Cold spraying copper coating and preparation method thereof

Abstract

The invention discloses a cold spraying copper coating and a preparation method thereof, according to the cold spraying copper coating and the preparation method thereof, oxidation of copper powder under a high-temperature condition is avoided by adopting a cold spraying technology, so that the excellent conductivity and corrosion resistance of the copper coating are kept, and the cold spraying technology does not cause thermal damage to a base material; according to the cold spraying copper coating and the preparation method thereof, through the steps of wet grinding dispersion and viscosity adjustment, it is guaranteed that copper powder is evenly distributed in the coating, and the cold spraying copper coating and the preparation method thereof have the advantages that the method is suitable for wider base materials including heat-sensitive materials, internal stress generated in the cold spraying process is low, the adhesive force between the coating and the base materials is improved, and the durability of the coating is improved; according to the cold spraying copper coating and the preparation method thereof, the overall quality and the surface smoothness of the coating are improved, nano-scale silicon oxide powder is added as a high-wear-resistance additive, the wear resistance of the coating is remarkably improved, and particularly under the conditions of high load and high-speed movement, the cold spraying copper coating and the preparation method thereof are more environmentally friendly compared with a traditional thermal spraying technology and a traditional cold spraying technology.

Description

Technical Field

[0001] The invention relates to the technical field of metal coatings, in particular to a cold sprayed copper coating and a preparation method thereof. Background Art

[0002] Cold spray technology is an advanced coating preparation method that uses compressed gas to spray powdered materials onto substrates at low temperatures. Compared with traditional thermal spray technology, cold spray avoids the problems of material oxidation and thermal damage caused by high temperatures. However, existing cold spray technology still has some limitations and challenges.

[0003] First, the existing cold spray technology still has room for improvement in powder dispersion and coating uniformity. Powder particles may aggregate during the spraying process, resulting in uneven coating thickness and a rough surface. Second, cold spray technology also has challenges in coating adhesion. Due to the lack of sufficient thermal energy during the spraying process to promote the bonding of the material, the coating may have problems with insufficient adhesion, especially at the interface between the coating and the substrate.

[0004] In addition, although cold spraying technology reduces the oxidation of materials, in some cases, in order to further improve the conductivity and corrosion resistance of the coating, the sprayed material still needs to be specially treated, which increases the complexity and cost of the treatment.

[0005] Therefore, how to improve and give full play to the advantages of cold spraying technology, while solving the shortcomings of existing technologies and broadening its application scope in industrial applications has become a problem that needs to be solved urgently. Summary of the invention

[0006] The object of the present invention is to provide a cold sprayed copper coating and a preparation method thereof, so as to solve the problems existing in the prior art mentioned in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution, a cold sprayed copper coating and a preparation method thereof, wherein the components are composed of the following components in parts by weight:

[0008] 50-70 parts of nano copper powder;

[0009] 20-30 parts of binder;

[0010] 3 to 8 parts of thickener;

[0011] 5 to 20 parts of additives;

[0012] 2 to 5 parts of high wear resistant additives.

[0013] Preferably, the average particle size of the nano-scale copper powder is 20 to 50 nanometers.

[0014] Preferably, the binder is a mixture of epoxy resin and polyurethane resin, wherein:

[0015] Epoxy resin accounts for 15-25 parts;

[0016] The polyurethane resin accounts for 5 to 10 parts.

[0017] Preferably, the thickener is sodium carboxymethyl cellulose.

[0018] Preferably, the auxiliary agent includes a leveling agent, a defoaming agent and a dispersant, wherein:

[0019] The leveling agent accounts for 1 to 3 parts to eliminate brush marks and orange peel on the coating surface;

[0020] Defoaming agent accounts for 0.5 to 2 parts to prevent the formation of bubbles in the coating;

[0021] The dispersant accounts for 1 to 4 parts to keep the copper powder evenly distributed in the coating.

[0022] Preferably, the highly wear-resistant additive is nano-scale silicon oxide powder.

[0023] A cold spray copper coating, the preparation method of which is as follows:

[0024] S11) weighing raw materials: accurately weighing nano copper powder, binder, thickener, additive and high wear-resistant additive;

[0025] S12) Mixing reaction: mixing the weighed raw materials in a certain proportion to ensure that the components are evenly dispersed;

[0026] S13) wet grinding and dispersion: wet grinding the mixed material to further improve the dispersibility of the copper powder in the coating material;

[0027] S14) degassing treatment: vacuum degassing the wet-grinded coating material to remove bubbles and impurities in the material;

[0028] S15) adjusting viscosity: adjusting the viscosity of the coating material according to the requirements of the spraying equipment;

[0029] S16) Cold spraying: The coating material with adjusted viscosity is sprayed on the substrate by cold spraying technology, and the spraying pressure and distance are controlled to obtain the ideal coating thickness and surface quality.

