CMAS-corrosion-resistant modified monosilicate ceramic material as well as preparation method and application thereof

Abstract

The invention discloses a modified monosilicate ceramic material resistant to CMAS corrosion and a preparation method and application thereof, and relates to the technical field of aero-engine coating materials, the modified monosilicate ceramic material is (Yb1-XScX) 2SiO5, X = 0.1-0.3, the (Yb1-XScX) 2SiO5 is prepared from Yb2O3 powder, Sc2O3 powder and SiO2 powder, and the molar ratio of the Yb2O3 powder to the Sc2O3 powder to the SiO2 powder is (10-10) x: 10 x: 10. According to the modified monosilicate ceramic material resistant to CMAS corrosion, a modified monosilicate (Yb1-XScX) 2SiO5 block is obtained through dry pressing forming and high-temperature sintering, the corrosion rate of rare earth ions and CMAS is reduced through doping of Sc < 3 + >, and therefore the CMAS corrosion resistance of the material is more excellent than that of a single rare earth monosilicate Yb2SiO5 ceramic material, and the material is suitable for serving under the high-temperature complex working condition; and the service life of the environment barrier coating is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of aeroengine coating materials, and particularly relates to a modified monosilicate ceramic material resistant to CMAS corrosion, a preparation method thereof, and an application thereof. Background Art

[0002] For aeroengine superalloy components serving in a high-temperature, high-pressure, and harsh turbine environment for a long time, the surface environmental barrier coating ceramic material must meet the following requirements: good fracture toughness to improve the stress-strain tolerance of the coating and avoid failure caused by coating stress concentration; high hardness to resist particle erosion and impact in the gas; excellent CMAS corrosion resistance to extend the service life of the thermal barrier coating, etc.

[0003] The single-component rare-earth monosilicate material has become one of the candidate systems for environmental barrier coatings due to its better water and oxygen corrosion resistance than YSZ. However, its comprehensive mechanical, thermal, and CMAS corrosion resistance properties have limitations and cannot provide stable guarantee for the long-life service of environmental barrier coatings. With the continuous development and improvement of the monosilicate ceramic system, a large number of studies have confirmed that after doping and modification design of various monosilicate ceramics with excellent properties, the comprehensive mechanical, thermal, and corrosion resistance properties of the ceramic materials are usually more excellent than those of single-component monosilicates, making them have broad development potential in the field of aerospace high-temperature structural materials. Summary of the Invention

[0004] The purpose of the present invention is to overcome and supplement the deficiencies existing in the prior art, and provide a modified monosilicate ceramic material resistant to CMAS corrosion, a preparation method thereof, and an application thereof, so as to solve the problem of poor CMAS corrosion resistance of environmental barrier coating materials.

[0005] To solve the problems of the prior art, the technical solution adopted by the present invention is as follows:

[0006] A preparation method of a modified monosilicate ceramic material resistant to CMAS corrosion, comprising the following steps:

[0007] Step S1. Weigh Yb2O3 powder, Sc2O3 powder, and SiO2 powder according to a molar ratio of 10 - 10x:10x:10, and add a ball-milling medium for ball milling to obtain a uniform mixed solution;

[0008] Step S2. After drying the mixed solution, perform a high-temperature solid-phase reaction to obtain a modified monosilicate ceramic powder;

[0009] Step S3. After grinding, sieving, PVA granulation, dry pressing, debinding, and sintering the modified monosilicate ceramic powder in sequence, obtain a modified monosilicate ceramic material resistant to CMAS corrosion.

[0010] As an improvement, in step S1, the ball milling rotation speed is 300 - 400 rpm, and the ball milling time is 6 - 24 h.

[0011] As an improvement, in step S2, the drying temperature is 80 - 90 °C, the drying time is 12 - 24 h, the high-temperature solid-phase reaction temperature is 1500 - 1550 °C, and the reaction time is 5 - 10 h.

[0012] As an improvement, in step S3, the mesh number of sieving is 120 - 150 meshes; dry pressing and forming are carried out with two pressurizations. The pressure of the first pressurization is 100 - 180 MPa, the time is 1 - 2 min, the pressure of the second pressurization is 60 - 100 MPa, and the time is 20 s - 50 s.

