Ceramic Oxide Coating and Its Preparation Method

Abstract

Embodiments of the present invention relate to the field of liquid metal technology, and specifically relate to a ceramic oxide coating and a preparation method thereof. The surface of the ceramic oxide coating is an uneven structure. The ceramic oxide coating is configured to cover the surface of a substrate structure, and the substrate structure covered with the ceramic oxide coating is suitable for accommodating liquid metal. The ceramic oxide coating provided by the present invention improves problems such as difficult removal of surface contamination caused by the rapid wetting of liquid metal on the material surface under high-temperature conditions. Moreover, the coating provided by the present invention can be realized on most metal substrates. On the drainage material prepared with this coating, it can be realized that the drainage device will not have surface contamination phenomena in the temperature range of 150°C - 400°C, solving the cleaning problem of the liquid metal drainage device and the adhesion and waste problems that occur during the drainage process of liquid metal, bringing great convenience to practical applications.

Description

Technical Field

[0001] The present invention relates to the field of liquid metal processes, and particularly to a ceramic oxide coating that is non-wetting with liquid metal under high-temperature environments and a preparation method thereof. Background Art

[0002] The surface tension of liquid metal is very large, and its droplets often exist in a spherical shape under the action of surface tension and hardly wet other materials. However, as the temperature rises, the wettability increases. When the temperature reaches a certain level, the liquid metal will completely spread on the material surface.

[0003] However, in some processes of treating or using liquid metal, they are often completed under high-temperature environments. In actual high-temperature processes, in some working conditions, it is desired that the contact between the liquid metal and the material surface remains non-wetting during the operation.

[0004] For example, in the canning, melting, drainage, filling and discharging operations of liquid metal, it is desired that the drainage device only fills the liquid metal into the specified container, and the drainage surface still needs to remain clean. If the liquid metal adheres to the drainage device, too much liquid metal will adhere to the surface of the drainage device, which will cause waste of liquid metal and increase the difficulty of cleaning. Summary of the Invention

[0005] Based on this, the present invention provides a ceramic oxide coating that is non-wetting with liquid metal under high-temperature environments and a preparation method thereof, which solves the problem that the liquid metal wets and adheres to the container drainage device under high-temperature operating conditions.

[0006] According to one aspect of the present invention, a ceramic oxide coating is provided. The surface of the ceramic oxide coating is an uneven structure, and the ceramic oxide coating is configured to cover the surface of the substrate structure. The substrate structure covered with the ceramic oxide coating is suitable for accommodating liquid metal; the uneven structure includes a granular convex structure.

[0007] According to another aspect of the present invention, a method for preparing the above-mentioned ceramic oxide coating is provided, including: pre-treating the surface of the substrate structure to obtain a clean substrate; pre-treating the clean substrate to obtain an activated substrate; spraying the activated substrate with atomized spherical powder of ceramic oxide to obtain a pre-product; and cooling the pre-product in the furnace to room temperature to obtain the ceramic oxide coating with a granular convex structure.

[0008] It can be seen from the above technical solutions that the ceramic oxide coating and the preparation method provided by the present invention have the following beneficial effects:

[0009] The ceramic oxide coating provided by the present invention improves problems such as difficult removal of surface contamination caused by the rapid wetting of liquid metal on the material surface under high-temperature conditions. Moreover, the coating provided by the present invention can be realized on most metal substrates. On the drainage material prepared with this coating, it can be achieved that the drainage device will not have surface contamination phenomenon within the temperature range of 150°C - 400°C, solving the cleaning problem of the liquid metal drainage device and the adhesion and waste problems that occur during the drainage process of liquid metal, bringing great convenience to practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is the preparation flow chart of the ceramic oxide in the embodiment of the present invention;

[0011] Figure 2 is the microscopic surface structure diagram of the ceramic oxide of Sample 1 in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0012] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following further describes the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0013] The surface tension of liquid metal is very large, and its droplets often exist in a spherical shape under the action of surface tension and hardly wet other materials. However, as the temperature rises, the wettability increases. When the temperature reaches a certain level, the liquid metal will completely spread on the material surface.

[0014] However, in some processes of processing or using liquid metal, they are often completed in a high-temperature environment. In actual high-temperature processes, in some working conditions, it is desired that the contact between the liquid metal and the material surface remains non-wetting during the operation process.

[0015] For example, in the operations of canning, melting, draining, and filling and discharging of liquid metal, it is desired that the drainage device only cans the liquid metal into the specified container, and the drainage surface still needs to remain clean. If the liquid metal adheres to the emitter tube of the drainage device, too much liquid metal will adhere to the surface of the drainage device, which will cause waste of liquid metal and increase the difficulty of cleaning.

