High-entropy rare earth silicate nanorod toughened high-entropy rare earth aluminate and its preparation method

Abstract

The present invention provides a preparation method of high-entropy rare-earth silicate nanorod toughened high-entropy rare-earth aluminate, belonging to the technical field of the preparation of thermal barrier coating materials. The specific steps include: synthesizing high-entropy rare-earth aluminate powder by solid-phase reaction method with RE2O3 and Al2O3, then mixing the high-entropy rare-earth aluminate powder and silicon dioxide in a certain proportion to form a composite powder, and then pressing the composite powder into tablets and performing pressureless sintering to form high-entropy rare-earth silicate nanorod toughened high-entropy rare-earth aluminate. The high-entropy rare-earth silicate nanorod toughened high-entropy rare-earth aluminate prepared by the present invention has good high-temperature stability and fracture toughness.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of thermal barrier coating materials, and relates to a high-entropy rare earth aluminate toughened by high-entropy rare earth silicate nanorods and a preparation method thereof. Background Art

[0002] With the pursuit of high thrust-to-weight ratio and high inlet temperature by aeroengines, the environment faced by the hot-end components of the engine is becoming increasingly harsh. Therefore, in order to isolate and protect the components of a gas turbine engine from high damage by hot gases, a thermal barrier coating is prepared on the surface of the components, thereby increasing the operating temperature and operating efficiency of the gas turbine engine.

[0003] Currently used thermal barrier materials include: Al 2 O 3 , mullite, yttria-stabilized zirconia (YSZ), etc. Among them, YSZ is one of the most widely used coating materials. However, after the use temperature of the YSZ material exceeds 1200 °C, phase transformation and rapid sintering will occur, resulting in a significant reduction in the thermal insulation performance and strain tolerance of the coating, and the local stress generated will cause the coating to prematurely peel off and fail. Therefore, it is difficult for the YSZ material to meet the use requirements of the new generation of advanced aeroengines in high-temperature extreme environments, and it is necessary to develop a thermal barrier coating ceramic material that can stably serve above 1200 °C. Research shows that rare earth aluminate has attracted much attention due to its high melting point and good stability in a combustion environment. However, single-component rare earth aluminate has the disadvantages of high thermal conductivity and poor fracture toughness, making the coating prone to cracking and peeling during the thermal cycle process, which greatly limits the practical application of this material in the field of thermal barrier coatings (TBC).

[0004] "High entropy" is a new material design theory proposed in the 21st century, which refers to a solid solution material composed of five or more components. Its characteristics include four core effects, namely the high-entropy effect of thermodynamics, the lattice distortion effect of structure, the hysteresis effect of kinetics, and the "cocktail" effect of performance. Research shows that compared with single-component rare earth aluminate, high-entropy rare earth aluminate ceramics have low thermal conductivity, low grain growth rate, and good thermal stability, and are ideal candidate materials for the future new generation of TBC materials. However, the fracture toughness of rare earth aluminate is still poor after high-entropyization, which greatly limits the application of TBC. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a high-entropy rare earth aluminate toughened by high-entropy rare earth silicate nanorods and a preparation method thereof.

[0006] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] The high-entropy rare earth aluminate toughened by high-entropy rare earth silicate nanorods [(xRE(1 / x) ) y Al (1-y) 2 SiO 5 / (xRE 1 / x )AlO 3 is prepared from SiO 2 and high-entropy rare-earth aluminate powder (xRE 1 / x )AlO 3 , and the mass ratio of silicon dioxide to high-entropy rare-earth aluminate powder is 1 / 20 to 1 / 10; where RE is a rare-earth element, x is the number of components, and y is the number of atoms.

