conductive paste is composed of the following components by mass percentage: 40%-50% ruthenium oxide, 3.8%-5% carbon nanotubes, 5%-10% PbO-B2O3-SiO2, 3%-8% ethyl cellulose, 21%-28% terpineol, 9%-12% butyl carbitol, 0.7%-1% ammonium polyacrylate, and 1%-2% dibutyl phthalate; the mass ratio of terpineol to butyl carbitol is 7:
3.
2. The conductive paste according to claim 1, characterized in that, The conductive paste is composed of the following components by weight percentage: 50% ruthenium oxide, 5% carbon nanotubes, 10% PbO-B2O3-SiO2, 3% ethyl cellulose, 21% terpineol, 9% butyl carbitol, 1% ammonium polyacrylate, and 1% dibutyl phthalate.
3. A method for preparing the conductive paste according to claim 1, characterized in that, Includes the following steps: S1. Ruthenium oxide powder is vacuum dried at 180-210℃ for 2-3 hours to obtain activated ruthenium oxide; S2. After cooling the activated ruthenium oxide obtained in S1 to room temperature, mix it with ammonium polyacrylate and ultrasonically disperse it at 42-45 kHz for 30-35 min to obtain a ruthenium oxide-ammonium polyacrylate composite dispersion system. S3. Mix terpineol and butylcarbitol to prepare a mixed solvent; S4. Add the PbO-B2O3-SiO2, carbon nanotubes and ruthenium oxide-ammonium polyacrylate composite dispersion system to the mixed solvent, and ball mill for 4-5 hours to obtain the ball-milled mixture; S5. The ball-milled mixture obtained in S4 is ultrasonically dispersed to obtain a finely dispersed mixture; S6. Add ethyl cellulose and dibutyl phthalate to the finely dispersed mixture obtained in S5, stir, and sieve to obtain a conductive paste containing ruthenium oxide.
4. The method according to claim 3, characterized in that, The ruthenium oxide powder in S1 has a particle size of 50-100 nm.
5. The method according to claim 3, characterized in that, The carbon nanotubes in S4 have a diameter of 10-20 nm and an aspect ratio of 50-100.
6. The method according to claim 3, characterized in that, The ball milling in S4 is a zirconia ball mill with a rotation speed of 300-350 rpm.
7. The method according to claim 3, characterized in that, The ultrasonic power for ultrasonic dispersion in S5 is 500W, and the ultrasonic dispersion time is 20-30min.
8. The method according to claim 3, characterized in that, In step S6, the stirring is performed using magnetic stirring, and the stirring temperature is 60-65℃.
9. The application of the conductive paste according to claim 1 or claim 2 in the preparation of electronic components.
Citation Information
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