A phosphorescent temperature measurement coating and a method of making the same

Abstract

The application provides a phosphorescent temperature measurement coating and a preparation method thereof, and belongs to the field of phosphorescent temperature measurement. The application provides a preparation method of a phosphorescent temperature measurement coating. The mixture of an adhesive containing ceramic, graphite and water and phosphorescent temperature measurement powder is coated on the surface of a metal substrate, and then solidified to obtain the phosphorescent temperature measurement coating. The preparation method of the application utilizes the adhesive to adhere the phosphorescent temperature measurement powder to the surface of the metal substrate, and the preparation of the phosphorescent temperature measurement coating can be realized without granulation, and the obtained coating has less influence on the original powder luminous intensity.

Description

Technical Field

[0001] This invention relates to the field of phosphorescent thermometry, and more specifically to a phosphorescent thermometric coating and its preparation method. Background Technology

[0002] Turbine blades operate in the harshest environment of an engine, bearing the highest pressure and temperature loads. As the thrust of aero engines continues to increase, there are even higher requirements for the high-temperature resistance of turbine blades.

[0003] Thermal barrier coating (TBC) technology is an active thermal protection technique used to reduce heat exchange between turbine blades and the high-temperature external airflow. TBCs are typically prepared using low thermal conductivity, high-temperature resistant materials such as zirconium oxide and yttrium oxide. Due to their excellent high thermal resistance, they can isolate the turbine alloy blades from direct contact with the high-temperature combustion gas, thereby forming a large temperature gradient on the outer edge of the turbine blades. The temperature distribution on the turbine blade surface can predict the failure of the TBC and is also an important basis for turbine blade cooling design.

[0004] Phosphorescent thermography is an emerging temperature testing technology that forms a temperature-sensing layer by spraying phosphorescent powder onto the surface of turbine blades. When illuminated by an external light source, the layer emits phosphorescence, thus transmitting temperature information. Atmospheric plasma spraying (APS) is currently the most commonly used method for preparing this temperature-sensing layer. In the APS process, the phosphorescent powder needs to be granulated into a free-flowing granulated powder to be fed into the plasma flame. However, granulation significantly reduces the luminescence intensity, affecting the temperature measurement performance of the phosphorescent thermographic coating. Summary of the Invention

[0005] This invention provides a phosphorescent thermometric coating and its preparation method. The preparation method of this invention can achieve the preparation of phosphorescent thermometric coating without granulation, and the obtained coating has less impact on the luminescence intensity of the original powder.

[0006] This invention provides a method for preparing a phosphorescent thermometric coating, wherein a mixture of a binder containing ceramics, graphite and water and phosphorescent thermometric powder is coated onto the surface of a metal substrate and then cured to obtain the phosphorescent thermometric coating.

[0007] Preferably, the phosphorescent thermometric powder comprises yttrium oxide-stabilized zirconium oxide-doped dysprosium and / or yttrium aluminum garnet-doped dysprosium; the average particle size of the phosphorescent thermometric powder is 25–100 nm.

[0008] Preferably, the method for preparing the yttrium aluminum garnet-doped dysprosium includes the following steps:

[0009] A solution containing dysprosium nitrate, yttrium nitrate, and aluminum nitrate is mixed with a precipitant solution to carry out a precipitation reaction, thereby obtaining a precipitate;

[0010] The precipitate was dried and then calcined to obtain the yttrium aluminum garnet-doped dysprosium.

[0011] Preferably, the ceramic comprises alumina;

[0012] The adhesive containing ceramics, graphite, and water has a dynamic viscosity of 2500–80000 cP, a specific gravity of 1.8–2.15 g / cc, and an upper temperature resistance of 1650–1760 °C.

[0013] Preferably, the adhesive containing ceramic, graphite and water includes Aremco's 813-A, 670 or 671.

[0014] Preferably, the mass ratio of the binder containing ceramics, graphite, and water to the phosphorescent thermometric powder is 3 to 4:1.

[0015] Preferably, the coating includes air spraying.

[0016] Preferably, the nozzle diameter of the air spray gun is 1.0-1.5 mm, the spraying distance is 150-200 mm, the air pressure is 0.09-0.18 MPa, the air consumption is 40-60 L / min, the spray material output is 50-60 mL / min, and the spray width is 100-150 mm.

[0017] The air spray gun is the Anast Iwata W-71 Japanese Iwata spray gun.

