Multilayer gradient reinforced high-temperature resistant waterproof ceramic coating and preparation method thereof

Abstract

The application discloses a multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating and a preparation method thereof. The method comprises the following steps: mixing Y2O3, Al2O3 and SiO2, melting, quenching with water to obtain yttrium aluminum silicon glass, crushing, mixing with ethanol to form a yttrium aluminum silicon glass slurry; spraying the yttrium aluminum silicon glass slurry on the surface of a substrate, drying and sintering to obtain a yttrium aluminum silicon glass coating; ball-milling boron aluminum silicate glass, water, boric acid, sodium nitrite and tungsten carbide nanoparticles to obtain a tungsten carbide modified glass-ceramic coating spraying material; spraying the tungsten carbide modified glass-ceramic coating spraying material on the yttrium aluminum silicon glass coating, drying and sintering to obtain the multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating. The ceramic coating prepared by the method has the advantages of high compactness, good waterproof and heat insulation performance, high strength, high heat resistance and chemical resistance, good wear resistance, low thermal conductivity and thermal expansion coefficient, good bonding with the substrate, low dielectric constant and small dielectric loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic coating preparation, in particular to a multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating and a preparation method thereof, and belongs to the field of inorganic non-metallic materials. BACKGROUND

[0002] The radar cover has the effect of protecting the radar antenna to normally play the functions of guidance and communication in complex natural environment, and its use environment requires it to have the characteristics of high heat resistance, high strength and high wave transmission performance. The basic material of the radar antenna cover is composite quartz ceramic (SiO 2f / SiO2) which is composed of quartz fiber (SiO 2f ), silicon dioxide (SiO2), combined water, free water, impurities and the like. At the same time, SiO 2f / SiO2 has many pores and a large number of hydrophilic silicon hydroxyl groups (Si—OH), so SiO 2f / SiO2 is easy to absorb moisture in the environment and has a high water absorption rate. Since the dielectric constant and dielectric loss of water are very large, the dielectric constant and dielectric loss of the material after absorbing moisture will also increase accordingly, which will seriously affect the wave transmission performance of the material. The antenna cover and the heat insulation material will also encounter rain erosion, thermal shock, even air particle erosion and scouring, etc. when working.

[0003] At present, the method of introducing a hydrophobic group or coating a coating on SiO 2f / SiO2 is usually used to reduce its water absorption rate in production, but the method of introducing a hydrophobic group has no obvious effect on the improvement of waterproof performance. The hydrophobic coating is mostly inorganic coating prepared from SiO2, silicon nitride and microcrystalline glass, and organic fluororesin coating, organic silicon resin and other organic coating. The resin coating has a low water absorption rate and good wave transmission performance, but the moisture-proof effect of the resin coating is poor and it is easy to fall off or crack. The coating prepared from a single organic or inorganic material cannot completely meet the performance requirements.

[0004] The waterproof coating of fused quartz ceramic reported at present, such as the patent with publication number CN106336117A, discloses a preparation method of a waterproof coating of fused quartz ceramic, which uses the glaze slurry method to prepare a microcrystalline glass coating. However, the combination degree of microcrystalline glass and ceramic is poor, the high-temperature resistance and friction resistance are low, and the overall strength of the ceramic is also low, which limits the application field of the composite material. SUMMARY

[0005] The application aims to provide a multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating and a preparation method thereof.

[0006] The technical scheme adopted by the application is as follows: a multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating comprises two different ceramic coatings coated on a quartz ceramic substrate, and the coatings are yttrium aluminum silicon glass coating and tungsten carbide modified glass-ceramic coating from the inner layer to the outer layer.

[0007] Preferably, the thickness of the yttrium aluminum silicon glass coating is 50-100 μm, and the thickness of the tungsten carbide modified glass-ceramic coating is 80-150 μm.

[0008] To achieve the above-mentioned application purposes, the application further provides a preparation method of the multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating, comprising the following steps.