[0016] Therefore, it is desired to design a coating that can reduce the contact between the liquid metal and the surface of the production, drainage, or storage device. Spraying this coating can solve the above problems.

[0017] According to the general inventive concept of one aspect of the present invention, a ceramic oxide coating is provided. The surface of the ceramic oxide coating is an uneven structure. The ceramic oxide coating is configured to cover the surface of the substrate structure, and the substrate structure covered with the ceramic oxide coating is suitable for accommodating liquid metal.

[0018] The ceramic oxide coating provided by the present invention improves problems such as difficult removal of surface contamination caused by the rapid wetting of liquid metal on the material surface under high-temperature conditions. Moreover, the coating provided by the present invention can be achieved on most metal substrates. On the drainage material prepared with this coating, it can be realized that the surface of the drainage device will not be contaminated within the temperature range of 150°C - 400°C, solving the cleaning problem of the liquid metal drainage device and the problem of adhesion and waste of liquid metal during the drainage process, bringing great convenience to practical applications.

[0019] According to an embodiment of the present invention, the concavo-convex structure includes a granular convex structure.

[0020] The surface structure of the ceramic oxide coating can reduce the degree of attachment of liquid metal, and cooperating with a ceramic oxide coating with generally poor wettability with liquid metal can effectively reduce the degree of rapid wetting of liquid metal on the material surface.

[0021] According to an embodiment of the present invention, the thickness of the ceramic oxide coating is 5 - 500 μm.

[0022] For example, the thickness of the ceramic oxide coating can be 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm and other dimensions, and can be selected according to the attachment situation of the liquid metal or the working conditions of the matrix structure.

[0023] According to an embodiment of the present invention, the liquid metal includes at least one of the following: lead, lead-bismuth, sodium, potassium, sodium-potassium alloy, lithium.

[0024] According to an embodiment of the present invention, the ceramic oxide coating includes an alumina coating.

[0025] According to an embodiment of the present invention, the ceramic oxide coating can be an alumina coating or other ceramic oxide coatings with generally poor wettability with ceramic oxides and liquid metals.

[0026] Figure 1 It is a preparation flow chart of the ceramic oxide according to the embodiment of the present invention.

[0027] According to another general inventive concept of the present invention, as Figure 1 shown, a method for preparing a ceramic oxide coating is provided, including:

[0028] S100: Pretreat the surface of the matrix structure to obtain a clean matrix.

[0029] S200: Pretreat the clean matrix to obtain an activated matrix.

[0030] S300: Spray the activated matrix with atomized spherical powder of ceramic oxide to obtain a pre-finished product.

[0031] S400: Cool the pre - product in the furnace to room temperature to obtain a ceramic oxide coating with a convex structure having particles.

[0032] The ceramic oxide coating provided by the present invention improves problems such as difficult removal of surface contamination caused by the rapid wetting of liquid metal on the material surface under high - temperature conditions. And the coating provided by the present invention can be achieved on most metal substrates. On the drainage material prepared with this coating, it can be realized that the surface of the drainage device will not be contaminated in the temperature range of 150°C - 400°C, solving the cleaning problem of the liquid - metal drainage device and the problem of adhesion and waste of liquid metal during the drainage process, bringing great convenience to practical applications.

[0033] According to an embodiment of the present invention, in S100, the pretreatment includes cleaning and degreasing the surface of the substrate structure.

[0034] According to an embodiment of the present invention, in S200, the pre - treatment includes sand - blasting treatment and pre - heating treatment on the cleaned substrate surface.

[0035] According to an embodiment of the present invention, in S200, the sand - blasting treatment is used to remove the adsorbate and oxide layer on the cleaned substrate surface.

[0036] The sand - blasting treatment can remove the adsorbate and oxide layer on the surface of the substrate metal to increase surface activity and improve the bonding strength between the coating and the substrate.

[0037] According to an embodiment of the present invention, in S200, the abrasive material used in the sand - blasting treatment includes one of white fused alumina, brown fused alumina or zirconium corundum, and the particle size of the abrasive material is 60 - 120 mesh.

[0038] For example, the particle size of the abrasive material can be 60 mesh, 70 mesh, 80 mesh, 90 mesh, 100 mesh, 110 mesh, 120 mesh, etc.

