1. The thermal barrier/infrared low-emissivity integrated coating based on the fluorescent sublayer is characterized by being of a multilayer structure and sequentially comprising a metal bonding layer, a thermal barrier ceramic inner layer, a rare earth fluorescent sublayer and an infrared low-emissivity layer from inside to outside.

2. The thermal barrier/infrared low emissivity integral coating of claim 1, wherein the metallic bond coat is an MCrAlY coating, M is Co, Ni or CoNi; the thermal barrier ceramic inner layer is a 6-8 YSZ ceramic layer.

3. The thermal barrier/infrared low emissivity integrated coating of claim 1, wherein the rare earth phosphor sublayer is LaMgAl₁₁O_l9R is a coating layer, R is Eu³⁺、Tb³⁺、Dy³⁺、Sm³⁺Or Ce³⁺(ii) a The doping amount of R is 0.5-10.0 mol%.

4. The thermal barrier/infrared low emissivity integrated coating of claim 1, wherein the infrared low emissivity layer is Bi₂O₃-Al₂O₃-TiO₂-Li₂O-SiO₂The coating is prepared by using low-melting-point glass as a binding phase and AgPd as a conductive phase.

5. The thermal barrier/infrared low emissivity integrated coating of claim 1, wherein the metallic bond layer has a thickness of 0.03-0.10 mm, the thermal barrier ceramic inner layer has a thickness of 0.05-2.0 mm, the rare earth phosphor sublayer has a thickness of 0.02-2.0 mm, and the infrared low emissivity layer has a thickness of 0.01-0.04 mm.

6. A method for preparing the thermal barrier/infrared low emissivity integrated coating as claimed in any one of claims 1 to 5, comprising the steps of:

(1) roughening the substrate;

(2) preparing a metal bonding layer on the surface of the substrate obtained in the step (1) by adopting an atmospheric plasma spraying process;

(3) preparing a thermal barrier ceramic inner layer on the surface of the metal bonding layer obtained in the step (2) by adopting an atmospheric plasma spraying process;

(4) adopting an atmosphere plasma spraying process to spray LaMgAl₁₁O_l9Coating the R spraying material on the surface of the inner layer of the thermal barrier ceramic obtained in the step (3) to obtain a rare earth fluorescent sublayer;

(5) and (4) preparing an infrared low-emissivity layer on the surface of the rare earth fluorescent sub-layer obtained in the step (4) by using the infrared low-emissivity coating as a raw material through an air spraying-heat treatment process, and completing the preparation of the thermal barrier/infrared low-emissivity integrated coating.

7. The production method according to claim 6, wherein in the step (1), the roughening treatment is: placing the substrate in a box type sand blasting machine for sand blasting and coarsening treatment, wherein the process parameters of the sand blasting and coarsening treatment are as follows: the pressure is 0.3-0.5 MPa, the sand blasting distance is 80-120 mm, the sand grain diameter is 80-120 mu m, and the sand blasting time is 1-5 min;

in the step (2), the process parameters of the atmospheric plasma spraying process are as follows: the flow rate of argon gas is 30-50L/min, and the flow rate of hydrogen gas is 5-13L/min; the current is controlled to be 450-550A, and the power is 25-38 kW; the flow of the powder-feeding argon gas is 1.0-5.0L/min, and the powder-feeding amount is 25-50 g/min; the spraying distance is 80-140 mm;

in the step (3), the process parameters of the atmospheric plasma spraying process are as follows: the flow rate of argon gas is 25-45L/min, and the flow rate of hydrogen gas is 7-14L/min; the current is controlled to be 530-600A, and the power is 25-35 kW; the flow of the powder-feeding argon gas is 2.0-5.0L/min, and the powder-feeding amount is 10-30 g/min; the spraying distance is 80-200 mm;

in the step (4), the process parameters of the atmospheric plasma spraying process are as follows: the flow rate of argon gas is 25-45L/min, and the flow rate of hydrogen gas is 7-14L/min; the current is controlled to be 530-600A, and the power is 25-35 kW; the flow of the powder-feeding argon gas is 2.0-5.0L/min, and the powder-feeding amount is 10-30 g/min; the spraying distance is 80-200 mm;

in the step (5), the heat treatment process parameters are as follows: the peak sintering temperature is 300-500 ℃, the temperature rising speed is 15-25 ℃/min, the sintering time is 10-60 min, and the sintering atmosphere is air.

8. The method of claim 6, wherein the Lamgal is present in the solution₁₁O_l9The preparation method of the R material comprises the following steps:

mixing raw materials: weighing lanthanum oxide, magnesium oxide, aluminum oxide and rare earth oxide powder according to a stoichiometric ratio, wherein the rare earth oxide is europium oxide, terbium oxide, dysprosium oxide, samarium oxide or cerium oxide, ball-milling and mixing the powder, and then drying and grinding the powder to obtain mixed powder;

high temperature solid phase synthesis of powder: will be described in detailCalcining the obtained mixed powder at high temperature to obtain LaMgAl₁₁O_l9R powder, R is Eu³⁺、Tb³⁺、Dy³⁺、Sm³⁺Or Ce³⁺；

Preparation of the spray coating material: will be described in detailThe obtained LaMgAl₁₁O_l9R powder, deionized water, Arabic gum powder and triammonium citrate are mixed uniformly by a ball milling process, and quasi-spherical agglomerated powder particles are prepared by a spray drying process to finish the LaMgAl₁₁O_l9R preparation of the spray coating material.