[0008] The preparation method of the high-entropy rare-earth silicate nanorod toughened high-entropy rare-earth aluminate is as follows:

[0009] Step 1, preparation of high-entropy rare-earth aluminate (xRE 1 / x )AlO 3 powder: First, RE 2 O 3 , Al 2 O 3 powders are wet ball-milled and mixed in a ball mill for 24 h according to a molar ratio of 1:1 to obtain a slurry; then the obtained slurry is placed in an oven and dried at 80 °C for 10 h to obtain a dried powder; then the dried powder is calcined at a temperature of 1450-1550 °C for 2 h to obtain (xRE 1 / x )AlO 3 powder;

[0010] Step 2, preparation of silicon dioxide and high-entropy rare-earth aluminate composite SiO 2 / (xRE 1 / x )AlO 3 powder: The (xRE 1 / x )AlO 3 powder prepared in Step 1 and SiO 2 are wet ball-milled and mixed in a ball mill for 12 h to obtain a slurry; then the obtained slurry is placed in an oven and dried at 80 °C for 10 h to obtain a dried powder, and then passed through a 120-mesh sieve to obtain SiO 2 / (xRE 1 / x )AlO 3 composite powder;

[0011] Step 3, sample sintering: The SiO 2 / (xRE 1 / x )AlO 3 ​The composite powder is pressed into a ceramic block, and then sintered without pressure at 1500 - 1600 °C for 10 h with a heating rate of 5 °C / min to prepare a high-entropy rare earth aluminosilicate nanorod toughened high-entropy rare earth aluminate [(xRE (1 / x) ) y Al (1-y) 2 SiO 5 / (xRE 1 / x )AlO 3 .

[0012] Preferably, in RE 2 O 3 in step 1, RE is a rare earth element, and RE is any 5 of Y, Yb, Nd, Eu, Gd, Er, La elements. x is the number of components, and y is the number of atoms. Among them, the number of components x is 5; the number of atoms y is 0.8 - 0.95.

[0013] Preferably, in the SiO 2 / (xRE 1 / x )AlO 3 composite powder in step 2, the mass ratio of silicon dioxide to high-entropy rare earth aluminate powder is 1 / 20 - 1 / 10.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] (1) The preparation method of TBC usually adopts the thermal spraying process. The present invention prepares high-entropy rare earth aluminosilicate nanorod toughened high-entropy rare earth aluminate by regulating the raw material components, which is convenient for the subsequent preparation of the coating;

[0016] (2) During the preparation of the sample, the generated high-entropy rare earth silicate has a high-entropy stabilization effect and has good high-temperature stability in an extremely high-temperature environment, thereby enhancing the structural stability of the high-entropy rare earth aluminate-based TBC;

[0017] (3) In the high-entropy ceramic material, the generated high-entropy rare earth silicate is relatively uniformly dispersed in the sample, thus greatly improving the fracture toughness of the high-entropy rare earth aluminate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the XRD pattern of [(5RE (1 / 5) ) 0.95 Al 0.05 2 SiO 5 / (5RE 1 / 5 )AlO 3 prepared in Example 3 of the present invention;

[0019] Figure 2 ​​SEM image of [(5RE (1 / 5) ) 0.95 Al 0.05 2 SiO 5 / (5RE 1 / 5 )AlO 3 prepared in Example 3 of the present invention;

[0020] Figure 3 EDS image of [(5RE (1 / 5) ) 0.95 Al 0.05 2 SiO 5 / (5RE 1 / 5 )AlO 3 prepared in Example 3 of the present invention. Detailed implementation mode

[0021] The present invention will be further described below with reference to the accompanying drawings:

[0022] The toughened high-entropy rare earth aluminate [(xRE (1 / x) ) y Al (1-y) 2 SiO 5 / (xRE 1 / x )AlO 3 is prepared from SiO 2 and the high-entropy rare earth aluminate powder (xRE 1 / x )AlO 3 , and the mass ratio of silicon dioxide to the high-entropy rare earth aluminate powder is 1 / 20 to 1 / 10; wherein RE is a rare earth element, x is the number of components, and y is the number of atoms.

[0023] Preparation method of toughened high-entropy rare earth aluminate with high-entropy rare earth silicate nanorods. The preparation steps are as follows: First, (xRE 2 O 3 and Al 2 O 3 are synthesized into (xRE 1 / x )AlO 3 powder by solid-state reaction method, then SiO 2 and (xRE 1 / x )AlO 3 powder are mixed to form SiO 2 / (xRE 1 / x )AlO 3 composite powder, and then the SiO 2 / (xRE 1 / x )AlO 3 composite powder is pressed into tablets and sintered without pressure to form [(xRE​​​(1 / x) ) y Al (1-y) 2 SiO 5 / (xRE 1 / x )AlO 3 , the high-entropy effect promotes [(xRE (1 / x) ) y Al (1-y) 2 SiO 5 / (xRE 1 / x )AlO 3 to have good high-temperature stability, and the toughening effect of rod-shaped grains can greatly improve its fracture toughness.