[0030] Preferably, the method further comprises a method for testing the corrosion resistance of the cold sprayed copper coating, comprising the following steps:

[0031] S21) preparing test samples: cutting the cold-sprayed copper coating into test pieces of a specified size;

[0032] S22) Conducting a corrosion test: exposing the test piece to a corrosive medium and measuring the difference in quality before and after corrosion to evaluate the corrosion resistance of the coating.

[0033] Preferably, the method further comprises a method for testing the electrical conductivity of a cold sprayed copper coating, comprising the following steps:

[0034] S31) preparing test samples: cutting the cold-sprayed copper coating into test pieces of a specified size;

[0035] S32) Conducting conductivity test: using standard conductivity test equipment to test the test piece;

[0036] S33) The resistivity of the test piece is recorded by the test equipment, and the conductivity is calculated to verify whether the conductivity of the coating meets the application requirements.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The cold-sprayed copper coating and its preparation method avoid oxidation of copper powder under high temperature conditions by adopting cold spraying technology, thereby maintaining the excellent conductivity and corrosion resistance of the copper coating. The cold spraying technology will not cause thermal damage to the substrate, making the method applicable to a wider range of substrates, including heat-sensitive materials. The internal stress generated during the cold spraying process is low, which helps to improve the adhesion between the coating and the substrate and enhance the durability of the coating;

[0039] 2. The cold spray copper coating and its preparation method ensure the uniform distribution of copper powder in the coating through wet grinding dispersion and viscosity adjustment steps, improve the overall quality and surface finish of the coating, and add nano-scale silicon oxide powder as a high wear-resistant additive to significantly improve the wear resistance of the coating, especially under high load and high-speed movement conditions;

[0040] 3. Compared with the traditional thermal spraying technology, the cold spraying copper coating and its preparation method are more environmentally friendly, reduce the emission of harmful gases and dust, meet the current environmental protection requirements, and are easy to operate. The coating can be quickly completed at room temperature, which improves production efficiency and economic benefits. Since high-temperature equipment and complex heat treatment processes are not required, cold spraying technology helps to reduce production costs;

[0041] 4. The excellent performance of the cold-sprayed copper coating and its preparation method makes it have broad application prospects in many fields such as electronics, aviation, and automobiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a preparation flow chart of the preparation method of the present invention;

[0043] Figure 2This is a summary table of test results of Example 1, Example 2, and Example 3 of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the description of the invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0046] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] See also Figure 1-2 The present invention provides a technical solution: a cold spray copper coating and a preparation method thereof, wherein the components are composed of the following components in parts by weight:

[0048] 50-70 parts of nano copper powder;

[0049] 20-30 parts of binder;

[0050] 3 to 8 parts of thickener;

[0051] 5 to 20 parts of additives;

[0052] 2 to 5 parts of high wear resistant additives.

[0053] Specifically, the use of nano-scale copper powder provides excellent electrical and thermal conductivity while maintaining coating uniformity and mechanical properties.

[0054] The average particle size of the nano-scale copper powder is 20 to 50 nanometers. Specifically, the particle size range of the nano-scale copper powder ensures the uniformity and excellent mechanical properties of the coating.

[0055] The binder is a mixture of epoxy resin and polyurethane resin, wherein:

[0056] Epoxy resin accounts for 15-25 parts;

[0057] The polyurethane resin accounts for 5 to 10 parts.

[0058] Specifically, a mixture of epoxy resin and polyurethane resin provides excellent chemical stability and adhesion while increasing the flexibility and wear resistance of the coating.

[0059] The thickener is sodium carboxymethyl cellulose. Specifically, sodium carboxymethyl cellulose is used as a thickener to effectively control the rheological properties of the coating and adapt to different spraying conditions.

[0060] The additives include leveling agents, defoamers and dispersants, wherein:

[0061] The leveling agent accounts for 1 to 3 parts to eliminate brush marks and orange peel on the coating surface;

[0062] Defoaming agent accounts for 0.5 to 2 parts to prevent the formation of bubbles in the coating;

[0063] The dispersant accounts for 1 to 4 parts to keep the copper powder evenly distributed in the coating.

