Ceramic coating and its preparation method, application and use method

Abstract

The present invention belongs to the field of coating technology and provides a ceramic coating, its preparation method, and its application and use. The ceramic coating of the present invention comprises, by weight percentage, 20-34% high-entropy zirconate, 1-2% Al2O3 whiskers, 1-3% hexagonal boron nitride, 1-3% silicon nitride, 2-4% cordierite, 6-8% chromium oxide, 0.3-1% wetting and dispersing agent, 0.3-1% leveling agent, 0.3-1% defoamer, 0.3-1% thickener, 35-50% composite binder (including organic and inorganic binders), and 10-20% water. The high-entropy zirconate has the chemical formula A2Zr2O7, with the A-position containing at least four of the following elements: La, Sm, Nd, Gd, Eu, Yb, Y, and Sc, with the elements in the A-position being in equimolar ratios. The ceramic coating formed by the ceramic coating of the present invention can meet high-temperature requirements while exhibiting excellent adhesion and resistance to fouling and slagging.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a ceramic coating and a preparation method, application and use method thereof. Background Art

[0002] For a long time, fouling and slagging have been major threats to the safe operation of power plant boilers. Currently, with the widespread use of low-cost high-sulfur coal and abundant high-sodium coal (such as Zhundong coal), fouling and slagging on the heating surfaces of power plant boilers, such as water walls, superheaters, and reheaters, has become increasingly serious. This has led to problems such as insufficient heat absorption by the water walls, high furnace outlet flue gas temperatures, and excessively high tube wall temperatures, significantly impacting the safety and economic efficiency of power plant operations.

[0003] In order to alleviate this contamination and slagging and the accompanying corrosion problem, domestic and foreign scholars have conducted extensive research and proposed effective protection methods, mainly focusing on the following four aspects:

[0004] (1) Coal pretreatment: The coal is upgraded to reduce its sulfur, chlorine and alkali metal content, which inhibits the formation of corrosive deposits to a certain extent and reduces the adhesion on the heated surface;

[0005] (2) Coal modification: adding kaolin and corundum to the coal to change its silicon-aluminum ratio, which plays a role in fixing volatile alkali metal elements, while increasing its melting point and alleviating the degree of contamination and slagging;

[0006] (3) Boiler structure design and modification: including boiler type and size design, combustion equipment optimization design, flue gas recirculation design, horizontal rich and thin air combustion technology and wall-mounted air technology, etc., to optimize the combustion process, promote the oxidation of sediments in the flame, and inhibit the generation of reducing atmosphere on the surface of the heating surface, thereby effectively reducing the risk of contamination and slagging;

[0007] (4) Coating protection: Use thermal spraying methods such as arc spraying, plasma spraying and supersonic flame spraying to atomize powdered or filamentary metal into molten droplets, which impact the surface of the heated surface at high speed to form a corrosion-resistant protective layer with a certain thickness, effectively protecting the boiler substrate from damage.

[0008] Given the difficulty of large-scale coal modification and the high cost of large-scale boiler structural modifications, the use of protective coatings to address fouling and slagging on boiler heating surfaces has become the mainstream approach. However, traditional thermal spraying techniques suffer from shortcomings such as poor working environment, severe dust pollution, low material utilization, and long construction times, necessitating the development of a new protective method.

[0009] Among existing protective coatings, one type is organic high-temperature-resistant coatings, which primarily use silicone resin as a binder, with functional fillers and additives added in a certain proportion. However, these coatings have limited heat resistance, with their maximum long-term operating temperature generally ranging from 400 to 500°C. Furthermore, the organic resin molecular chains are prone to breakage and cracking at high temperatures, significantly reducing the coating's corrosion resistance.

[0010] The other type is inorganic high-temperature-resistant coatings, which primarily use silicate water glass or inorganic silicone resin as a film-forming material, along with a variety of high-temperature-resistant fillers. These coatings generally offer good high-temperature resistance but poor resistance to salt spray corrosion. Furthermore, due to the significant difference in thermal expansion coefficient between the inorganic film-forming material and the carbon steel substrate, the coatings are susceptible to stress concentration during alternating hot and cold cycles, leading to cracking and even flaking.

[0011] Therefore, developing an anti-fouling and slagging coating that can meet the requirements of high-temperature use and has excellent adhesion has very important engineering application value. Summary of the Invention

[0012] In view of this, the present invention aims to provide a ceramic coating and its preparation method, application, and use method. The ceramic coating formed by the ceramic coating provided by the present invention can meet the requirements of high-temperature use and has excellent adhesion and anti-fouling and slagging properties.

[0013] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0014] The present invention provides a ceramic coating comprising the following components, calculated by weight percentage:

[0015] High entropy zirconate 20-34%, Al2O3 whiskers 1-2%, hexagonal boron nitride 1-3%, silicon nitride 1-3%, cordierite 2-4%, chromium oxide 6-8%, wetting and dispersing agent 0.3-1%, leveling agent 0.3-1%, defoaming agent 0.3-1%, thickener 0.3-1%, composite binder 35-50%, water 10-20%;

[0016] The chemical formula of the high entropy zirconate is A2Zr2O7, wherein the A position contains at least four elements of La, Sm, Nd, Gd, Eu, Yb, Y, and Sc, and the elements in the A position are in equal molar ratios;

[0017] The composite binder includes an organic binder and an inorganic binder.

[0018] Preferably, the particle size of the high entropy zirconate is less than 1 μm, and the specific surface area is 30 to 80 m 2 / g;

[0019] The particle size of the hexagonal boron nitride is 200-300 nm;

[0020] The particle size of the silicon nitride is 600-800 nm;

[0021] The particle size of the cordierite is less than 1 μm;

[0022] The particle size of the chromium oxide is less than 1 μm.