[0024] Example 1

[0025] In this example, Y, Yb, Nd, Eu, and Gd elements, SiO 2 and (Y 0.2 Yb 0.2 Nd 0.2 Eu 0.2 Gd 0.2 )AlO 3 powders are prepared in a mass ratio of 1:20 to prepare high-entropy rare-earth silicate nanorod toughened high-entropy rare-earth aluminate [(5RE (1 / 5) ) 0.8 Al 0.2 2 SiO 5 / (5RE 1 / 5 )AlO 3 , including the following steps:

[0026] Step 1, preparation of high-entropy rare-earth aluminate (5RE 1 / 5 )AlO 3 powder: RE 2 O 3 (RE is a rare-earth element, RE = Y, Yb, Nd, Eu, Gd), Al 2 O 3 are mixed at a molar ratio of 1:1 respectively. The mixed powder is wet ball-milled in a ball mill for 24 h to obtain a slurry; then the obtained slurry is put into an oven and dried at 80 °C for 10 h to obtain a dried powder; then the dried powder is calcined at 1450 °C for 2 h to obtain (5RE 1 / 5 )AlO 3 powder.

[0027] Step 2, compounding of silicon dioxide and high-entropy rare-earth aluminate SiO 2 / (5RE 1 / 5 )AlO 3 ​​​Powder preparation: The (5RE 1 / 5 )AlO 3 powder prepared in Step 1 was wet ball-milled and mixed in a ball mill for 12 h at a mass ratio of SiO 2 to (5RE 1 / 5 )AlO 3 powder of 1:20 to obtain a slurry; then the obtained slurry was placed in an oven and dried at 80 °C for 10 h to obtain a dried powder, which was then passed through a 120-mesh sieve to obtain SiO 2 / (5RE 1 / 5 )AlO 3 composite powder.

[0028] Step 3, sample sintering step: The SiO 2 / (5RE 1 / 5 )AlO 3 composite powder obtained in Step 2 was pressed into a block and sintered without pressure at 1550 °C for 10 h with a heating rate of 5 °C / min to prepare high-entropy rare-earth silicate nanorod toughened high-entropy rare-earth aluminate [(5RE (1 / 5) ) 0.8 Al 0.2 2 SiO 5 / (5RE 1 / 5 )AlO 3 .

[0029] The sample [(5RE (1 / 5) ) 0.8 Al 0.2 2 SiO 5 / (5RE 1 / 5 )AlO 3 prepared in this example after heat preservation at 1550 °C for 10 h has a fracture toughness increased by 2.21 MPa·m 1 / 2 compared with single-component rare-earth aluminate.

[0030] Example 2

[0031] In this example, Y, Eu, Er, Gd, and La elements were selected, and the mass ratio of SiO 2 to (Y 0.2 Eu 0.2 Er 0.2 Gd 0.2 La 0.2 )AlO 3 powder was 1:15 to prepare high-entropy rare-earth silicate nanorod toughened high-entropy rare-earth aluminate [(5RE (1 / 5) ) 0.85 Al 0.15 2 ​​​SiO 5 / (5RE 1 / 5 )AlO 3 , including the following steps:

[0032] Step 1, preparation of high-entropy rare-earth aluminate (5RE 1 / 5 )AlO 3 powder: Mix RE 2 O 3 (RE is a rare-earth element, RE = Y, Eu, Er, Gd, La), and Al 2 O 3 in a molar ratio of 1:1 respectively. Wet ball-mill the mixed powder in a ball mill for 24 h to obtain a slurry; then put the obtained slurry into an oven and dry it at 80 °C for 10 h to obtain a dried powder; then calcine the dried powder at 1500 °C for 2 h to obtain (5RE 1 / 5 )AlO 3 powder.

