Preparation method of high-temperature coating containing cerium dioxide-based infrared low-emissivity material

Abstract

The invention discloses a preparation method of a high-temperature coating containing a cerium dioxide-based infrared low-emissivity material, which comprises the following steps: (1) preparing an inorganic binder coating: adding water glass and Ce < 0.8 > Sm < 0.16 > Ca < 0.04 > O < 1.88 > into a solvent, adding a proper amount of deionized water for dilution, and fully and uniformly mixing to obtain the inorganic binder coating; (2) preparing a resin coating: adding organic silicon resin and Ce < 0.8 > Sm < 0.16 > Ca < 0.04 > O < 1.88 > into an organic solvent, adding a proper amount of butyl acetate for dilution, and fully and uniformly mixing to obtain the resin coating; (3) uniformly spraying an inorganic binder coating on the surface of the base material, drying to form an inorganic binder layer, uniformly spraying a resin coating on the surface of the inorganic binder layer, and drying to obtain a resin layer; and (4) the step (3) is repeated at least twice, and the high-temperature coating is obtained on the surface of the base material. The prepared coating is good in temperature resistance at the temperature of 500 DEG C, the coating can be kept complete and does not fall off for 30 min or above, and the infrared emissivity at the temperature of 500 DEG C is 0.325.

Description

Technical Field

[0001] The invention relates to a method for preparing a high-temperature coating containing a cerium dioxide-based infrared low-emission material. Background Art

[0002] Coating materials, as a key material with both protective and functional characteristics, play a vital role in the field of high temperature protection. By forming a protective barrier on the surface of the substrate, it can effectively isolate the substrate from the direct effects of the high temperature environment, thereby extending the service life of the substrate and maintaining its stable performance.

[0003] However, traditional silicone resin coatings gradually expose their performance bottlenecks when facing higher temperature challenges. Specifically, the upper temperature limit of such coatings is usually around 400°C, a temperature threshold that is difficult to meet the needs in many emerging high-temperature application scenarios. Although pure inorganic binder water glass performs well in high-temperature performance and can meet the requirements of use in high-temperature environments, its high emissivity affects the overall performance of the coating to a certain extent. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a method for preparing a high-temperature coating containing a cerium dioxide-based infrared low-emission material, which can effectively improve the high-temperature resistance of the high-temperature protective coating while significantly reducing its infrared emissivity, thereby effectively improving the comprehensive performance of the coating.

[0005] Technical solution: The method for preparing the high temperature coating of the present invention comprises the following steps:

[0006] (1) Preparation of inorganic binder coating: Add water glass and Ce to the solvent. 0.8 Sm 0.16 Ca 0.04 O 1.88 , after fully mixing, an inorganic binder coating is obtained;

[0007] (2) Preparation of resin coating: Add silicone resin and Ce to organic solvent. 0.8 Sm 0.16 Ca 0.04 O 1.88 , after fully mixing, a resin coating is obtained;

[0008] (3) spraying an inorganic binder coating uniformly on the surface of the substrate to form an inorganic binder layer after drying, and then spraying a resin coating uniformly on the surface of the inorganic binder layer to obtain a resin layer after drying;

[0009] (4) Repeat step (3) at least twice to obtain a high-temperature coating on the surface of the substrate.

[0010] Among them, in step (1), deionized water is generally selected as the solvent for preparing the inorganic binder coating, and the mass ratio of the added sodium silicate and Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 is 3.5 - 4:1; the solid content of the prepared inorganic binder coating is not higher than 34%.

[0011] Among them, in step (2), butyl acetate is generally selected as the solvent for preparing the resin coating, and the mass ratio of the added silicone resin and Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 is 2.5 - 3:1; the solid content of the prepared resin coating is not higher than 60%.

[0012] Among them, in step (3), the inorganic binder coating is evenly sprayed on the surface of the substrate, one layer is sprayed, and the thickness of the formed inorganic binder layer is generally 50 μm; after drying, the resin coating is evenly sprayed on the surface of the inorganic binder layer, and a total of two layers are sprayed successively, and the thickness of each formed resin layer is generally also 50 μm.

[0013] Among them, when the inorganic binder coating is evenly sprayed on the surface of the substrate, after spraying one layer, it is surface-dried for 30 - 60 minutes, and then placed in an oven and dried at 300 °C for 4 h.

[0014] Among them, when the resin coating is evenly sprayed on the surface of the inorganic binder layer, after spraying one layer, it is surface-dried for 30 - 60 minutes, then the second layer is sprayed, and after surface-drying, it is placed in an oven and dried at 200 °C for 8 h.

