Lanthanum-Gadolinium-Samarium-based High Entropy Thermal Insulation Coating and Method for Producing the Same

Abstract

The present invention belongs to the technical field of heat insulation coatings for aero-engines, and relates to a lanthanum-gadolinium-samarium-based high-entropy heat insulation coating material and a manufacturing method thereof, in which the molecular formula of the lanthanum-gadolinium-samarium-based high-entropy target is La 0.4 Gd 0.4 Sm 0.4 A 0.4 B 0.4 Zr2O7 (where A and B are different rare earth elements). The selective deposition process parameters are that the vacuum degree of the deposition chamber is less than 5×10 -4 Torr, the beam intensity of the electron beam is 1.6 - 1.8 A, the temperature of the sample is 1000 - 1050 °C, and the evaporation time is 30 - 60 minutes. Finally, a lanthanum-gadolinium-samarium-based high-entropy heat insulation coating is obtained on the rotating sample. The heat insulation coating material of the present invention has a thermal expansion coefficient relatively close to that of YSZ and a low thermal conductivity. Also, by means of the electron beam physical vapor deposition technology, the lanthanum-gadolinium-samarium-based high-entropy heat insulation coating has a unique columnar crystal structure and an excellent service life. According to the present invention, it is possible to ensure a decrease in the thermal conductivity of the coating, improve the use temperature of the coating, and improve the actual problems of insufficient service life of the coating and low thermal expansion coefficient.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal insulation coatings for aeroengines, and relates to a lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating and a manufacturing method thereof.

Background Art

[0002] Currently, with the improvement of the thrust and operating efficiency of gas turbines, the gas intake temperature is also increasing, and the operating temperature of nickel-based superalloys used for turbine blades and other hot-end components is approaching its service temperature limit. Thermal Barrier Coatings (TBCs) are surface protection technologies that utilize the high temperature resistance, corrosion resistance, and low thermal conductivity of ceramic materials to form a coating and combine it with a metal substrate. This improves the operating temperature of metal components, enhances the high temperature resistance of hot-end components, extends the service life of hot-end components, and improves the operating efficiency of engines. Currently, the long-term maximum service temperature of the widely used YSZ (6-8 mass% Y2O3 partially stabilized ZrO2) thermal insulation coating material cannot exceed 1200 °C. During the cooling process, a monoclinic phase is generated due to a phase transition, resulting in volume expansion and coating failure. However, the long-term service temperature of the next-generation high-performance aeroengine thermal insulation coating material needs to exceed 1200 °C. Therefore, the research on new thermal insulation coating materials has become an important issue in the development of next-generation high-performance aeroengines.

Summary of the Invention

[0003] The present invention is designed in view of the above-mentioned drawbacks of the prior art, and provides a lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating and a manufacturing method thereof. The purpose is to solve the problems of the insufficient service life of a single zirconate thermal insulation coating and the YSZ service temperature being below 1200 °C by high-entropization of the lanthanum-gadolinium-samarium system, and at the same time, reduce the thermal conductivity of the material and improve the thermal expansion coefficient of the material.

[0004] To solve this technical problem, the technical solution of the present invention is as follows.

[0005] In one aspect, a lanthanum-gadolinium-samarium-based high-entropy thermal barrier coating material with the chemical formula La 0.4 Gd 0.4 Sm 0.4 A 0.4 B 0.4 Zr2O7 (where A and B are different rare earth elements other than lanthanum, gadolinium, and samarium) is provided.

[0006] The rare earth elements are Ce, Pr, Nd, Yb, Er, Dy, or Eu.

[0007] In another aspect, a method for manufacturing a lanthanum-gadolinium-samarium-based high-entropy thermal barrier coating material including the following steps is provided. Step 1: Mix La2O3, Gd2O3, Sm2O3, A2O3, B2O3, and ZrO2 as raw materials in the ratio of the molecular formula of the materials, and synthesize a lanthanum-gadolinium-samarium-based high-entropy target by the high-temperature solid-phase method (the synthesis temperature is 2000 - 2200 °C). Step 2: Use a vacuum arc plating apparatus (the voltage is 650 - 700 V and the current is 15 - 25 A) to manufacture NiCoCrAlYHf as the metal underlayer of the thermal barrier coating. Step 3: Load the lanthanum-gadolinium-samarium-based high-entropy target into an electron beam physical vapor deposition apparatus, and evaporate the lanthanum-gadolinium-samarium-based high-entropy target by an electron beam (the beam intensity of the electron beam is 1.6 - 1.8 A and the temperature of the sample is 1000 - 1050 °C) to manufacture a lanthanum-gadolinium-samarium-based high-entropy thermal barrier coating on the NiCoCrAlYHf underlayer.