[0009] (1) mixing Y2O3, Al2O3 and SiO2 to obtain a mixture, then melting the mixture in a furnace, and finally quenching the yttrium aluminum silicon glass by water to obtain a raw material powder, and mixing the raw material powder with ethanol to form a yttrium aluminum silicon glass slurry with a solid content of 30-40%;

[0010] (2) using an atomizing spray gun to spray the yttrium aluminum silicon glass slurry obtained in step (1) on the surface of the quartz ceramic substrate, and then sequentially drying and sintering the sprayed sample in a N2 atmosphere to obtain a yttrium aluminum silicon glass coating;

[0011] (3) using a ball mill to grind boron aluminum silicate glass, boric acid and sodium nitrite as initial materials, and then adding tungsten carbide nanoparticles to obtain a tungsten carbide modified glass-ceramic coating spraying material;

[0012] (4) using a spray gun to spray the tungsten carbide modified glass-ceramic coating spraying material obtained in step (3) on the yttrium aluminum silicon glass coating obtained in step (2) by using a wet spraying method, and then sequentially drying and sintering the sprayed sample to finally obtain a multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating on the surface of the quartz ceramic substrate.

[0013] Preferably, in step (1), the Y2O3, Al2O3 and SiO2 account for 35-40%, 20-30% and 40-45% of the mass of the mixture respectively; the melting temperature is 1550-1650 ℃, and the melting time is 2-4 h.

[0014] Preferably, in step (1), the ball milling speed is 300-600 r / min, the ball milling time is 60-72 h; and the median particle size of the raw material powder is 1-5 µm.

[0015] Preferably, in step (2), the drying temperature is 80-100 ℃, the drying time is 12-24 h; the sintering temperature is 1250-1350 ℃, and the heating rate and cooling rate during sintering are 1-5 ℃ / min and 5-10 ℃ / min, respectively.

[0016] Preferably, in step (2), the spray gun is perpendicular to the surface of the quartz ceramic substrate during spraying; the nozzle diameter of the spray gun is 0.2-5 mm, the spraying distance is 10-20 cm, and the moving speed of the spray gun is 5-20 cm / s.

[0017] Preferably, in step (3), the borosilicate glass, boric acid and sodium nitrite account for 94-95%, 4-5% and 0.5-1% of the mass of the initial material, respectively, and water accounts for 20-30% of the mass of the sprayed material; tungsten carbide nanoparticles account for 5-10% of the mass of the sprayed material; grinding is performed for 1-3 h, and the mixture is ball milled for 2-5 h.

[0018] Preferably, in step (4), the drying temperature is 80-90 ℃, and the drying time is 18-24 h; the sintering process parameters are as follows: sintering at a temperature of 750-800 ℃ at a heating rate of 1-3 ℃ / min, and the holding time is 10-30 min.

[0019] Preferably, in step (4), the nozzle diameter of the spray gun is 0.2-5 mm, the spraying distance is 10-20 cm, and the moving speed of the spray gun is about 5-20 cm / s.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1. The tungsten carbide modified glass-ceramic coating of the outer layer in the present application has high mechanical resistance, heat resistance, chemical resistance and wear resistance; the yttrium aluminum silicon glass coating in contact with the quartz ceramic substrate has strong mechanical properties, low thermal conductivity and thermal expansion coefficient, light weight, good heat shock resistance, low dielectric constant and small dielectric loss; the use of multiple layers of gradient modulus not only reduces the thermal stress during the heat shock process, but also inhibits the propagation of cracks, thereby improving the toughness and structural stability of the ceramic coating and ensuring its waterproof performance.

[0022] 2. The ceramic coating prepared by the present application has the advantages of high density, good waterproof and heat insulation performance, high strength, good heat resistance, chemical resistance and wear resistance, low thermal conductivity and thermal expansion coefficient, good bonding with the substrate, low dielectric constant and small dielectric loss.

[0023] 3、The multilayer gradient reinforced high-temperature resistant waterproof ceramic coating prepared by the spraying method has simple process, low cost and high product yield, and is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 SEM image of the multilayer gradient reinforced high-temperature resistant waterproof ceramic coating prepared for Example 1 of the present application. DETAILED DESCRIPTION

[0025] The present application will be further described in detail below in combination with the drawings and specific examples.