[0015] Among them, in steps (1) and (2), Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 is prepared by the following method. Specifically, according to the stoichiometric ratio, the corresponding amounts of cerium dioxide, calcium oxide and samarium oxide are mixed, ball-milled, and then calcined at high temperature in an air atmosphere. After calcination, it is ball-milled again to obtain Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 .

[0016] Among them, the ball-to-material ratio of the first ball-milling is 5:1, the ball-milling time is 6 - 10 h, and the ball-milling speed is 500 - 550 r / min.

[0017] Among them, the high-temperature calcination process is as follows: keep the temperature at 600-650 °C for 3-5 h, then raise the temperature to 1100-1400 °C and keep it for 3-5 h; the heating rate is 5-6 °C / min. The purpose of the first calcination is to remove impurities, and the purpose of the second calcination is to dope Sm and Ca into the lattice of Ce.

[0018] Among them, the ball-to-material ratio of the secondary ball milling is 5:1, the ball milling time is 6-10 h, and the ball milling speed is 500-600 r / min.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: the coating prepared by the present invention has good heat resistance at 500 °C, the coating can remain intact without peeling for more than 30 min, and the infrared emissivity at 500 °C is 0.325. Description of the Drawings

[0020] Figure 1 for Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 XRD pattern of the CeO2 powder;

[0021] Figure 2 High-temperature emissivity diagrams of Example 1 and Comparative Examples 1-5;

[0022] Figure 3 Adhesion diagrams of Example 1 and Comparative Examples 1-5 after being treated at 500 °C for 30 min;

[0023] Figure 4 for Ce in Example 1 0.8 Sm 0.16 Ca 0.04 O 1.88 SEM diagrams of the powder (a) and the CeO2 powder (b); Detailed Description of the Invention

[0024] Example 1

[0025] The preparation method of the high-temperature coating of the present invention includes the following steps:

[0026] (1) Clean and pretreat the surface of the nickel-based superalloy substrate to be coated to remove oil stains and impurities;

[0027] (2) Prepare an inorganic binder coating: fully stir 78.43 g of inorganic binder water glass, 20 g of Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 and 39.22 g of deionized water to obtain an inorganic binder coating;

[0028] (3) Prepare the resin coating: Thoroughly stir 55.56 g of silicone resin, 20 g of Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 and 55.56 g of butyl acetate to obtain the resin coating;

[0029] (4) Evenly spray the inorganic binder coating on the surface of the substrate, spray one layer, allow it to dry on the surface for 60 minutes after spraying, and then place it in an oven to dry at 300 °C for 4 h to obtain the inorganic binder layer; then evenly spray the resin coating on the surface of the inorganic binder layer, spray two layers, allow it to dry on the surface for 60 minutes after spraying the first layer and then spray the second layer, and after drying on the surface for 60 min, place it in an oven to dry at 200 °C for 8 h to obtain the resin layer;

[0030] (5) Repeat the operation in step (4) twice. Specifically: Evenly spray the inorganic binder coating on the surface of the resin layer, spray one layer, allow it to dry on the surface for 60 minutes after spraying, and then place it in an oven to dry at 300 °C for 4 h to obtain the inorganic binder layer; then evenly spray the resin coating on the surface of the inorganic binder layer, spray one layer, allow it to dry on the surface for 60 minutes after spraying and then spray the second layer, and after drying on the surface for 60 min, place it in an oven to dry at 200 °C for 8 h to obtain the resin layer; A high-temperature coating is obtained on the surface of the substrate.

[0031] Among them, Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 is prepared by the following method, including the following steps:

[0032] (1.1) Place 20 g in total mass, cerium dioxide, calcium oxide, and samarium oxide with a molar ratio of 20:1:4 in a ball mill, where the ball-to-material ratio is 5:1, the rotation speed is 500 r / min, and ball mill for 6 h;

[0033] (1.2) Place the ball-milled powder in a muffle furnace for calcination. Set the program as the heating rate of 5 °C / min, keep it at 600 °C for 3 h first, then heat up to 1300 °C and keep it for 3 h, and cool down with the furnace;

[0034] (1.3) Perform secondary ball milling on the calcined material, where the ball-to-material ratio is 5:1, the rotation speed is 500 r / min, and ball mill for 6 h; Obtain the Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 powder.

[0035] It can be seen through Figure 4 that the Ce prepared in Example 1 0.8 Sm 0.16 Ca 0.04 O 1.88The powder particle size distribution is uniform, all around 2 to 5 microns, and it has good dispersibility.