[0033] Step 2, preparation of silica and high-entropy rare-earth aluminate composite SiO 2 / (xRE 1 / 5 )AlO 3 powder: Take the (5RE 1 / 5 )AlO 3 powder prepared in Step 1, and wet ball-mill it in a ball mill for 12 h at a mass ratio of SiO 2 and (xRE 1 / 5 )AlO 3 powder of 1:15 to obtain a slurry; then put the obtained slurry into an oven and dry it at 80 °C for 10 h to obtain a dried powder, and then pass it through a 120-mesh sieve to obtain SiO 2 / (5RE 1 / 5 )AlO 3 composite powder.

[0034] Step 3, sample sintering: Press the SiO 2 / (5RE 1 / 5 )AlO 3 composite powder obtained in Step 2 into a block, and use pressureless sintering. Keep it at 1550 °C for 10 h with a heating rate of 5 °C / min to prepare high-entropy rare-earth silicate nanorod toughened high-entropy rare-earth aluminate [(5RE (1 / 5) ) 0.85 Al 0.15 2 SiO 5 / (5RE 1 / 5 )AlO 3 .

[0035] ​The sample prepared in this example after heat preservation at 1550 °C for 10 h [(5RE (1 / 5) ) 0.85 Al 0.15 2 SiO 5 / (5RE 1 / 5 )AlO 3 , compared with single-component rare earth aluminate, the fracture toughness is increased to 2.56 MPa·m 1 / 2 .

[0036] Example 3

[0037] In this example, elements Y, Nd, Eu, Gd, and La were selected, and the mass ratio of SiO 2 and (Y 0.2 Nd 0.2 Eu 0.2 Gd 0.2 La 0.2 )AlO 3 powder was 1:10. High-entropy rare earth silicate nanorod toughened high-entropy rare earth aluminate [(5RE (1 / 5) ) 0.95 Al 0.05 2 SiO 5 / (5RE 1 / 5 )AlO 3 was prepared, including the following steps:

[0038] Step 1, preparation of high-entropy rare earth aluminate (5RE 1 / 5 )AlO 3 powder: RE 2 O 3 (RE is a rare earth element, RE = Y, Nd, Eu, Gd, La), and Al 2 O 3 were mixed at a molar ratio of 1:1 respectively. The mixed powder was wet ball-milled in a ball mill for 24 h to obtain a slurry; then the obtained slurry was put into an oven and dried at 80 °C for 10 h to obtain a dried powder; then the dried powder was calcined at 1500 °C for 2 h to obtain (5RE 1 / 5 )AlO 3 powder.

[0039] Step 2, preparation of composite SiO 2 / (5RE 1 / 5 )AlO 3 powder: The (5RE 1 / 5 )AlO 3 powder prepared in Step 1 was used. According to the ratio of SiO 2 and (5RE 1 / 5 ​​)AlO 3 The powders were wet ball milled in a ball mill at a mass ratio of 1:10 for 12 h, and then the obtained slurry was placed in an oven and dried at 80 °C for 10 h to obtain dried powders. The powders were then passed through a 120-mesh sieve to obtain SiO 2 / (5RE 1 / 5 )AlO 3 composite powders.

[0040] Step 3, sample sintering: The obtained SiO 2 / (5RE 1 / 5 )AlO 3 composite powders were pressed into blocks and sintered without pressure at 1600 °C for 10 h with a heating rate of 5 °C / min to prepare high-entropy rare-earth aluminates toughened by high-entropy rare-earth silicate nanorods [(5RE (1 / 5) ) 0.95 Al 0.05 2 SiO 5 / (5RE 1 / 5 )AlO 3 .

[0041] The sample [(5RE (1 / 5) ) 0.95 Al 0.05 2 SiO 5 / (5RE 1 / 5 )AlO 3 prepared in this example after holding at 1600 °C for 10 h has a fracture toughness increased to 3.10 MPa·m 1 / 2 .

[0042] The sample in Example 3 was characterized by XRD as Figure 1 shown. High-entropy rare-earth silicate and high-entropy rare-earth aluminate exist in the sample. At the same time, the sample was analyzed by SEM, and EDS analysis was performed on the Figure 3 boxed area in Figure 2 、 3 shown. It was found that the high-entropy rare-earth aluminate is in the form of massive grains, and the silicon element is distributed in the rod-shaped grains, which are high-entropy rare-earth silicates, further proving the existence of high-entropy silicate nanorods in the high-entropy rare-earth aluminate matrix.

