Complex-phase yttrium aluminum garnet ceramic precursor and preparation method thereof

Abstract

The invention provides a complex-phase yttrium aluminum garnet ceramic precursor and a preparation method thereof. The complex-phase yttrium aluminum garnet ceramic precursor is composed of yttrium aluminum garnet and hafnium oxide, and continuous ceramic fibers composed of YAG-HfO2 complex phases are obtained by introducing a second component hafnium oxide. By designing and adjusting the proportion of hafnium oxide, the variety and proportion of a complexing agent, the feeding mode and the like, YAG-HfO2 multiphase ceramic precursors with different proportions are prepared, and the YAG-HfO2 continuous ceramic fiber is prepared through melt spinning and post-treatment processes. The obtained YAG-HfO2 continuous ceramic fiber is excellent in mechanical property.

Description

Technical Field

[0001] This invention belongs to the field of composite fiber materials technology, specifically relating to a multiphase yttrium aluminum garnet ceramic precursor and its preparation method. Background Technology

[0002] Continuous ceramic fiber is a fibrous refractory material with a diameter in the micrometer range. It has the advantages of being lightweight, having low thermal conductivity, good thermal stability, thermal shock resistance, and high temperature resistance. It is mainly used as a high-temperature structural reinforcement to improve the fracture brittleness of ceramic matrix composites, prevent the propagation of cracks generated in ceramics under stress, improve damage tolerance, and achieve the strengthening and toughening of ceramic matrix composites. It has a very broad application prospect in aerospace and other fields.

[0003] Continuous ceramic fibers can be mainly divided into non-oxide ceramic fibers and oxide ceramic fibers. Among them, oxide fibers possess excellent high-temperature resistance, thermal stability, outstanding mechanical properties, and oxidation resistance, making them important in high-temperature oxygen-containing thermal insulation and structural applications. Based on their chemical composition, oxide continuous ceramic fibers can be classified into alumina fibers, zirconium oxide fibers, mullite fibers, yttrium aluminum garnet fibers, and related multiphase oxide fibers. Yttrium aluminum garnet (YAG) fiber, a novel inorganic ceramic fiber developed in the 1990s, exhibits a low high-temperature creep rate, strong thermal shock resistance, good physical and chemical stability, low thermal conductivity, and good resistance to water vapor corrosion, making it of significant research and application value.

[0004] For continuous fibers, ceramic precursors, as spinning raw materials, have a significant impact on the spinning process and are closely related to the structure and properties of the final ceramic fibers. Many institutions both domestically and internationally have conducted research on the preparation of YAG precursors. Whitepaterson Air Force Base, USA (…) J. Eur. Ceram. Soc. 35 (2015) 4251-4258) Commercially available YAG powder, adhesives, plasticizers, etc., are mixed in water to form a slurry, which is then physically extruded into fibers. The additives are then removed at high temperature to obtain YAG fibers; Nagoya Institute of Industrial Science, Japan ( Composites: Part A 32 (2001) 1127-1131) YAG fibers were obtained by reflux hydrolysis of organoaluminum salts and organoyttrium salts in a solvent to produce a spinnable precursor sol, followed by hand-drawing and post-treatment. Shaanxi University of Technology (CN102011215B) prepared a YAG precursor sol using inorganic aluminum salts, metallic aluminum powder, and yttrium oxide powder via a sol-gel method. After adding spinning aids, YAG fibers were obtained through spinning, drying, and calcination. However, the mechanical properties of these YAG fibers still have considerable room for improvement.

[0005] In the previous work, our research group ( Ceram. Inter.49 (2023) 32318-32323) prepared a solid YAG ceramic precursor with melt-spinning properties by hydrolyzing and polycondensing organoaluminate salts and organoyttrium salts in an organic solvent. YAG continuous ceramic fibers were prepared by melt spinning of the precursor. The highest average tensile strength reached 1.56 GPa and the modulus reached 252 GPa, which is significantly better than the tensile strength of previously reported yttrium aluminum garnet continuous fibers.

[0006] Based on previous work, this invention designs a multiphase composition for the YAG ceramic precursor and introduces a second component with excellent high-temperature grain size stability, which is expected to further improve the mechanical properties of the fiber.