[0023] Preferably, the wetting and dispersing agent is an anionic wetting and dispersing agent;

[0024] The leveling agent is an organic silicon leveling agent;

[0025] The defoaming agent is one or more of an organosilicon defoaming agent, a polyether siloxane defoaming agent and a mineral oil defoaming agent;

[0026] The thickener is a polyurethane thickener and / or a nonionic thickener.

[0027] Preferably, the organic binder comprises one or more of styrene acrylic emulsion, silicone acrylic emulsion and pure acrylic emulsion; in the ceramic coating, the mass percentage of the organic binder is 15-25%;

[0028] The inorganic binder includes one or more of potassium silicate water glass, sodium silicate water glass and lithium silicate water glass; in the ceramic coating, the mass percentage of the inorganic binder is 20-35%.

[0029] The present invention provides a method for preparing the ceramic coating described in the above technical solution, comprising the following steps:

[0030] first mixing a wetting and dispersing agent, a leveling agent, a defoaming agent, a thickener, and water to obtain a first system;

[0031] a second mixing of high entropy zirconate, Al2O3 whiskers, hexagonal boron nitride, silicon nitride, cordierite, chromium oxide and a composite binder to obtain a second system;

[0032] The first system and the second system are mixed for the third time and then ground to obtain the ceramic coating.

[0033] Preferably, the first mixing speed is 2000-2500 r / min, and the time is 5-15 min;

[0034] The second mixing speed is 600-800 r / min and the time is 10-20 min;

[0035] The third mixing speed is 200-300 r / min and the time is 30-40 min;

[0036] The grinding balls used in the grinding are zirconia grinding balls, the grinding speed is 300-500 rpm, and the grinding time is 2-3 hours.

[0037] The present invention also provides the application of the ceramic coating described in the above technical solution in the field of protection.

[0038] The present invention also provides a method for using the ceramic coating described in the above technical solution, comprising the following steps:

[0039] Performing sandblasting treatment on the substrate to be protected to obtain a treated substrate;

[0040] The ceramic coating described in the above technical solution is sprayed on the treated substrate, and sequentially undergoes a first curing and a second curing to form a protective layer.

[0041] Preferably, the parameters of the sandblasting process include: the particle size of the corundum sand is 24-150 mesh, the pressure is 0.5-2 MPa;

[0042] The spraying pressure is 0.4-1.5 MPa, the ambient temperature is 15-25° C., and the relative air humidity is 40-60%.

[0043] Preferably, the first curing time is 12 to 24 hours;

[0044] The second curing temperature is 200-600° C., and the time is 2-6 hours.

[0045] The present invention provides a ceramic coating.

[0046] The beneficial effects of the present invention are:

[0047] 1. This invention utilizes high-entropy zirconate as the primary functional filler. Through high-entropy design, multi-component doping at the A-site of A2Zr2O7 zirconate produces a single-phase solid solution with a pyrochlore structure. Significant differences in ionic radius and mass between the different doping elements result in severe lattice distortion. By leveraging the high-entropy effect, lattice distortion, hysteretic diffusion, and "cocktail" effect of high-entropy zirconate, the ceramic coating exhibits excellent thermal expansion coefficient, thermal conductivity, and emissivity, improving both high-temperature resistance and adhesion.

[0048] 2. This invention utilizes low-surface-energy materials, hexagonal boron nitride and silicon nitride, as functional fillers, which are crucial for improving the ceramic coating's anti-fouling and slagging properties. Both hexagonal boron nitride and silicon nitride are nanoscale, allowing them to be evenly distributed within the coating during the spraying process. During the secondary curing process of the ceramic coating, they connect to form a low-surface-energy layer, effectively inhibiting the adhesion of coal combustion products to the surface.

[0049] 3. The present invention combines an inorganic binder with an organic binder to impart excellent high-temperature resistance and extremely high toughness to the ceramic coating. Al2O3 whiskers are added to the composite binder to absorb energy through the weak interface between the composite binder and the second cured coating substrate, causing cracks to deflect and bifurcate during propagation, effectively strengthening and toughening the coating.

[0050] 4. The ceramic coating formed by the ceramic coating provided by the present invention has excellent thermal shock resistance. The steel materials for water-cooled wall tubes of power station boilers include 20G, 20MnG, 15MoG, 15CrMoG, 12Cr1MoVG, etc., and the thermal expansion coefficient is distributed in the range of 9~13×10 -6 K -1 According to the GB / T 7320-2018 "Coefficient of Thermal Expansion of Coatings" test standard, the thermal expansion coefficient of the coating formed by the ceramic coating of the present invention is 9.5~11.8×10 -6 K -1 , matching the substrate, can effectively reduce the thermal stress caused by the mismatch of thermal expansion coefficients between the coating and the substrate during hot and cold alternation, and improve the adhesion of the ceramic coating.

[0051] 5. The ceramic coating formed by the ceramic paint provided by the present invention has excellent resistance to SO2 gas corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Schematic diagram of a device for measuring the wettability of a ceramic coating surface formed by the ceramic coating provided by the present invention with coal slag;

[0053] Figure 2 These are photos of the ceramic coating formed by the ceramic coating obtained in Example 1 before and after thermal shock testing;

[0054] Figure 3 These are actual photos of the ceramic coating formed by the ceramic paint obtained in Example 1 before and after SO2 gas corrosion. DETAILED DESCRIPTION

[0055] The present invention provides a ceramic coating comprising the following components, calculated by weight percentage:

[0056] High entropy zirconate 20-34%, Al2O3 whiskers 1-2%, hexagonal boron nitride 1-3%, silicon nitride 1-3%, cordierite 2-4%, chromium oxide 6-8%, wetting and dispersing agent 0.3-1%, leveling agent 0.3-1%, defoaming agent 0.3-1%, thickener 0.3-1%, composite binder 35-50%, water 10-20%;

[0057] The chemical formula of the high entropy zirconate is A2Zr2O7, wherein the A position contains at least four elements of La, Sm, Nd, Gd, Eu, Yb, Y, and Sc, and the elements in the A position are in equal molar ratios;

[0058] The composite binder includes an organic binder and an inorganic binder.