[0008] The purity of the raw materials La2O3, Gd2O3, Sm2O3, A2O3, B2O3, and ZrO2 in Step 1 is 99% or more.

[0009] The mixing of raw materials in the above step 1 is carried out by mechanical milling, and the time is 16 hours or more.

[0010] The synthesis time by the high-temperature solid-phase method in the above step 1 is 20 hours or more.

[0011] The degree of vacuum of the vacuum arc plating device in the above step 2 is less than 1×10 -2 Pa, and the deposition time is 100 minutes or more.

[0012] In the above step 3, the degree of vacuum of the electron beam physical vapor deposition device is less than 5×10 -2 Pa, the evaporation time of the heat-insulating coating is 30 to 60 minutes, the heat-insulating coating is cooled to 200°C or less in the furnace, and the cooling is natural cooling.

Effect of the Invention

[0013] As a new type of heat-insulating coating material, the present invention adopts the design of high-entropyization of rare-earth zirconate, selects high-entropy rare-earth zirconate (Re X )2Zr2O7 as the heat-insulating coating material. For the high-entropyization of both the rare-earth site and the Zr site, the high-entropyization of a single rare-earth site can improve the stability of the high-temperature phase of the material well, and the high chemical compatibility of the material can also be maintained at a single Zr site. At the same time, in the later coating manufacturing process, the phase structure of the material is easier to be stabilized and segregation is less likely to occur. The lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating manufactured by the electron beam physical vapor deposition technology does not undergo a phase transition after long-term heat treatment at high temperature and has high phase stability. These have a thermal expansion coefficient relatively close to that of YSZ and have a low thermal conductivity and a good thermal expansion coefficient. At the same time, when manufacturing a lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating layer using the electron beam physical vapor deposition technology, the heat-insulating coating layer has a unique columnar crystal structure, and the coating layer has a good strain tolerance rate and good thermal cycle performance.

Brief Description of the Drawings

[0014]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Mode for Carrying Out the Invention

[0015] In order to clarify the object, technical solution and advantages of the embodiments of the present invention, hereinafter, while referring to the drawings in the embodiments of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are some of the embodiments of the present invention, not all of them. All other embodiments obtained on the premise that those skilled in the art do not make creative labor based on the embodiments of the present invention belong to the protection scope of the present invention.

[0016] Hereinafter, the features of each aspect of the embodiments of the present invention will be described in detail. In the following detailed description, many specific details are proposed in order to fully understand the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without these specific details. The following description of the embodiments is only for showing examples of the present invention to better understand the present invention. The present invention is not limited to any specific installation and method provided below, and includes any improvement, replacement, etc. of all product structures and methods covered on the premise of not departing from the spirit of the present invention.

[0017] In addition, in each figure and the following description, in order to avoid ambiguity in the understanding of the present invention, known configurations and technologies are not shown.

[0018] The lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating material of the present invention has a chemical formula of La 0.4 Gd 0.4 Sm 0.4 A0.4 B 0.4 Zr2O7 (where A and B are different rare earth elements).

[0019] The manufacturing method of the coating of the lanthanum-gadolinium-samarium-based high-entropy heat insulation coating material includes the following steps.

[0020] Mix La2O3, Gd2O3, Sm2O3, A2O3, B2O3, and ZrO2 as raw materials in the ratio of the material molecular formula. Among them, the purity of the raw materials is 99% or more, the mixing method is mechanical milling, and the mixing time is 16 hours or more.

[0021] Synthesize the lanthanum-gadolinium-samarium-based high-entropy target by the high-temperature solid-phase method. Among them, the synthesis temperature is 2000 - 2200 °C, and the synthesis time is 20 hours or more.

[0022] Use a vacuum arc plating device to manufacture NiCoCrAlYHf as the metal underlayer of the heat insulation coating. Among them, the vacuum degree is less than 1×10 -2 Pa, the voltage is 650 - 700 V, the current is 15 - 25 A, and the deposition time is 100 minutes or more.

[0023] Load the manufactured target into an electron beam physical vapor deposition device to manufacture the heat insulation coating. Among them, the vacuum degree is less than 5×10 -2 Pa, the beam intensity of the electron beam is 1.6 - 1.8 A, and the evaporation time is 30 - 60 minutes.

[0024] Naturally cool the heat insulation coating in the furnace to 200 °C or below.