[0064] Specifically, the use of the additive improves the fluidity and surface finish of the coating and prevents the generation of bubbles in the coating.

[0065] The highly wear-resistant additive is nano-scale silicon oxide powder. Specifically, nano-scale silicon oxide powder as a highly wear-resistant additive significantly improves the wear resistance of the coating and prolongs its service life.

[0066] A cold spray copper coating, the preparation method of which is as follows:

[0067] S11) weighing raw materials: accurately weighing nano copper powder, binder, thickener, additive and high wear-resistant additive;

[0068] S12) Mixing reaction: mixing the weighed raw materials in a certain proportion to ensure that the components are evenly dispersed;

[0069] S13) wet grinding and dispersion: wet grinding the mixed material to further improve the dispersibility of the copper powder in the coating material;

[0070] S14) degassing treatment: vacuum degassing the wet-grinded coating material to remove bubbles and impurities in the material;

[0071] S15) adjusting viscosity: adjusting the viscosity of the coating material according to the requirements of the spraying equipment;

[0072] S16) Cold spraying: The coating material with adjusted viscosity is sprayed on the substrate by cold spraying technology, and the spraying pressure and distance are controlled to obtain the ideal coating thickness and surface quality.

[0073] A cold sprayed copper coating and a preparation method thereof, further comprising a method for testing the corrosion resistance of the cold sprayed copper coating, comprising the following steps:

[0074] S21) preparing test samples: cutting the cold-sprayed copper coating into test pieces of a specified size;

[0075] S22) Conducting a corrosion test: exposing the test piece to a corrosive medium and measuring the difference in quality before and after corrosion to evaluate the corrosion resistance of the coating.

[0076] A cold sprayed copper coating and a preparation method thereof, and also a method for testing the electrical conductivity of the cold sprayed copper coating, comprising the following steps:

[0077] S31) preparing test samples: cutting the cold-sprayed copper coating into test pieces of a specified size;

[0078] S32) Conducting conductivity test: using standard conductivity test equipment to test the test piece;

[0079] S33) The resistivity of the test piece is recorded by the test equipment, and the conductivity is calculated to verify whether the conductivity of the coating meets the application requirements.

[0080] Example 1

[0081] S11. Weighing raw materials: accurately weigh out 60 parts of nano-copper powder (average particle size 35 nanometers), 25 parts of epoxy resin, 5 parts of polyurethane resin, 5 parts of sodium carboxymethyl cellulose, 15 parts of additives (including 2 parts of leveling agent, 1 part of defoaming agent, 3 parts of dispersant) and 4 parts of nano-silicon oxide powder.

[0082] S12. Mixing reaction: Mix the above raw materials according to the proportion, and use a high-speed stirrer at 3000 rpm for 30 minutes to ensure that the components are evenly dispersed.

[0083] S13. Wet grinding and dispersion: The mixed material is wet-milled using a bead mill at 1500 rpm for 2 hours to further improve the dispersibility of the copper powder in the coating material.

[0084] S14. Degassing treatment: The wet-grinded coating material is subjected to vacuum degassing with a vacuum degree of 0.1 MPa for 10 minutes to remove bubbles and impurities in the material.

[0085] S15. Adjust viscosity: According to the requirements of the spraying equipment, adjust the viscosity of the coating material to 5000cps by adding an appropriate amount of diluent.

[0086] S16. Cold spraying: The coating material with adjusted viscosity is sprayed on the substrate by cold spraying technology, the spraying pressure is controlled at 2.8 MPa, the distance is controlled at 20 cm, and the spraying speed is 50 cm / s to obtain a uniform coating with a thickness of 0.5 mm.

[0087] Example 2

[0088] S11. Weighing raw materials: accurately weigh out 50 parts of nano-copper powder (average particle size 25 nanometers), 20 parts of epoxy resin, 10 parts of polyurethane resin, 3 parts of sodium carboxymethyl cellulose, 10 parts of additives (including 1 part of leveling agent, 0.5 parts of defoaming agent, 2 parts of dispersant) and 3 parts of nano-silicon oxide powder.

[0089] S12. Mixing reaction: Mix the above raw materials according to the proportion, and use a high-speed stirrer at 3500 rpm for 20 minutes to ensure that the components are evenly dispersed.