[0026] Example 1

[0027] A preparation method of a multilayer gradient reinforced high-temperature resistant waterproof ceramic coating, comprising the following steps:

[0028] (1) mixing Y2O3, Al2O3 and SiO2 to obtain a mixture, wherein the Y2O3, Al2O3 and SiO2 account for 40%, 30% and 40% of the mass of the mixture respectively; then melting the mixture in a furnace, wherein the melting temperature is 1550℃ and the melting time is 2h; finally, quenching the molten mixture in water to obtain yttrium aluminum silicon glass; crushing the yttrium aluminum silicon glass and then ball milling to obtain raw powder with a median particle size of about 1μm, wherein the ball milling speed is 300r / min and the ball milling time is 72h; mixing the raw powder with ethanol to form a yttrium aluminum silicon glass slurry with a solid content of 30%;

[0029] (2) using an atomizing spray gun to spray the yttrium aluminum silicon glass slurry obtained in step (1) on the surface of a quartz ceramic substrate, wherein the spray gun is perpendicular to the surface of the sample during spraying, the nozzle diameter of the spray gun is 0.2mm, the spraying distance is 10cm, and the moving speed of the spray gun is 5cm / s; then drying and sintering the sprayed sample in N2 atmosphere to obtain a yttrium aluminum silicon glass coating, wherein the drying temperature is 80℃ and the drying time is 24h, and the sintering temperature is 1250℃, and the heating rate and the cooling rate during sintering are 1℃ / min and 5℃ / min respectively;

[0030] (3) using boron aluminum silicate glass, boric acid and sodium nitrite as initial materials, wherein the boron aluminum silicate glass, boric acid and sodium nitrite account for 95%, 4.5% and 0.5% of the mass of the initial materials respectively; grinding the initial materials and water using a ball mill for 1h, then adding tungsten carbide nanoparticles, and mixing and ball milling for 2h to obtain tungsten carbide modified glass-ceramic coating spraying material; wherein the water accounts for 20% of the mass of the spraying material, and the tungsten carbide nanoparticles account for 5% of the mass of the spraying material;

[0031] (4) using a spray gun to spray the tungsten carbide modified glass-ceramic coating material obtained in step (3) on the yttrium aluminum silicon glass coating obtained in step (2), the nozzle diameter of the spray gun is 0.2 mm, the spraying distance is 10 cm, and the moving speed of the spray gun is about 5 cm / s; then the sprayed sample is sequentially subjected to drying and sintering, and finally a multilayer gradient reinforced high-temperature resistant waterproof ceramic coating is obtained on the surface of the quartz ceramic substrate; the drying temperature is 80 ℃, and the drying time is 24 h; the sintering process parameters are as follows: sintering at 750 ℃ at a heating rate of 1 ℃ / min, and the holding time is 30 min. The multilayer gradient reinforced high-temperature resistant waterproof ceramic coating prepared in this embodiment is tested for bending strength, thermal conductivity, dielectric constant, thermal shock resistance, and heat resistance, and the test results are shown in Table 1.

[0032] Figure 1 The SEM image of the multilayer gradient reinforced high-temperature resistant waterproof ceramic coating prepared in Example 1 is shown in the figure, from which it can be seen that the coatings are tightly combined with each other and with the quartz substrate, which will help to reduce thermal stress during thermal shock and inhibit crack propagation; in addition, the particles are uniformly dispersed, the yttrium aluminum silicon glass has high density, and the waterproof performance is improved.

[0033] Example 2

[0034] A preparation method of a multilayer gradient reinforced high-temperature resistant waterproof ceramic coating, comprising the following steps:

[0035] (1) mixing Y2O3, Al2O3 and SiO2 to obtain a mixture, wherein the Y2O3, Al2O3 and SiO2 account for 40%, 30% and 40% of the mass of the mixture respectively; then melting the mixture in a furnace, the melting temperature is 1600 ℃, and the melting time is 3 h; finally, quenching with water to obtain yttrium aluminum silicon glass; crushing the yttrium aluminum silicon glass and then ball milling to obtain raw powder with a median particle size of about 3 μm, the ball milling speed is 450 r / min, and the ball milling time is 60 h; mixing the raw powder with ethanol to form a yttrium aluminum silicon glass slurry with a solid content of 35%;

[0036] (2) using an atomizing spray gun to spray the yttrium aluminum silicon glass slurry obtained in step (1) on the surface of a quartz ceramic substrate, wherein the spray gun is perpendicular to the sample surface during spraying, the nozzle diameter of the spray gun is 0.5 mm, the spraying distance is 15 cm, and the moving speed of the spray gun is 10 cm / s; then sequentially subjecting the sprayed sample to drying and sintering in a N2 atmosphere to obtain a yttrium aluminum silicon glass coating; the drying temperature is 90 ℃, and the drying time is 18 h; the sintering temperature is 1300 ℃, and the heating rate and the cooling rate during sintering are 3 ℃ / min and 7 ℃ / min respectively;