[0013] As an improvement, in step S3, the debinding temperature is 550 - 650 °C, the debinding time is 2.5 - 4 h, and sintering is carried out in stages. The temperature of the first sintering is 1600 - 1700 °C, the sintering time is 20 - 30 min, and the temperature of the second sintering is 1580 - 1600 °C, and the sintering time is 5 - 20 h.

[0014] As an improvement, the modified monosilicate ceramic material is prepared from Yb2O3 powder, Sc2O3 powder and SiO2 powder according to a molar ratio of 10 - 10x:10x:10, and its structural formula is (Yb 1-X Sc X )2SiO5, where x = 0.1 - 0.3; the modified monosilicate ceramic material is a single phase, with a stable structure, does not decompose at 1650 °C, has good high-temperature stability and excellent CMAS resistance performance.

[0015] The application of the above-mentioned CMAS corrosion-resistant modified monosilicate ceramic material in preparing an environmental barrier coating on the surface of a hot-end component of an aero-engine.

[0016] Beneficial effects:

[0017] Compared with the prior art, a CMAS corrosion-resistant modified monosilicate ceramic material, its preparation method and application of the present invention obtain a modified monosilicate (Yb 1-X Sc X )2SiO5 bulk material through dry pressing and high-temperature sintering. The doping of Sc 3+ reduces the corrosion rate of rare earth ions and CMAS, which drops from 7.1 μm / h of the undoped to 4.9 μm / h. Therefore, the CMAS corrosion resistance of this material is more excellent than that of the single rare earth monosilicate Yb2SiO5 ceramic material, is suitable for serving under high-temperature complex working conditions, and is beneficial to improving the service life of the environmental barrier coating. Description of the drawings

[0018] Figure 1 XRD schematic diagram of the ceramic material prepared for the present invention.

[0019] Figure 2 (a) and Figure 2 (b) are respectively the schematic diagrams of the surface microtopographies of Example 1 and Example 2.

[0020] Figure 3 Schematic diagram for comparing the hardness and elastic modulus of Example 1, Example 2 and Comparative Example 1.

[0021] Figure 4 Schematic diagram for comparing the corrosion layers of Example 1, Example 2 and Comparative Example 1.

[0022] Figure 5 Schematic diagram for comparing the corrosion layer thicknesses of Example 1, Example 2 and Comparative Example 1.

[0023] Figure 6 Schematic diagram for comparing the corrosion rates of Example 1, Example 2 and Comparative Example 1. Detailed implementation manners

[0024] The present invention will be further described below in conjunction with specific drawings and examples.

[0025] Example 1

[0026] A preparation method of a modified monosilicate ceramic material resistant to CMAS corrosion includes the following steps:

[0027] Step S1. Weigh Yb2O3 powder, Sc2O3 powder and SiO2 powder according to the molar ratio of 9:1:10, add ball-milling media for ball milling, the ball-milling speed is 400 rpm, and the ball-milling time is 24 h to obtain a uniform mixed solution;

[0028] Step S2. Dry the mixed solution, the drying temperature is 80 °C, the drying time is 12 h, and then perform a high-temperature solid-state reaction. The temperature of the high-temperature solid-state reaction is 1550 °C, and the reaction time is 5 h to obtain a modified monosilicate ceramic powder;

[0029] Step S3. The modified monosilicate ceramic powder is successively subjected to grinding, sieving, PVA granulation, dry pressing, debinding, and sintering to obtain a modified monosilicate ceramic material resistant to CMAS corrosion. The mesh number for sieving is 120 meshes; the concentration of PVA during PVA granulation is 5%, aiming to enhance the plasticity of the modified ceramic powder to achieve the granulation effect. The dry pressing is carried out with two-stage pressing. The pressure for the first-stage pressing is 180 MPa and the time is 1 min, and the pressure for the second-stage pressing is 80 MPa and the time is 30 s; the debinding temperature is 550 °C and the debinding time is 2.5 h. The temperature for the first-stage sintering is 1650 °C and the sintering time is 3 h, and the temperature for the second-stage sintering is 1600 °C and the sintering time is 10 h.