[0059] Unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0060] The ceramic coating provided herein comprises 20-34% by mass of a high-entropy zirconate, preferably 20%, 21%, 22%, 23%, 24%, 25%, 26%, 26.33%, 27%, 28%, 28.34%, 29%, 29.55%, 30%, 30.23%, 31%, 32%, 33%, or 34%. In the present invention, the high-entropy zirconate has the chemical formula A2Zr2O7, wherein the A position comprises at least four of the following elements: La, Sm, Nd, Gd, Eu, Yb, Y, and Sc, more preferably a combination of La, Nd, Sm, Eu, and Gd; a combination of Yb, Nd, Sm, Eu, and Gd; a combination of Gd, Yb, Y, and Sc; or a combination of La, Nd, Yb, and Y; and the elements in the A position are in equal molar ratios. In the present invention, the method for preparing the high-entropy zirconate preferably comprises the following steps: mixing at least four of La2O3, Sm2O3, Nd2O3, Gd2O3, Eu2O3, Yb2O3, Y2O3, and Sc2O3 with ZrO2, followed by calcination and ball milling to obtain the high-entropy zirconate. In the present invention, the ratio of the total molar amount of the at least four of La2O3, Sm2O3, Nd2O3, Gd2O3, Eu2O3, Yb2O3, Y2O3, and Sc2O3 to the molar amount of ZrO2 is preferably 1:2. In the present invention, the mixing is preferably performed in a powder mixer, and the mixing time is preferably 2 hours. In the present invention, the calcination temperature is preferably 1450-1600°C, specifically preferably 1450°C, 1500°C, 1510°C, 1520°C, 1530°C, 1540°C, 1550°C, 1560°C, 1570°C, 1580°C, 1590°C or 1600°C; the holding time is preferably 10-16 hours, specifically preferably 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours or 16 hours. In the present invention, the ball milling speed is preferably 200-500 rpm, specifically preferably 200 rpm, 300 rpm, 400 rpm or 500 rpm, and the time is preferably 1-2 hours, specifically preferably 1 hour, 1.5 hours or 2 hours. The ball milling is preferably carried out in a planetary ball mill, and the grinding balls of the ball mill are preferably zirconia grinding balls. In the present invention, the particle size of the high entropy zirconate is preferably less than 1 μm, and the specific surface area is preferably 30 to 80 m 2 / g, specifically preferably 30m 2 / g, 40m 2 / g, 50m 2 / g, 60m 2 / g、70m 2 / g or 80m 2 / g. In this invention, a high-entropy design employs multi-component doping at the A-site of the high-entropy zirconate A2Zr2O7, resulting in a single-phase solid solution with a pyrochlore structure. Significant differences in ionic radius and mass exist between the different doping elements (including at least four of La, Sm, Nd, Gd, Eu, Yb, Y, and Sc), resulting in severe lattice distortion. By leveraging the high-entropy effect, lattice distortion, hysteretic diffusion, and "cocktail" effect of the high-entropy zirconate, the ceramic coating exhibits excellent thermal expansion coefficient, thermal conductivity, and emissivity, improving its high-temperature resistance and adhesion.

[0061] In terms of mass percentage, the ceramic coating provided by the present invention includes 1-2% Al2O3 whiskers, and specifically preferably 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%.

[0062] The ceramic coating provided herein comprises, by weight percentage, 1-3% hexagonal boron nitride, preferably 1%, 1.5%, 2%, 2.5%, or 3%. In the present invention, the hexagonal boron nitride preferably has a particle size of 200-300 nm, preferably 200 nm or 300 nm.

[0063] In terms of mass percentage, the ceramic coating provided by the present invention includes 1-3% silicon nitride, and more preferably 1%, 1.5%, 2%, 2.5% or 3%. In the present invention, the particle size of the silicon nitride is preferably 600-800nm, and more preferably 600nm, 700nm or 800nm. In the present invention, the use of low surface energy materials hexagonal boron nitride and silicon nitride as part of the functional fillers is crucial for improving the anti-fouling and slagging performance of the ceramic coating. Both hexagonal boron nitride and silicon nitride are nano-scale and can be evenly distributed within the coating during the spraying process. During the second curing process of the ceramic coating, they connect with each other to form a low surface energy layer, which effectively inhibits the adhesion of coal combustion products to the surface.

[0064] The ceramic coating provided herein comprises 2-4% cordierite by weight, preferably 2%, 2.5%, 3%, 3.2%, 3.5%, or 4%. In the present invention, the cordierite particle size is preferably less than 1 μm, more preferably 500-800 nm, and more preferably 500 nm, 600 nm, 700 nm, or 800 nm.

[0065] The ceramic coating provided herein comprises 6-8% chromium oxide, preferably 6%, 6.5%, 7%, 7.5%, or 8%, by weight. In the present invention, the chromium oxide particle size is preferably less than 1 μm, more preferably 500-900 nm, and more preferably 500 nm, 600 nm, 700 nm, 800 nm, or 900 nm.

[0066] The ceramic coating provided herein comprises, by weight percentage, 0.3-1% of a wetting and dispersing agent, preferably 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. In the present invention, the wetting and dispersing agent is preferably an anionic wetting and dispersing agent, preferably one or more of TEGO-750W weak anionic polymer wetting and dispersing agent, TEGO-757W anionic polymer wetting and dispersing agent, and TEGO-715W anionic wetting and dispersing agent.