9. The preparation method of claim 8, wherein the molar ratio of lanthanum oxide to magnesium oxide to aluminum oxide is 1:2:11, and the doping amount of R is 0.5-10.0 mol%;

said step (c) isThe medium and high temperature calcination process parameters are as follows: the temperature is 1200-1600 ℃, and the time is 12-36 h;

said step (c) isIn the process, the mass fraction of the deionized water is 40-65%, the mass fraction of the Arabic gum powder is 0.5-3.8%, the mass fraction of the triammonium citrate is 0.5-4.5%, and the balance is LaMgAl₁₁O_l9R powder; the parameters of the spray drying process are as follows: the outlet temperature is 120-150 ℃, the inlet temperature is 230-280 ℃, the slurry feeding speed is 0.5-5.0L/min, and the rotating speed of the atomizing disc is 15000-21000 r/min.

10. The preparation method according to claim 6, wherein in the step (5), the preparation method of the infrared low-emissivity coating comprises the following steps: uniformly mixing glass raw material powder, smelting at 1400-1500 ℃ for 3-4 h to obtain a glass melt, and then pouring the obtained glass melt into deionized water for quenching to obtain glass slag; ball-milling the glass slag into glass powder, uniformly mixing the glass powder and the silver-palladium powder to form mixed powder, and then mixing and grinding the mixed powder with an organic carrier to prepare the infrared low-emissivity coating;

the glass raw material powder comprises the following components in percentage by mass:

Bi₂O₃ 25~65%

TiO₂ 2~20%

Al₂O₃ 3~10%

SiO₂ 15~25%

Li₂O 2~10%

CaO 3%~5%

MgO 3~5%

B₂O₃ 3~5%；

in the infrared low-emissivity coating, the mass fraction of the mixed powder is 70-85%, the mass fraction of the organic carrier is 15-30%, and the mass fraction of the silver-palladium powder in the mixed powder is 70-85%; the organic carrier mainly comprises 80-90% of tributyl citrate, 2-5% of cellulose nitrate and 5-15% of lecithin by mass;

the mixing of the glass powder and the silver-palladium powder is carried out in a planetary gravity mixer, the revolution speed of the planetary gravity mixer is 1000-1300 rpm, the rotation speed is 40-60% of the revolution speed, and the mixing time is 50-85 min;

the mixing process of the mixed powder and the organic carrier is carried out in a three-roller grinding machine, the rotating speed of the three-roller grinding machine is 300-450 r/min, and the grinding and mixing time is 2-4 h.

Background

The infrared radiation characteristic signals of the high-temperature parts of the aircraft are remarkable, so that the aircraft faces the threat of infrared guidance. In contrast, the reduction of the surface infrared emissivity of the part becomes a main technical approach for realizing the infrared stealth of the high-temperature part at present, wherein the high-temperature infrared stealth coating has the advantages of small influence on the appearance of the aircraft, simple process, low cost, high reliability and the like, and is widely applied to the high-temperature part of the aviation equipment. However, in the service process of the aircraft in the whole life cycle, due to the phenomena of part collision, friction, local over-temperature of an engine and the like, the infrared low-emissivity layer is easy to fall off, ablate, wear and the like. In order to maintain the stable infrared stealth characteristic of the aircraft in the whole life cycle, the damaged part of the coating must be discovered, accurately positioned, accurately evaluated and quickly repaired as soon as possible. Therefore, a new detection and evaluation means is needed, the change of the stealth performance of the aircraft can be rapidly and accurately detected on the spot (workshop, apron, hangar and the like), maintenance suggestions are given, and the time and cost required by aircraft maintenance are reduced. However, at present, a high-temperature infrared stealth coating system lacks a system maintenance and guarantee technology, the performance of the coating cannot be accurately monitored, an outfield rapid online detection means is relatively backward, a mature technology for early discovery and accurate positioning of stealth material damage is not available, the performance evaluation of a coating in a full life cycle is difficult to realize, and designing a high-temperature infrared low-emissivity coating with a rapid in-situ detection function becomes a main technical problem concerned by technicians in this field. Therefore, the invention discloses a thermal barrier/infrared low-emissivity integrated coating based on a fluorescent sublayer and a preparation method thereof, and aims at the application requirements that a high-temperature infrared stealth coating in the whole life cycle can be designed, detected and evaluated.

Disclosure of Invention

The invention aims to provide a thermal barrier/infrared low-emissivity integrated coating based on a fluorescent sublayer and a preparation method thereof, so that the defects and shortcomings in the background art are overcome.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

the thermal barrier/infrared low-emissivity integrated coating based on the fluorescent sublayer is of a multilayer structure and sequentially comprises a metal bonding layer, a thermal barrier ceramic inner layer, a rare earth fluorescent sublayer and an infrared low-emissivity layer from inside to outside.