[0039] According to an embodiment of the present invention, in S200, in the sand - blasting treatment, the sand - blasting pressure is 0.2 - 0.5 MPa, the sand - blasting distance is 50 - 100 mm, and the moving speed of the spray gun is 90 - 150 mm / s.

[0040] For example, the sand - blasting pressure control can be 0.2 MPa, 0.3 MPa, 0.4 MPa or 0.5 MPa.

[0041] The sand - blasting distance can be 50 mm, 60 mm, 70 mm, 80 mm, 90 mm or 100 mm, etc.

[0042] The moving speed of the spray gun can be controlled at 90 mm / s, 100 mm / s, 110 mm / s, 120 mm / s, 130 mm / s, 140 mm / s, 150 mm / s, etc. Specific process parameters can be selected according to the abrasive material used in sandblasting.

[0043] According to an embodiment of the present invention, in S200, between the sandblasting treatment and the preheating treatment, it further includes: using compressed air to blow off the sand grains or dust remaining on the roughened substrate.

[0044] According to an embodiment of the present invention, in S200, the preheating treatment includes: putting the roughened substrate after sandblasting into a sample fixture, and preheating the substrate using a plasma flame under the condition of no powder feeding.

[0045] Through the preheating treatment, the temperature of the contact surface between the coating and the substrate can be increased, the stress generated due to the different thermal expansion coefficients of the coating and the substrate materials can be reduced, and the bonding strength between the coating and the substrate can be improved.

[0046] According to an embodiment of the present invention, in S200, the treatment temperature of the preheating treatment is the temperature of the liquid metal flowing on the surface of the substrate.

[0047] According to an embodiment of the present invention, in S200, during the preheating treatment, under the conditions that the plasma spray gun current is 200 - 500 A, the flow rate of nitrogen is 30 - 45 L / min, the flow rate of hydrogen is 2 - 8 L / min, the spray distance is 50 - 100 nm, and the moving distance of the plasma spray gun is 300 - 500 mm / s, the roughened substrate is preheated using a plasma flame.

[0048] For example, the plasma spray gun current can be 200 A, 300 A, 400 A, 500 A.

[0049] The flow rate of nitrogen can be 30 L / min, 32 L / min, 35 L / min, 38 L / min, 40 L / min, 43 L / min, 45 L / min, etc.

[0050] The flow rate of hydrogen can be 2 L / min, 3 L / min, 4 L / min, 5 L / min, 6 L / min, 7 L / min, 8 L / min, etc.

[0051] The spray distance can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, etc.

[0052] The moving distance of the plasma spray gun can be 300 mm / s, 350 mm / s, 400 mm / s, 450 mm / s, 500 mm / s, etc.

[0053] According to an embodiment of the present invention, in S200, the treatment temperature of the preheating treatment can be 150°C - 400°C.

[0054] For example, the treatment temperature of the preheating treatment can be temperatures such as 150°C, 200°C, 250°C, 300°C, 350°C, or 400°C.

[0055] According to an embodiment of the present invention, in S300, the spraying process can adopt spraying processes such as atmospheric plasma spraying, supersonic flame spraying, micro-plasma spraying, and arc spraying.

[0056] According to an embodiment of the present invention, in S300, the activated substrate is sprayed with atomized spherical powder of ceramic oxide to obtain a pre-product. Spraying is carried out using the atomized spherical powder under the conditions that the plasma gun current is 300 - 700 A, the nitrogen flow rate is 30 - 50 L / min, and the hydrogen flow rate is 5 - 10 L / min.

[0057] For example, the plasma gun current can be 300 A, 400 A, 500 A, 600 A, or 700 A, etc.

[0058] The nitrogen flow rate can be 30 L / min, 35 L / min, 40 L / min, 45 L / min, or 50 L / min, etc.

[0059] The hydrogen flow rate can be 5 L / min, 6 L / min, 7 L / min, 8 L / min, 9 L / min, or 10 L / min, etc.

[0060] According to an embodiment of the present invention, in S300, the particle size of the ceramic oxide powder is 5 - 80 μm.

[0061] For example, the particle size of the ceramic oxide powder is 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, or 80 μm.

[0062] According to an embodiment of the present invention, in S300, the powder feeding rate of the atomized spherical powder is 30 - 50 g / min, the spraying distance is 70 - 120 mm, and the gun moving speed is 300 - 600 mm / s.

[0063] For example, the powder feeding rate can be 30 g / min, 35 g / min, 40 g / min, 45 g / min, or 50 g / min.

[0064] The spraying distance is 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, or 120 mm.

[0065] The gun moving speed is 300 mm / s, 400 mm / s, 500 mm / s, or 600 mm / s, etc.