[0043] It should be noted that in the preparation of (xRE 1 / x )AlO 3 powders, RE 2 O 3 、Al 2 O 3 ​​The proportional relationship between them is well-known technology, and those skilled in the art know at what ratio they can prepare (xRE 1 / x )AlO 3 powder.

[0044] In the preparation of the SiO 2 / (xRE 1 / x )AlO 3 composite powder in Step 2, any reasonable ratio can be used for mixing to achieve the object of the present invention, but the most preferred mass ratio of silica to high-entropy rare earth aluminate powder is 1 / 20 to 1 / 10.

Claims

1. A high-entropy rare-earth aluminosilicate toughened by high-entropy rare-earth silicate nanorods, Characterized in that: The toughened high-entropy rare-earth aluminates [(xRE (1 / x) ) y Al (1-y) 2 SiO 5 / (xRE 1 / x )AlO 3 is prepared from SiO 2 and high-entropy rare-earth aluminate powder (xRE 1 / x )AlO 3 , and the mass ratio of silicon dioxide to high-entropy rare-earth aluminate powder is 1 / 20 to 1 / 10; wherein, RE is a rare-earth element, x is the number of components, and y is the number of atoms.​ 2. The high-entropy rare-earth aluminosilicate toughened by high-entropy rare-earth silicate nanorods according to claim 1, Characterized in that: RE is any 5 of the elements Y, Yb, Nd, Eu, Gd, Er, La.

3. The high-entropy rare-earth aluminosilicate toughened by high-entropy rare-earth silicate nanorods according to claim 1, Characterized in that, The number of components x is 5; the number of atoms y is 0.8 - 0.

95.

4. A preparation method of the high-entropy rare-earth aluminosilicate toughened by high-entropy rare-earth silicate nanorods according to claim 1, Characterized in that, The specific steps of this preparation method are as follows: Step 1, preparation of high-entropy rare-earth aluminate (xRE 1 / x )AlO 3 powder: Mix RE 2 O 3 , Al 2 O 3 powders in a certain molar ratio to obtain (xRE 1 / x )AlO 3 powder; Step 2, preparation of silica and high-entropy rare earth aluminate composite powder SiO 2 / (xRE 1 / x )AlO 3 Mix silica with the powder of (xRE 1 / x )AlO 3 obtained in Step 1, where the mass ratio of silica to high-entropy rare earth aluminate powder is 1 / 20 to 1 / 10, so as to obtain SiO 2 / (xRE 1 / x )AlO 3 composite powder; Step 3, sample sintering step: Press the SiO 2 / (xRE 1 / x )AlO 3 composite powder into a block, and then use pressureless sintering to prepare a high-entropy rare-earth aluminosilicate [(xRE (1 / x) ) y Al (1-y) 2 SiO 5 / (xRE 1 / x )AlO 3 .​ 5. The preparation method of the high-entropy rare-earth aluminosilicate toughened by high-entropy rare-earth silicate nanorods according to claim 4, Characterized in that, In step 1, RE 2 O 3 , Al 2 O 3 powders are wet ball-milled and mixed in a ball mill for 24 h according to a molar ratio of 1:1 to obtain a slurry; then the obtained slurry is placed in an oven and dried at 80 °C for 10 h to obtain a dried powder; then the dried powder is calcined at a temperature of 1450 - 1550 °C for 2 h to obtain (xRE 1 / x )AlO 3 powder.

6. The preparation method of the high-entropy rare-earth aluminosilicate toughened by high-entropy rare-earth silicate nanorods according to claim 4, Characterized in that, In step 2, the (xRE 1 / x )AlO 3 powder and SiO 2 are wet ball-milled and mixed in a ball mill for 12 h to obtain a slurry; then the obtained slurry is placed in an oven and dried at 80 °C for 10 h to obtain a dried powder, and then sieved through a 120-mesh sieve to obtain the SiO 2 / (xRE 1 / x )AlO 3 composite powder.

7. The preparation method of the high-entropy rare-earth aluminosilicate toughened by high-entropy rare-earth silicate nanorods according to claim 4, Characterized in that, In step 3, the pressureless sintering is carried out at 1500 - 1600 °C for 10 h with a heating rate of 5 °C / min.

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