[0067] The ceramic coating provided herein includes a leveling agent in an amount of 0.3-1% by weight, preferably 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. In the present invention, the leveling agent is preferably a silicone leveling agent, and more preferably one or more of BYK-300, BYK-333, and TEGO Glide 440.

[0068] The ceramic coating provided herein includes a defoamer in an amount of 0.3-1%, preferably 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, by weight. In the present invention, the defoamer is preferably one or more of an organosilicon defoamer, a polyether siloxane defoamer, and a mineral oil defoamer. The organosilicon defoamer is preferably BYK-024 organosilicon defoamer, the polyether siloxane defoamer is preferably TEGO-901W polyether siloxane defoamer, and the mineral oil defoamer is preferably Deform W-082 mineral oil defoamer.

[0069] The ceramic coating provided herein includes a thickener in an amount of 0.3-1% by weight, preferably 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. In the present invention, the thickener is preferably a polyurethane thickener and / or a nonionic thickener. The polyurethane thickener is preferably TEGO ViscoPlus 3030 polyurethane thickener, and the nonionic thickener is preferably TEGO ViscoPlus 3060 nonionic thickener.

[0070] The ceramic coating provided herein comprises, by weight percentage, 35-50% of the composite binder, more preferably 40-45%, and more preferably 35%, 36%, 37%, 38%, 39%, 40%, 41%, 41.45%, 43%, 45%, or 50%. In the present invention, the organic binder preferably comprises one or more of a styrene-acrylic emulsion, a silicone-acrylic emulsion, and a pure acrylic emulsion. In the present invention, the solids content of the organic binder is preferably 40-60%, and more preferably 40%, 45%, 50%, 55%, or 60%. In one embodiment of the present invention, the styrene-acrylic emulsion is preferably BASF Angosol 7538, the silicone-acrylic emulsion is preferably BF-400 silicone-acrylic emulsion, and the pure acrylic emulsion is preferably BASF Angosol 7051. In the ceramic coating, the organic binder comprises 15-25% by weight, and more preferably 15%, 19.45%, 20%, or 25%. In the present invention, the inorganic binder preferably includes one or more of potassium silicate water glass, sodium silicate water glass, and lithium silicate water glass; the modulus of the inorganic binder is preferably 2.6-3.8. In the present invention, the mass percentage of the inorganic binder in the ceramic coating is preferably 20-35%, and more preferably 20%, 22%, 25%, 26%, 28%, 30%, 32%, or 35%. In the present invention, the inorganic binder and the organic binder are combined to impart excellent high-temperature resistance and extremely high toughness to the ceramic coating. Simultaneously, Al2O3 whiskers are added to the composite binder to absorb energy through the weak interface between the composite binder and the second cured coating substrate, causing cracks to deflect and bifurcate during propagation, thereby effectively strengthening and toughening the coating.

[0071] The ceramic coating provided herein comprises 10-20% water by weight, preferably 10%, 10.26%, 11%, 11.17%, 11.6%, 12%, 13%, 13.37%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%. In the present invention, the water is preferably deionized water.

[0072] The present invention provides a method for preparing the ceramic coating described in the above technical solution, comprising the following steps:

[0073] first mixing a wetting and dispersing agent, a leveling agent, a defoaming agent, a thickener, and water to obtain a first system;

[0074] a second mixing of high entropy zirconate, Al2O3 whiskers, hexagonal boron nitride, silicon nitride, cordierite, chromium oxide and a composite binder to obtain a second system;

[0075] The first system and the second system are mixed for the third time and then ground to obtain the ceramic coating.

[0076] The present invention first mixes a wetting and dispersing agent, a leveling agent, a defoaming agent, a thickener, and water to obtain a first system. In the present invention, the first mixing speed is preferably 2000-2500 r / min, specifically preferably 2000 r / min, 2100 r / min, 2200 r / min, 2300 r / min, 2400 r / min, or 2500 r / min; and the mixing time is preferably 5-15 minutes, specifically preferably 5 minutes, 10 minutes, or 15 minutes.

[0077] The present invention comprises a second mixing of high entropy zirconate, Al2O3 whiskers, hexagonal boron nitride, silicon nitride, cordierite, chromium oxide, and a composite binder to obtain a second system. In the present invention, the second mixing is preferably performed at a speed of 600 to 800 rpm, more preferably 600 rpm, 650 rpm, 700 rpm, 750 rpm, or 800 rpm; and for a time of 10 to 20 minutes, more preferably 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes.

[0078] After obtaining the first and second systems, the present invention further subjects the first and second systems to a third mixing process, followed by grinding, to obtain the ceramic coating. In the present invention, the third mixing process preferably occurs at a speed of 200 to 300 rpm, more preferably 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or 300 rpm; and for a duration of 30 to 40 minutes, more preferably 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 minutes. In the present invention, the grinding balls used for grinding are preferably zirconia grinding balls. The grinding speed is preferably 300-500 rpm, more preferably 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm. The grinding time is preferably 2-3 hours, more preferably 2 hours, 2.5 hours, or 3 hours. In the present invention, the grinding is preferably performed in a planetary ball mill. After the ball milling, the present invention preferably further comprises filtering, and the pore size of the filtering screen is preferably 1000-2000 mesh, more preferably 1000 mesh or 2000 mesh.

[0079] The present invention also provides the application of the ceramic coating described in the above technical solution in the field of protection.

[0080] In the present invention, the protection preferably includes aerospace protection or boiler protection. In the present invention, the boiler protection is further preferably boiler water wall protection, and the material of the boiler water wall preferably includes 20G steel, 20MnG steel, 15MoG steel, 15CrMoG steel, or 12Cr1MoVG steel.

[0081] The present invention also provides a method for using the ceramic coating described in the above technical solution, comprising the following steps:

[0082] Performing sandblasting treatment on the substrate to be protected to obtain a treated substrate;

[0083] The ceramic coating described in the above technical solution is sprayed on the treated substrate, and sequentially undergoes a first curing and a second curing to form a protective layer.