[0007] In view of this, the present invention is hereby proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a novel multiphase yttrium aluminum garnet (YAG) ceramic precursor and its preparation method. The multiphase YAG ceramic precursor is composed of yttrium aluminum garnet and hafnium oxide. By introducing a second component, hafnium oxide, continuous ceramic fibers with a YAG-HfO2 multiphase composition are obtained. By designing and adjusting the proportion of hafnium oxide, the type and proportion of complexing agents, and the feeding method, YAG-HfO2 multiphase ceramic precursors with different proportions were prepared. Continuous YAG-HfO2 ceramic fibers were then prepared through melt spinning and post-processing.

[0009] The method for preparing multiphase yttrium aluminum garnet ceramic precursors provided by the present invention includes the following steps: 1) Dissolution: Add the aluminum source and yttrium source to solvent a, and stir at a heating temperature of 60-120°C until dissolved; 2) Coordination: At a heating temperature of 55-90°C, ligand b is added in a certain proportion, and coordination is completed under stirring; 3) Hydrolysis: Add a certain proportion of deionized water at a certain dripping rate, and reflux for 0.5-3 hours after the dripping is complete to complete the hydrolysis; 4) Introducing a hafnium source The hafnium source is introduced in one of the following three ways: a) a certain proportion of the hafnium source is dispersed in solvent c at 55-120°C, mixed with the solution obtained in step 1), and then the coordination process in step 2) and the hydrolysis process in step 3) are carried out; b) a certain proportion of the hafnium source is dispersed in solvent c at 55-120°C, then a certain proportion of ligand d is added, coordination is completed under stirring, and the solution is mixed with the solution obtained in step 2), and then the hydrolysis process in step 3) is carried out; c) a certain proportion of the hafnium source is dispersed in solvent c at 55-120°C, then a certain proportion of ligand d is added, coordination is completed under stirring, then a certain proportion of deionized water is added at a certain dropping rate, refluxed for 0.5-3 h after dropping, and mixed with the solution obtained in step 3). 5) Polycondensation: The solution obtained in step 4) is distilled under reduced pressure at a heating temperature of 180-260°C for 2-8 hours, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor.

[0010] In step 1) of the above method, the aluminum source is selected from at least one of aluminum isopropoxide, aluminum n-propoxide, and aluminum ethoxide; The yttrium source is selected from at least one of yttrium acetylacetone, yttrium isopropanol, and yttrium acetate; The amount of aluminum source and yttrium source fed into the plant is converted to an Al:Y molar ratio of 5:3. The solvent a is selected from at least one of methanol, n-propanol, isopropanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, and ethylene glycol butyl ether; In step 2) of the above method, the ligand b is selected from at least one of butanedione, acetylacetone, acetic acid, and ethyl acetoacetate; The total amount of metal elements in the aluminum and yttrium sources, and the molar ratio of ligand b, is 1:0.2-5; The stirring time can be 0.5-3 hours; In step 3) of the above method, the dripping rate is 0.5-5 drops / s; The total molar ratio of metal elements in the aluminum and yttrium sources to deionized water is 1:0.2-3; In step 4) of the above method, the hafnium source is selected from at least one of ethanol hafnium, n-propanol hafnium, and tert-butanol hafnium; The amount of hafnium source fed into the source, converted to an Al:Hf molar ratio of 5:0.1-1, is 1:1. The solvent c is selected from at least one of methanol, n-propanol, isopropanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, and ethylene glycol butyl ether; The ligand d is selected from at least one of butanedione, acetylacetone, acetic acid, and ethyl acetoacetate; The ratio of ligand d is such that the molar ratio of Hf element to ligand d is 1:0.2-5; The stirring time in steps b) and c) can be 0.5-3 hours; The deionized water ratio is such that the molar ratio of Hf element to deionized water is 1:0.2-3; The drip rate is 0.5-5 drops / s; The softening point of the obtained solid multiphase yttrium aluminum garnet ceramic precursor can be 120-150°C.

[0011] In the above method, the type and ratio of the ligands mainly affect the reaction site and degree of hydrolysis, which in turn affect the structure of the precursor and the distribution of metal elements, ultimately resulting in differences in the mechanical properties of ceramic fibers.