The technical scheme of the invention is mainly based on the following principle: due to the special 4f electronic configuration energy level, the 4f5d energy level and the charge transfer band structure of the rare earth ions, the absorption, excitation and emission spectra of the rare earth luminescent material show wide and abundant optical spectra and luminescent characteristics. The rare earth fluorescent ions are doped into the ceramic crystal lattice as an activator to obtain the rare earth luminescent material with fluorescence characteristics, and the rare earth fluorescent sublayer is a ceramic layer which can emit fluorescence which is visible to the naked eye and has good monochromaticity under the irradiation of ultraviolet light with specific wavelength by utilizing the rare earth luminescent material and is used for indicating a damaged or fallen area of the coating. Generally, the rare earth luminescent material is doped with a small amount of activator ions, has excellent fluorescence characteristics, and simultaneously, the crystal structure of the ceramic material is not changed, so that the thermophysical properties of the coating are not influenced.

Preferably, in the thermal barrier/infrared low-emissivity integrated coating, the metal bonding layer is an MCrAlY coating, and M is Co, Ni or CoNi; the inner layer of the thermal barrier ceramic is a 6-8 YSZ (yttria stabilized zirconia with the mass fraction of 6-8%) ceramic layer.

Preferably, in the thermal barrier/infrared low-emissivity integrated coating, the rare earth fluorescent sublayer is LaMgAl₁₁O_l9R coatingLayer, wherein R is Eu³⁺、Tb³⁺、Dy³⁺、Sm³⁺Or Ce³⁺And the doping amount of the R is 0.5-10.0 mol%. In magnetoplumbite LaMgAl₁₁O_l9Rare earth fluorescent ions are doped into the (LMA) crystal lattice, so that the (LMA) crystal lattice can emit fluorescence under the excitation of ultraviolet light with specific wavelength, and the fluorescence is used as a fluorescence sub-layer for indicating the failure part of the coating. Magnetoplumbite LaMgAl₁₁O_l9The (LMA) also has excellent performances of low thermal conductivity, high-temperature oxygen impermeability, high-temperature structure and chemical stability and the like, the YSZ material has excellent thermophysical characteristics and is the most classical Thermal Barrier Coating (TBC) material, and by combining the advantages of the two materials, the thermal cycle life of the designed YSZ/LMA double-layer ceramic structure is longer than that of a single LMA or YSZ ceramic layer. In addition, the flaky structure particles in the LMA coating can effectively improve the stress tolerance of the coating surface, relieve the shrinkage stress caused by the rapid sintering of the low-infrared-emissivity coating, and reduce the residual stress generated in the coating preparation process.

Preferably, in the thermal barrier/infrared low-emissivity integrated coating, the infrared low-emissivity layer is Bi₂O₃-Al₂O₃-TiO₂-Li₂O-SiO₂The coating is prepared by using low-melting-point glass as a binding phase and AgPd as a conductive phase.

Preferably, in the thermal barrier/infrared low-emissivity integrated coating, the thickness of the metal bonding layer is 0.03-0.10 mm, the thickness of the thermal barrier ceramic inner layer is 0.05-2.0 mm, the thickness of the rare earth fluorescent sublayer is 0.02-2.0 mm, and the thickness of the infrared low-emissivity layer is 0.01-0.04 mm.

A preparation method of the thermal barrier/infrared low-emissivity integrated coating comprises the following steps:

(1) roughening the substrate;

(2) preparing a metal bonding layer on the surface of the substrate obtained in the step (1) by adopting an atmospheric plasma spraying process;

(3) preparing a thermal barrier ceramic inner layer on the surface of the metal bonding layer obtained in the step (2) by adopting an atmospheric plasma spraying process;

(4) by using a largeLaMgAl is sprayed by gas plasma spraying process₁₁O_l9Coating the R spraying material on the surface of the inner layer of the thermal barrier ceramic obtained in the step (3) to obtain a rare earth fluorescent sublayer;

(5) and (4) preparing an infrared low-emissivity layer on the surface of the rare earth fluorescent sub-layer obtained in the step (4) by using the infrared low-emissivity coating as a raw material through an air spraying-heat treatment process, and completing the preparation of the thermal barrier/infrared low-emissivity integrated coating.

Preferably, in the above preparation method, in the step (1), the roughening treatment is: placing the substrate in a box type sand blasting machine for sand blasting and coarsening treatment, wherein the process parameters of the sand blasting and coarsening treatment are as follows: the pressure is 0.3-0.5 MPa, the sand blasting distance is 80-120 mm, the sand grain diameter is 80-120 mu m, and the sand blasting time is 1-5 min;

in the step (2), the process parameters of the atmospheric plasma spraying process are as follows: the flow rate of argon gas is 30-50L/min, and the flow rate of hydrogen gas is 5-13L/min; the current is controlled to be 450-550A, and the power is 25-38 kW; the flow of the powder-feeding argon gas is 1.0-5.0L/min, and the powder-feeding amount is 25-50 g/min; the spraying distance is 80-140 mm;

in the step (3), the process parameters of the atmospheric plasma spraying process are as follows: the flow rate of argon gas is 25-45L/min, and the flow rate of hydrogen gas is 7-14L/min; the current is controlled to be 530-600A, and the power is 25-35 kW; the flow of the powder-feeding argon gas is 2.0-5.0L/min, and the powder-feeding amount is 10-30 g/min; the spraying distance is 80-200 mm;

in the step (4), the process parameters of the atmospheric plasma spraying process are as follows: the flow rate of argon gas is 25-45L/min, and the flow rate of hydrogen gas is 7-14L/min; the current is controlled to be 530-600A, and the power is 25-35 kW; the flow of the powder-feeding argon gas is 2.0-5.0L/min, and the powder-feeding amount is 10-30 g/min; the spraying distance is 80-200 mm;

in the step (5), the heat treatment process parameters are as follows: the peak sintering temperature is 300-500 ℃, the temperature rising speed is 15-25 ℃/min, the sintering time is 10-60 min, and the sintering atmosphere is air.