[0084] The present invention performs sandblasting on a substrate to be protected to obtain a treated substrate. In the present invention, the sandblasting parameters include: the particle size of the corundum sand is preferably 24 to 150 mesh, and more preferably 24 mesh, 30 mesh, 50 mesh, 60 mesh, 70 mesh, 80 mesh, 90 mesh, 100 mesh, 110 mesh, 120 mesh, 130 mesh, 140 mesh, or 150 mesh; the pressure is preferably 0.5 to 2 MPa, and more preferably 0.5 MPa, 1 MPa, 1.5 MPa, or 2 MPa. The present invention does not impose any specific restrictions on the sandblasting time, as long as the surface cleanliness of the substrate to be protected reaches Sa2.5.

[0085] After obtaining the treated substrate, the present invention sprays the ceramic coating described in the above technical solution onto the treated substrate, and sequentially undergoes a first curing and a second curing to form a protective layer.

[0086] In the present invention, the spraying pressure is preferably 0.4~1.5MPa, specifically preferably 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1.0MPa, 1.1MPa, 1.2MPa, 1.3MPa, 1.4MPa or 1.5MPa; the ambient temperature is preferably 15~25℃, specifically preferably 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃ or 25℃; the relative air humidity is preferably 40~60%, specifically preferably 40%, 45%, 50%, 55% or 60%. In the present invention, the thickness of the wet film obtained by spraying is preferably 100-200 μm, specifically preferably 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm or 200 μm.

[0087] In the present invention, the temperature of the first curing is preferably room temperature, that is, no additional heating or cooling is required, and the time is preferably 12 to 24 hours, specifically preferably 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours.

[0088] In the present invention, the temperature of the second curing is preferably 200-600°C, specifically preferably 200°C, 300°C, 400°C, 500°C or 600°C; the heating rate to the temperature of the second curing is preferably 1-10°C / min, specifically preferably 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min; the time is preferably 2-6 hours, specifically preferably 2 hours, 3 hours, 4 hours, 5 hours or 6 hours; the second curing is preferably carried out in a box furnace. After the second curing, the present invention preferably further includes furnace cooling.

[0089] The ceramic coating provided by the present invention, its preparation method, application and use method are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0090] Example 1

[0091] 1. Raw Materials Preparation

[0092] A high entropy zirconate ceramic coating (1000g) resistant to high temperature fouling and slagging, composed of the following components: La2O332.6g (0.1mol), Nd2O333.6g (0.1mol), Sm2O334.8g (0.1mol), Eu2O335.2g (0.1mol), Gd2O336.3g (0.1mol), ZrO2123g (1mol), Al2O3 Whiskers 12g, hexagonal boron nitride (particle size 300nm) 20g, silicon nitride (particle size 800nm) 20g, cordierite (particle size 800nm) 32g, chromium oxide (particle size 800nm) 70g, wetting and dispersing agent (TEGO-750W) 3g, leveling agent (BYK-300) 9g, defoaming agent (BYK-024) 5g, thickener (TEGOViscoPlus 3030) 3g, sodium silicate water glass (modulus 2.6~2.7) 220g, silicone acrylic emulsion (BF-400 silicone acrylic emulsion) 194.5g, deionized water 116g.

[0093] 2. Coating Preparation

[0094] (1) The prepared wetting and dispersing agent, leveling agent, defoaming agent and thickener were added to deionized water in sequence and stirred evenly at a stirring speed of 2200 r / min for 10 min to obtain the first system.

[0095] (2) The prepared La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3 and ZrO2 were mixed in a powder mixer for 2 h, then calcined at 1550 °C for 14 h, and finally ball milled in a planetary ball mill using zirconia balls at a ball milling speed of 300 rpm for 1 h to obtain high entropy zirconate (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic powder, particle size less than 1μm, specific surface area of ​​70m 2 / g.

[0096] (3) Prepare the 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 powder, Al2O3 whiskers, hexagonal boron nitride, silicon nitride, cordierite and chromium oxide are sequentially added to the composite binder (sodium silicate water glass and silicone acrylic emulsion) and stirred evenly at a stirring speed of 600 r / min for 10 min to obtain the second system.

[0097] (4) The first system and the second system were mixed and stirred evenly at a stirring speed of 200 r / min for 30 min, and then dispersed by ball milling using zirconium oxide grinding balls in a planetary ball mill at a ball milling speed of 300 rpm for 2 h. Finally, the mixture was filtered through a 2000 mesh sieve to obtain high entropy zirconate (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic coating.

[0098] 3. Coating Preparation

[0099] (1) Pretreatment: Use 150 mesh corundum sand to sandblast the 20G substrate at a pressure of 0.5 MPa to make the surface cleanliness reach Sa2.5 level.

[0100] (2) Spraying: High entropy zirconate (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic coating was deposited on the surface of 20G substrate with a spraying pressure of 0.4MPa, an ambient temperature of 18℃, and a relative air humidity of 50%, obtaining a wet film with a thickness of 130μm±20μm.

[0101] (3) High temperature curing: The wet film sample was cured at room temperature for 24 h, and then heated to 600 °C in a box furnace at a heating rate of 5 °C / min. The high temperature curing time was 2 h, and then cooled in the furnace to obtain a dry film high entropy zirconate (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic coating.

[0102] 4. Performance Testing

[0103] (1) Coal slag wettability: The coal slag was ground into powder and then pressed into small cylinders with a diameter and height of 3 mm. The cylinders were placed on the surface of the coating sample and heated to 600 °C at a heating rate of 5 °C / min. A high-speed camera was used to record the morphological evolution of the coal slag cylinders in real time and measure the contact angle. The schematic diagram is shown in the figure. Figure 1 shown.