[0012] The multiphase yttrium aluminum garnet ceramic precursor prepared by the above method and its application in the preparation of materials with at least one of the properties of structural reinforcement and high-temperature insulation are also within the scope of protection of this invention.

[0013] Compared with the prior art, the present invention has the following advantages: 1. This invention, through the design of a multiphase composition of yttrium aluminum garnet ceramic precursors, introduces a second component with excellent high-temperature grain size characteristics, which is expected to further improve the mechanical properties of continuous fibers; 2. The yttrium aluminum garnet ceramic precursor prepared by this invention has the advantage of designable molecular structure. By adjusting the proportion of elements, the type and proportion of complexing agents, and the feeding method during the synthesis process, the spinnability of the precursor is improved, providing high-quality spinning raw materials for subsequent fiber preparation. 3. The yttrium aluminum garnet ceramic precursor prepared by this invention does not require the addition of spinning aids, and the solid precursor has a very low solvent content, which reduces the volatilization of organic solvents and waste gas during fiber formation and sintering, making it environmentally friendly. Attached Figure Description

[0014] Figure 1 The viscosity-temperature curves of the multiphase yttrium aluminum garnet ceramic precursor obtained in Example 1 of this invention are shown.

[0015] Figure 2 The image shows the XRD pattern of the multiphase yttrium aluminum garnet ceramic fiber obtained in Example 2 of this invention.

[0016] Figure 3 This is a SEM image of the multiphase yttrium aluminum garnet ceramic fiber obtained in Example 3 of the present invention.

[0017] Figure 4 The image shows the XRD pattern of the multiphase yttrium aluminum garnet ceramic fiber obtained in Example 3 of this invention. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0019] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0020] Example 1 1) Precursor synthesis: Solution A: Aluminum propoxide and yttrium isopropoxide were added to isopropanol as aluminum and yttrium sources, respectively, and stirred at 75°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium is 5:3. Subsequently, ethyl acetoacetate was added at 70°C and stirred for 3 h to complete coordination. The molar ratio of the total amount of Al and Y to ethyl acetoacetate was 1:5. Next, deionized water was added at a rate of 0.5 drops / s. The molar ratio of the total amount of Al and Y to deionized water was 1:3. After the addition was complete, the mixture was refluxed for 1 h to complete hydrolysis.

[0021] Solution B: Hafnium tert-butoxide was used as the hafnium source and dispersed in isopropanol at 70°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.31. Subsequently, ethyl acetoacetate ligand was added and stirred for 3 h to complete coordination. The molar ratio of Hf to ethyl acetoacetate was 1:0.2. Then, deionized water was added at a rate of 0.5 drops / s. The molar ratio of Hf to deionized water was 1:0.2. After the addition was complete, the mixture was refluxed for 1 h.

[0022] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 180°C for 6 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 120°C.

[0023] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 155°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the precursor fiber.

[0024] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0025] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.31 GPa.

[0026] The viscosity-temperature curve of the multiphase yttrium aluminum garnet ceramic solid precursor obtained in this embodiment is as follows: Figure 1 As shown. This solid precursor is fusible upon heating, and its viscosity decreases with increasing temperature, exhibiting rheological behavior similar to that of conventional polymers.

[0027] Example 2 1) Precursor synthesis: Solution A: Aluminum ethoxide and yttrium acetate were added to methanol as aluminum and yttrium sources, respectively, and stirred at 60°C until dissolved. The molar ratio of aluminum ethoxide to yttrium acetate was 5:3 (Al:Y). Subsequently, dimethylglyoxal (DME) ligand was added at 55°C, and coordination was completed after stirring for 0.5 h. The molar ratio of total Al and Y elements to DME was 1:0.2. Next, deionized water was added at a rate of 5 drops / s, with the molar ratio of total Al and Y elements to deionized water being 1:0.2. After the addition was complete, the mixture was refluxed for 0.5 h to complete hydrolysis.

[0028] Solution B: Hafnium ethanol was used as the hafnium source and dispersed in methanol at 55°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.1. Then, dimethylglyoxal (DME) ligand was added and stirred for 0.5 h to complete the coordination. The molar ratio of Hf to DME was 1:3. Next, deionized water was added at a rate of 5 drops / s. The molar ratio of Hf to deionized water was 1:2. After the addition was complete, the mixture was refluxed for 0.5 h.