[0036] Comparative Example 1

[0037] A method for preparing a high-temperature coating includes the following steps:

[0038] (1) Clean and pretreat the nickel-based superalloy substrate to be coated to remove oil stains and impurities;

[0039] (2) Prepare an inorganic binder coating: Thoroughly stir 78.43 g of inorganic binder water glass, 20 g of Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 and 39.22 g of deionized water to obtain an inorganic binder coating.

[0040] (3) Uniformly spray the inorganic binder coating on the surface of the substrate, spray one layer, and dry it at the surface for 60 minutes after spraying;

[0041] (4) Repeat the operation of step (3) six times, and then place it in an oven and dry it at 300 °C for 4 h; a high-temperature coating is obtained on the surface of the substrate.

[0042] Comparative Example 2

[0043] A method for preparing a high-temperature coating includes the following steps:

[0044] (1) Clean and pretreat the nickel-based superalloy substrate to be coated to remove oil stains and impurities;

[0045] (2) Prepare a resin coating: Thoroughly stir 55.56 g of silicone resin, 20 g of Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 and 55.56 g of butyl acetate to obtain a resin coating;

[0046] (3) Uniformly spray the resin coating on the surface of the substrate, spray one layer, and dry it at the surface for 60 minutes after spraying;

[0047] (4) Repeat the operation of step (3) six times, and then place it in an oven and dry it at 200 °C for 8 h; a high-temperature coating is obtained on the surface of the substrate.

[0048] Comparative Example 3

[0049] A method for preparing a high-temperature coating includes the following steps:

[0050] (1) Clean and pretreat the nickel-based superalloy substrate to be coated to remove oil stains and impurities;

[0051] (2) Prepare the inorganic binder coating: Thoroughly stir 78.43 g of inorganic binder sodium silicate, 20 g of CeO₂, and 39.22 g of deionized water to obtain the inorganic binder coating.

[0052] (3) Prepare the resin coating: Thoroughly stir 55.56 g of silicone resin, 20 g of CeO₂, and 55.56 g of butyl acetate to obtain the resin coating;

[0053] (4) Uniformly spray the inorganic binder coating on the surface of the substrate, spray one layer, after spraying, the surface dries for 60 minutes, then place it in an oven and dry at 300 °C for 4 h to obtain the inorganic binder layer; then uniformly spray the resin coating on the surface of the inorganic binder layer, spray one layer, after spraying, the surface dries for 60 minutes, and then spray another layer, after the surface dries for 60 minutes, place it in an oven and dry at 200 °C for 8 h to obtain the resin layer;

[0054] (5) Repeat the operation in step (4) twice to obtain a high-temperature coating on the surface of the substrate.

[0055] Among them, CeO₂ is prepared by the following method: Place 20 g of cerium dioxide powder with a total mass in a muffle furnace for calcination, set the program as a heating rate of 5 °C / min, keep it at 600 °C for 3 h first, then heat up to 1300 °C and keep it for 3 h, and cool with the furnace; then place it in a ball mill, where the ball-to-material ratio is 5:1, the rotation speed is 500 r / min, and ball mill for 6 h to obtain CeO₂ powder.

[0056] Comparative Example 4

[0057] A method for preparing a high-temperature coating, comprising the following steps:

[0058] (1) Clean and pretreat the surface of the nickel-based superalloy substrate to be coated to remove oil stains and impurities;

[0059] (2) Prepare the inorganic binder coating: Thoroughly stir 78.43 g of inorganic binder sodium silicate, 20 g of CeO₂, and 39.22 g of deionized water to obtain the inorganic binder coating.

[0060] (3) Uniformly spray the inorganic binder coating on the surface of the substrate, spray one layer, after spraying, the surface dries for 60 minutes;

[0061] (4) Repeat the operation in step (3) six times, and then place it in an oven and dry at 300 °C for 4 h to obtain a high-temperature coating on the surface of the substrate.

[0062] Comparative Example 5

[0063] A method for preparing a high-temperature coating, comprising the following steps:

[0064] (1) Clean and pretreat the nickel-based superalloy substrate to be coated to remove oil stains and impurities;

[0065] (2) Prepare the resin coating: Thoroughly stir 55.56 g of silicone resin, 20 g of CeO2, and 55.56 g of butyl acetate to obtain the resin coating;

[0066] (3) Uniformly spray the resin coating on the surface of the substrate, spray one layer, and dry the surface for 60 minutes after spraying;

[0067] (4) Repeat the operation in step (3) six times, and then place it in an oven and dry it at 200 °C for 8 h to obtain a high-temperature coating on the surface of the substrate.

