A method for preparing a tantalate thermal barrier coating
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-29
- Publication Date
- 2026-08-14
AI Technical Summary
[0004]然而，热障涂层的实际隔热性能面临诸多挑战；目前，传统的YSZ材质热障涂层由于在1200℃下发生相变的原因，在超过该温度的服役条件下难以长时间稳定工作；稀土钽酸盐作为一种新型的热障涂层材料，其拥有较低的导热系数，更高的使用温度等性能，有望成为下一代热障涂层体系材料；然而，作为稀土材料，该材料的制备成本较高，且制备工艺繁琐，限制了该材料在实际的工业化应用的可能性
[0014]本发明提出的一种钽酸盐热障涂层的制备方法，操作简便，操作步骤简短，利用等离子喷涂过程中的高温环境及热障涂层服役过程的高温环境，替代了钽酸盐材料合成中的烧结热处理步骤，通过等离子火焰喷涂的高温环境以及热障涂层服役时的高温环境，将原料之间合成为所需材料的涂层，相比于传统的先合成，再造粒，再喷涂的工艺操作更为简便，工艺步骤更少，且省去了烧结反应的设备，成本更低，具有较高的实际应用价值。。
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aero-engine technology, and specifically relates to a method for preparing a tantalate thermal barrier coating. Background Technology
[0002] Thermal barrier coatings are ceramic functional layers applied to the surface of high-temperature resistant metal or alloy substrates. Their core function is to significantly reduce the actual operating temperature of the substrate material by utilizing their excellent thermal insulation properties, thereby providing reliable protection for the long-term stable operation of critical hot-end components such as aero engines and gas turbines in extreme high-temperature environments. Applying this coating to the surface of engine components not only helps improve thermal efficiency and reduce fuel consumption, but also effectively extends the service life of the components.
[0003] Currently, the combustion gas temperature in aero-engine combustion chambers has reached 1500–1600°C, while the surface temperature of turbine blades is approximately 1100°C. However, as the thrust-to-weight ratio of engines continues to increase, the temperature and pressure of the combustion gas within the combustion chamber will continue to rise. In the future, the combustion chamber temperature is expected to exceed 1800°C or even 2000°C, and correspondingly, the surface temperature of turbine blades will also rise to approximately 1500°C. Under these increasingly demanding thermal conditions, whether the thermal barrier coating possesses sufficiently superior heat insulation capabilities will directly determine its ability to effectively protect the metal substrate in high-temperature environments.
[0004] However, the actual thermal insulation performance of thermal barrier coatings faces many challenges. Currently, traditional YSZ thermal barrier coatings are difficult to operate stably for long periods under service conditions exceeding 1200℃ due to the phase transition that occurs at that temperature. Rare earth tantalates, as a novel thermal barrier coating material, have lower thermal conductivity and higher operating temperature, and are expected to become the next generation of thermal barrier coating system materials. However, as a rare earth material, its preparation cost is high and the preparation process is complicated, which limits the possibility of its practical industrial application.
[0005] With the continuous advancement of my country's aviation technology, the operating temperatures faced by gas turbines are constantly increasing, placing higher demands on the thermal insulation capabilities of thermal barrier coatings. Therefore, in-depth research into the preparation process of next-generation thermal barrier coatings and exploration of industrial production methods for novel thermal barrier coatings will not only help optimize the thermal protection effect of existing coating systems but also provide important basis and technical support for the research and development of next-generation high-performance thermal barrier coating materials. Summary of the Invention
[0006] The purpose of this invention is to propose a method for preparing tantalate thermal barrier coatings. This method mainly utilizes the high-temperature environment of plasma flame spraying and the high-temperature environment during the service of thermal barrier coatings to synthesize the raw materials into the desired coating. Compared with the traditional process of first synthesizing, then granulating, and then spraying, this method is simpler, has fewer process steps, eliminates the need for sintering reaction equipment, lowers costs, and has high practical application value.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a tantalate thermal barrier coating includes the following steps: Tantalum oxide, gadolinium oxide, and yttrium oxide micropowders are prepared as raw materials; polyvinyl alcohol solution (PVA solution) is used as a binder; and ammonium polyacrylate solution is used as a dispersant. The prepared yttrium oxide, gadolinium oxide, and tantalum oxide are uniformly mixed in a ratio where the mass of tantalum oxide is greater than the total mass of yttrium oxide and gadolinium oxide. Deionized water is added to adjust the solid content to 50%-60%. Then, 0.5%-0.8% of the total mass of the raw materials is added, followed by 0.1% of the total mass of the raw materials is added. A 0.5% polyacrylic acid ammonium solution was thoroughly stirred to obtain a mixed slurry. The prepared mixed slurry was then used to form tantalate precursor microspheres of uniform size using a spray granulation device. The tantalate precursor microspheres were dried in an oven to obtain tantalate precursor spraying material. The tantalate precursor spraying material was placed in the powder feeding tank of a plasma flame spraying device for flame spraying to prepare a tantalate precursor coating. Under the high-temperature service conditions of the thermal barrier coating, the tantalate precursor coating underwent a further sintering reaction, eventually transforming into a tantalate thermal barrier coating.
[0008] The plasma flame spraying equipment must include a spray gun, a powder feeder, and a robotic arm.
[0009] The particle size of the tantalum oxide, yttrium oxide, and gadolinium oxide micro powders is required to be in the micrometer or nanometer range.