Preferably, in the above preparation method, the LaMgAl is₁₁O_l9The preparation method of the R material comprises the following steps:

mixing raw materials: weighing lanthanum oxide, magnesium oxide, aluminum oxide and rare earth oxide powder according to a stoichiometric ratio, wherein the rare earth oxide is europium oxide, terbium oxide, dysprosium oxide, samarium oxide or cerium oxide, ball-milling and mixing the powder, and then drying and grinding the powder to obtain mixed powder;

② high-temperature solid-phase synthesis of powder: calcining the mixed powder obtained in the step I at high temperature to obtain LaMgAl₁₁O_l9R powder, R is Eu³⁺、Tb³⁺、Dy³⁺、Sm³⁺Or Ce³⁺；

Preparing a spraying material: the LaMgAl obtained in the step two₁₁O_l9R powder, deionized water, Arabic gum powder and triammonium citrate are mixed uniformly by a ball milling process, and quasi-spherical agglomerated powder particles are prepared by a spray drying process to finish the LaMgAl₁₁O_l9R preparation of the spray coating material.

Preferably, in the preparation method, in the step (i), the molar ratio of lanthanum oxide, magnesium oxide and aluminum oxide is 1:2:11, and the doping amount of the rare earth fluorescent ions is 0.5-10.0 mol%;

in the second step, the high-temperature calcination process parameters are as follows: the temperature is 1200-1600 ℃, and the time is 12-36 h;

in the third step, the mass fraction of the deionized water is 40-65%, the mass fraction of the Arabic gum powder is 0.5-3.8%, the mass fraction of the triammonium citrate is 0.5-4.5%, and the balance is LaMgAl₁₁O_l9R powder; the parameters of the spray drying process are as follows: the outlet temperature is 120-150 ℃, the inlet temperature is 230-280 ℃, the slurry feeding speed is 0.5-5.0L/min, and the rotating speed of the atomizing disc is 15000-21000 r/min.

Preferably, in the above preparation method, in the step (5), the preparation method of the infrared low-emissivity coating includes the following steps: uniformly mixing glass raw material powder, smelting at 1400-1500 ℃ for 3-4 h to obtain a glass melt, and then pouring the obtained glass melt into deionized water for quenching to obtain glass slag; ball-milling the glass slag into glass powder, uniformly mixing the glass powder and the silver-palladium powder to form mixed powder, and then mixing and grinding the mixed powder with an organic carrier to prepare the infrared low-emissivity coating;

the glass raw material powder comprises the following components in percentage by mass:

in the infrared low-emissivity coating, the mass fraction of the mixed powder is 70-85%, the mass fraction of the organic carrier is 15-30%, and the mass fraction of the silver-palladium powder in the mixed powder is 70-85%; the organic carrier mainly comprises 80-90% of tributyl citrate, 2-5% of cellulose nitrate and 5-15% of lecithin by mass;

the mixing of the glass powder and the silver-palladium powder is carried out in a planetary gravity mixer, the revolution speed of the planetary gravity mixer is 1000-1300 rpm, the rotation speed is 40-60% of the revolution speed, and the mixing time is 50-85 min;

the mixing process of the mixed powder and the organic carrier is carried out in a three-roller grinding machine, the rotating speed of the three-roller grinding machine is 300-450 r/min, and the grinding and mixing time is 2-4 h.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the thermal barrier/infrared low-emissivity integrated coating, aiming at the urgent application requirements of thermal shock resistance life improvement and external field in-situ detection of the high-temperature infrared stealth coating, a rare earth fluorescent sub-layer technology, a thermal barrier ceramic layer technology and a high-temperature infrared low-emissivity coating technology are combined, a rare earth fluorescent sub-layer is added into a ceramic layer, damage indication of the infrared low-emissivity layer is achieved, and meanwhile the low infrared emissivity characteristic of the high-temperature low-emissivity coating and the excellent heat insulation characteristic of the ceramic layer are utilized, so that the coating has heat insulation performance and high-temperature infrared stealth performance.

2. The invention relates to a thermal barrier/infrared low emissivity integrated coating, and uses thereofThe rare earth fluorescent ions can emit fluorescence under the irradiation of ultraviolet light, and the doping of a small amount of rare earth fluorescent ions can not change the characteristic of the coating material, so that the coating material has the characteristics of LaMgAl₁₁O_l9The material is doped with a proper amount of rare earth fluorescent ions to obtain a rare earth fluorescent sub-layer, and the rapid nondestructive detection of the damage condition of the infrared low-emissivity coating is realized by utilizing the light-emitting characteristic of the rare earth fluorescent sub-layer.