[0104] (2) High temperature stability: Place the coating sample in a box furnace, heat it to 800°C at a heating rate of 10°C / min, and keep it warm for 720 h. After taking it out, measure the phase structure of the coating and observe the surface morphology of the coating.

[0105] (3) Thermal shock resistance: The coating sample was placed in a box furnace and heated to 600°C at a heating rate of 10°C / min. The sample was kept at this temperature for 55 min and then air-cooled for 5 min. This constituted a cycle. After 70 cycles, the surface morphology of the coating was observed.

[0106] (4) Corrosion resistance: The test shall be carried out in accordance with GB / T 9789-2008 Metals and other inorganic coatings - Sulfur dioxide corrosion test under normal condensation conditions.

[0107] (5) Hardness: Determine the hardness of paint films according to GB / T 6739-2006 Paints and varnishes - Pencil method.

[0108] (6) Tensile strength: Measured in accordance with GB / T 5210-2006 Paints and varnishes - Adhesion test by pull-off method.

[0109] (7) Infrared emissivity: measured in accordance with GB 4653-1984 General Technical Requirements for Infrared Radiation Coatings.

[0110] The performance indicators of the coating are shown in Table 1.

[0111] Example 2

[0112] 1. Raw Materials Preparation

[0113] A high entropy zirconate ceramic coating (1000g) resistant to high temperature fouling and slagging, composed of the following components: Yb2O339.4g (0.1mol), Nd2O333.6g (0.1mol), Sm2O334.8g (0.1mol), Eu2O335.2g (0.1mol), Gd2O336.3g (0.1mol), ZrO2123g (1mol), Al 20g 2O3 whiskers, 30g hexagonal boron nitride (particle size 200nm), 30g silicon nitride (particle size 600nm), 30g cordierite (particle size 800nm), 80g chromium oxide (particle size 500nm), 5g wetting and dispersing agent (TEGO-715W), 10g leveling agent (BYK-333), 3g defoaming agent (TEGO-901W), 6g thickener (TEGO ViscoPlus 3030), 200g potassium silicate water glass (modulus 3.0~3.1), 150g pure acrylic emulsion (BASF Anguli 7051), and 133.7g deionized water.

[0114] 2. Coating Preparation

[0115] (1) The prepared wetting and dispersing agent, leveling agent, defoaming agent and thickener were added to deionized water in sequence and stirred evenly at a stirring speed of 2000 r / min for 10 min to obtain the first system.

[0116] (2) The prepared Yb2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3 and ZrO2 were mixed in a powder mixer for 2 h, then calcined at 1580 °C for 12 h, and finally ball milled in a planetary ball mill using zirconia balls at a ball milling speed of 300 rpm for 1 h to obtain high entropy zirconate (Yb 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic powder, particle size less than 1μm, specific surface area of ​​50m 2 / g.

[0117] (3) Prepare (Yb 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 powder, Al2O3 whiskers, hexagonal boron nitride, silicon nitride, cordierite and chromium oxide were added to the composite binder (potassium silicate water glass and BASF Anguli 7051) in sequence and stirred evenly at a stirring speed of 800 r / min for 15 minutes to obtain the second system.

[0118] (4) The first system and the second system were mixed and stirred evenly at a stirring speed of 200 r / min for 30 min, and then ball-milled in a planetary ball mill using zirconium oxide grinding balls at a ball milling speed of 300 rpm for 2 h. Finally, the mixture was filtered through a 2000 mesh sieve to obtain high entropy zirconate (Yb 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic coating.

[0119] 3. Coating Preparation

[0120] (1) Pretreatment: Use 150 mesh corundum sand to sandblast the 12Cr1MoVG substrate at a pressure of 0.5 MPa to make the surface cleanliness reach Sa2.5 level.

[0121] (2) Spraying: High entropy zirconate (Yb 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic coating was deposited on the surface of 12Cr1MoVG substrate with a spraying pressure of 0.4MPa, an ambient temperature of 23℃, and a relative air humidity of 60%, obtaining a wet film with a thickness of 150μm±20μm.

[0122] (3) High temperature curing: The wet film sample was cured at room temperature for 24 h, and then heated to 600 °C in a box furnace at a heating rate of 5 °C / min. The high temperature curing time was 2 h, and then cooled in the furnace to obtain a dry film high entropy zirconate (Yb 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic coating.

[0123] 4. Performance Testing

[0124] The coating test method refers to "4. Performance Test" in Example 1, and the performance indicators are shown in Table 1.

[0125] Example 3

[0126] 1. Raw Materials Preparation

[0127] A high-entropy zirconate ceramic coating (1000 g) resistant to high-temperature fouling and slagging is composed of the following components: 45.4 g (0.125 mol) of Gd2O3, 49.3 g (0.125 mol) of Yb2O3, 28.3 g (0.125 mol) of Y2O3, 17.3 g (0.125 mol) of Sc2O3, 123 g (1 mol) of ZrO2, 20 g of Al2O3 whiskers, 15 g of hexagonal boron nitride (particle size of 200 nm), 15 g of silicon nitride (particle size of 700 nm), 40 g of cordierite (particle size of 500 nm), 80 g of chromium oxide (particle size of 900 nm), 5 g of a wetting and dispersing agent (TEGO-757W), 5 g of a leveling agent (TEGO Glide 440), and 5 g of a defoaming agent (Hemmings Deform) W-082) 5g, thickener (TEGO ViscoPlus 3060) 10g, potassium silicate water glass (modulus 3.0~3.1) 280g, silicone acrylic emulsion (BF-400 silicone acrylic emulsion) 150g, deionized water 111.7g.