[0018] Preferably, the curing is performed by LED lamp heating curing, and the light intensity of the LED lamp heating curing is 1200-1500 mW / cm². 2 The wavelength is 365–420 nm, the temperature is 150–200 °C, and the time is 0.5–2 h.

[0019] The present invention also provides a phosphorescent thermometric coating prepared by the preparation method described in the above technical solution.

[0020] The preparation method of the present invention uses an adhesive to adhere phosphorescent thermometric powder to the surface of a metal substrate, and can achieve the preparation of phosphorescent thermometric coating without granulation, and the resulting coating has less impact on the luminescence intensity of the original powder.

[0021] Furthermore, compared to the prior art, where the rotation angle of the spray gun used in atmospheric plasma spraying is limited, making it difficult to deposit a temperature-sensing layer on the surface of irregularly shaped parts, the spraying angle of the air spray gun in the air spraying of the present invention can be freely adjusted, thus enabling better spraying of phosphorescent temperature-sensing coatings on the surface of irregularly shaped parts.

[0022] The air spray gun selected in this invention has the characteristics of wide spray width, fine atomization, and high nozzle hardness. It is suitable for spraying high viscosity slurries, and the sprayed chemical adhesive coating has uniform thickness, smooth surface, and high coating bonding strength. Attached Figure Description

[0023] Figure 1 This is a process flow diagram for an example;

[0024] Figure 2 The temperature field diagram of the phosphorescent thermometric coating of Example 1 at 450°C is shown.

[0025] Figure 3 The temperature field diagram is the phosphorescent thermometric coating of Example 1 measured at 900°C. Detailed Implementation

[0026] This invention provides a method for preparing a phosphorescent thermometric coating, wherein a mixture of a binder containing ceramics, graphite and water and phosphorescent thermometric powder is coated onto the surface of a metal substrate and then cured to obtain the phosphorescent thermometric coating.

[0027] In this invention, the pre-coating process preferably includes: immersing the metal substrate in acetone for soaking and then ultrasonically cleaning it, followed by washing and drying the ultrasonically cleaned metal substrate.

[0028] In this invention, the soaking time is preferably 10-15 minutes; the ultrasonic cleaning frequency is preferably 40 kHz, and the time is preferably 5 minutes. Ultrasonic cleaning can thoroughly remove stubborn impurities.

[0029] In this invention, the detergent used for washing preferably includes distilled water; the number of washings is preferably two or more, and the washing time for each washing is preferably 2 minutes.

[0030] This invention does not impose any specific limitations on the drying method, as long as no water stains remain. In specific embodiments of this invention, the drying method may be wiping with a lint-free cloth or drying with an air gun.

[0031] In this invention, the preferred mass ratio of the adhesive to the phosphorescent thermometric powder is 3-4:1; the ceramic component in the adhesive preferably includes alumina; the preferred dynamic viscosity of the adhesive is 2500-80000 cP, the preferred specific gravity is 1.8-2.15 g / cc, and the preferred upper temperature resistance is 1650-1760℃. In specific embodiments of this invention, the dynamic viscosity can be 2500 cP, 5000 cP, 10000 cP, 20000 cP, 30000 cP, 40000 cP, 50000 cP, etc. The specific gravity is preferably 1.8–2.15 g / cc, and in specific embodiments of the present invention, the specific gravity can be 1.8, 1.9, 2, 2.1, or 2.15. The upper limit of temperature resistance is preferably 1650–1760℃, and in specific embodiments of the present invention, the upper limit of temperature resistance can be 1650℃, 1700℃, 1750℃, or 1760℃. The adhesive preferably includes Aremco's 813-A, 670, or 670, and more preferably 813-A. Aremco's 813-A adhesive has good optical transmission characteristics, strong adhesion, high upper limit of temperature resistance, and the coating is not easily deformed at high temperatures, which can well meet the requirements of phosphorescent thermometric coatings. The mass ratio of adhesive to phosphorescent powder affects the luminescence performance of the coating. When the mass ratio is too high, the luminescence intensity of the coating is weak and the viscosity of the slurry further increases, making it difficult for the air spray gun to spray the suspension. When the mass ratio is too low, the phosphorescent powder is difficult to suspend completely in the binder, resulting in a decrease in the temperature measurement performance of the coating.

[0032] In this invention, the phosphorescent thermometric powder preferably comprises yttrium oxide-stabilized zirconium oxide-doped dysprosium and / or yttrium aluminum garnet-doped dysprosium; the average particle size of the phosphorescent thermometric powder is preferably 25-100 nm. In specific embodiments of this invention, the average particle size of the phosphorescent thermometric powder can be 25 nm, 50 nm, 75 nm, or 100 nm; the chemical composition of the yttrium aluminum garnet-doped dysprosium preferably includes Y3Al5O. 12 Dy, with the preferred crystal structure being the YAG phase.