3. The thermal barrier/infrared low-emissivity integrated coating utilizes LaMgAl₁₁O_l9The material has the advantages of low thermal conductivity, good thermal stability, long thermal cycle life and the like, and the thermal cycle life of the prepared double-layer ceramic structure is longer than that of a single coating by compounding the material with a YSZ thermal barrier coating, so that the comprehensive service life of the coating is effectively prolonged.

4. The thermal barrier/infrared low-emissivity integrated coating can regulate and control the thickness, the type and the doping amount of doped rare earth fluorescent ions according to different practical application requirements to realize the performance regulation of the coating.

5. The preparation method of the thermal barrier/infrared low-emissivity integrated coating has the advantages of simple process, maturity and stability, uniform coating thickness on the surface of a complex and special-shaped curved surface member, low cost and easy large-scale production and application.

Drawings

FIG. 1 is a schematic structural view of a thermal barrier/infrared low emissivity integral coating based on a fluorescent sublayer of the present invention.

FIG. 2 shows LaMgAl prepared in example 1 of the present invention₁₁O_l9:Eu³⁺Powder photograph.

FIG. 3 is a photo of a thermal barrier/IR low emissivity integral coating flat sheet sample prepared in example 1 of the present invention.

FIG. 4 is an effect diagram of a photo of a thermal barrier/infrared low emissivity integrated coating flat panel sample prepared in example 1 of the present invention under 254nm ultraviolet light.

Description of the main reference numerals:

1-substrate, 2-metal bonding layer, 3-ceramic inner layer, 4-rare earth fluorescent sublayer and 5-infrared low emissivity layer.

Detailed Description

The following detailed description of specific embodiments of the invention is provided, but it should be understood that the scope of the invention is not limited to the specific embodiments.

Example 1

A thermal barrier/infrared low-emissivity integrated coating based on a fluorescent sublayer is shown in figure 1 and is of a multilayer structure, and comprises a CoNiCrAlY metal bonding layer, an 8YSZ ceramic inner layer and a LaMgAl layer from inside to outside in sequence from a substrate₁₁O_l9:Eu³⁺A fluorescent sublayer and an infrared low emissivity layer. Wherein, LaMgAl₁₁O_l9:Eu³⁺Eu in fluorescent sublayer³⁺The doping amount of (A) is 1.0 mol%; the infrared low-emissivity layer is formed by AgPd conductive phase and Bi₂O₃-TiO₂-Al₂O₃-SiO₂-Li₂O-CaO-MgO-B₂O₃The glass bonding phase, and the AgPd conductive phase accounts for 85% of the total mass of the infrared low-emissivity layer. The thickness of the CoNiCrAlY metal bonding layer is 0.05mm, the thickness of the 8YSZ ceramic inner layer is 0.2mm, and the thickness of the LaMgAl ceramic inner layer is₁₁O_l9:Eu³⁺The thickness of the fluorescent sub-layer is 0.2mm, the thickness of the infrared low-emissivity layer is 0.02mm, and the total thickness of the coating is 0.47 mm.

The preparation method of the thermal barrier/infrared low-emissivity integrated coating comprises the following steps:

(1)LaMgAl₁₁O_l9:Eu³⁺preparation of the material:

mixing raw materials: weighing lanthanum oxide, magnesium oxide and aluminum oxide powder according to a stoichiometric ratio (the molar ratio is 1:2:11), adding europium oxide powder (the doping amount of europium ions is 1.0 mol%), performing ball milling and mixing on the powder, and then drying and grinding to obtain mixed powder;

② high-temperature solid-phase synthesis of powder: placing the ground mixed powder into a muffle furnace, calcining at 1600 ℃ for 24h, and grinding the high-temperature calcined product to obtain LaMgAl₁₁O_l9:Eu³⁺Powder, as shown in fig. 2;

③ LaMgAl for spraying₁₁O_l9:Eu³⁺Preparation of the material: the LaMgAl obtained in the step II₁₁O_l9:Eu³⁺Uniformly mixing the powder with deionized water, Arabic gum powder and triammonium citrate by a ball milling process, wherein the mass fraction of the deionized water is 49.3%, the mass fraction of the Arabic gum powder is 1%, the mass fraction of the triammonium citrate is 0.6%, and the balance is LaMgAl₁₁O_l9:Eu³⁺Powder is prepared into spheroidal agglomerated powder particles by adopting a spray drying process, and the spheroidal agglomerated powder particles are sieved to obtain LaMgAl with certain fluidity₁₁O_l9:Eu³⁺A material; the spray drying process parameters are as follows: the outlet temperature is 120 ℃, the inlet temperature is 250 ℃, the slurry feeding speed is 1.5L/min, and the rotating speed of an atomizing disc is 18000 r/min; screening the powder after spray drying by adopting an automatic vibrating screen, wherein the mesh number of the vibrating screen is 80 meshes and 300 meshes;