[0090] S13. Wet grinding and dispersion: The mixed material is wet-milled using a bead mill at 2000 rpm for 1 hour to further improve the dispersibility of the copper powder in the coating material.

[0091] S14. Degassing treatment: The wet-grinded coating material is vacuum degassed with a vacuum degree of 0.09 MPa for 15 minutes to remove bubbles and impurities in the material.

[0092] S15. Adjust viscosity: According to the requirements of the spraying equipment, adjust the viscosity of the coating material to 6000cps by adding an appropriate amount of diluent.

[0093] S16. Cold spraying: The coating material with adjusted viscosity is sprayed on the substrate by cold spraying technology, the spraying pressure is controlled at 3.0 MPa, the distance is controlled at 25 cm, and the spraying speed is 60 cm / s to obtain a uniform coating with a thickness of 0.3 mm.

[0094] Example 3

[0095] S11. Weighing raw materials: accurately weigh out 70 parts of nano-copper powder (average particle size 45 nanometers), 30 parts of epoxy resin, 8 parts of polyurethane resin, 8 parts of sodium carboxymethyl cellulose, 20 parts of additives (including 3 parts of leveling agent, 2 parts of defoaming agent, 5 parts of dispersant) and 5 parts of nano-silicon oxide powder.

[0096] S12. Mixing reaction: Mix the above raw materials according to the proportion, and use a high-speed stirrer at 2500 rpm for 40 minutes to ensure that the components are evenly dispersed.

[0097] S13. Wet grinding and dispersion: The mixed material is wet-milled using a bead mill at 1000 rpm for 3 hours to further improve the dispersibility of the copper powder in the coating material.

[0098] S14. Degassing treatment: The wet-grinded coating material is subjected to vacuum degassing with a vacuum degree of 0.08 MPa for 20 minutes to remove bubbles and impurities in the material.

[0099] S15. Adjust viscosity: According to the requirements of the spraying equipment, adjust the viscosity of the coating material to 4500cps by adding an appropriate amount of diluent.

[0100] S16. Cold spraying: The coating material with adjusted viscosity is sprayed on the substrate by cold spraying technology. The spraying pressure is controlled at 2.5 MPa, the distance is controlled at 15 cm, and the spraying speed is 40 cm / s to obtain a uniform coating with a thickness of 0.7 mm.

[0101] Test Example 1

[0102] The corrosion resistance test was carried out on Example 1, Example 2 and Example 3:

[0103] 1. Prepare test samples: Cut test pieces of 10 cm x 10 cm from the cold sprayed copper coatings prepared in Example 1, Example 2, and Example 3, respectively.

[0104] 2. Carry out corrosion test: Expose the test piece to 5% saline solution and soak it for 24 hours continuously.

[0105] 3. Measure the amount of wear: Use a precision electronic balance to measure the mass difference before and after corrosion of the test piece and record the mass loss.

[0106] Test Example 2

[0107] Conductive performance test was performed on Example 1, Example 2 and Example 3:

[0108] 1. Prepare test samples: Cut test pieces of 10 cm x 10 cm from the cold sprayed copper coatings prepared in Example 1, Example 2, and Example 3, respectively.

[0109] 2. Conduct electrical conductivity test: Use a four-point probe tester to test on the test piece.

[0110] 3. Record resistivity: The test results show the resistivity of the test piece to verify the conductive properties of the coating.

[0111] Test Example 3

[0112] Adhesion test was performed on Example 1, Example 2 and Example 3:

[0113] 1. Prepare test samples: Cut test pieces of 2 cm x 2 cm from the cold sprayed copper coatings prepared in Example 1, Example 2, and Example 3, respectively.

[0114] 2. Perform adhesion test: Use a tensile testing machine to perform a tensile test on the test piece.

[0115] 3. Record the tensile force: During the test, the adhesion between the test piece and the substrate reaches a certain value, indicating the adhesion between the coating and the substrate.

[0116] The test data of the cold sprayed copper coatings obtained in Example 1, Example 2 and Example 3 are as follows:

[0117]

[0118]

[0119] From the data in the above table, we can draw the following conclusions:

[0120] Conclusion of Example 1:

[0121] Example 1 shows a balanced formulation where the amount of nano copper powder used matches the ratio of binder to ensure good conductivity and mechanical strength. The corrosion resistance test shows a small mass loss, indicating that the coating has good corrosion resistance. The conductivity test results show that the coating has excellent conductivity and is suitable for applications requiring good conductivity. The adhesion test results show that the coating has strong adhesion to the substrate, which is very important for long-term stability.

