A transition coating suitable for ceramic cold spraying, its preparation method and application

Abstract

This invention belongs to the field of ceramic substrate surface spraying technology, specifically relating to a transition coating suitable for ceramic cold spraying, its preparation method, and its application. The transition coating for ceramic cold spraying provided by this invention comprises 19.5–94.5 wt% glaze, 0.1–0.5 wt% carboxymethyl cellulose, and 5–80 wt% nickel powder. The key to this invention lies in using a specific ratio of glaze, carboxymethyl cellulose, and nickel powder as raw materials, and forming a transition coating on the surface of ceramic materials through heat treatment. This transition coating not only has good bonding performance with the ceramic material surface but also alters the surface properties of the ceramic material, enabling the ceramic surface with the transition coating to form a metallic coating through cold spraying. It also enhances the bonding strength between the metallic coating and the ceramic material surface, improving the reliability of the metallic coating. This provides a solution to the problem of difficulty in forming metallic coatings on ceramic surfaces through cold spraying and the poor reliability of such metallic coatings.

Description

Technical Field

[0001] This invention belongs to the field of ceramic substrate surface spraying technology, specifically relating to a transition coating suitable for ceramic cold spraying, its preparation method and application. Background Technology

[0002] Ceramic materials are widely used in electronics, aerospace, and other fields due to their excellent properties such as high chemical stability, good thermal stability, strong corrosion resistance, low dielectric constant, and high hardness. Coating ceramic materials with different types of metal or alloy coatings adds the properties of the different metals to their original excellent properties, such as superior electrical and magnetic conductivity. Currently, commonly used methods for ceramic metallization include screen printing, magnetron sputtering, direct copper plating (DBC), activated Mo-Mn sintering, active metal brazing (AMB), and cold spraying. Among these, cold spraying is an aerodynamic-based coating technique that involves solid particles with a certain degree of plasticity impacting the substrate surface at high speed, causing the particles to undergo intense plastic deformation and deposit onto the substrate surface to form a coating. However, since cold spraying relies primarily on the kinetic energy of particles rather than thermal energy, when particles impact the substrate surface at different velocities, the following phenomena may occur: the particles may be bounced off the substrate or impact the ceramic, producing fragments that prevent the metal powder from depositing on the ceramic surface or result in poor bonding strength with the ceramic material. Therefore, it is crucial to find a method that enables the acquisition of high-performance metal coatings on ceramic substrates through cold spraying. Summary of the Invention

[0003] One of the objectives of this invention is to address the shortcomings of existing technologies that make it difficult to obtain metal coatings on ceramic surfaces through cold spraying, or where the reliability of the metal coatings is poor. This invention provides a transition coating and preparation method suitable for cold spraying of ceramics. By first forming a transition coating on the surface of the ceramic substrate, a high-performance metal coating can be formed by cold spraying on the surface of the ceramic substrate.

[0004] Specifically, the transition coating for ceramic cold spraying comprises 19.5–94.5 wt% glaze, 0.1–0.5 wt% carboxymethyl cellulose, and 5–80 wt% nickel powder.

[0005] In a preferred embodiment, the average particle size of the nickel powder is 5–15 μm.

[0006] In a preferred embodiment, the glaze comprises silica, feldspar, calcite, dolomite, zinc oxide, aluminum oxide, opacifier, kaolin, and glass powder.

[0007] In a preferred embodiment, based on the total mass of the glaze, the content of silica is 25-35 wt%, the content of feldspar is 25-30 wt%, the content of calcite is 12-18 wt%, the content of dolomite is 3-6 wt%, the content of zinc oxide is 2-5 wt%, the content of alumina is 2-5 wt%, the content of opacifier is 10-14 wt%, the content of kaolin is 2-5 wt%, and the content of glass powder is 0.5-1 wt%.

[0008] In a preferred embodiment, the feldspar is selected from at least one of methyl feldspar, sodium feldspar, and calcium feldspar.

[0009] In a preferred embodiment, the emulsifier is selected from at least one of zirconium oxide, tin oxide, and cerium oxide.

[0010] The second objective of this invention is to provide a method for preparing the transition coating applicable to ceramic cold spraying, the method comprising mixing glaze, carboxymethyl cellulose and metallic nickel powder evenly, coating it onto the surface of a ceramic substrate, and then performing heat treatment, thereby forming a transition coating on the surface of the ceramic substrate.

