A quinary zirconia solid solution material, a preparation method and application thereof

Abstract

The application provides a five-element zirconia solid solution material and a preparation method and application thereof. The five-element zirconia solid solution material is composed of the following raw materials in terms of molar percentage: 1mol% La2O3, 2-6mol% Gd2O3, 2mol% Yb2O3, 3.5mol% Y2O3 and 87.5-91.5mol% ZrO2. The five-element zirconia solid solution material has a single tetragonal phase structure, and has good phase consistency, which is beneficial to fully exert the excellent performance thereof. Meanwhile, the material also exhibits excellent mechanical properties, and is an ideal ceramic layer material for preparing high-temperature-resistant thermal barrier coatings.

Description

Technical Field

[0001] This invention relates to a pentagonal zirconium oxide solid solution material, its preparation method and application, belonging to the field of thermal protective coating technology. Background Technology

[0002] The aero-engine industry continues to advance technologically, striving to improve the thermal efficiency and durability of hot-end components. However, the nickel-based superalloys currently used in industry are nearing their service limits, making the improvement of the metal's high-temperature resistance a challenging task. To address this issue, thermal barrier coatings (TBCs) have emerged as a promising solution. As a high-temperature protective layer, TBCs effectively increase the operating temperature of the metal substrate, thereby improving engine thermal efficiency and lifespan. Dual-layer TBC systems, consisting of an adhesive layer and a ceramic topcoat, have proven to effectively provide the substrate with excellent thermal insulation and oxidation resistance. Currently, the most widely used TBC topcoat material is yttrium-stabilized zirconium oxide (YSZ), which possesses low thermal conductivity, a coefficient of thermal expansion matching the high-temperature alloy substrate, and high fracture toughness. However, as aero-engines develop towards higher thrust-to-weight ratios, turbine inlet temperatures are continuously increasing, with hot-end component operating temperatures reaching 1300°C. However, YSZ will undergo phase transformation and sintering under long-term thermal cycling conditions exceeding 1200℃, which will lead to high thermal stress accumulation and crack generation, limiting the applicability of the coating.

[0003] Rare earth zirconates and rare earth tantalates have been found to possess excellent high-temperature phase stability and good thermal insulation properties. However, the mismatch between their coefficients of thermal expansion and the matrix material, along with their poor fracture toughness, limits their application in thermal barrier coatings. Therefore, research on the design and preparation technologies of high-temperature protective coating materials is urgently needed. This will improve the service performance and lifespan of aero-engines and provide key technological support and reserves for the development of new aerospace equipment. Summary of the Invention

[0004] The present invention aims to provide a pentagonal zirconia solid solution material, its preparation method and application. The pentagonal zirconia solid solution material is a single tetragonal phase, and no phase instability phenomenon was observed at high temperature (1500℃), and it has excellent mechanical properties.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a pentagonal zirconium oxide solid solution material, which is composed of the following raw materials in molar percentages: 1 mol% La₂O₃, 2-6 mol% Gd₂O₃, 2 mol% Yb₂O₃, 3.5 mol% Y₂O₃, and 87.5-91.5 mol% ZrO₂. It can be seen that the raw materials of this material are composed of La₂O₃, Gd₂O₃, Yb₂O₃, Y₂O₃, and ZrO₂, with a molar percentage of (1):(2-6):(2):(3.5):(87.5-91.5), and the total amount of each component is 100%.

[0006] Furthermore, the pentagonal zirconia solid solution material is composed of a single tetragonal phase, and retains its single tetragonal phase structure even after high-temperature annealing treatment at no more than 1500°C for no more than 100 hours.

[0007] The present invention also provides a method for preparing the above-mentioned pentagonal zirconium oxide solid solution material, the specific steps of which are as follows: (1) Using dry La2O3, Gd2O3, Yb2O3, Y2O3 and ZrO2 powders as raw materials, the raw materials are mixed and ball-milled; the resulting suspension I is dried and sieved in sequence to obtain mixed powder; (2) The mixed powder is subjected to high-temperature sintering to obtain a sintered product; (3) The sintered product is ball-milled, and the resulting suspension II is dried and sieved in sequence to obtain the five-element zirconium oxide solid solution material in powder form.