[0029] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 190°C for 2 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 150°C.

[0030] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 185°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the precursor fiber.

[0031] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0032] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 900°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.24 GPa.

[0033] The crystal structure of the multiphase yttrium aluminum garnet continuous ceramic fiber obtained in this embodiment is as follows: Figure 2 As shown, the main crystal structure of the fiber is composed of YAG, which is because the amount of hafnium oxide added is so small that the diffraction peaks could not be detected by the instrument.

[0034] Example 3 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium acetylacetonate were added to n-propanol as aluminum and yttrium sources, respectively, and stirred at 90°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetylacetonate was 5:3 (Al:Y). Subsequently, acetylacetonate ligand was added at 80°C, and coordination was completed after stirring for 1 h. The molar ratio of total Al and Y elements to acetylacetonate was 1:0.6. Next, deionized water was added at a rate of 1 drop / s, with the molar ratio of total Al and Y elements to deionized water being 1:0.6. After the addition was complete, the mixture was refluxed for 2 h to complete hydrolysis.

[0035] Solution B: Hafnium n-propoxide was used as the hafnium source and dispersed in n-propanol at 80°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.31. Then, acetylacetone ligand was added and stirred for 1 h to complete the coordination. The molar ratio of Hf to acetylacetone was 1:1. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of Hf to deionized water was 1:0.4. After the addition was completed, the mixture was refluxed for 2 h.

[0036] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 230°C for 4 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0037] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 170°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the original fiber.

[0038] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0039] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.72 GPa.

[0040] The scanning electron microscope image of the multiphase yttrium aluminum garnet continuous ceramic fiber obtained in this embodiment is as follows: Figure 3 As shown, the XRD pattern is as follows Figure 4 As shown, the fiber has a uniform diameter, a smooth and dense surface, no obvious defects, and its main crystal structure is YAG and HfO2.

[0041] Example 4 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium isopropoxide were added to isopropanol as aluminum and yttrium sources, respectively, and stirred at 75°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium is 5:3. Subsequently, ethyl acetoacetate was added at 70°C and stirred for 1.5 h to complete coordination. The molar ratio of total Al and Y to ethyl acetoacetate was 1:1. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of total Al and Y to deionized water was 1:0.6. After the addition was complete, the mixture was refluxed for 2 h to complete hydrolysis.

[0042] Solution B: Hafnium n-propoxide was used as the hafnium source and dispersed in isopropanol at 70°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.31. Then, ethyl acetoacetate ligand was added and stirred for 1.5 h to complete the coordination. The molar ratio of Hf to ethyl acetoacetate was 1:2. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of Hf to deionized water was 1:0.4. After the addition was completed, the mixture was refluxed for 2 h.

[0043] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 210°C for 3 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0044] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 170°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the original fiber.

[0045] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0046] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.53 GPa.

[0047] Example 5 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium acetate were added to methanol as aluminum and yttrium sources, respectively, and stirred at 60°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetate was 5:3 (Al:Y). Subsequently, acetic acid ligand was added at 55°C and stirred for 2 h to complete coordination. The molar ratio of total Al and Y elements to acetic acid was 1:2. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of total Al and Y elements to deionized water was 1:0.6. After the addition was complete, the mixture was refluxed for 2 h to complete hydrolysis.

[0048] Solution B: Hafnium propoxide was used as the hafnium source and dispersed in methanol at 55°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.31. Then, acetic acid ligand was added and stirred for 2 h to complete the coordination. The molar ratio of Hf to acetic acid was 1:4. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of Hf to deionized water was 1:0.4. After the addition was completed, the mixture was refluxed for 2 h.

[0049] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 200°C for 4 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0050] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 165°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the precursor fiber.

[0051] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0052] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.38 GPa.