[0037] (3) taking boron-aluminum-silicate glass, boric acid and sodium nitrite as initial materials, the boron-aluminum-silicate glass, boric acid and sodium nitrite account for 94%, 5% and 1% of the mass of the initial materials respectively, grinding the initial materials and water by using a ball mill for 2h, then adding tungsten carbide nanoparticles and mixing and ball milling for 3h to obtain a tungsten carbide modified glass-ceramic coating spraying material; water accounts for 25% of the mass of the spraying material; tungsten carbide nanoparticles account for 7.5% of the mass of the spraying material;

[0038] (4) using a spray gun to spray the tungsten carbide modified glass-ceramic coating spraying material obtained in step (3) on the yttrium-aluminum-silicon glass coating obtained in step (2) by using a wet spraying method, the nozzle diameter of the spray gun is 2mm, the spraying distance is 15cm, and the moving speed of the spray gun is about 15cm / s; then the sprayed sample is sequentially subjected to drying and sintering to finally obtain a multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating on the surface of the quartz ceramic substrate; the drying temperature is 90℃, and the drying time is 18h; the sintering process parameters are as follows: sintering at 770℃ with a heating rate of 2℃ / min, and the holding time is 20min. The multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating prepared in this embodiment is tested for bending strength, thermal conductivity, dielectric constant, heat shock resistance and heat resistance, and the test results are shown in Table 1.

[0039] Example 3

[0040] A preparation method of a multilayer gradient reinforced high-temperature-resistant waterproof ceramic coating, comprising the following steps:

[0041] (1) mixing Y2O3, Al2O3 and SiO2 to obtain a mixture, the Y2O3, Al2O3 and SiO2 account for 35%, 21.7% and 43.3% of the mass of the mixture respectively; then melting the mixture in a furnace, the melting temperature is 1650℃, and the melting time is 4h; finally, quenching by water to obtain yttrium-aluminum-silicon glass; crushing the yttrium-aluminum-silicon glass and then performing ball milling to obtain raw powder with a median particle size of about 5μm, the ball milling speed is 600r / min, and the ball milling time is 72h; mixing the raw powder with ethanol to form a yttrium-aluminum-silicon glass slurry with a solid content of 40%;

[0042] (2) using an atomizing spray gun to spray the yttrium-aluminum-silicon glass slurry obtained in step (1) on the surface of a quartz ceramic substrate, in the spraying process, the spray gun is perpendicular to the sample surface, the nozzle diameter of the spray gun is 5mm, the spraying distance is 20cm, and the moving speed of the spray gun is 20cm / s; then sequentially subjecting the sprayed sample to drying and sintering in a N2 atmosphere to obtain a yttrium-aluminum-silicon glass coating; the drying temperature is 100℃, and the drying time is 12h; the sintering temperature is 1350℃, and the heating rate and the cooling rate during sintering are 5℃ / min and 10℃ / min respectively;

[0043] (3) taking boron-aluminum-silicate glass, boric acid and sodium nitrite as initial materials, the boron-aluminum-silicate glass, boric acid and sodium nitrite account for 95%, 4% and 1% of the mass of the initial materials respectively, grinding the initial materials and water by using a ball mill for 3h, then adding tungsten carbide nanoparticles and mixing and ball milling for 5h to obtain a tungsten carbide modified glass-ceramic coating spraying material; water accounts for 30% of the mass of the spraying material; tungsten carbide nanoparticles account for 10% of the mass of the coating material;

[0044] (4) using a spray gun to spray the tungsten carbide modified glass-ceramic coating spraying material obtained in step (3) on the yttrium-aluminum-silicon glass coating obtained in step (2) by using a wet spraying method, the nozzle diameter of the spray gun is 5mm, the spraying distance is 20cm, and the moving speed of the spray gun is about 20cm / s; then the sprayed sample is sequentially subjected to drying and sintering, and finally a multilayer gradient reinforced high-temperature resistant waterproof ceramic coating is obtained on the surface of the quartz ceramic substrate; the drying temperature is 90℃, and the drying time is 24h; the sintering process parameters are: sintering at a temperature increasing rate of 3℃ / min to 800℃, and the holding time is 10min. The multilayer gradient reinforced high-temperature resistant waterproof ceramic coating prepared in this embodiment is tested for bending strength, thermal conductivity, dielectric constant, heat shock resistance and heat resistance, and the test results are shown in Table 1.