(2) carrying out roughening treatment on the surface of the metal substrate in a box type sand blasting machine by adopting a sand blasting roughening process; the coarsening treatment process parameters are as follows: the pressure is 0.3MPa, the sand blasting distance is 80mm, the sand grain diameter is 100 mu m, and the sand blasting time is 2 min;

(3) and (3) spraying a CoNiCrAlY metal bonding layer on the surface of the metal substrate obtained in the step (2) by adopting an atmospheric plasma spraying process, wherein the atmospheric plasma spraying process parameters are as follows: the argon flow is 35L/min, and the hydrogen flow is 6L/min; the current is controlled to be 480A, and the power is 32 kW; the flow of the powder feeding argon gas is 1.5L/min, and the powder feeding amount is 28 g/min; the spraying distance is 100 mm;

(4) and (3) taking 8YSZ spraying powder as a spraying material, and preparing an 8YSZ ceramic inner layer on the surface of the CoNiCrAlY metal bonding layer obtained in the step (3) by adopting an atmospheric plasma spraying process, wherein the process parameters of the atmospheric plasma spraying process are as follows: the argon flow is 40L/min, and the hydrogen flow is 9L/min; the current is controlled to be 550A, and the power is 34 kW; the flow of the powder feeding argon gas is 2.5L/min, and the powder feeding amount is 20 g/min; the spraying distance is 120 mm;

(5) the LaMgAl obtained in the step (1)₁₁O_l9:Eu³⁺The material is a spraying material, and the LaMgAl is prepared on the surface of the inner layer of the 8YSZ ceramic obtained in the step (4) by adopting an atmospheric plasma spraying process₁₁O_l9:Eu³⁺A fluorescent sublayer; the technological parameters of the atmospheric plasma spraying process are as follows: the argon flow is 40L/min, and the hydrogen flow is 9L/min; the current is controlled to be 550A, and the power is 34 kW; the flow of the powder feeding argon gas is 2.5L/min, and the powder feeding amount is 20 g/min; the spraying distance is 120 mm;

(6) the LaMgAl obtained in the step (5) by using the infrared low-emissivity coating as a raw material through an air spraying-heat treatment process₁₁O_l9:Eu³⁺Preparing an infrared low-emissivity layer on the surface of the fluorescent sublayer, wherein the heat treatment process parameters are as follows: the peak value sintering temperature is 400 ℃, the temperature rising speed is 20 ℃/min, the sintering time is 20min, the sintering atmosphere is air, and the preparation of the thermal barrier/infrared low-emissivity integrated coating based on the fluorescent sub-layer is completed.

The infrared low-emissivity coating is prepared by the following method: uniformly mixing glass raw material powder, smelting at 1500 ℃ for 3h to obtain a glass melt, and then pouring the obtained glass melt into deionized water for quenching to obtain glass slag; ball-milling glass slag into glass powder, mixing the glass powder and silver palladium powder into mixed powder in a planetary gravity mixer, wherein the revolution speed of the planetary gravity mixer is 1250rpm, the rotation speed is 45 percent of the revolution speed, and the mixing time is 80 min; and grinding and mixing the mixed powder and the organic carrier in a three-roll grinder, wherein the rotating speed of the three-roll grinder is 380r/min, and the grinding and mixing time is 3h, so as to obtain the infrared low-emissivity coating. The viscosity of the infrared low emissivity coating is 180 pas. In the infrared low-emissivity coating, the mass fraction of the mixed powder is 78%, the mass fraction of the organic carrier is 22%, and the mass fraction of the silver-palladium powder in the mixed powder is 85%; the organic vehicle consisted essentially of 84% by mass of tributyl citrate, 3% of nitrocellulose and 13% lecithin. The glass raw material powder comprises the following components in percentage by mass: bi₂O₃52％，TiO₂6％，Al₂O₃ 4％，SiO₂23％，Li₂O 4％，CaO4％，MgO3％，B₂O₃ 4％。

Fig. 3 is a thermal barrier/infrared low-emissivity integrated coating flat plate sample prepared by the embodiment, wherein the middle blank part is a defect part of a manufactured infrared low-emissivity layer, and the thickness of the coating is 0.47 mm. FIG. 4 is an effect diagram of a thermal barrier/infrared low-emissivity integrated coating flat plate sample under 254nm ultraviolet light, the coating flat plate sample under the irradiation of the 254nm ultraviolet light, the damaged part of the infrared low-emissivity layer emits obvious orange-red fluorescence, and no fluorescence is generated at the other parts, so that the damage indication of the infrared low-emissivity layer is realized. The thermal barrier/infrared low-emissivity integrated coating has the infrared radiation temperature of 602 ℃ and the emissivity of 0.31 at 900 ℃. The thermal cycle life of the thermal barrier/infrared low-emissivity integrated coating of the embodiment is 1500 times at 970 ℃. The thermal cycle life test of the coating adopts a controllable thermal barrier coating automatic thermal cycler self-made by the subject group to carry out determination, and the specific steps are as follows: the surface of the coating is heated by adopting gas-oxygen flame, the cooling gas at the back is compressed air, the surface of the coating can quickly reach the highest temperature required to be reached within 20s in the thermal cycle process, the heating time of the coating is 5min, after 5min, the flame spray gun is automatically moved away, the coating is cooled to the room temperature by the cooling gas at the back, and the cooling time is 2 min. One thermal cycle includes one heating and one cooling process, which is repeated until the coating fails.