[0053] Example 6 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium acetylacetonate were added to n-propanol as aluminum and yttrium sources, respectively, and stirred at 90°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetylacetonate was 5:3 (Al:Y). Subsequently, dimethylglyoxal (DME) ligand was added at 80°C, and coordination was completed after stirring for 1 h. The molar ratio of total Al and Y elements to DME was 1:0.6. Next, deionized water was added at a rate of 1 drop / s, with the molar ratio of total Al and Y elements to deionized water being 1:0.6. After the addition was complete, the mixture was refluxed for 2 h to complete hydrolysis.

[0054] Solution B: Hafnium ethanol was used as the hafnium source and dispersed in n-propanol at 80°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.31. Then, dimethylglyoxal (DME) ligand was added and stirred for 1 h to complete the coordination. The molar ratio of Hf to DME was 1:1. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of Hf to deionized water was 1:0.4. After the addition was complete, the mixture was refluxed for 2 h.

[0055] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 230°C for 4 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0056] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 170°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the original fiber.

[0057] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0058] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.41 GPa.

[0059] Example 7 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium acetylacetonate were added to n-propanol as aluminum and yttrium sources, respectively, and stirred at 90°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetylacetonate was 5:3 (Al:Y). Subsequently, acetylacetonate ligand was added at 80°C, and coordination was completed after stirring for 2.5 h. The molar ratio of total Al and Y elements to acetylacetonate was 1:3. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of total Al and Y elements to deionized water was 1:1.5. After the addition was complete, the mixture was refluxed for 2 h to complete hydrolysis.

[0060] Solution B: Hafnium n-propoxide was used as the hafnium source and dispersed in n-propanol at 80°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.31. Then, acetylacetone ligand was added and stirred for 2.5 h to complete coordination. The molar ratio of Hf to acetylacetone was 1:5. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of Hf to deionized water was 1:3. After the addition was complete, the mixture was refluxed for 2 h.

[0061] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 230°C for 4 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0062] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 170°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the original fiber.

[0063] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0064] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.59 GPa.

[0065] Example 8 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium acetylacetonate were added to n-propanol as aluminum and yttrium sources, respectively, and stirred at 90°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetylacetonate was 5:3 (Al:Y). Subsequently, acetylacetonate ligand was added at 80°C, and coordination was completed after stirring for 1 h. The molar ratio of total Al and Y elements to acetylacetonate was 1:0.6. Next, deionized water was added at a rate of 3 drops / s, with the molar ratio of total Al and Y elements to deionized water being 1:0.6. After the addition was complete, the mixture was refluxed for 3 h to complete hydrolysis.

[0066] Solution B: Hafnium n-propoxide was used as the hafnium source and dispersed in n-propanol at 80°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.31. Then, acetylacetone ligand was added and stirred for 1 h to complete coordination. The molar ratio of Hf to acetylacetone was 1:1. Next, deionized water was added at a rate of 3 drops / s. The molar ratio of Hf to deionized water was 1:0.4. After the addition was completed, the mixture was refluxed for 3 h.

[0067] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 230°C for 4 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0068] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 170°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the original fiber.

[0069] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0070] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.22 GPa.

[0071] Example 9 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium acetylacetonate were added to ethylene glycol monomethyl ether as aluminum and yttrium sources, respectively, and stirred at 110°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetylacetonate was 5:3 (Al:Y). Subsequently, acetylacetonate ligand was added at 85°C, and coordination was completed after stirring for 1 h. The molar ratio of total Al and Y elements to acetylacetonate was 1:0.6. Next, deionized water was added at a rate of 1 drop / s, with the molar ratio of total Al and Y elements to deionized water being 1:0.6. After the addition was complete, the mixture was refluxed for 2 h to complete hydrolysis.

[0072] Solution B: Hafnium propoxide was used as the hafnium source and dispersed in ethylene glycol methyl ether at 85°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.15. Then, acetylacetone ligand was added and stirred for 1 h to complete coordination. The molar ratio of Hf to acetylacetone was 1:1. Next, deionized water was added at a rate of 1 drop / s. The molar ratio of Hf to deionized water was 1:0.4. After the addition was complete, the mixture was refluxed for 2 h.

[0073] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 250°C for 5 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0074] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 175°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the precursor fiber.

[0075] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0076] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1000°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.55 GPa.