[0011] In a preferred embodiment, the heat treatment conditions include a temperature of 1000–1400°C and a time of 5–24 hours.

[0012] In a preferred embodiment, the thickness of the transition coating is 0.2 to 1.0 mm.

[0013] The third objective of this invention is to provide a cold spraying process, which includes the following steps: (1) forming the above-mentioned transition coating on the surface of a ceramic material; (2) forming a metal coating on the surface of the transition coating by cold spraying.

[0014] A fourth objective of this invention is to provide the application of the aforementioned transition coating suitable for ceramic cold spraying in the metallization of ceramic cold spraying.

[0015] The key to this invention lies in using a specific ratio of glaze, carboxymethyl cellulose, and nickel powder as raw materials. After heat treatment, a transition coating is formed on the surface of a ceramic material. This transition coating not only has good bonding performance with the ceramic material surface, but also changes the surface properties of the ceramic material, making it easier for the ceramic material surface to bond with the target metal coating through the action of the transition layer. This enables the formation of a metal coating on the ceramic material surface through a cold spraying process, enhances the bonding strength between the metal coating and the ceramic material surface, and improves the reliability of the metal coating. This provides a solution to the problem that it is difficult to form a metal coating on the ceramic surface through cold spraying and that the reliability of such a metal coating is poor. Attached Figure Description

[0016] Figure 1 It is the transition coating on the surface of the ceramic material prepared in Example 1.

[0017] Figure 2 It is a metal coating formed by cold spraying on the surface of the transition coating prepared in Example 1. Detailed Implementation

[0018] The transition coating for ceramic cold spraying provided by this invention comprises a glaze, carboxymethyl cellulose, and nickel powder. The glaze content is 19.5–94.5 wt%, such as 19.5 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 70 wt%, 90 wt%, 94.5 wt%, or any value between therewith. The carboxymethyl cellulose content is 0.1–0.5 wt%, such as 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, or any value between therewith. The nickel powder content is 5–80 wt%, such as 5 wt%, 10 wt%, 20 wt%, 40 wt%, 50 wt%, 60 wt%, 80 wt%, or any value between therewith.

[0019] In this invention, the average particle size of the nickel powder is preferably 5 to 15 μm, such as 5 μm, 8 μm, 10 μm, 12 μm, 15 μm or any value between them.

[0020] In this invention, the glaze comprises silicon dioxide, feldspar, calcite, dolomite, zinc oxide, aluminum oxide, opacifier, kaolin, and glass powder. Based on the total mass of the glaze, the silica content is preferably 25-35 wt%, such as 25 wt%, 28 wt%, 30 wt%, 32 wt%, 35 wt%, or any value between them; the feldspar content is preferably 25-30 wt%, such as 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, or any value between them; the calcite content is preferably 12-18 wt%, such as 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, or any value between them; the dolomite content is preferably 3-6 wt%, such as 3 wt%, 4 wt%, 5 wt%, 6 wt%; and the zinc oxide content is preferably 2-5 wt%, such as 2 wt%, 2.5 wt%, 3 wt%, ... The content of the alumina is preferably 2-5 wt%, such as 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or any value between them; the content of the opacifier is preferably 10-14 wt%, such as 10 wt%, 11 wt%, 12 wt%, 113 wt%, 14 wt%, or any value between them; the content of the kaolin is preferably 2-5 wt%, such as 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or any value between them; the content of the glass powder is preferably 0.5-1 wt%, such as 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, or any value between them.

[0021] In this invention, the method for preparing the transition coating includes uniformly mixing glaze, carboxymethyl cellulose and metallic nickel powder, coating it onto the surface of a ceramic material, and then performing heat treatment to obtain the transition coating.