[0008] In the preferred step (1), the mass fraction of the five oxides required for the La2O3, Gd2O3, Yb2O3, Y2O3 and ZrO2 powder raw materials is greater than 99.9% in their respective raw material powders.

[0009] Furthermore, in steps (1) and (3), the ball milling medium used in the ball milling process is anhydrous ethanol, and the grinding balls are silicon carbide grinding balls.

[0010] Furthermore, in step (1), the ball milling time is 6 to 12 hours, the ball milling speed is 200 to 500 r / min, the drying temperature is 50 to 80°C, and the drying time is 5 to 10 hours. In step (3), the ball milling time is 8 to 24 hours, the ball milling speed is 200 to 500 r / min, the drying temperature is 70 to 120℃, and the drying time is 10 to 24 hours.

[0011] Furthermore, in step (2), the high-temperature sintering temperature is 1450-1550℃, the time is 10-20h, and the sintering atmosphere is air.

[0012] Furthermore, it also includes: (4) hot pressing and sintering the powdered pentagonal zirconium oxide solid solution material to obtain the block-shaped pentagonal zirconium oxide solid solution material.

[0013] Furthermore, in step (4), the hot pressing process includes two steps: mold dry pressing and heating and pressurizing sintering, which are performed sequentially. The pressure range of mold dry pressing is 2 to 10 MPa, and the mold dry pressing time is 3 to 10 minutes. The pressure of hot pressing sintering is 20 to 50 MPa, the temperature of hot pressing sintering is 1400 to 1550 °C, the sintering atmosphere is argon, the holding time is 1 to 3 hours, and then the furnace is cooled to room temperature and removed.

[0014] Furthermore, step (1) also includes: calcining the La2O3, Gd2O3, Yb2O3, Y2O3, and ZrO2 powders to obtain dry La2O3, Gd2O3, Yb2O3, Y2O3, and ZrO2 powders; wherein the calcination temperature is 900–1200℃ and the time is 2–5 h. After calcination, the powder is cooled to room temperature in the furnace to remove the adsorbed moisture from the raw material powders.

[0015] The present invention also provides the application of the above-mentioned pentagonal zirconium oxide solid solution material in the field of thermal barrier coating.

[0016] The technical solution provided by this invention has at least the following advantages and beneficial effects: This invention provides a pentagonal zirconium oxide solid solution material, its preparation method, and its applications. This pentagonal zirconium oxide solid solution material employs four trivalent rare earth ions co-doped with ZrO2 to form a highly distorted tetragonal zirconium oxide structure. This effectively reduces interatomic diffusion and improves its resistance to sintering. Through a rational ion combination, this invention successfully achieves La, the rare earth ion with the largest radius. 3+ The solid solution prevents the precipitation of the La2ZrO7 phase and inhibits the formation of the monoclinic phase in the material. Secondly, the doping of rare earth ions improves the phase stability of the tetragonal phase of the zirconia solid solution, maintaining a single tetragonal phase structure even after long-term high-temperature annealing treatment at no more than 1500℃ for no more than 100 hours. In addition, the doping of rare earth ions also enhances the mechanical properties of the material.

[0017] Furthermore, because this pentagonal zirconia solid solution material possesses a single tetragonal phase structure with excellent phase consistency, it is beneficial for fully utilizing its superior properties. Combined with its high hardness and good fracture toughness, this material is an ideal ceramic layer material for preparing high-temperature thermal barrier coatings. Therefore, the pentagonal zirconia solid solution material provided by this invention not only effectively improves the phase stability of the coating but also possesses excellent mechanical properties, providing long-lasting protection in high-temperature environments and significantly extending the service life of related equipment and components. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 (a) X-ray diffraction (XRD) pattern of the pentagonal zirconium oxide solid solution material prepared for Example 1 and (b) XRD pattern after heat treatment at 1500 °C for 100 h; Figure 2 (a) XRD pattern of the pentagonal zirconium oxide solid solution material prepared in Example 2 and (b) XRD pattern after heat treatment at 1500°C for 100 h; Figure 3 (a) XRD pattern of the pentagonal zirconium oxide solid solution material prepared in Example 3 and (b) XRD pattern after heat treatment at 1500°C for 100 h; In the figure, the horizontal axis 2θ represents the diffraction angle (degree), and the vertical axis Intensity represents the relative intensity (au). Detailed Implementation

[0020] In this invention, unless otherwise specified, all raw materials required for preparation are commercially available products well known to those skilled in the art.