[0033] In this invention, the method for preparing yttrium aluminum garnet doped with dysprosium preferably includes the following steps:

[0034] A solution containing dysprosium nitrate, yttrium nitrate, and aluminum nitrate is mixed with a precipitant solution to carry out a precipitation reaction, thereby obtaining a precipitate;

[0035] The precipitate was dried and then calcined to obtain the yttrium aluminum garnet-doped dysprosium.

[0036] This invention involves mixing a solution containing dysprosium nitrate, yttrium nitrate, and aluminum nitrate with a precipitant solution to induce a precipitation reaction, thereby obtaining a precipitate.

[0037] In this invention, the mixing preferably includes adding a solution containing dysprosium nitrate, yttrium nitrate and aluminum nitrate together with a precipitant solution dropwise into the reaction vessel.

[0038] In this invention, the concentration of dysprosium nitrate in the solution containing dysprosium nitrate, yttrium nitrate and aluminum nitrate is preferably 0.0012 mol / L, the concentration of yttrium nitrate is preferably 0.3 mol / L, and the concentration of aluminum nitrate is preferably 0.5 mol / L.

[0039] In this invention, the volume ratio of the solution containing dysprosium nitrate, yttrium nitrate, and aluminum nitrate to the precipitant solution is preferably 1:2; the precipitant in the precipitant solution preferably includes ammonium bicarbonate and ammonium nitrate; and the molar ratio of ammonium bicarbonate to ammonium sulfate is preferably 10:1.

[0040] In this invention, the precipitation reaction time is preferably 24 hours.

[0041] After the precipitation reaction, the present invention preferably performs solid-liquid separation and washing on the obtained product to obtain the precipitate.

[0042] After obtaining the precipitate, the present invention preferably calcines the precipitate after drying to obtain the yttrium aluminum garnet-doped dysprosium.

[0043] In this invention, the drying temperature is preferably 80°C and the drying time is preferably 24 hours.

[0044] In this invention, the calcination temperature is preferably 1100℃ and the calcination time is preferably 2h.

[0045] After calcination, the present invention preferably further ball-mills the resulting product to obtain the phosphorescent thermometric powder.

[0046] In this invention, the coating preferably includes air spraying; during air spraying, the nozzle diameter of the air spray gun is preferably 1.0–1.5 mm, the spraying distance is preferably 150–200 mm, the air pressure is preferably 0.09–0.18 MPa, the air consumption is preferably 40–60 L / min, the abrasive output is preferably 50–60 mL / min, and the spray width is preferably 100–150 mm; in specific embodiments of this invention, the nozzle diameter can be 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm. The spraying distance can be 150mm, 160mm, 170mm, 180mm, 190mm or 200mm, the spraying air pressure can be 0.09Mpa, 0.12Mpa, 0.15Mpa or 0.18Mpa, the air consumption can be 40L / min, 50L / min or 60L / min, the aerosol output can be 50mL / min, 55mL / min or 60mL / min, and the spray width can be 100mm, 110mm, 120mm, 130mm, 140mm or 150mm.

[0047] In this invention, the air spray gun is preferably the Anast Iwata W-71 Japanese Iwata spray gun.

[0048] In this invention, the air spraying process preferably includes repeated air spraying, the number of repetitions is preferably 2 to 3 times, and the interval between two adjacent air sprayings is preferably 5 minutes.

[0049] In this invention, the curing is preferably performed by heating with an LED lamp, and the light intensity of the LED lamp for heating and curing is preferably 1200–1500 mW / cm². 2 In a specific embodiment of the present invention, the light intensity can be 1200 mW / cm². 2 1300mW / cm 2 1400mW / cm 2 Or 1500mW / cm 2 The preferred wavelength is 365–420 nm, the preferred temperature is 200℃, and the preferred time is 2 hours. Compared to box oven heating and curing, LED lamp heating and curing offers better controllability. Both curing temperature and curing time affect the curing effect of the adhesive coating. If the curing time is too short, the adhesive coating will lack adhesion and strength, leading to peeling or blistering and deformation at high temperatures.

[0050] The present invention also provides a phosphorescent thermometric coating prepared by the preparation method described in the above technical solution.