[0022] Specifically, the mixing order of the glaze, carboxymethyl cellulose, and nickel powder can be either simultaneous mixing of all three materials, or mixing any two materials first, followed by adding the remaining material and mixing until homogeneous. Preferably, this invention involves first mixing the glaze with carboxymethyl cellulose, and then mixing it evenly with the nickel powder to obtain the transition coating material composition. The mixing method for the glaze, carboxymethyl cellulose, and nickel powder can be manual grinding in a mortar and pestle, mixing using a ball mill, mechanical stirring in a mixer, or other mixing methods, with mechanical stirring being preferred. This invention does not impose specific limitations on the mixing conditions of the glaze, carboxymethyl cellulose, and nickel powder, as long as the three materials are mixed evenly to obtain a suspension. Preferably, the mixing time can be 5–10 hours, such as 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, or any value between them, and mixing at room temperature is acceptable. The present invention does not impose specific restrictions on the method of coating the glaze, carboxymethyl cellulose and nickel powder onto the surface of the ceramic material. Various coating methods in the prior art can be used, such as brush coating, scraping coating, spin coating, etc., as long as the raw materials of the transition coating can be uniformly coated onto the surface of the ceramic material. Brush coating is preferred.

[0023] In this invention, the heat treatment conditions include a temperature preferably between 1000 and 1400°C, such as 1000°C, 1100°C, 11200°C, 1300°C, 1400°C, or any value between them; and a time preferably between 5 and 24 hours, such as 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, 24 hours, or any value between them.

[0024] In this invention, the thickness of the transition coating will affect its state after heat treatment, and is preferably 0.2 to 1.0 mm, such as 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm or any value between them.

[0025] The present invention will be described in detail below through specific embodiments.

[0026] Example 1: Preparation of the transition coating

[0027] A suspension was formed by grinding 39.7 wt% of glaze (30 wt% silica, 28 wt% feldspar, 15.5 wt% calcite, 4.5 wt% dolomite, 3.5 wt% zinc oxide, 2.8 wt% alumina, 11.5 wt% zirconium oxide, 3.5 wt% kaolin, and 0.7 wt% glass powder) and 0.3 wt% carboxymethyl cellulose. Then, 60 wt% pure nickel powder (average particle size of 10 μm) was added and mixed evenly to obtain a suspension. The mixed transition coating material composition was brushed onto the surface of the ceramic material and then heat-treated at 1200℃ for 12 h to obtain a transition coating (thickness of 0.5 mm).

[0028] from Figure 1 As can be seen, a uniform transition coating is formed on the surface of the ceramic material.

[0029] Example 2: Preparation of the transition coating

[0030] A suspension was formed by grinding 20 wt% of glaze (30 wt% silica, 28 wt% feldspar, 15.5 wt% calcite, 4.5 wt% dolomite, 3.5 wt% zinc oxide, 2.8 wt% alumina, 11.5 wt% zirconium oxide, 3.5 wt% kaolin, and 0.7 wt% glass powder) and 0.1 wt% carboxymethyl cellulose. Then, 79.1 wt% pure nickel powder (average particle size of 10 μm) was added and mixed evenly to obtain a suspension. The mixed transition coating material composition was brushed onto the surface of the ceramic material using a cold spraying process. Then, it was heat-treated at 1000℃ for 16 hours to obtain a transition coating (thickness of 0.2 mm).

[0031] Example 3: Preparation of the transition coating

[0032] A suspension was formed by grinding 89.5 wt% of glaze (30 wt% silica, 28 wt% feldspar, 15.5 wt% calcite, 4.5 wt% dolomite, 3.5 wt% zinc oxide, 2.8 wt% alumina, 11.5 wt% zirconium oxide, 3.5 wt% kaolin, and 0.7 wt% glass powder) and 0.5 wt% carboxymethyl cellulose. Then, 10 wt% pure nickel powder (average particle size of 10 μm) was added and mixed evenly to obtain a suspension. The mixed transition coating material composition was brushed onto the surface of the ceramic material using a cold spraying process. Then, it was heat-treated at 1400℃ for 8 hours to obtain a transition coating (thickness of 0.8 mm).

[0033] Preparation of the reference transition coating in Comparative Example 1

[0034] The reference transition coating was prepared according to the method of Example 1, except that carboxymethyl cellulose was not added, while all other conditions were the same, thus obtaining the reference transition coating.

[0035] Preparation of the reference transition coating in Comparative Example 2

[0036] A reference transition coating was prepared according to the method in Example 1, except that the glaze was replaced with the same mass of metallic nickel powder, while all other conditions remained the same, thus obtaining the reference transition coating.