[0010] The binder can be any water-soluble liquid binder available on the market, and the dispersant can be any water-soluble liquid or solid dispersant available on the market.
[0011] The particle size range of the tantalate precursor microspheres should be between 0 and 100 micrometers.
[0012] The drying temperature should be between 40-60℃.
[0013] The high-temperature service conditions shall not be lower than 1200℃.
[0014] This invention proposes a method for preparing a tantalate thermal barrier coating. The method is simple to operate and involves few steps. It utilizes the high-temperature environment of plasma spraying and the high-temperature environment during the service life of the thermal barrier coating to replace the sintering heat treatment step in the synthesis of tantalate materials. By combining the high-temperature environment of plasma flame spraying and the high-temperature environment during the service life of the thermal barrier coating, the raw materials are synthesized into the desired coating. Compared to the traditional process of first synthesizing, then granulating, and then spraying, this method is simpler, has fewer steps, eliminates the need for sintering equipment, and is less costly, thus possessing high practical application value. Detailed Implementation
[0015] The present invention will be described in conjunction with the given embodiments: Example 1: A Praxair 7700 plasma flame spraying system equipped with an ABB robotic arm and a German DIOSNA spray granulator were prepared. 2 kg of tantalum oxide, gadolinium oxide, and yttrium oxide micropowders were weighed at a mass ratio of 1:2:4 and placed in a planetary ball mill jar. An appropriate amount of deionized water was added to adjust the solid content to 60%. Then, 10 g of PVA solution and 2 g of polyacrylic acid ammonium solution were added sequentially, and the mixture was stirred at high speed for 2 hours to obtain a mixed slurry. The slurry was pumped into a spray granulation tower (inlet temperature 220℃, outlet temperature 110℃) to collect spherical precursor microspheres with a particle size of 30–80 μm. These microspheres were dried in a forced-air oven at 120℃ for 4 hours and then sieved for later use. The dried microspheres were loaded into a powder feeding hopper (powder feeding rate 25 g / min). The robotic arm held the spray gun 100 mm away from the substrate and performed atmospheric plasma spraying at a scanning speed of 300 mm / s to prepare a coating with a thickness of approximately 200 μm. The resulting coating undergoes an in-situ sintering reaction during high-temperature service, eventually transforming into a dense tantalate thermal barrier coating.
[0016] Example 2: Prepare a Praxair 100-HE plasma flame spraying system equipped with an ABB robotic arm and a Swiss Buqi small spray granulator. Weigh 10 kg of yttrium oxide, gadolinium oxide, and tantalum oxide in a mass ratio of 1:1:4 and place them in a high-speed mixer. Add an appropriate amount of deionized water to adjust the solid content to 50%, then add 50 g of PVA solution and 8 g of polyacrylic acid ammonium solution in sequence. Stir at high speed for 3 hours to obtain a mixed slurry. Pump the slurry into a spray granulation tower (inlet temperature 220℃, outlet temperature 110℃) and collect spherical precursor microspheres with a particle size of 50-100 μm. Dry them in a forced-air oven at 120℃ for 4 hours and sieve them for later use. Load the dried microspheres into a powder feeding hopper (powder feeding rate 25 g / min). Hold the spray gun 100 mm away from the substrate with the robotic arm and perform atmospheric plasma spraying at a scanning speed of 300 mm / s to prepare a coating with a thickness of approximately 250 μm. The resulting coating undergoes an in-situ sintering reaction during high-temperature service, eventually transforming into a dense tantalate thermal barrier coating.
Claims
1. A method for preparing a tantalate thermal barrier coating, characterized in that: The preparation method is as follows: Tantalum oxide, gadolinium oxide, and yttrium oxide micropowders are prepared as raw materials, polyvinyl alcohol solution is used as a binder, and ammonium polyacrylate solution is used as a dispersant. The prepared yttrium oxide, gadolinium oxide, and tantalum oxide are uniformly mixed in a ratio where the mass of tantalum oxide is greater than the total mass of yttrium oxide and gadolinium oxide. Deionized water is added to adjust the solid content to 50%-60%. Then, 0.5%-0.8% of the total mass of the raw materials is added to the polyvinyl alcohol solution, and 0.1%-0.5% of the total mass of the raw materials is added to the ammonium polyacrylate solution. The mixture is thoroughly stirred to obtain a slurry. The prepared slurry is then used to form uniformly sized tantalate precursor microspheres using a spray granulation device. The tantalate precursor microspheres are dried in an oven to obtain a tantalate precursor spraying material. The tantalate precursor spraying material is placed in the powder feeding tank of a plasma flame spraying device for flame spraying to prepare a tantalate precursor coating. Under the high-temperature service conditions of the thermal barrier coating, the tantalate precursor coating undergoes further sintering reaction, eventually transforming into a tantalate thermal barrier coating.
2. The method for preparing a tantalate thermal barrier coating as described in claim 1, characterized in that: The particle size of the tantalum oxide, yttrium oxide, and gadolinium oxide micro powders is required to be in the micrometer or nanometer range.
3. The method for preparing a tantalate thermal barrier coating as described in claim 1, characterized in that: The particle size range of the tantalate precursor microspheres should be between 0 and 100 micrometers.
4. The method for preparing a tantalate thermal barrier coating as described in claim 1, characterized in that: The drying temperature should be between 40-60℃.
5. The method for preparing a tantalate thermal barrier coating as described in claim 1, characterized in that: The high-temperature service conditions shall not be lower than 1200℃.