Cmas powder for thermal barrier coating multi-factor coupling environment simulation test equipment and preparation method thereof

Abstract

The application provides a CMAS powder for a thermal barrier coating multi-factor coupling environment simulation test device and a preparation method thereof, and belongs to the technical field of thermal barrier coatings.The application obtains an oxide melt by sequentially performing ball milling, pre-calcination, high-temperature melting and quenching on raw material powder, and further sequentially performs high-energy ball milling, spray granulation and high-temperature densification heat treatment on the oxide melt, so that the CMAS powder for the thermal barrier coating multi-factor coupling environment simulation test device is obtained.The CMAS powder obtained by the application has the advantages of low cost and stable and controllable quality, and the preparation method is simple and suitable for batch production.

Description

Technical Field

[0001] This invention relates to the field of thermal barrier coating technology, and in particular to a CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings and its preparation method. Background Technology

[0002] With the formulation of my country's strategic goals of building a manufacturing powerhouse and modernizing national defense, developing industries such as aerospace, aviation, nuclear energy, shipbuilding, and machinery has become an important foundation for enhancing national defense capabilities and developing high-tech industries. Aero engines and gas turbines (collectively referred to as "the two engines") use fossil fuels as energy sources, converting chemical energy into mechanical energy to power aircraft. They are the heart and power source of various aircraft, rockets, and industrial equipment, and are hailed as the "pearl in the crown of modern industry" and the "flower of industry," embodying a nation's industrial technological level. Thermal barrier coatings (TBCs) technology is a key technology for high-temperature protection of hot-end components in modern aero engines and gas turbines. It possesses protective properties such as corrosion resistance, high-temperature resistance, and erosion resistance, and has been widely applied to high-temperature components such as turbine rotor blades, guide vanes, combustion chambers, and nozzles, directly determining the thermal efficiency, service life, and reliability of aero engines and gas turbines. Currently, atmospheric plasma spraying (APS), electron beam physical vapor deposition (EB-PVD), and plasma spray-physical vapor deposition (PS-PVD) are the mainstream technologies for preparing thermal barrier coatings. The thermal barrier coating system represented by the 7-8wt% YSZ / MCrAlY bilayer thermal barrier coating prepared by EB-PVD is considered to have the best comprehensive performance and is widely used in the thermal protection of turbine blades of various types of in-service aero-engines. However, with the booming development of the aviation industry and the demands of military operations, aircraft frequently need to fly over volcanic zones and desert regions. Large amounts of dust, volcanic ash, and various environmental pollutants in the air are inevitably drawn into the engine under high-speed airflow. Under high temperatures, mixed oxide melts (CMAS), primarily composed of CaO, MgO, Al2O3, and SiO2, adhere to the surface of the thermal barrier coating. These melt and penetrate into the ceramic top layer, inducing thermo-mechanical-chemical coupled damage effects such as corrosion, phase transformation, and stress. This has become one of the key factors restricting the service reliability of thermal barrier coatings for engine turbine blades. Furthermore, due to differences in geographical location and formation conditions, the chemical composition of CMAS varies significantly, exhibiting different high-temperature melting properties, fluidity, activity, and wetting and spreading characteristics. This makes the corrosion damage mechanism and corrosion resistance evaluation extremely complex. Conducting CMAS corrosion testing and evaluation research has become a research hotspot and challenge in the field of thermal barrier coatings.

[0003] The multi-factor coupled environment simulation test equipment for thermal barrier coatings (CMAS) produced by MK TECHNOLOGY in Germany is my country's first equipment to truly simulate engine operating conditions for evaluating the multi-factor coupled performance of CMAS coatings. It can comprehensively assess the corrosion performance of CMAS coatings under simulated engine operating conditions. During the experimental evaluation, CMAS powder is supplied to the combustion chamber of the equipment via a particle injection system using pneumatic transmission. The CMAS powder is required to possess excellent pneumatic transmission flowability and high collapse strength, and to have similar chemical composition, high-temperature melting properties, and melt activity to those under actual engine operating conditions. Therefore, this invention addresses the technical shortcomings of existing CMAS powders, such as poor pneumatic transmission flowability, poor high-temperature melting properties, and low melt activity, which prevent them from meeting the requirements of multi-factor coupled environment simulation test equipment. This invention proposes a low-cost, high-quality, and mass-producible CMAS ceramic powder for multi-factor coupled environment simulation test equipment for CMAS coatings, along with its preparation method, which is currently the technical problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a CMAS powder for a multi-factor coupled environment simulation test equipment for thermal barrier coatings and its preparation method, so as to solve the technical problems of existing CMAS powders, such as poor pneumatic transport flowability, poor high-temperature melting and low melt activity, which lead to the inability to meet the requirements of multi-factor coupled environment simulation test equipment.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings, which is prepared from raw material powder containing the following mass percentages:

[0007] CaO 15~40%, MgO 5~15%, Al2O310~20%, SiO236~55%, Fe2O3≤15%;

[0008] The particle size of the raw material powder is 200-300 mesh.