[0037] Preparation of the reference transition coating in Comparative Example 3

[0038] The reference transition coating was prepared according to the method of Example 1, except that the same mass of glaze was used instead of nickel powder, while all other conditions were the same, thus obtaining the reference transition coating.

[0039] Test case

[0040] A metallic coating is formed on the surface of the transition coatings prepared in the above embodiments and comparative examples using a conventional cold spraying process, wherein, for example... Figure 2 As shown, a uniform metallic coating was formed on the surface of the ceramic material with a transition coating prepared in Example 1. The performance of the transition coating and the metallic coating on the surface of the prepared ceramic material was tested according to the following methods, and the results are shown in Table 1.

[0041] (1) Bond strength test: The bond strength test shall be carried out in accordance with the method of "Determination of tensile bond strength of thermal spray coating" (GB / T8642-2002) and the universal testing machine shall be used.

[0042] Table 1

[0043]

[0044] As shown in Table 1, compared to the performance test results of the comparative examples, the transition coating provided in this embodiment of the invention exhibits good bonding strength with the ceramic material surface. Furthermore, the presence of the transition coating alters the surface properties of the ceramic material, enabling the formation of a metal coating on the ceramic material surface via cold spraying. This solves the problem of the difficulty in forming a metal coating on the ceramic surface through cold spraying. Moreover, this metal coating possesses good bonding strength and reliability, demonstrating promising application prospects. The test results of Comparative Examples 1-3 show that the transition coating formed without any one of the three raw materials—carboxymethyl cellulose, glaze, and nickel powder—cannot form a metal coating on the ceramic material surface via cold spraying, or the formed metal coating is uneven and has poor bonding strength, failing to meet application requirements.

[0045] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A transition coating suitable for cold spraying of ceramics, characterized in that, The transition coating comprises 19.5–94.5 wt% glaze, 0.1–0.5 wt% carboxymethyl cellulose, and 5–80 wt% nickel powder; the average particle size of the nickel powder is 5–15 μm. The glaze includes silica, feldspar, calcite, dolomite, zinc oxide, aluminum oxide, opacifier, kaolin, and glass powder; The method for preparing the transition coating includes: mixing glaze, carboxymethyl cellulose and nickel powder evenly, coating it onto the surface of a ceramic material, and then performing heat treatment to obtain the transition coating; The aforementioned transition coating is formed on the surface of the ceramic material, and a metal coating is formed on the surface of the transition coating by cold spraying.

2. The transition coating for ceramic cold spraying according to claim 1, characterized in that, Based on the total mass of the glaze, the content of silica is 25-35 wt%, the content of feldspar is 25-30 wt%, the content of calcite is 12-18 wt%, the content of dolomite is 3-6 wt%, the content of zinc oxide is 2-5 wt%, the content of alumina is 2-5 wt%, the content of opacifier is 10-14 wt%, the content of kaolin is 2-5 wt%, and the content of glass powder is 0.5-1 wt%.

3. The transition coating for ceramic cold spraying according to claim 1, characterized in that, The feldspar is selected from at least one of spodumene, albite, and calcium feldspar.

4. The transition coating for ceramic cold spraying according to claim 1, characterized in that, The opacifier is selected from at least one of zirconium oxide, tin oxide, and cerium oxide.

5. The method for preparing a transition coating suitable for ceramic cold spraying according to any one of claims 1 to 4, characterized in that, The method involves uniformly mixing glaze, carboxymethyl cellulose and nickel powder, coating it onto the surface of a ceramic material, and then performing heat treatment to obtain a transition coating.

6. The method for preparing a transition coating suitable for ceramic cold spraying according to claim 5, characterized in that, The heat treatment conditions include a temperature of 1000~1400℃ and a time of 5~24h.

7. The method for preparing a transition coating suitable for ceramic cold spraying according to claim 5, characterized in that, The thickness of the transition coating is 0.2~1.0 mm.

8. A cold spraying process, characterized in that, The cold spraying process includes the following steps: (1) forming a transition coating as described in any one of claims 1 to 4 on the surface of the ceramic material; (2) forming a metal coating on the surface of the transition coating by cold spraying.

9. The application of the transition coating for ceramic cold spraying as described in any one of claims 1 to 4 in the metallization of ceramic cold spraying.

Images