[0066] The technical solution of the present invention will be described in detail through preferred embodiments. It should be noted that the specific embodiments below are only for illustration and do not limit the present invention.

[0067] Example 1: Preparation of samples.

[0068] Sample 1:

[0069] Degrease and remove oil from the 316L stainless steel probe substrate, and perform sandblasting on the surface. Use brown fused alumina with a particle size of 60 mesh, a sandblasting pressure of 0.2 MPa, a sandblasting distance of 90 mm, and a spray gun moving speed of 120 mm / s. Blow off any possible remaining sand grains or dust with compressed air. Place the sample in the sample fixture and perform preheating treatment under the conditions of a plasma spray gun current of 500 A, nitrogen 38 L / min, hydrogen 5 L / min, a spraying distance of 100 mm, and a spray gun moving speed of 500 mm / s. After preheating the sample to 350 °C, spray it, with a plasma spray gun current of 500 A, nitrogen 40 L / min, hydrogen 10 L / min, a powder feeding rate of 35 g / min, a powder particle diameter of 20 μm, a spraying distance of 100 mm, and a spray gun moving speed of 500 mm / s. After the spraying is completed, cool the sample in the furnace to 15 - 35 °C and then take out the sample. The coating thickness is 50 μm, and Sample 1 is obtained.

[0070] Sample 2:

[0071] Degrease and remove oil from the 316L stainless steel probe substrate, and perform sandblasting on the surface. Use zirconium corundum with a particle size of 80 mesh, a sandblasting pressure of 0.3 MPa, a sandblasting distance of 90 mm, and a spray gun moving speed of 120 mm / s. Blow off any possible remaining sand grains or dust with compressed air. Place the sample in the sample fixture and perform preheating treatment under the conditions of a plasma spray gun current of 400 A, nitrogen 37 L / min, hydrogen 4 L / min, a spraying distance of 100 mm, and a spray gun moving speed of 400 mm / s. After preheating the sample to 400 °C, spray it, with a plasma spray gun current of 550 A, nitrogen 42 L / min, hydrogen 9 L / min, a powder feeding rate of 40 g / min, a powder particle diameter of 10 μm, a spraying distance of 105 mm, and a spray gun moving speed of 500 mm / s. After the spraying is completed, cool the sample in the furnace to 15 - 35 °C and then take out the sample. The coating thickness is 140 μm, and Sample 2 is obtained.

[0072] Sample 3:

[0073] The 316L stainless steel probe substrate was degreased and defatted, and the surface was sandblasted using white fused alumina with a particle size of 60 mesh, a sandblasting pressure of 0.4 MPa, a sandblasting distance of 100 mm, and a spray gun moving speed of 120 mm / s. The possible remaining sand grains or dust were blown off with compressed air. The sample was placed in a sample fixture and preheated under the conditions of a plasma spray gun current of 500 A, nitrogen 40 L / min, hydrogen 4 L / min, a spraying distance of 100 mm, and a spray gun moving speed of 500 mm / s. After the sample was preheated to 300 °C, it was sprayed with a plasma spray gun current of 520 A, nitrogen 45 L / min, hydrogen 7 L / min, a powder feeding rate of 45 g / min, a powder particle diameter of 30 μm, a spraying distance of 95 mm, and a spray gun moving speed of 90 - 150 mm / s. After the spraying was completed, the sample was taken out after furnace cooling to 15 - 35 °C. The substrate material was a refractory metal, and the coating thickness was 130 μm, obtaining Sample 3.

[0074] Sample 4:

[0075] The 316L stainless steel probe substrate was degreased and defatted, and the surface was sandblasted using zirconium corundum with a particle size of 80 mesh, a sandblasting pressure of 0.35 MPa, a sandblasting distance of 90 mm, and a spray gun moving speed of 120 mm / s. The possible remaining sand grains or dust were blown off with compressed air. The sample was placed in a sample fixture and preheated under the conditions of a plasma spray gun current of 400 A, nitrogen 38 L / min, hydrogen 5 L / min, a spraying distance of 100 mm, and a spray gun moving speed of 400 mm / s. After the sample was preheated to 320 °C, it was sprayed with a plasma spray gun current of 530 A, nitrogen 44 L / min, hydrogen 8 L / min, a powder feeding rate of 42 g / min, a powder particle diameter of 15 μm, a spraying distance of 95 mm, and a spray gun moving speed of 490 mm / s. After the spraying was completed, the sample was taken out after furnace cooling to 15 - 35 °C, and the coating thickness was 160 μm, obtaining Sample 4.