[0128] 2. Coating Preparation

[0129] (1) The prepared wetting and dispersing agent, leveling agent, defoaming agent and thickener were added to deionized water in sequence and stirred evenly at a stirring speed of 2500 r / min for 5 min to obtain the first system.

[0130] (2) The prepared Gd2O3, Yb2O3, Y2O3, Sc2O3 and ZrO2 were mixed in a powder mixer for 2 h, then calcined at 1600 °C for 10 h, and finally ball milled in a planetary ball mill using zirconia grinding balls at a ball milling speed of 300 rpm for 1 h to obtain high entropy zirconate (Gd 0.25 Yb 0.25 Y 0.25 Sc 0.25 )2Zr2O7 ceramic powder, particle size less than 1μm, specific surface area of ​​60m 2 / g.

[0131] (3) Prepare (Gd 0.25 Yb 0.25 Y 0.25 Sc 0.25 )2Zr2O7 powder, Al2O3 whiskers, hexagonal boron nitride, silicon nitride, cordierite and chromium oxide were added to the composite binder (potassium silicate water glass and BF-400 silicone acrylic emulsion) in sequence and stirred evenly at a stirring speed of 600 r / min for 10 min to obtain the second system.

[0132] (4) The first system and the second system were mixed and stirred evenly at a stirring speed of 200 r / min for 30 min, and then dispersed by ball milling using zirconium oxide grinding balls in a planetary ball mill at a ball milling speed of 300 rpm for 2 h. Finally, the mixture was filtered through a 1000 mesh sieve to obtain high entropy zirconate (Gd 0.25 Yb 0.25 Y 0.25 Sc 0.25 )2Zr2O7 ceramic coating.

[0133] 3. Coating Preparation

[0134] (1) Pretreatment: Use 150 mesh corundum sand to sandblast the 15CrMoG substrate at a pressure of 0.5 MPa to make the surface cleanliness reach Sa2.5 level.

[0135] (2) Spraying: High entropy zirconate (Gd 0.25 Yb 0.25 Y 0.25 Sc 0.25 )2Zr2O7 ceramic coating was deposited on the surface of 15CrMoG substrate with a spraying pressure of 0.4MPa, an ambient temperature of 20℃, and a relative air humidity of 50%, obtaining a wet film with a thickness of 180μm±20μm.

[0136] (3) High temperature curing: The wet film sample was cured at room temperature for 24 h, and then heated to 600 °C in a box furnace at a heating rate of 5 °C / min. The high temperature curing time was 2 h, and then cooled in the furnace to obtain a dry film high entropy zirconate (Gd 0.25 Yb 0.25 Y 0.25 Sc 0.25 )2Zr2O7 ceramic coating.

[0137] 4. Performance Testing

[0138] The test method of the coating refers to the content of "4. Performance Test" in Example 1, and the various performance indicators are shown in Table 1.

[0139] Example 4

[0140] 1. Raw Materials Preparation

[0141] A high entropy zirconate ceramic coating (1000g) resistant to high temperature fouling and slagging, composed of the following components: La2O340.8g (0.125mol), Nd2O342g (0.125mol), Yb2O349.3g (0.125mol), Y2O328.3g (0.125mol), ZrO2123g (1mol), Al2O3 whiskers 18g, hexagonal Boron nitride (particle size 300nm) 30g, silicon nitride (particle size 600nm) 30g, cordierite (particle size 600nm) 30g, chromium oxide (particle size 600nm) 70g, wetting and dispersing agent (TEGO-750W) 4g, leveling agent (BYK-300) 8g, defoaming agent (TEGO-901W) 6g, thickener (TEGOViscoPlus 3060) 8g, lithium silicate water glass (modulus 3.6~3.8) 260g, styrene acrylic emulsion (BASF Anguli 7538) 150g, deionized water 102.6g.

[0142] 2. Coating Preparation

[0143] (1) The prepared wetting and dispersing agent, leveling agent, defoaming agent and thickener were added to deionized water in sequence and stirred evenly at a stirring speed of 2500 r / min for 10 min to obtain the first system.

[0144] (2) The prepared La2O3, Nd2O3, Yb2O3, Y2O3 and ZrO2 were mixed in a powder mixer for 2 h, then calcined at 1600 °C for 10 h, and finally ball milled in a planetary ball mill using zirconia balls at a ball milling speed of 300 rpm for 1 h to obtain high entropy zirconate (La 0.25 Nd 0.25 Yb 0.25 Y 0.25 )2Zr2O7 ceramic powder, particle size less than 1μm, specific surface area of ​​60m 2 / g.

[0145] (3) Prepare the 0.25 Nd 0.25 Yb 0.25 Y 0.25 )2Zr2O7, Al2O3 whiskers, hexagonal boron nitride, silicon nitride, cordierite and chromium oxide were added to the composite binder (lithium silicate water glass and BASF Anguli 7538) in sequence and stirred evenly at a stirring speed of 600 r / min for 20 min to obtain the second system.

[0146] (4) The first system and the second system were mixed and stirred evenly at a stirring speed of 200 r / min for 30 min, and then dispersed by ball milling using zirconium oxide grinding balls in a planetary ball mill at a ball milling speed of 300 rpm for 2 h. Finally, the mixture was filtered through a 1000 mesh sieve to obtain high entropy zirconate (La 0.25 Nd 0.25 Yb 0.25 Y 0.25 )2Zr2O7 ceramic coating.

[0147] 3. Coating Preparation

[0148] (1) Pretreatment: Use 150 mesh corundum sand to sandblast the 20MnG substrate at a pressure of 0.5 MPa to make the surface cleanliness reach Sa2.5 level.

[0149] (2) Spraying: High entropy zirconate (La 0.25 Nd 0.25 Yb 0.25 Y 0.25 )2Zr2O7 ceramic coating was deposited on the surface of 20MnG substrate with a spraying pressure of 0.4MPa, an ambient temperature of 25℃, and a relative air humidity of 40%, obtaining a wet film with a thickness of 150μm±20μm.