[0025] In the above process, the synthesis temperature of the lanthanum-gadolinium-samarium-based high-entropy target by the high-temperature solid-phase method, the voltage and current in the production of the NiCoCrAlYHf metal underlayer, and the beam intensity of the electron beam are important key factors. By determining the synthesis temperature by the high-temperature solid-phase method, the generation of microcracks in the target can be well avoided, and the uniformity of the synthesized target can be improved. By selecting NiCoCrAlYHf as the metal underlayer of the thermal barrier coating, the service life of the thermal barrier coating can be improved. By adjusting the voltage and current, the NiCoCrAlYHf metal underlayer produced can be made into an equiaxed crystal structure. By adjusting the beam intensity of the electron beam, the production of a unique columnar crystal structure can be realized, and finally the service life of the thermal barrier coating can be greatly improved.

Example

[0026] Example 1 (1) Raw material formulation The chemical formula of the lanthanum-gadolinium-samarium-based high-entropy thermal barrier coating material is La 0.4 Gd 0.4 Sm 0.4 A 0.4 B 0.4 Zr2O7. However, A is the rare earth element Ce, and B is the rare earth element Pr. (2) High-temperature solid-phase synthesis The raw materials were mechanically milled for 20 hours, and a lanthanum-gadolinium-samarium-based high-entropy target was synthesized by the high-temperature solid-phase method at 2050 °C. The synthesis time was 24 hours. (3) Production of the underlayer Using a vacuum arc plating apparatus, NiCoCrAlYHf was produced as the metal underlayer of the thermal barrier coating. The degree of vacuum was less than 1×10 -2 Pa, the voltage was 675 V, the current was 18 A, and the deposition time was 175 minutes. (4) Production of the thermal barrier coating The lanthanum-gadolinium-samarium-based high-entropy oxygen target was loaded into an electron beam physical vapor deposition facility. The deposition process parameters were that the degree of vacuum was 5×10 -2It is less than Pa, the electron beam current intensity is 1.65 A, and the evaporation time is 60 minutes. After cooling to 200 °C or below, the deposition device was opened to obtain a lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating. The manufactured lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating has a thermal conductivity of 0.86 W / (mK) at 1000 °C and a coefficient of thermal expansion of 11.35×10 -6 K -1 and a thermal life of 898 hours.

[0027] Example 2 (1) Raw material formulation The chemical formula of the lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating material is La 0.4 Gd 0.4 Sm 0.4 A 0.4 B 0.4 Zr2O7. However, A is the rare earth element Yb and B is the rare earth element Ce. (2) High-temperature solid-phase synthesis The raw materials were mechanically milled for 24 hours, and a lanthanum-gadolinium-samarium-based high-entropy target was synthesized by the high-temperature solid-phase method at 2100 °C. The synthesis time was 28 hours. (3) Manufacture of the base layer NiCoCrAlYHf was manufactured as the metal base layer of the thermal insulation coating using a vacuum arc plating device. The degree of vacuum is 1×10 -2 less than Pa, the voltage is 700 V, the current is 20 A, and the deposition time is 150 minutes. (4) Manufacture of the thermal insulation coating The lanthanum-gadolinium-samarium-based high-entropy target was loaded into an electron beam physical vapor deposition facility. The deposition process parameters are that the degree of vacuum is 5×10 -2 less than Pa, the electron beam current intensity is 1.70 A, and the evaporation time is 50 minutes. After cooling to 200 °C or below, the deposition device was opened to obtain a lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating. The manufactured lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating has a thermal conductivity of 0.91 W / (mK) at 1000 °C, a coefficient of thermal expansion of 11.05×10 -6 K -1 and a thermal life of 818 hours.

[0028] Example 3 (1) Raw material formulation The chemical formula of the lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating material is La 0.4 Gd 0.4 Sm 0.4 A 0.4 B 0.4 Zr2O7. However, A is the rare earth element Eu, and B is the rare earth element Pr. (2) High-temperature solid-phase synthesis The raw materials were mechanically milled for 28 hours, and a lanthanum-gadolinium-samarium-based high-entropy target was synthesized by the high-temperature solid-phase method at 2150 °C. The synthesis time was 30 hours. (3) Manufacture of the underlayer NiCoCrAlYHf was manufactured as the metal underlayer of the thermal insulation coating using a vacuum arc plating apparatus. The degree of vacuum was less than 1×10 -2 Pa, the voltage was 725 V, the current was 22 A, and the deposition time was 125 minutes. (4) Manufacture of the thermal insulation coating The lanthanum-gadolinium-samarium-based high-entropy target was loaded into an electron beam physical vapor deposition facility. The deposition process parameters were that the degree of vacuum was less than 5×10 -2 Pa, the electron beam current intensity was 1.75 A, and the evaporation time was 40 minutes. After cooling to 200 °C or below, the deposition apparatus was opened to obtain a lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating. The manufactured lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating has a thermal conductivity of 0.95 W / (mK) at 1000 °C, a coefficient of thermal expansion of 10.95×10 -6 K -1 and a thermal life of 830 hours.