[0122] Conclusion of Example 2:

[0123] Example 2 uses less nano-copper powder and binder, but increases the proportion of polyurethane resin, which is to improve the flexibility of the coating. Due to the reduction in copper powder content, the corrosion resistance and conductivity are slightly lower than those of Example 1. However, due to the increase in polyurethane resin, the adhesion is slightly improved, which enhances the elasticity of the coating and adhesion to the substrate.

[0124] Conclusion of Example 3:

[0125] The use of nano-scale copper powder in Example 3 is the highest, which leads to higher conductivity, as shown in the resistivity test. At the same time, the higher use of binder and additives may help improve the overall quality and durability of the coating. Although the adhesion is slightly lower than that of Example 2, it is still within an acceptable range, indicating that there is good bonding between the coating and the substrate.

[0126] Overall, all three examples demonstrate the effectiveness of cold spray copper coatings, each with its own unique formulation and performance characteristics. Example 1 provides balanced performance, Example 2 may be more suitable for applications requiring higher flexibility, and Example 3 provides the best conductive properties. These conclusions show that by adjusting the proportions of various ingredients in the formulation, the properties of the coating can be customized to meet different application requirements.

[0127] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cold sprayed copper coating and a preparation method thereof, characterized in that: Its ingredients are composed of the following components in parts by weight: 50-70 parts of nano copper powder; 20-30 parts of binder; 3 to 8 parts of thickener; 5 to 20 parts of additives; 2 to 5 parts of high wear resistant additives.

2. A cold sprayed copper coating according to claim 1, characterized in that: The average particle size of the nano-scale copper powder is 20 to 50 nanometers.

3. A cold sprayed copper coating and a preparation method thereof according to claim 1, characterized in that: The binder is a mixture of epoxy resin and polyurethane resin, wherein: Epoxy resin accounts for 15-25 parts; The polyurethane resin accounts for 5 to 10 parts.

4. The cold sprayed copper coating according to claim 1, characterized in that: The thickener is sodium carboxymethyl cellulose.

5. The cold sprayed copper coating according to claim 1, characterized in that: The additives include leveling agents, defoamers and dispersants, wherein: The leveling agent accounts for 1 to 3 parts to eliminate brush marks and orange peel on the coating surface; Defoaming agent accounts for 0.5 to 2 parts to prevent the formation of bubbles in the coating; The dispersant accounts for 1 to 4 parts to keep the copper powder evenly distributed in the coating.

6. The cold sprayed copper coating according to claim 1, characterized in that: The highly wear-resistant additive is nano-scale silicon oxide powder.

7. The cold sprayed copper coating according to claim 1, wherein the preparation method is: S11) weighing raw materials: accurately weighing nano copper powder, binder, thickener, additive and high wear-resistant additive; S12) Mixing reaction: mixing the weighed raw materials in a certain proportion to ensure that the components are evenly dispersed; S13) wet grinding and dispersion: wet grinding the mixed material to further improve the dispersibility of the copper powder in the coating material; S14) degassing treatment: vacuum degassing the wet-grinded coating material to remove bubbles and impurities in the material; S15) adjusting viscosity: adjusting the viscosity of the coating material according to the requirements of the spraying equipment; S16) Cold spraying: The coating material with adjusted viscosity is sprayed on the substrate by cold spraying technology, and the spraying pressure and distance are controlled to obtain the ideal coating thickness and surface quality.

8. A cold sprayed copper coating and a preparation method thereof according to any one of claims 1 to 7, characterized in that: Also included is a method for testing the corrosion resistance of a cold sprayed copper coating, comprising the following steps: S21) preparing test samples: cutting the cold-sprayed copper coating into test pieces of a specified size; S22) Conducting a corrosion test: exposing the test piece to a corrosive medium and measuring the difference in quality before and after corrosion to evaluate the corrosion resistance of the coating.

9. A cold sprayed copper coating and a preparation method thereof according to any one of claims 1 to 7, characterized in that: Also included is a method for testing the electrical conductivity of a cold sprayed copper coating, comprising the following steps: S31) preparing test samples: cutting the cold-sprayed copper coating into test pieces of a specified size; S32) Conducting conductivity test: using standard conductivity test equipment to test the test piece; S33) The resistivity of the test piece is recorded by the test equipment, and the conductivity is calculated to verify whether the conductivity of the coating meets the application requirements.

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