[0076] Example 2: Detection of sample performance.

[0077] 1. Detection of thermal shock resistance:

[0078] Figure 2 This is the microscopic surface structure diagram of the ceramic oxide of Sample 1 in the embodiment of the present invention.

[0079] The alumina coating sample prepared from Sample 1 was selected and subjected to 100 thermal cycles in liquid metal (lead-bismuth alloy) at a cycling rate of 60 °C / s for a thermal cycling test at 400 - 600 °C.

[0080] The thermal shock resistance of Samples 1 to 4 under the impact of high-temperature liquid metal was measured. The results are asFigure 2 As shown Figure 2 Figure 2 shows the surface structure of Sample 1 after being impacted by high-temperature liquid metal. It can be seen therefrom that the coating matrix interface is well-bonded, without cracks or peeling. This indicates that the alumina coating in this embodiment has good thermal shock resistance.

[0081] 2. Detection of the wetting performance of liquid sodium metal:

[0082] Select the alumina coating sample prepared from Sample 4 and place it on the heating plate in the Ar atmosphere glove box. Use a K-type surface temperature-measuring thermocouple to measure the surface temperature of the sample. When the surface temperature of Sample 4 reaches 350 °C, use a dropper to take 2 ml of sodium and drop it on the surface of the sample. It is found that the sodium drop cannot stand on the surface of the sample but immediately rolls off the surface of the sample. Due to the super poor wetting between the sample surface and liquid metal sodium and the fact that the surface in the ordinary environment is not absolutely horizontal, it is impossible to measure the contact angle between the coating sample and the sodium drop, which is also an indication of the poor wetting performance of the sodium drop on the coating surface.

[0083] 3. Contact angle measurement:

[0084] Select the alumina coating sample prepared from Sample 1 and use a dropper to take 2 ml of sodium-potassium alloy liquid and drop it on the surface of the sample. It is found that the liquid drop still cannot stand on the surface of the sample but immediately rolls off the surface of the sample. Due to the super poor wetting between the sample surface and liquid metal sodium and the fact that the surface in the ordinary environment is not absolutely horizontal, it is impossible to measure the contact angle between the coating sample and the sodium-potassium alloy liquid drop, which is also an indication of the poor wetting performance of the sodium-potassium alloy liquid drop on the coating surface.

[0085] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A ceramic oxide coating, characterized in that, The surface of the ceramic oxide coating is an uneven structure, and the ceramic oxide coating is configured to cover the surface of the substrate structure. The substrate structure covered with the ceramic oxide coating is suitable for accommodating liquid metal; The uneven structure includes granular convex structures to reduce the degree of adhesion of the liquid metal; The ceramic oxide coating is configured to not cause surface contamination with the liquid metal within the temperature range of 150°C - 400°C; The ceramic oxide coating is provided on the surface of a stainless - steel probe with a drainage function.

2. The ceramic oxide coating according to claim 1, wherein, The thickness of the ceramic oxide coating is 5 - 500 μm.

3. The ceramic oxide coating according to claim 1, wherein The ceramic oxide coating includes an alumina coating.

4. A method for preparing the ceramic oxide coating according to any one of claims 1 to 3, characterized in that, It includes: Pre - treating the surface of the substrate structure to obtain a clean substrate; Performing pre - treatment on the clean substrate to obtain an activated substrate; Spraying the activated substrate with atomized spherical powder of ceramic oxide to obtain a pre - product; Cooling the pre - product in the furnace to room temperature to obtain the ceramic oxide coating with granular convex structures.

5. The method according to claim 4, wherein The pre - treatment includes cleaning and degreasing the surface of the substrate structure.

6. The method according to claim 4, wherein The pre - treatment includes sandblasting and pre - heating the surface of the clean substrate.

7. The method according to claim 6, characterized in that, The sandblasting is used to remove the adsorbate and oxide layer on the surface of the clean substrate.

8. The method according to claim 7, wherein In the sandblasting treatment, the sandblasting pressure is 0.2 - 0.5 MPa, the sandblasting distance is 50 - 100 mm, and the moving speed of the spray gun is 90 - 150 mm / s.

9. The method according to claim 6, characterized in that, The pre - heating treatment includes: putting the roughened substrate after sandblasting into a sample fixture and pre - heating the roughened substrate with a plasma flame under the condition of no powder feeding.

10. The method according to claim 9, wherein The treatment temperature of the pre - heating treatment is the temperature of the liquid metal drained on the surface of the substrate.

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