[0009] This invention provides a method for preparing CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings, comprising the following steps:

[0010] 1) The raw material powders are mixed and then sequentially ball-milled and pre-calcined to obtain a mixed oxide;

[0011] 2) The mixed oxides are sequentially melted and quenched at high temperatures to obtain oxide frit;

[0012] 3) The oxide frit is ball-milled at high energy and then spray-granulated to obtain CMAS granulated powder;

[0013] 4) The CMAS granulated powder is subjected to high-temperature densification heat treatment to obtain the CMAS powder for the multi-factor coupled environment simulation test equipment of thermal barrier coating.

[0014] Furthermore, in step 1), the grinding medium used in the ball mill is alumina ceramic balls, the ball-to-material ratio is 4-8:1, the ball mill speed is 100-300 r / min, and the ball milling time is 4-8 h.

[0015] Furthermore, the pre-calcination temperature is 900–1200°C, and the pre-calcination time is 2–6 hours.

[0016] Furthermore, in step 2), the high-temperature melting temperature is 1400–1650°C, the heating rate is 2–5°C / min, and the holding time is 1–3h.

[0017] Furthermore, in step 3), water is used as the dispersion medium and polyethylene glycol is used as the dispersant during the high-energy ball milling process;

[0018] The mass ratio of the oxide frit to water is 30-40:50-60, and the mass ratio of the oxide frit to polyethylene glycol is 100:1.0-3.0.

[0019] Furthermore, the high-energy ball mill operates at a rotation speed of 800–1200 r / min, a ball-to-material ratio of 2–3:1, and a high-energy ball milling time of 4–8 h.

[0020] Furthermore, the grinding media of the high-energy ball mill is alumina ceramic balls of 0.5-0.6 mm.

[0021] Furthermore, a binder is added during the spray granulation process, the binder comprising polyvinyl alcohol, and the mass ratio of the mixed oxide to the binder is 100:1.0 to 3.0.

[0022] Furthermore, the atomizer of the spray granulation has a rotation speed of 8000-12000 r / min, the inlet air temperature of the spray granulation is 220-250℃, and the outlet air temperature is 90-105℃.

[0023] The high-temperature densification heat treatment is carried out in an air atmosphere, and the temperature of the high-temperature densification heat treatment is 900-1200℃, and the time is 0.5-1.5h.

[0024] The beneficial effects of this invention are:

[0025] The CMAS powder of this invention can meet the requirements of the multi-factor coupled environment simulation test equipment for thermal barrier coatings. The beneficial effects are specifically manifested as follows: 1) The pneumatic conveying performance of the powder meets the requirements: Poor pneumatic conveying flow can lead to difficulty in controlling the supply of CMAS powder to the combustion chamber of the equipment, and may even result in the CMAS powder being unable to be conveyed. This requires that the CMAS powder has excellent dispersibility, sphericity, appropriate particle size and high collapse strength; 2) The high temperature melting and melt activity of the powder meet the requirements: Under the premise of ensuring that the CMAS powder can be stably conveyed to the combustion chamber of the equipment, when the CMAS powder arrives at the combustion chamber, it is required that the CMAS powder can be conveyed to the surface of the thermal barrier coating under the action of a high energy density flame beam and fully melt and have high melt activity. This requires the powder to have excellent high temperature melting and melt activity. Attached Figure Description

[0026] Figure 1 The XRD patterns of the phase structure of CMAS powders in Examples 1-3 under different heat treatment conditions are shown.

[0027] Figure 2 This is a differential scanning calorimetry (DSC) graph of the CMAS powder obtained in Example 1. Detailed Implementation

[0028] This invention provides a CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings, which is prepared from raw material powder containing the following mass percentages:

[0029] CaO 15~40%, MgO 5~15%, Al2O310~20%, SiO236~55%, Fe2O3≤15%;

[0030] The particle size of the raw material powder is 200-300 mesh.

[0031] In this invention, the content of CaO is preferably 20-35%, more preferably 25-30%, and even more preferably 27%.

[0032] In this invention, the content of MgO is preferably 8-12%, and more preferably 10%.