[0077] Example 10 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium acetylacetonate were added to ethylene glycol butyl ether as aluminum and yttrium sources, respectively, and stirred at 120°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetylacetonate was 5:3 (Al:Y). Subsequently, acetylacetonate ligand was added at 90°C, and coordination was completed after stirring for 1 h. The molar ratio of total Al and Y elements to acetylacetonate was 1:0.6. Next, deionized water was added at a rate of 1 drop / s, with the molar ratio of total Al and Y elements to deionized water being 1:0.6. After the addition was complete, the mixture was refluxed for 2 h to complete hydrolysis.

[0078] Solution B: Hafnium propoxide was used as the hafnium source and dispersed in ethylene glycol butyl ether at 90°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.7. Subsequently, acetylacetone ligand was added and stirred for 1 h to complete coordination. The molar ratio of Hf to acetylacetone was 1:1. Then, deionized water was added at a rate of 1 drop / s. The molar ratio of Hf to deionized water was 1:0.4. After the addition was completed, the mixture was refluxed for 2 h.

[0079] After mixing solution A and solution B, the mixture was distilled under reduced pressure at a heating temperature of 260°C for 5 h, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0080] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 180°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the precursor fiber.

[0081] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0082] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.39 GPa.

[0083] Example 11 1) Precursor synthesis: Solution A: Aluminum isopropoxide and yttrium acetylacetonate were added to n-propanol as aluminum and yttrium sources, respectively, and stirred at 90°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetylacetonate was 5:3 (Al:Y). Subsequently, acetylacetonate ligand was added at 80°C, and coordination was completed after stirring for 1 h. The molar ratio of the total amount of Al and Y to acetylacetonate was 1:0.6. Solution B: Hafnium n-propoxide was used as the hafnium source and dispersed in n-propanol at 80°C. The amount of hafnium source added was converted to an elemental molar ratio of Al:Hf of 5:0.31. Subsequently, acetylacetone ligand was added and the coordination was completed after stirring for 1 h. The molar ratio of Hf element to acetylacetone was 1:1. After mixing solution A and solution B, deionized water was added at a rate of 1 drop / s. The total amount of Al, Y and Hf elements was added to deionized water in a molar ratio of 1:1. The mixture was then refluxed for 2 hours after the addition was complete. The solid-state multiphase yttrium aluminum garnet ceramic precursor was obtained by vacuum distillation at a heating temperature of 230°C for 4 h, followed by cooling to room temperature, with a softening point of 135°C.

[0084] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 170°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the original fiber.

[0085] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0086] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.48 GPa.

[0087] Example 12 1) Precursor synthesis: Aluminum isopropoxide, yttrium acetylacetonate, and hafnium n-propoxide were added to n-propanol as aluminum, yttrium, and hafnium sources, respectively, and stirred at 90°C until dissolved. The molar ratio of aluminum isopropoxide and yttrium acetylacetonate was 5:3 (Al:Y), and the molar ratio of hafnium source to Al:Hf was 5:0.31. Subsequently, acetylacetonate ligand was added at 80°C, and coordination was completed after stirring for 1 h. The total molar ratio of Al, Y, and Hf to acetylacetonate was 1:1.6. Next, deionized water was added at a rate of 1 drop / s, with the total molar ratio of Al, Y, and Hf to deionized water being 1:1. The mixture was then refluxed for 2 h. The solid-state multiphase yttrium aluminum garnet ceramic precursor was obtained by vacuum distillation at a heating temperature of 230°C for 4 h, followed by cooling to room temperature, with a softening point of 135°C.

[0088] 2) Melt spinning: The solid multiphase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 170°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the original fiber.

[0089] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0090] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain multiphase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.32 GPa.

[0091] As can be seen from Examples 3, 11, and 12, the average tensile strength of the multiphase yttrium aluminum garnet continuous ceramic fibers prepared by dissolving, coordinating, and hydrolyzing aluminum isopropoxide and yttrium acetylacetonate, and then dissolving, coordinating, and hydrolyzing hafnium n-propoxide to prepare solution B, and then mixing solution B with solution A, is better.