[0021] In its specific implementation, this invention provides a pentagonal zirconium oxide solid solution material and its preparation method. The preparation method includes the following raw materials: La₂O₃, Gd₂O₃, Yb₂O₃, Y₂O₃, and ZrO₂ powders are used as raw materials. The preferred purity of La₂O₃ is 99.9 wt%, the preferred purity of Gd₂O₃ is 99.9 wt%, the preferred purity of Yb₂O₃ is 99.9 wt%, and the preferred purity of ZrO₂ is 99.9 wt%. The particle size of these powders is in the micrometer range, and commercially available micrometer-sized La₂O₃, Gd₂O₃, Yb₂O₃, Y₂O₃, and ZrO₂ powders can be used.

[0022] The prepared pentagonal zirconium oxide solid solution material was analyzed as follows: X-ray diffraction analysis: This analysis can be performed using a D8 Advance X-ray diffractometer from Bruker GmbH, Germany. The specific experimental conditions are as follows: Cu target, scanning speed of 10° / min, step size of 0.02°, and scanning angle range of 20°~80°.

[0023] The fracture toughness test was conducted as follows: The material to be tested was kept at 1500℃ and 30 MPa for 2 hours, and during the heat treatment, it was pressed into a cylindrical specimen with a diameter of 50 mm and a height of 5 mm. Specific specimens were cut using a diamond scribing machine, and the specimens were embedded in epoxy resin. Following standard metallographic sample preparation procedures, the specimens were polished sequentially with SiC abrasive paper of grades 120#, 240#, 400#, 600#, 800#, 1000#, 1500#, 2000#, and 3000#. Then, the cross-section was finely polished sequentially with diamond polishing paste with particle sizes of 2.5 μm, 1.5 μm, and 0.5 μm until the obtained cross-section showed no scratches under 500x magnification of an optical microscope. Finally, a Vickers microhardness test was performed on the specimen cross-section using a Vickers microhardness tester. The test conditions were: a load of 500 g, a holding time of 15 seconds, and at least 10 effective indentations were obtained.

[0024] Furthermore, the fracture toughness of the material can be obtained through a four-point bending test. The single-sided notched beam method is used for testing. The sample size is 2mm × 4mm × 36mm, the notch depth is 2mm, the width is 0.1mm, the span is 30mm, and the indenter moving speed is 0.05mm / min. The four-point bending test can be performed on a universal testing machine. The fracture toughness K is then calculated. IC The formula is as follows: (1) Where P is the maximum load at which the specimen breaks, L is the span, b is the specimen width, h is the specimen height, a is the specimen notch depth, and Y is the specimen shape factor, the expression of which is as follows: (2) The present invention will be further described in detail below through specific embodiments.

[0025] Example 1 La2O3, Gd2O3, Yb2O3, Y2O3 and ZrO2 powder raw materials were respectively loaded into different zirconium oxide crucibles and placed in a box-type resistance furnace for calcination at 1000℃ for 2 hours. After calcination, the furnace was cooled to room temperature to remove adsorbed moisture.

[0026] The calcined powder raw materials were mixed in a molar percentage ratio of La2O3, Gd2O3, Yb2O3, Y2O3, and ZrO2 of 1:2:2:3.5:91.5, and then placed in an agate ball mill jar. Anhydrous ethanol and silicon carbide balls were added. The ball mill jar was then placed in a planetary ball mill for mechanical ball milling for 8 hours at a speed of 300 rpm.

[0027] After ball milling, the resulting suspension I was placed in a drying oven and dried at 80°C for 8 hours to obtain a dried mixed powder.

[0028] The mixed powder was placed in a zirconia crucible and sintered at 1500℃ for 12 hours in air, then cooled to room temperature to obtain the sintered product. The sintered product was then ground to obtain sintered powder.