[0029] As can be seen from Fig. 1, the manufactured lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating had a significantly lower thermal conductivity compared to the YSZ material. As can be seen from Fig. 2, due to the high entropy of the lanthanum-gadolinium-samarium system, its coefficient of thermal expansion was equivalent to that of the YSZ material. As can be seen from Fig. 3, due to the high entropy of the lanthanum-gadolinium-samarium system, its thermal life was well improved. As can be seen from Fig. 4, the manufactured lanthanum-gadolinium-samarium-based high-entropy thermal insulation coating had a typical columnar crystal structure and could well release thermal stress during the thermal cycle process.

[0030] Finally, it should be noted that the above embodiments are only for explaining the technical solution of the present invention, and the protection scope of the present invention is not limited thereto. Those skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and all of these modifications or substitutions should be included within the protection scope of the present invention.

Claims

1. The chemical formula is La ０．４ Gd ０．４ Sm ０．４ A ０．４ B ０．４ Zr ２ O ７ (wherein A and B are different rare earth elements other than lanthanum, gadolinium, and samarium), characterized by being a lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating material.

2. The lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating material according to claim 1, wherein the rare earth element is Ce, Pr, Nd, Yb, Er, Dy or Eu.

3. A method for manufacturing a lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating material according to claim 1, comprising the following steps. Step 1: La as a raw material ２ O ３ , Gd ２ O ３ , Sm ２ O ３ , A ２ O ３ , B ２ O ３ , ZrO ２ are mixed in the ratio of the molecular formula of the materials, and a lanthanum-gadolinium-samarium-based high-entropy target is synthesized by the high-temperature solid-phase method (the synthesis temperature is 2000 - 2200 °C). Step 2: Using a vacuum arc plating apparatus (with a voltage of 650 to 700 V and a current of 15 to 25 A), NiCoCrAlYHf is manufactured as the metal base layer of the heat-insulating coating. Step 3: Loading a lanthanum-gadolinium-samarium-based high-entropy target into an electron beam physical vapor deposition apparatus, and evaporating the lanthanum-gadolinium-samarium-based high-entropy target by an electron beam (with an electron beam intensity of 1.6 to 1.8 A and a sample temperature of 1000 to 1050 °C) to manufacture a lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating on the NiCoCrAlYHf base layer.

4. The raw material La in the step 1 ２ O ３ , Gd ２ O ３ , Sm ２ O ３ , A ２ O ３ , B ２ O ３ , ZrO ２ The method for manufacturing a lanthanum-gadolinium-samarium-based high-entropy heat insulation coating according to claim 1, characterized in that the purity of is 99% or more.

5. The method for manufacturing a lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating according to claim 1, wherein the mixing of the raw materials in step 1 is performed by mechanical milling for a time of 16 hours or more.

6. The method for manufacturing a lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating according to claim 1, wherein the synthesis time by the high-temperature solid-phase method in step 1 is 20 hours or more.

7. The degree of vacuum of the vacuum arc plating apparatus in the step 2 is less than 1 × 10 －２ Pa, and the deposition time is 100 minutes or more. A method for manufacturing a lanthanum-gadolinium-samarium-based high-entropy heat insulation coating according to claim 1.

8. In the step 3, the degree of vacuum of the electron beam physical vapor deposition apparatus is less than 5×10 －２ Pa, and the method for manufacturing a lanthanum-gadolinium-samarium-based high entropy heat insulating coating according to claim 1 is characterized by this.

9. The method for manufacturing a lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating according to claim 1, wherein in step 3, the evaporation time of the heat-insulating coating by electron beam physical vapor deposition is 30 to 60 minutes.

10. The method for manufacturing a lanthanum-gadolinium-samarium-based high-entropy heat-insulating coating according to claim 1, wherein in step 3, the heat-insulating coating by electron beam physical vapor deposition is cooled to 200 °C or lower in a furnace, and the cooling is natural cooling.

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