[0051] Figure 1The process flow diagram for the embodiment is as follows: After mixing the adhesive and phosphorescent powder at a mass ratio of 3:1, the mixture is sprayed with air onto the surface to be tested after cleaning with acetone to form a phosphorescent coating. After curing (heating to 200°C for 200 min), a hard phosphorescent coating is obtained.

[0052] The following detailed description of the phosphorescent thermometric coating and its preparation method provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0053] The adhesive used in the examples is Aremco's 813-A, which has a dynamic viscosity of 40,000 cP, a specific gravity of 2 g / cc, and an upper limit of temperature resistance of 1650°C.

[0054] Aremco's 670 has a dynamic viscosity of 2500 cP, a specific gravity of 1.80, and a maximum temperature of 1650°C.

[0055] Aremco's 671 has a dynamic viscosity of 40,000 cP, a specific gravity of 2.05, and a maximum temperature of 1760°C.

[0056] The preparation method of the phosphorescent thermometric powder in the example is as follows:

[0057] Dysprosium nitrate, yttrium nitrate, and aluminum nitrate were mixed with deionized water to prepare a metal ion solution (0.0012 mol / L for dysprosium nitrate, 0.3 mol / L for yttrium nitrate, and 0.5 mol / L for aluminum nitrate). Ammonium bicarbonate and ammonium sulfate were mixed at a molar ratio of 10:1 to prepare a 2.5 mol / L precipitant solution. Both solutions (800 mL of metal ion solution and 1600 mL of precipitant solution) were added dropwise to a third beaker to form a suspension. The suspension was allowed to stand for 24 hours to allow the solid components to separate. The separated solid components were washed with deionized water and ethanol and dried in a drying oven at 80°C for 24 hours to form a precursor. The precursor was calcined in a box furnace at 1100°C for 2 hours, and then ball-milled at 450 r / min for 6 hours to obtain yttrium aluminum garnet-doped dysprosium phosphorescent thermometric powder.

[0058] Example 1

[0059] Step 1: Immerse the metal substrate (sheet-shaped, high-temperature alloy GH4037) in acetone solution for 10–15 minutes. Use an ultrasonic cleaner set to 40 kHz for 5 minutes to thoroughly remove stubborn impurities. After cleaning, rinse the metal substrate at least twice with high-purity distilled water, 2 minutes each time. Dry the metal substrate with a lint-free cloth or air gun, ensuring no water residue remains.

[0060] Step 2: Take adhesive 813-A and yttrium aluminum garnet-doped dysprosium phosphorescent thermometric powder in a weight ratio of 3:1. Add the phosphorescent thermometric powder to the adhesive while stirring with a mechanical stirrer at a speed of 500 rpm for 15 minutes to ensure thorough mixing and obtain a suspension.

[0061] Step 3: Pour the suspension into the feed tank of the air spray gun (Anest Iwata W-71 Japanese air spray gun). The nozzle diameter of the air spray gun is 1.0mm, the spraying distance is 200mm, the spraying air pressure is 0.09Mpa, the air consumption is 50L / min, the spray volume is 55mL / min, and the spray width is 100mm. Move the spray gun evenly and quickly at a speed of 0.1m / s to ensure a uniform coating. Repeat the spraying 3 times, with a 5-minute interval between each coat to allow for slight drying.

[0062] Step 4: Place the sprayed metal substrate under a curing lamp for LED heat curing. The light intensity of the LED lamp for heat curing is 1200mW / cm². 2 The wavelength is 365–420 nm, the temperature is 150°C, and the curing time is 30 minutes to ensure complete curing of the coating. After curing, allow it to cool naturally to room temperature to avoid rapid cooling that could cause the coating to crack.

[0063] Example 2

[0064] Step 1: Immerse the metal substrate (sheet-shaped, high-temperature alloy GH4037) in acetone solution for 10–15 minutes. Use an ultrasonic cleaner set to 40 kHz for 5 minutes to thoroughly remove stubborn impurities. After cleaning, rinse the metal substrate at least twice with high-purity distilled water, 2 minutes each time. Dry the metal substrate with a lint-free cloth or air gun, ensuring no water residue remains.

[0065] Step 2: Take adhesive 813-A and yttrium oxide-stabilized zirconia-doped dysprosium phosphorescent thermometric powder (composition: yttrium oxide (8 at%): zirconia (92 at%), doped with Dy ions (1 at%), chemical formula YSZ:Dy (1%)) in a 3:1 weight ratio. Add the phosphorescent thermometric powder to the adhesive while stirring with a mechanical stirrer at 500 rpm for 15 minutes to ensure thorough mixing and obtain a suspension.