[0068] As Figure 2 shown, it can be seen from Example 1 and Comparative Example 1 and Comparative Example 2 that the infrared emissivity of the high-temperature composite coating in Example 1 is 0.325 at 500 °C, the infrared emissivity of the inorganic binder coating in Comparative Example 1 is 0.355 at 500 °C, and the infrared emissivity of the silicone resin coating in Comparative Example 2 is 0.368 at 500 °C. The composite coating exhibits good low-emission characteristics at high temperatures. By Figure 3 knowing, the adhesion of the high-temperature composite coating in Example 1 after heat treatment at 500 °C for 30 min is 7.2 Mpa, which is basically equivalent to that of the inorganic coating in Comparative Example 1 (7.3 Mpa), and is significantly higher than that of the silicone resin coating in Comparative Example 2 (3.2 Mpa); and higher than those of the high-temperature coatings in Comparative Example 3 (6.8 Mpa), Comparative Example 4 (7.0 Mpa), and Comparative Example 5 (3.0 Mpa).

[0069] By comparing Example 1 with Comparative Example 3, and Comparative Example 4 with Comparative Example 5, it can be seen that the infrared emissivities of Comparative Example 3, Comparative Example 4, and Comparative Example 5 using CeO2 filler are 0.452, 0.455, and 0.465 at 500 °C, indicating that using Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 filler, Example 1 not only has a lower emissivity at high temperatures but also has better high-temperature resistance.

Claims

1. A preparation method of a high-temperature coating containing a cerium dioxide-based infrared low-emission material, characterized in that, It includes the following steps: (1) Preparation of inorganic binder coating: Add water glass and Ce to the solvent. 0.8 Sm 0.16 Ca 0.04 O 1.88 , after fully mixing, an inorganic binder coating is obtained; (2) Prepare the resin coating: Add silicone resin and Ce to the organic solvent 0.8 Sm 0.16 Ca 0.04 O 1.88 , and after fully mixing, obtain the resin coating; (3) Uniformly spray the inorganic binder coating on the surface of the substrate, and after drying, form an inorganic binder layer. Then, uniformly spray the resin coating on the surface of the inorganic binder layer, and after drying, obtain a resin layer; (4) Repeat step (3) at least twice to obtain a high-temperature coating on the surface of the substrate.

2. The method for preparing a high-temperature coating according to claim 1, characterized in that: In step (1), the mass ratio of the addition of sodium silicate and Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 is 3.5 - 4:1; the solid content of the prepared inorganic binder coating is not higher than 34%.

3. The method for preparing a high-temperature coating according to claim 1, characterized in that: In step (2), the mass ratio of the addition of silicone resin and Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 is 2.5 - 3:1; the solid content of the prepared resin coating is not higher than 60%.

4. The preparation method of the high-temperature coating according to claim 1, wherein: In steps (1) and (2), Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 is prepared by the following method, specifically: according to the stoichiometric ratio, the corresponding amounts of cerium dioxide, calcium oxide and samarium oxide are mixed, ball-milled, and then calcined at high temperature in an air atmosphere. After calcination, secondary ball-milling is carried out to obtain Ce 0.8 Sm 0.16 Ca 0.04 O 1.88 .

5. The preparation method of the high-temperature coating according to claim 4, characterized in that: The ball milling time for the first ball milling is 6 - 10 h, and the ball milling speed is 500 - 550 r / min.

6. The method for preparing a high-temperature coating according to claim 4, wherein: The high-temperature calcination process is as follows: Keep the temperature at 600 - 650 °C for 3 - 5 h, then raise the temperature again to 1100 - 1400 °C and keep it for 3 - 5 h; The heating rate is 5 - 6 °C / min.

7. The method for preparing a high-temperature coating according to claim 4, characterized in that: The ball milling time for the second ball milling is 6 - 10 h, and the ball milling speed is 500 - 600 r / min.

8. The preparation method of the high-temperature coating according to claim 1, wherein: In step (3), uniformly spray the inorganic binder coating on the surface of the substrate, spray one layer, and the thickness of the formed inorganic binder layer is 40 - 60 μm; After drying, uniformly spray the resin coating on the surface of the inorganic binder layer, spray one layer, and the thickness of the formed resin layer is 40 - 60 μm.

9. The method for preparing a high-temperature coating according to claim 8, characterized in that: Uniformly spray the inorganic binder coating on the surface of the substrate, spray one layer, and after surface drying, place it in an oven at 300 - 350 °C and dry for 3.5 - 4 h.

10. The method for preparing a high-temperature coating according to claim 8, characterized in that: Uniformly spray the resin coating on the surface of the inorganic binder layer, spray one layer and then surface dry, then spray another layer, and after surface drying, place it in an oven at 200 - 250 °C and dry for 7 - 8 h.

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