[0029] The sintered powder was placed in a ball mill jar, anhydrous ethanol and silicon carbide balls were added, and the ball mill jar was placed in a planetary ball mill for mechanical ball milling for 12 hours at a speed of 300 rpm.

[0030] After ball milling, the resulting suspension II was placed in a drying oven and dried at 80°C for 10 hours to obtain a pentagonal zirconia solid solution material in powder form.

[0031] Phase composition analysis: The pentagonal zirconium oxide solid solution material prepared in Example 1 was subjected to XRD testing, and the test results are as follows: Figure 1 As shown in the figure, the diffraction peaks are long, narrow, and free of impurities, indicating that the pentagonal zirconia solid solution material has few impurities and high purity. Analysis of the phase composition of the pentagonal zirconia solid solution material based on the test results shows that the phase structure of the pentagonal zirconia solid solution material is all tetragonal zirconia, indicating that the pentagonal zirconia solid solution material has a single-phase structure and can fully utilize its excellent properties. Figure 1 Curve (b) shows the XRD pattern after holding at 1500℃ for 100 hours. By comparing curves (a) and (b), it can be concluded that the pentagonal zirconia solid solution material before and after treatment at 1500℃ is a single tetragonal phase, with no peaks of other phases. This indicates that the pentagonal zirconia solid solution material did not undergo a phase transition and demonstrates good phase stability under high-temperature conditions, making it suitable as a thermal barrier coating material for long-term high-temperature service.

[0032] Example 2 The difference between this embodiment and Embodiment 1 is that the powder raw materials are mixed in the ratio of La2O3, Gd2O3, Yb2O3, Y2O3 and ZrO2 of 1:4:2:3.5:89.5 to obtain a pentagonal zirconium oxide solid solution material.

[0033] The pentagonal zirconium oxide solid solution material prepared in Example 2 was subjected to XRD testing, and the test results are as follows: Figure 2 As shown.

[0034] Example 3 The difference between this embodiment and Embodiment 1 is that the powder raw materials are mixed in the ratio of La2O3, Gd2O3, Yb2O3, Y2O3 and ZrO2 of 1:6:2:3.5:87.5 to obtain a pentagonal zirconium oxide solid solution material.

[0035] The pentagonal zirconium oxide solid solution material prepared in Example 3 was subjected to XRD testing, and the test results are as follows: Figure 3 As shown.

[0036] from Figure 2 and Figure 3 Observed conclusions and Figure 1 Consistent with this, the phase structure of the pentagonal zirconia solid solution materials prepared in Examples 2 and 3 is tetragonal zirconia, and the pentagonal zirconia solid solution materials before and after treatment at 1500℃ are both a single tetragonal phase.

[0037] It is understood that, in some other embodiments provided by the present invention, the powdered pentagonal zirconia solid solution material obtained in Examples 1 to 3 can also be subjected to hot pressing sintering treatment to obtain a blocky pentagonal zirconia solid solution material.

[0038] Specifically, the hot pressing sintering process includes two steps: mold dry pressing and heated pressure sintering. The pressure range of mold dry pressing is 2-10 MPa, and the mold dry pressing time is 3-10 minutes. The pressure of hot pressing sintering is 20-50 MPa, the temperature of hot pressing sintering is 1400-1550℃, the sintering atmosphere is argon, the holding time is 1-3 hours, and then it is cooled to room temperature with the furnace and taken out.

[0039] Example 4 The pentagonal zirconia solid solution materials prepared in Examples 1, 2, and 3 were subjected to Vickers hardness tests. The test results showed that the Vickers hardness of the pentagonal zirconia solid solution material prepared in Example 1 was 14.4 GPa, the Vickers hardness of the pentagonal zirconia solid solution material prepared in Example 2 was 14.6 GPa, and the Vickers hardness of the pentagonal zirconia solid solution material prepared in Example 3 was 14.9 GPa. The Vickers hardness of the pentagonal zirconia solid solution materials prepared in Examples 1, 2, and 3 were similar.