[0066] Step 3: Pour the suspension into the feed tank of the air spray gun (Anest Iwata W-71 Japanese air spray gun). The nozzle diameter of the air spray gun is 1.0mm, the spraying distance is 200mm, the spraying air pressure is 0.09Mpa, the air consumption is 50L / min, the spray volume is 55mL / min, and the spray width is 100mm. Move the spray gun evenly and quickly at a speed of 0.1m / s to ensure a uniform coating. Repeat the spraying 3 times, with a 5-minute interval between each coat to allow for slight drying.

[0067] Step 4: Place the sprayed metal substrate under a curing lamp for LED heat curing. The light intensity of the LED lamp for heat curing is 1200mW / cm². 2 The wavelength is 365–420 nm, the temperature is 150°C, and the curing time is 30 minutes to ensure complete curing of the coating. After curing, allow it to cool naturally to room temperature to avoid rapid cooling that could cause the coating to crack.

[0068] Performance testing:

[0069] The phosphorescent thermometric coating of Example 1 was excited using 355nm excitation light at a frequency of 10Hz. The phosphorescence intensity at 448nm and 494nm was collected and compared. The relationship between the ratio and temperature was fitted, and the entire temperature field was obtained based on this. The data are as follows: Figures 2-3 As shown. Among them, Figure 2 This is a temperature field diagram measured at 450℃ for a phosphorescent thermometric coating. Figure 3 This is a temperature field diagram of the phosphorescent thermometric coating measured at 900℃.

[0070] Depend on Figures 2-3 It can be seen that the coating temperature distribution is uniform at low temperatures, indicating good temperature measurement performance. At high temperatures, the temperature distribution shows a greater difference between high and low temperatures, indicating a significant difference in light intensity between the two different wavelengths, which may be due to an inappropriate selection of the temperature measurement band. Meanwhile, the coating can still emit light signals at high temperatures, proving the feasibility of chemical adhesive phosphorescent thermometric coatings at high temperatures.

[0071] Example 3

[0072] The only difference from Example 1 is that the adhesive used is Aremco 670.

[0073] Example 4

[0074] The only difference from Example 1 is that the adhesive used is Aremco 671.

[0075] The three coatings prepared in Examples 1, 3, and 4 were heated from room temperature to 1100 degrees Celsius. The 670 and 671 chemical adhesives peeled off when the temperature reached approximately 1000 degrees Celsius, while the 813-A chemical adhesive did not peel off during the test.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a phosphorescent thermometric coating, characterized in that, Includes the following steps: The mixture of adhesive and phosphorescent thermometric powder is coated onto the surface of a metal substrate and then cured to obtain the phosphorescent thermometric coating. The adhesives include Aremco's 813-A, 670, or 671. The coating includes air spraying.

2. The preparation method according to claim 1, characterized in that, The phosphorescent thermometric powder comprises yttrium oxide-stabilized zirconium oxide-doped dysprosium and / or yttrium aluminum garnet-doped dysprosium; the average particle size of the phosphorescent thermometric powder is 25~100 nm.

3. The preparation method according to claim 2, characterized in that, The method for preparing the yttrium aluminum garnet-doped dysprosium includes the following steps: A solution containing dysprosium nitrate, yttrium nitrate, and aluminum nitrate is mixed with a precipitant solution to carry out a precipitation reaction, thereby obtaining a precipitate; The precipitate was dried and then calcined to obtain the yttrium aluminum garnet-doped dysprosium.

4. The preparation method according to claim 1, characterized in that, The mass ratio of the adhesive to the phosphorescent thermometric powder is 3~4:

1.

5. The preparation method according to claim 1, characterized in that, The nozzle diameter of the air spray gun used for air spraying is 1.0~1.5mm, the spraying distance is 150~200mm, the air pressure is 0.09~0.18Mpa, the air consumption is 40~60L / min, the material output is 50~60mL / min, and the spray width is 100~150mm. The air spray gun is the Anast Iwata W-71 Japanese Iwata spray gun.

6. The preparation method according to claim 1, characterized in that, The curing process is LED lamp heating curing, and the light intensity of the LED lamp heating curing is 1200~1500mW / cm². 2 The wavelength is 365~420nm, the temperature is 150~200℃, and the time is 0.5~2h.

7. The phosphorescent thermometric coating prepared by the preparation method according to any one of claims 1 to 6.

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