[0033] In this invention, the content of Al2O3 is preferably 12-18%, and more preferably 15%.

[0034] In this invention, the SiO2 content is preferably 38-50%, more preferably 40-48%, and even more preferably 45%.

[0035] In this invention, the content of Fe2O3 is preferably 1-14%, more preferably 5-13%, and even more preferably 8-11%.

[0036] In this invention, the particle size of the raw material powder is preferably 250 mesh, and the purity of the raw material powder is independently ≥99%, preferably ≥99.5%.

[0037] This invention provides a method for preparing CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings, comprising the following steps:

[0038] 1) The raw material powders are mixed and then sequentially ball-milled and pre-calcined to obtain a mixed oxide;

[0039] 2) The mixed oxides are sequentially melted and quenched at high temperatures to obtain oxide frit;

[0040] 3) The oxide frit is ball-milled at high energy and then spray-granulated to obtain CMAS granulated powder;

[0041] 4) The CMAS granulated powder is subjected to high-temperature densification heat treatment to obtain the CMAS powder for the multi-factor coupled environment simulation test equipment of thermal barrier coating.

[0042] In this invention, in step 1), the grinding medium used in the ball mill is alumina ceramic balls, the ball-to-material ratio is 4-8:1, preferably 5-7:1, and more preferably 6:1; the ball milling speed is 100-300 r / min, preferably 150-250 r / min, and more preferably 200 r / min; the ball milling time is 4-8 h, preferably 5-7:1, and more preferably 6:1.

[0043] In this invention, the pre-calcination temperature is 900-1200℃, preferably 1000-1100℃, and more preferably 1050℃; the pre-calcination time is 2-6h, preferably 3-5h, and more preferably 4h.

[0044] In this invention, in step 2), the high-temperature melting temperature is 1400-1650℃, preferably 1450-1600℃, and more preferably 1500-1550℃; the heating rate is 2-5℃ / min, preferably 3-4℃ / min; and the holding time is 1-3h, preferably 2h.

[0045] In this invention, the quenching is water cooling. Specifically, the water cooling involves rapidly removing the high-temperature molten oxide obtained after high-temperature melting from the muffle furnace in an air atmosphere and pouring it into deionized water for rapid quenching. The high-temperature molten oxide solidifies and cracks rapidly after rapid cooling to obtain oxide flocs.

[0046] In this invention, in step 3), water is preferably used as the dispersion medium and polyethylene glycol is used as the dispersant during the high-energy ball milling process.

[0047] In this invention, the mass ratio of the oxide frit to water is 30-40:50-60, preferably 32-38:52-58, and more preferably 35:55; the mass ratio of the oxide frit to polyethylene glycol is 100:1.0-3.0, preferably 100:1.5-2.5, and more preferably 100:2.0.

[0048] In this invention, the high-energy ball milling speed is 800-1200 r / min, preferably 900-1100 r / min, and more preferably 1000 r / min; the ball-to-material ratio is 2-3:1, preferably 2:1; and the high-energy ball milling time is 4-8 h, preferably 5-7 h, and more preferably 6 h.

[0049] In this invention, the grinding media of the high-energy ball mill is alumina ceramic balls of 0.5-0.6 mm.

[0050] In this invention, a binder is added during the spray granulation process. The binder is preferably polyvinyl alcohol. The mass ratio of the mixed oxide to the binder is 100:1.0 to 3.0, preferably 100:1.5 to 2.5, and more preferably 100:2.0.

[0051] In this invention, the rotational speed of the atomizer for spray granulation is 8000-12000 r / min, preferably 9000-11000 r / min, and more preferably 10000 r / min; the inlet air temperature for spray granulation is 220-250℃, preferably 230-240℃, and more preferably 235℃; the outlet air temperature is 90-105℃, preferably 95-100℃, and more preferably 98℃.

[0052] In this invention, the high-temperature densification heat treatment is carried out in an air atmosphere, and the temperature of the high-temperature densification heat treatment is 900-1200℃, preferably 1000-1100℃, and more preferably 1100℃; the time is 0.5-1.5h, preferably 1h.

[0053] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] Preparation of CMAS powder for thermal barrier coatings with 21wt% CaO, 7wt% MgO, 19wt% Al2O3, 42wt% SiO2, and 11wt% Fe2O3 for multi-factor coupled environmental simulation test equipment:

[0056] 1) Take the above-mentioned mass percentage of raw material powder (the purity of the raw material powder is greater than 99% and the particle size is 200 mesh) and mix them. Place them in a ball mill, use alumina ceramic balls as the grinding medium, the ball-to-material ratio is 5:1, and ball mill at 200 r / min for 6 h to obtain a mixture; calcine the mixture at 1100℃ for 5 h to obtain mixed oxides.