Comparative example 1

The thermal barrier/infrared low-emissivity integrated coating provided by the comparative example sequentially comprises a CoNiCrAlY metal bonding layer, an 8YSZ ceramic layer and an infrared low-emissivity layer from inside to outside. The infrared low-emissivity layer is formed by AgPd conductive phase and Bi₂O₃-TiO₂-Al₂O₃-SiO₂-Li₂O-CaO-MgO-B₂O₃The glass bonding phase, and the AgPd conductive phase accounts for 85% of the total mass of the infrared low-emissivity layer. The thickness of the CoNiCrAlY metal bonding layer is 0.05mm, the thickness of the 8YSZ ceramic layer is 0.4mm, the thickness of the infrared low-emissivity layer is 0.02mm, and the total thickness of the coating is 0.47 mm. The preparation process of each layer of the thermal barrier/infrared low-emissivity integrated coating of the comparative example is the same as that of the coating corresponding to the example 1.

According to the thermal barrier/infrared low-emissivity integrated coating sample prepared by the comparative example, under the irradiation of 254nm ultraviolet light, no fluorescence is generated at the defect part (artificial damage) of the infrared low-emissivity layer, and no damage indication of the infrared low-emissivity layer exists. The thermal cycle life of the thermal barrier/infrared low-emissivity integrated coating prepared by the comparative example is 1000 times at 970 ℃.

Comparative example 2

The thermal barrier/infrared low-emissivity integrated coating provided by the comparative example sequentially comprises a CoNiCrAlY metal bonding layer and a LaMgAl metal bonding layer from inside to outside from a substrate₁₁O_l9:Eu³⁺A fluorescent sublayer and an infrared low emissivity layer. The infrared low-emissivity layer is formed by AgPd conductive phase and Bi₂O₃-TiO₂-Al₂O₃-SiO₂-Li₂O-CaO-MgO-B₂O₃The glass bonding phase, and the AgPd conductive phase accounts for 85% of the total mass of the infrared low-emissivity layer. The thickness of the CoNiCrAlY metal bonding layer is 0.05mm, and the thickness of the LaMgAl metal bonding layer is₁₁O_l9:Eu³⁺The thickness of the fluorescent sub-layer is 0.4mm, the thickness of the infrared low-emissivity layer is 0.02mm, and the total thickness of the coating is 0.47 mm. The preparation process of each layer of the thermal barrier/infrared low-emissivity integrated coating of the comparative example is the same as that of the coating corresponding to the example 1.

According to the thermal barrier/infrared low-emissivity integrated coating sample prepared by the comparative example, under the irradiation of 254nm ultraviolet light, fluorescence is generated at the defect part (artificial damage) of the infrared low-emissivity layer, and fluorescence is generated at the other parts, so that the damage indication of the infrared low-emissivity layer can be realized. The thermal cycle life of the thermal barrier/infrared low-emissivity integrated coating prepared by the comparative example is 850 times at 970 ℃.

Example 2

A thermal barrier/infrared low-emissivity integrated coating based on a fluorescent sublayer is of a multilayer structure and sequentially comprises a NiCrAlY metal bonding layer, an 8YSZ ceramic inner layer and a LaMgAl layer from inside to outside from a substrate₁₁O_l9:Tb³⁺A fluorescent sublayer and an infrared low emissivity layer. Wherein, LaMgAl₁₁O_l9:Tb³⁺Tb in the fluorescent sublayer³⁺The doping amount of (A) is 1.5 mol%; the infrared low-emissivity layer is formed by AgPd conductive phase and Bi₂O₃-TiO₂-Al₂O₃-SiO₂-Li₂O-CaO-MgO-B₂O₃The glass bonding phase, and the AgPd conductive phase accounts for 83 percent of the total mass of the infrared low-emissivity layer. The thickness of the NiCrAlY metal bonding layer is 0.05mm, the thickness of the 8YSZ ceramic inner layer is 0.15mm, and the thickness of the LaMgAl ceramic inner layer is₁₁O_l9:Tb³⁺The thickness of the fluorescent sub-layer is 0.2mm, the thickness of the infrared low-emissivity layer is 0.02mm, and the total thickness of the coating is 0.42 mm.

The preparation method of the thermal barrier/infrared low-emissivity integrated coating comprises the following steps:

(1)LaMgAl₁₁O_l9:Tb³⁺preparation of the material:

mixing raw materials: weighing lanthanum oxide, magnesium oxide and aluminum oxide powder according to a stoichiometric ratio (the molar ratio is 1:2:11), adding terbium oxide powder (the doping amount of terbium ions is 1.5 mol%), performing ball milling and mixing on the powder, and then drying and grinding to obtain mixed powder;

② high-temperature solid-phase synthesis of powder: placing the ground mixed powder into a muffle furnace, calcining at 1600 ℃ for 24h, and grinding the high-temperature calcined product to obtain LaMgAl₁₁O_l9:Tb³⁺Powder;