[0030] Example 2

[0031] A preparation method of a modified monosilicate ceramic material resistant to CMAS corrosion includes the following steps:

[0032] Step S1. Weigh Yb2O3 powder, Sc2O3 powder, and SiO2 powder according to a molar ratio of 7:3:10, add ball milling media for ball milling. The ball milling speed is 400 rpm and the ball milling time is 24 h to obtain a uniform mixed solution;

[0033] Step S2. Dry the mixed solution. The drying temperature is 80 °C and the drying time is 12 h. Subsequently, carry out high-temperature solid-state reaction. The temperature of the high-temperature solid-state reaction is 1550 °C and the reaction time is 5 h to obtain a modified monosilicate ceramic powder;

[0034] Step S3. The modified monosilicate ceramic powder is successively subjected to grinding, sieving, PVA granulation, dry pressing, debinding, and sintering to obtain a modified monosilicate ceramic material resistant to CMAS corrosion. The mesh number for sieving is 120 meshes; the concentration of PVA during PVA granulation is 5%, aiming to enhance the plasticity of the modified ceramic powder to achieve the granulation effect. The dry pressing is carried out with two-stage pressing. The pressure for the first-stage pressing is 180 MPa and the time is 1 min, and the pressure for the second-stage pressing is 70 MPa and the time is 30 s; the debinding temperature is 550 °C and the debinding time is 2.5 h. The temperature for the first-stage sintering is 1650 °C and the sintering time is 3 h, and the temperature for the second-stage sintering is 1600 °C and the sintering time is 10 h.

[0035] Comparative Example 1

[0036] A monosilicate ceramic material, the monosilicate ceramic material is Yb2SiO5, and the Yb2SiO5 is prepared from Yb2O3 powder and SiO2 powder. The molar ratio of Yb2O3 powder and SiO2 is 1:1.

[0037] A preparation method of a single silicate ceramic material resistant to CMAS corrosion, comprising the following steps:

[0038] Step S1. Weigh Yb2O3 powder and SiO2 powder according to a molar ratio of 1:1. Then mix the above powders and add ball-milling media for ball-milling. The ball-milling speed is 400 rpm and the ball-milling time is 24 h to obtain a uniform mixed solution;

[0039] Step S2. Dry the mixed solution at a drying temperature of 80 °C for 12 h, and then carry out a high-temperature solid-state reaction at a high-temperature solid-state reaction temperature of 1500 °C for 5 h to obtain a single silicate ceramic powder;

[0040] Step S3. After the single silicate ceramic powder is successively ground, sieved, granulated with PVA, dry-pressed into shape, debinded, and sintered, a single silicate ceramic material is obtained. Among them, the mesh number of sieving is 120 meshes; the concentration of PVA during PVA granulation is 5%, aiming to enhance the plasticity of the modified ceramic powder to achieve the granulation effect. The dry pressing is carried out with two pressurizations. The pressure of the first pressurization is 180 MPa and the time is 1 min. The pressure of the second pressurization is 60 MPa and the time is 25 s; the debinding temperature is 550 °C and the debinding time is 2.5 h. The sintering temperature is 1550 °C and the sintering time is 10 h.

[0041] The performance test results are as Figures 1-6 shown. It can be seen from Figure 1 that the modified ceramic materials (Yb 0.9 Sc 0.1 )2SiO5 and (Yb 0.7 Sc 0.3 )2SiO5 are successfully synthesized by the solid-state reaction method;

[0042] As Figure 2 (a) and Figure 2 (b) show, the surface of the modified single silicate ceramic materials prepared in Examples 1-2 is dense and the porosity is low;

[0043] It can be seen from Figure 3 that the elastic modulus and hardness of Example 1 are 114.12 GPa and 6.13 GPa respectively, and the elastic modulus and hardness of Example 2 are 117.56 GPa and 7.06 GPa respectively, both of which are higher than the elastic modulus and hardness of 88.64 GPa and 4.93 GPa in Comparative Example 1, which is beneficial to enhancing the strain tolerance and anti-particle erosion ability of the coating material;

[0044] It can be seen from Figure 4It can be seen that in the early stage of internal corrosion of Example 1 and Example 2, black platy anorthite, grayish-white acicular apatite and large garnet appeared. Subsequently, the black anorthite began to decompose and decrease. Eventually, more apatite and inclusion garnet were retained inside, and part of the CMAS remained and did not completely react, indicating that the corrosion rate of the modified monosilicate ceramic by CMAS decreased, which is greatly related to the formation of an effective protective layer composed of apatite inside. In addition, a small amount of small garnet and a large amount of apatite were observed from the cross-section of Comparative Example 1, indicating that the modified monosilicate improved the anti-CMAS corrosion ability of Yb2SiO5;