[0057] 2) The mixed oxides were placed in a mullite crucible and heated to 1650°C in an air-atmosphere muffle furnace at a rate of 3°C / min for high-temperature melting. The temperature was held for 2 hours to obtain molten oxides. The molten oxides were quickly removed from the air-atmosphere muffle furnace and poured into deionized water for rapid quenching. The high-temperature molten oxides solidified rapidly and cracked after rapid cooling to obtain oxide flocs.

[0058] 3) The oxide frit was mixed with water and polyethylene glycol and placed in a high-energy ball mill. The mixture was ball-milled at 1200 r / min for 6 hours to obtain a ball-milled slurry. The mass ratio of oxide frit to water was 33:50, the mass ratio of oxide frit to polyethylene glycol was 100:2.0, and the ball-to-material ratio was 2:1. The ball-milled slurry was then mixed with polyvinyl alcohol and spray-granulated to obtain CMAS granulated powder. The mass ratio of the mixed oxide to polyvinyl alcohol was 100:3.0. The atomizer speed for spray granulation was 12000 r / min, the inlet air temperature was 220℃, and the outlet air temperature was 105℃.

[0059] 4) The CMAS granulated powder is subjected to high-temperature densification heat treatment in air atmosphere at a temperature of 1200℃ for 1 hour.

[0060] Example 2

[0061] Preparation of CMAS powder for thermal barrier coatings with 25wt% CaO, 5wt% MgO, 11wt% Al2O3, 50wt% SiO2, and 9wt% Fe2O3 for multi-factor coupled environmental simulation test equipment:

[0062] 1) Take the above-mentioned mass percentage of raw material powder (the purity of the raw material powder is greater than 99% and the particle size is 200 mesh) and mix them. Place them in a ball mill, use alumina ceramic balls as the grinding medium, the ball-to-material ratio is 6:1, and ball mill at 250 r / min for 6 h to obtain a mixture; calcine the mixture at 1200℃ for 5 h to obtain mixed oxides.

[0063] 2) The mixed oxides were placed in a mullite crucible and heated to 1550°C in an air-atmosphere muffle furnace at a rate of 3°C / min for high-temperature melting. The temperature was held for 2 hours to obtain molten oxides. The molten oxides were quickly removed from the air-atmosphere muffle furnace and poured into deionized water for rapid quenching. The high-temperature molten oxides solidified rapidly and cracked after rapid cooling to obtain oxide flocs.

[0064] 3) The oxide frit was mixed with water and polyethylene glycol and placed in a high-energy ball mill. The mixture was ball-milled at 1200 r / min for 6 hours to obtain a ball-milled slurry. The mass ratio of oxide frit to water was 33:50, the mass ratio of oxide frit to polyethylene glycol was 100:3.0, and the ball-to-material ratio was 2:1. The ball-milled slurry was then mixed with polyvinyl alcohol and spray-granulated to obtain CMAS granulated powder. The mass ratio of the mixed oxide to polyvinyl alcohol was 100:3.0, the atomizer speed for spray granulation was 12000 r / min, the inlet air temperature for spray granulation was 220℃, and the outlet air temperature was 105℃.

[0065] 4) The CMAS granulated powder was subjected to high-temperature densification heat treatment in air atmosphere at a temperature of 1100℃ for 1 hour.

[0066] Example 3

[0067] Preparation of CMAS powder for thermal barrier coatings with 19wt% CaO-13wt% MgO-20wt% Al2O3-38wt% SiO2-10wt% Fe2O3 for multi-factor coupled environmental simulation test equipment:

[0068] 1) Take the above-mentioned mass percentage of raw material powder (the purity of the raw material powder is greater than 99% and the particle size is 200 mesh) and mix them. Place them in a ball mill, use alumina ceramic balls as the grinding medium, the ball-to-material ratio is 6:1, and ball mill at 250 r / min for 6 h to obtain a mixture; calcine the mixture at 1200℃ for 5 h to obtain mixed oxides.

[0069] 2) The mixed oxides were placed in a mullite crucible and heated to 1400°C in an air-atmosphere muffle furnace at a rate of 3°C / min for high-temperature melting. The temperature was held for 2 hours to obtain molten oxides. The molten oxides were quickly removed from the air-atmosphere muffle furnace and poured into deionized water for rapid quenching. The high-temperature molten oxides solidified rapidly and cracked after rapid cooling to obtain oxide flocs.