[0150] (3) High temperature curing: The wet film sample was cured at room temperature for 24 h, and then heated to 600 °C in a box furnace at a heating rate of 5 °C / min. The high temperature curing time was 2 h, and then cooled in the furnace to obtain a dry film high entropy zirconate (La 0.25 Nd 0.25 Yb 0.25 Y 0.25 )2Zr2O7 ceramic coating.

[0151] 4. Performance Testing

[0152] The test method of the coating refers to the content of "4. Performance Test" in Example 1, and the various performance indicators are shown in Table 1.

[0153] Comparative Example 1

[0154] The difference from Example 1 is that the high entropy zirconate (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )2Zr2O7 ceramic powder is replaced by Gd2Zr2O7, and the rest is the same as in Example 1.

[0155] Comparative Example 2

[0156] The difference from Example 1 is that the hexagonal boron nitride is omitted and the mixture is filled with water. Other aspects are the same as Example 1.

[0157] Comparative Example 3

[0158] The difference from Example 1 is that silicon nitride is omitted and the mixture is filled with water. Other aspects are the same as Example 1.

[0159] Comparative Example 4

[0160] The difference from Example 1 is that hexagonal boron nitride and silicon nitride are omitted and the amount is supplemented with water. Other aspects are the same as in Example 1.

[0161] Comparative Example 5

[0162] The difference from Example 1 is that the Al2O3 whiskers are omitted and water is used to fill the gap. Other aspects are the same as Example 1.

[0163] Comparative Example 6

[0164] The difference from Example 1 is that sodium silicate water glass is omitted and silicone acrylic emulsion is used to make up the difference. Other aspects are the same as Example 1.

[0165] Comparative Example 7

[0166] The difference from Example 1 is that the silicone acrylic emulsion is omitted and the sodium silicate water glass is used to make up the difference. The rest is the same as Example 1.

[0167] Table 1 Performance test results of coatings in Examples and Comparative Examples

[0168]

[0169] Figure 2 The ceramic coating formed by the ceramic coating obtained in Example 1 is a physical picture before and after the thermal shock test; Figure 2 It can be seen that after 70 thermal cycles from 600°C to room temperature, the obtained ceramic coating has no cracking, peeling or blistering on the coating surface.

[0170] Figure 3 The ceramic coating formed by the ceramic coating obtained in Example 1 is a physical picture before and after SO2 gas corrosion. Figure 3 It can be seen that: the ceramic coating is placed in a SO2 gas corrosion test chamber with a gas volume of 0.2dm 3 After 48 hours of corrosion, there is no cracking, peeling or blistering on the coating surface.

[0171] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A ceramic coating, characterized in that: 1000g of ceramic coating consists of the following components: High entropy zirconate (Gd 0.25 Yb 0.25 Y 0.25 Sc 0.25 ) 2Zr2O7, Al2O3 whiskers 20g, hexagonal boron nitride 15g, silicon nitride 15g, cordierite 40g, chromium oxide 80g, wetting and dispersing agent 5g, leveling agent 5g, defoamer 5g, thickener 10g, potassium silicate water glass 280g, silicone acrylic emulsion 150g, deionized water 111.7g; The particle size of the hexagonal boron nitride is 200 nm; The particle size of the silicon nitride is 700 nm; The particle size of the cordierite is 500 nm; The particle size of the chromium oxide is 900 nm; The wetting and dispersing agent is TEGO-757W; The leveling agent is TEGO Glide 440; The defoaming agent is Hemingway Deform W-082; The thickener is TEGO ViscoPlus 3060; The modulus of the potassium silicate water glass is 3.0-3.1; The silicone acrylic emulsion is BF-400 silicone acrylic emulsion; The (Gd 0.25 Yb 0.25 Y 0.25 Sc 0.25 )The raw materials for the preparation of 2Zr2O7 are Gd2O3 45.4g, Yb2O3 49.3g, Y2O3 28.3g, Sc2O3 17.3g, and ZrO2 123g.

2. The method for preparing the ceramic coating according to claim 1, wherein: The following steps are involved: first mixing a wetting and dispersing agent, a leveling agent, a defoaming agent, a thickener, and water to obtain a first system; The high entropy zirconate, Al2O3 whiskers, hexagonal boron nitride, silicon nitride, cordierite, chromium oxide, potassium silicate water glass and silicone acrylic emulsion are mixed to obtain a second system; The first system and the second system are mixed for the third time and then ground to obtain the ceramic coating.

3. The preparation method according to claim 2, characterized in that The first mixing speed is 2000-2500 r / min, and the time is 5-15 min; The second mixing speed is 600-800 r / min and the time is 10-20 min; The third mixing speed is 200-300 r / min and the time is 30-40 min; The grinding balls used in the grinding are zirconia grinding balls, the grinding speed is 300-500 rpm, and the grinding time is 2-3 hours.

4. Use of the ceramic coating according to claim 1 in the field of protection.

5. The method for using the ceramic coating according to claim 1, wherein: The following steps are involved: Performing sandblasting treatment on the substrate to be protected to obtain a treated substrate; The ceramic coating according to claim 1 is sprayed on a treated substrate, and sequentially subjected to a first curing and a second curing to form a protective layer.

6. The method of use according to claim 5, characterized in that: The parameters of the sandblasting process include: the particle size of the corundum sand is 24-150 mesh, the pressure is 0.5-2 MPa; The spraying pressure is 0.4-1.5 MPa, the ambient temperature is 15-25° C., and the relative air humidity is 40-60%.

7. The method of use according to claim 5, characterized in that: The first curing time is 12 to 24 hours; The second curing temperature is 200-600° C., and the time is 2-6 hours.

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