[0045] It can be seen from Figure 5 that the corrosion layer thicknesses of Example 1 and Example 2 at 5 h, 10 h and 20 h were 13.83, 19.94, 27.44 μm and 10.19, 15.64, 23.26 μm respectively. Both were smaller than the corrosion layer thicknesses of Comparative Example 1 at 5 h, 10 h and 20 h, which were 16.89, 22.27, 31.66 μm, indicating that the modified monosilicate improved the CMAS corrosion resistance of the monosilicate Yb2SiO5.

[0046] It can be seen from Figure 6 that the corrosion rates of Example 1 and Example 2 were 6.32 μm / h and 4.95 μm / h respectively, both lower than the corrosion rate of Comparative Example 1, which was 7.11 μm / h, indicating that the doping of Sc 3+ reduced the corrosion rate of the material with CMAS, so that the anti-CMAS corrosion ability of the material was more excellent than that of the single rare-earth monosilicate Yb2SiO5 ceramic material.

[0047] In summary, compared with the Yb2SiO5 of a single rare-earth component, the modified rare-earth monosilicate ceramic material of the present invention obtained a denser sample through segmented sintering, had higher hardness and elastic modulus and was more resistant to CMAS corrosion, and could meet the material selection requirements of environmental barrier coating materials for thermal properties.

[0048] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A preparation method of a modified single silicate ceramic material resistant to CMAS corrosion, characterized in that, It includes the following steps: Step S1. Weigh Yb2O3 powder, Sc2O3 powder and SiO2 powder according to the molar ratio of 10 - 10x:10x:10, and add ball-milling media for ball milling to obtain a uniform mixed solution; Step S2. After drying the mixed solution, carry out high-temperature solid-state reaction to obtain modified monosilicate ceramic powder; Step S3. After grinding, sieving, PVA granulation, dry pressing, debinding and sintering the modified monosilicate ceramic powder in sequence, obtain a modified monosilicate ceramic material resistant to CMAS corrosion.

2. The preparation method of the modified single silicate ceramic material resistant to CMAS corrosion according to claim 1, characterized in that: In step S1, the ball-milling speed is 300 - 400 rpm and the ball-milling time is 6 - 24 h.

3. The preparation method of the modified single silicate ceramic material resistant to CMAS corrosion according to claim 1, characterized in that: In step S2, the drying temperature is 80 - 90 °C, the drying time is 12 - 24 h, the high-temperature solid-state reaction temperature is 1500 - 1550 °C, and the reaction time is 5 - 10 h.

4. The preparation method of the modified single silicate ceramic material resistant to CMAS corrosion according to claim 1, wherein: In step S3, the mesh number of sieving is 120 - 150 meshes; the dry pressing is carried out with two pressurizations. The pressure of the first pressurization is 100 - 180 MPa and the time is 1 - 2 min. The pressure of the second pressurization is 60 - 100 MPa and the time is 20 s - 50 s.

5. The preparation method of the modified single silicate ceramic material resistant to CMAS corrosion according to claim 1, characterized in that: In step S3, the debinding temperature is 550 - 650 °C and the debinding time is 2.5 - 4 h. The sintering is carried out in stages. The temperature of the first sintering is 1600 - 1700 °C and the sintering time is 20 - 30 min. The temperature of the second sintering is 1580 - 1600 °C and the sintering time is 5 - 20 h.

6. The modified single silicate ceramic material resistant to CMAS corrosion prepared by the preparation method according to any one of claims 1-5, characterized in that: The modified monosilicate ceramic material is prepared from Yb2O3 powder, Sc2O3 powder and SiO2 powder according to a molar ratio of 10 - 10x:10x:10, and its structural formula is (Yb 1-X Sc X )2SiO5, where x = 0.1 - 0.3; the modified monosilicate ceramic material is a single phase, has a stable structure, does not decompose at 1650 °C, has good high-temperature stability, and excellent CMAS resistance.

7. Application of the modified monosilicate ceramic material resistant to CMAS corrosion according to claim 6 in preparing an environmental barrier coating on the surface of a hot-end component of an aeroengine.

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