[0070] 3) The oxide frit was mixed with water and polyethylene glycol and placed in a high-energy ball mill. The mixture was ball-milled at 1200 r / min for 6 hours to obtain a ball-milled slurry. The mass ratio of oxide frit to water was 33:50, the mass ratio of oxide frit to polyethylene glycol was 100:3.0, and the ball-to-material ratio was 2:1. The ball-milled slurry was then mixed with polyvinyl alcohol and spray-granulated to obtain CMAS granulated powder. The mass ratio of the mixed oxide to polyvinyl alcohol was 100:1.0, the atomizer speed for spray granulation was 12000 r / min, the inlet air temperature for spray granulation was 220℃, and the outlet air temperature was 105℃.

[0071] 4) The CMAS granulated powder is subjected to high-temperature densification heat treatment in air atmosphere at a temperature of 1000℃ for 1 hour.

[0072] from Figure 1 and Figure 2 As can be seen, after high-temperature densification heat treatment, diopside crystals precipitate from the amorphous matrix in the CMAS powder. The final CMAS powder has a melting point of 1259.6℃, exhibiting excellent high-temperature melting properties and solubility, which can meet the requirements of the multi-factor coupled environment simulation test equipment for thermal barrier coatings.

[0073] As can be seen from the above embodiments, the present invention provides a CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings and its preparation method. The CMAS powder provided by the present invention can meet the requirements of the multi-factor coupled environment simulation test device for thermal barrier coatings. The CMAS powder of the present invention has excellent dispersibility, sphericity, suitable particle size and high collapse strength. Moreover, the CMAS powder can be transported to the surface of the thermal barrier coating and fully melted under the action of a high-energy-density flame beam, and has high melt activity.

[0074] 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 CMAS powder for a multi-factor coupled environmental simulation test device for thermal barrier coatings, characterized in that, Includes the following steps: 1) The raw material powders are mixed and then sequentially ball-milled and pre-calcined to obtain a mixed oxide; 2) The mixed oxides are sequentially melted and quenched at high temperatures to obtain oxide frit; 3) The oxide frit is ball-milled at high energy and then spray-granulated to obtain CMAS granulated powder; 4) The CMAS granulated powder is subjected to high-temperature densification heat treatment to obtain the CMAS powder for the multi-factor coupled environment simulation test equipment of thermal barrier coating. The CMAS powder is prepared from the following raw material powders by mass percentage: CaO 15~40%, MgO 5~15%, Al2O3 10~20%, SiO2 36~55%, Fe2O3≤15%; The particle size of the raw material powder is 200-300 mesh. In step 3), water is used as the dispersion medium and polyethylene glycol is used as the dispersant during the high-energy ball milling process; the rotation speed of the high-energy ball mill is 800~1200 r / min, the ball-to-material ratio is 2~3:1, and the high-energy ball milling time is 4~8 h. The atomizer of the spray granulation has a rotation speed of 8000~12000 r / min, the inlet air temperature of the spray granulation is 220~250℃, and the outlet air temperature is 90~105℃. The high-temperature densification heat treatment is carried out in an air atmosphere, and the temperature of the high-temperature densification heat treatment is 900~1200℃, and the time is 0.5~1.5h.

2. The method for preparing CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings according to claim 1, characterized in that, In step 1), the grinding medium used in the ball mill is alumina ceramic balls, the ball-to-material ratio is 4~8:1, the ball mill speed is 100~300 r / min, and the ball milling time is 4~8 h.

3. The method for preparing CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings according to claim 1 or 2, characterized in that, The pre-calcination temperature is 900~1200℃, and the pre-calcination time is 2~6h.

4. The method for preparing CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings according to claim 3, characterized in that, In step 2), the high-temperature melting temperature is 1400~1650℃, the heating rate is 2~5℃ / min, and the holding time is 1~3h.

5. The method for preparing CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings according to claim 2 or 4, characterized in that, The mass ratio of the oxide frit to water is 30~40:50~60, and the mass ratio of the oxide frit to polyethylene glycol is 100:1.0~3.

0.

6. The method for preparing CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings according to claim 5, characterized in that, The grinding media of the high-energy ball mill is alumina ceramic balls with a diameter of 0.5~0.6 mm.

7. The method for preparing CMAS powder for a multi-factor coupled environment simulation test device for thermal barrier coatings according to claim 6, characterized in that, A binder is added during the spray granulation process. The binder contains polyvinyl alcohol, and the mass ratio of the mixed oxide to the binder is 100:1.0~3.0.

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