[0045] Table 1: Performance test results of samples prepared in each embodiment

[0046]

[0047] As can be seen from Table 1, the coating prepared by the present application has the advantages of heat resistance, strong mechanical properties, low thermal conductivity and thermal expansion coefficient, good heat shock resistance, low dielectric constant, small dielectric loss and the like.

[0048] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any modification, equivalent replacement and improvement made by any person skilled in the art within the technical range disclosed by the present application, as long as it is within the spirit and principles of the present application, should be covered within the protection scope of the present application.

Claims

1. A multilayer gradient-reinforced high-temperature-resistant water-resistant ceramic coating, characterized in that, The application relates to a multilayer gradient-enhanced high-temperature-resistant waterproof ceramic coating, which comprises two layers of different ceramic coatings coated on a quartz ceramic substrate, and the coatings are a yttrium aluminum silicon glass coating and a tungsten carbide modified glass-ceramic coating from the inner layer to the outer layer; the tungsten carbide modified glass-ceramic coating is prepared by the following steps: taking boron aluminum silicate glass, boric acid and sodium nitrite as initial materials, grinding the initial materials and water by using a ball mill, then adding tungsten carbide nanoparticles, mixing and ball milling to obtain a tungsten carbide modified glass-ceramic coating spraying material, and then sequentially performing spraying, drying and sintering; the boron aluminum silicate glass, the boric acid and the sodium nitrite account for 94-95%, 4-5% and 0.5-1% of the mass of the initial materials respectively, and the water accounts for 20-30% of the mass of the spraying material; and the tungsten carbide nanoparticles account for 5-10% of the mass of the spraying material.

2. The multilayer gradient reinforced high temperature resistant and waterproof ceramic coating according to claim 1, characterized in that, The thickness of the yttrium aluminum silicon glass coating is 50-100 mu m, and the thickness of the tungsten carbide modified glass-ceramic coating is 80-150 mu m.

3. A method of producing the multilayer gradient-reinforced high-temperature-resistant waterproof ceramic coating according to claim 1, characterized in that, The application further discloses a preparation method of the multilayer gradient-enhanced high-temperature-resistant waterproof ceramic coating. The application further discloses a preparation method of the multilayer gradient-enhanced high-temperature-resistant waterproof ceramic coating. The application further discloses a preparation method of the multilayer gradient-enhanced high-temperature-resistant waterproof ceramic coating. The application further discloses a preparation method of the multilayer gradient-enhanced high-temperature-resistant waterproof ceramic coating. The application further discloses a preparation method of the multilayer gradient-enhanced high-temperature-resistant waterproof ceramic coating.

4. The method of claim 3, wherein the multilayer gradient reinforced high-temperature resistant waterproof ceramic coating is prepared by the following steps: 1) preparing a first layer of a first ceramic material; 2) preparing a second layer of a second ceramic material; 3) preparing a third layer of a third ceramic material; and 4) preparing a fourth layer of a fourth ceramic material. The application further discloses a preparation method of the multilayer gradient-enhanced high-temperature-resistant waterproof ceramic coating.

5. A method for preparing a multi-layer gradient reinforced high-temperature waterproof ceramic coating according to claim 3 or 4, characterized in that, The application further discloses a preparation method of the multilayer gradient-enhanced high-temperature-resistant waterproof ceramic coating.

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8. A method for preparing a multi-layer gradient reinforced high-temperature waterproof ceramic coating according to claim 3 or 4, characterized in that, In step (3), the grinding is performed for 1-3 h, and the ball milling is performed for 2-5 h.

9. A method for preparing a multi-layer gradient-reinforced high-temperature waterproof ceramic coating according to claim 3 or 4, characterized in that, In step (4), the drying temperature is 80-90℃, and the drying time is 18-24 h; the sintering process parameters are as follows: sintering at a temperature rising speed of 1-3℃ / min to 750-800℃, and the holding time is 10-30 min.

10. The method of claim 3 or 4, wherein the multilayer gradient reinforced high-temperature resistant waterproof ceramic coating is prepared by the following steps: 1) preparing a first layer of a first ceramic material; 2) preparing a second layer of a second ceramic material; 3) preparing a third layer of a third ceramic material; and 4) preparing a fourth layer of a fourth ceramic material. In step (4), the nozzle diameter of the spray gun is 0.2-5 mm, the spraying distance is 10-20 cm, and the moving speed of the spray gun is 5-20 cm / s.

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