③ LaMgAl for spraying₁₁O_l9:Tb³⁺Preparation of the material: the LaMgAl obtained in the step II₁₁O_l9:Tb³⁺Uniformly mixing the powder with deionized water, Arabic gum powder and triammonium citrate by a ball milling process, wherein the mass fraction of the deionized water is 55%, the mass fraction of the Arabic gum powder is 2%, the mass fraction of the triammonium citrate is 1.5%, and the balance is LaMgAl₁₁O_l9:Tb³⁺Powder is prepared into spheroidal agglomerated powder particles by adopting a spray drying process, and the spheroidal agglomerated powder particles are sieved to obtain LaMgAl with certain fluidity₁₁O_l9:Tb³⁺A material; the spray drying process parameters are as follows: the outlet temperature is 120 ℃, the inlet temperature is 250 ℃, the slurry feeding speed is 1.5L/min, and the rotating speed of an atomizing disc is 18000 r/min; screening the powder after spray drying by adopting an automatic vibrating screen, wherein the mesh number of the vibrating screen is 80 meshes and 300 meshes;

(2) carrying out roughening treatment on the surface of the metal substrate in a box type sand blasting machine by adopting a sand blasting roughening process; the coarsening treatment process parameters are as follows: the pressure is 0.2MPa, the sand blasting distance is 100mm, the sand grain diameter is 100 mu m, and the sand blasting time is 2 min;

(3) and (3) spraying a NiCrAlY metal bonding layer on the surface of the metal substrate obtained in the step (2) by adopting an atmospheric plasma spraying process, wherein the atmospheric plasma spraying process parameters are as follows: the argon flow is 30L/min, and the hydrogen flow is 6L/min; the current is controlled to be 480A, and the power is 30 kW; the flow of the powder feeding argon gas is 1.5L/min, and the powder feeding amount is 25 g/min; the spraying distance is 100 mm;

(4) and (3) taking 8YSZ spraying powder as a spraying material, and preparing an 8YSZ ceramic layer on the surface of the NiCrAlY metal bonding layer obtained in the step (3) by adopting an atmospheric plasma spraying process, wherein the process parameters of the atmospheric plasma spraying process are as follows: the argon flow is 35L/min, and the hydrogen flow is 8L/min; the current is controlled to be 550A, and the power is 35 kW; the flow of the powder feeding argon gas is 2.5L/min, and the powder feeding amount is 20 g/min; the spraying distance is 120 mm;

(5) the LaMgAl obtained in the step (1)₁₁O_l9:Tb³⁺The material is a spraying material, and an atmospheric plasma spraying process is adopted to prepare LaMgAl on the surface of the 8YSZ ceramic layer obtained in the step (4)₁₁O_l9:Tb³⁺A fluorescent sublayer; the technological parameters of the atmospheric plasma spraying process are as follows: the argon flow is 35L/min, and the hydrogen flow is 8L/min; the current is controlled to be 550A, and the power is 35 kW; the flow of the powder feeding argon gas is 2.5L/min, and the powder feeding amount is 20 g/min; the spraying distance is 120 mm;

(6) the LaMgAl obtained in the step (5) by using the infrared low-emissivity coating as a raw material through an air spraying-heat treatment process₁₁O_l9:Tb³⁺Preparing an infrared low-emissivity layer on the surface of the fluorescent sublayer, wherein the heat treatment process parameters are as follows: the peak value sintering temperature is 380 ℃, the temperature rising speed is 20 ℃/min, the sintering time is 25min, the sintering atmosphere is air, and the preparation of the thermal barrier/infrared low-emissivity integrated coating is completed.

The infrared low-emissivity coating is prepared by the following method: uniformly mixing glass raw material powder, and smelting at 1500 ℃ for 3h to obtain the glass ceramicPouring the obtained glass melt into deionized water for quenching to obtain glass slag; ball-milling glass slag into glass powder, mixing the glass powder and silver palladium powder into mixed powder in a planetary gravity mixer, wherein the revolution speed of the planetary gravity mixer is 1300rpm, the rotation speed is 45 percent of the revolution speed, and the mixing time is 75 min; and grinding and mixing the mixed powder and the organic carrier in a three-roll grinder, wherein the rotating speed of the three-roll grinder is 350r/min, and the grinding and mixing time is 3h, so as to obtain the infrared low-emissivity coating. The viscosity of the infrared low emissivity coating is 190 pas. In the infrared low-emissivity coating, the mass fraction of the mixed powder is 75%, the mass fraction of the organic carrier is 25%, and the mass fraction of the silver-palladium powder in the mixed powder is 80%; the organic vehicle consisted essentially of 84% by mass of tributyl citrate, 3% of nitrocellulose and 13% lecithin. The glass raw material powder comprises the following components in percentage by mass: bi₂O₃55％，TiO₂5％，Al₂O₃3％，SiO₂22％，Li₂O 4％，CaO3％，MgO3％，B₂O₃5％。

In the thermal barrier/infrared low-emissivity integrated coating flat plate sample prepared by the embodiment, the thickness of the coating is 0.42 mm. The damaged part of the infrared layer of the flat plate sample emits obvious green fluorescence under the irradiation of 254nm ultraviolet light, and no fluorescence is generated at the other parts, so that the damage indication of the infrared low-emissivity layer is realized.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.