[0040] Example 5 The fracture toughness of the pentagonal zirconia solid solution materials prepared in Examples 1, 2, and 3 was tested. The test results showed that the fracture toughness of the pentagonal zirconia solid solution material prepared in Example 1 was 2.81 ± 0.21 MPa / m. 1 / 2 The fracture toughness of the pentagonal zirconium oxide solid solution material prepared in Example 2 was 2.52 ± 0.17 MPa m. 1 / 2 The fracture toughness of the pentagonal zirconium oxide solid solution material prepared in Example 3 was 1.70 ± 0.12 MPa m. 1 / 2 The pentagonal zirconia solid solution materials prepared in Examples 1 and 2 exhibited similar fracture toughness, both exceeding that of the pentagonal zirconia solid solution material prepared in Example 3. This indicates that the pentagonal zirconia solid solution materials prepared in Examples 1 and 2 possess higher fracture toughness.

[0041] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of the present invention. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A pentagonal zirconium oxide solid solution material, characterized in that, The pentagonal zirconia solid solution material is composed of the following raw materials in molar percentages: 1 mol% La2O3, 2~6 mol% Gd2O3, 2 mol% Yb2O3, 3.5 mol% Y2O3 and 87.5~91.5 mol% ZrO2.

2. The pentagonal zirconium oxide solid solution material according to claim 1, characterized in that, The pentagonal zirconia solid solution material consists of a single tetragonal phase and retains its single tetragonal phase structure even after high-temperature annealing at no more than 1500℃ for no more than 100 hours.

3. A method for preparing a pentagonal zirconium oxide solid solution material according to claim 1 or 2, characterized in that, The specific steps are as follows: (1) Using dry La2O3, Gd2O3, Yb2O3, Y2O3 and ZrO2 powders as raw materials, the raw materials are mixed and ball-milled; the resulting suspension I is dried and sieved in sequence to obtain mixed powder; (2) The mixed powder is subjected to high-temperature sintering to obtain a sintered product; (3) The sintered product is ball-milled, and the resulting suspension II is dried and sieved in sequence to obtain the five-element zirconium oxide solid solution material in powder form.

4. The method for preparing the pentagonal zirconium oxide solid solution material according to claim 3, characterized in that, In steps (1) and (3), the ball milling medium used for the ball milling process is anhydrous ethanol, and the grinding balls are silicon carbide grinding balls.

5. The method for preparing the pentagonal zirconium oxide solid solution material according to claim 3, characterized in that, In step (1), the ball milling time is 6 to 12 hours, the ball milling speed is 200 to 500 r / min, the drying temperature is 50 to 80℃, and the drying time is 5 to 10 hours. In step (3), the ball milling time is 8 to 24 hours, the ball milling speed is 200 to 500 r / min, the drying temperature is 70 to 120℃, and the drying time is 10 to 24 hours.

6. The method for preparing the pentagonal zirconium oxide solid solution material according to claim 3, characterized in that, In step (2), the high-temperature sintering temperature is 1450-1550℃, the time is 10-20h, and the sintering atmosphere is air.

7. The method for preparing the pentagonal zirconium oxide solid solution material according to claim 3, characterized in that, Also includes: (4) The powdered pentagonal zirconium oxide solid solution material is subjected to hot pressing and sintering to obtain the block-shaped pentagonal zirconium oxide solid solution material.

8. The method for preparing the pentagonal zirconium oxide solid solution material according to claim 7, characterized in that, In step (4), the hot pressing process includes two steps: mold dry pressing and heating and pressurizing sintering. The pressure range of mold dry pressing is 2 to 10 MPa, and the mold dry pressing time is 3 to 10 minutes. The pressure of hot pressing sintering is 20 to 50 MPa, the temperature of hot pressing sintering is 1400 to 1550 °C, the sintering atmosphere is argon, the holding time is 1 to 3 hours, and then the furnace is cooled to room temperature and removed.

9. The method for preparing the pentagonal zirconium oxide solid solution material according to claim 3, characterized in that, Step (1) also includes: calcining La2O3, Gd2O3, Yb2O3, Y2O3 and ZrO2 powders to obtain dry La2O3, Gd2O3, Yb2O3, Y2O3 and ZrO2 powders; The calcination treatment is carried out at a temperature of 900–1200°C for 2–5 hours.

10. The application of a pentagonal zirconium oxide solid solution material according to claim 1 or 2 in the field of thermal barrier coatings.

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