[0092] Comparative Example 1 1) Precursor synthesis: Aluminum isopropoxide and yttrium acetylacetonate were added to n-propanol as aluminum and yttrium sources, respectively, and stirred at 90°C until dissolved. The molar ratio of aluminum isopropoxide to yttrium acetylacetonate was 5:3 (Al:Y). Subsequently, acetylacetonate ligand was added at 80°C, and coordination was completed after stirring for 1 h. The molar ratio of total Al and Y elements to acetylacetonate was 1:0.6. Next, deionized water was added at a rate of 1 drop / s, with the molar ratio of total Al and Y elements to deionized water being 1:0.6. After the addition was complete, the mixture was refluxed for 2 h to complete hydrolysis.

[0093] Without adding a hafnium source, the above solution was directly distilled under reduced pressure at a heating temperature of 230°C for 4 h, and then cooled to room temperature to obtain a solid single-phase yttrium aluminum garnet ceramic precursor with a softening point of 135°C.

[0094] 2) Melt spinning: The solid single-phase yttrium aluminum oxide ceramic precursor prepared in step 1) is placed in the spinning machine barrel and heated to 170°C. After the solid precursor melts into a uniform melt and removes residual bubbles, the melt is extruded through a 0.2 mm spinneret orifice under a screw pressure of 15 MPa and drawn by a take-up roller with a rotation speed of 650 m / min to obtain the precursor fiber.

[0095] 3) High-temperature steam crosslinking and adhesive removal integrated treatment: The raw fibers obtained in step 2) are placed in a sealed steam furnace. During the debinding and sintering process, water vapor is continuously introduced at a rate of 60 L / h. The temperature is raised to 600°C at a rate of 1°C / min. When the temperature reaches 100°C, the steam inlet valve is opened. When the program reaches 600°C, the steam valve is closed. Then, the temperature is maintained for 3 hours to obtain inorganic fibers.

[0096] 4) Ceramization treatment: The inorganic fibers obtained in step 3) were placed in a muffle furnace and heated to 1100°C at a rate of 10°C / min, and held for 30 min to obtain single-phase yttrium aluminum garnet continuous ceramic fibers with an average diameter of 8 μm and an average tensile strength of 1.36 GPa.

[0097] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A method for preparing a multiphase yttrium aluminum garnet ceramic precursor, comprising the following steps: 1) Dissolution: Add the aluminum source and yttrium source to solvent a, and stir at a heating temperature of 60-120°C until dissolved; 2) Coordination: At a heating temperature of 55-90°C, ligand b is added in a certain proportion, and coordination is completed under stirring; 3) Hydrolysis: Add a certain proportion of deionized water at a certain dripping rate, and reflux for 0.5-3 hours after the dripping is complete to complete the hydrolysis; 4) Introducing a hafnium source The hafnium source is introduced in one of the following three ways: a) a certain proportion of the hafnium source is dispersed in solvent c at 55-120°C, mixed with the solution obtained in step 1), and then the coordination process in step 2) and the hydrolysis process in step 3) are carried out; b) a certain proportion of the hafnium source is dispersed in solvent c at 55-120°C, then a certain proportion of ligand d is added, coordination is completed under stirring, and the solution is mixed with the solution obtained in step 2), and then the hydrolysis process in step 3) is carried out; c) a certain proportion of the hafnium source is dispersed in solvent c at 55-120°C, then a certain proportion of ligand d is added, coordination is completed under stirring, then a certain proportion of deionized water is added at a certain dropping rate, refluxed for 0.5-3 h after dropping, and mixed with the solution obtained in step 3). 5) Polycondensation: The solution obtained in step 4) is distilled under reduced pressure at a heating temperature of 180-260°C for 2-8 hours, and then cooled to room temperature to obtain a solid multiphase yttrium aluminum garnet ceramic precursor.

2. The method according to claim 1, characterized in that, In step 1), the aluminum source is selected from at least one of aluminum isopropoxide, aluminum n-propoxide, and aluminum ethoxide; The yttrium source is selected from at least one of yttrium acetylacetone, yttrium isopropanol, and yttrium acetate; The amount of aluminum source and yttrium source fed into the plant is converted to an Al:Y molar ratio of 5:

3. The solvent a is selected from at least one of methanol, n-propanol, isopropanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, and ethylene glycol butyl ether.

3. The method according to claim 1 or 2, characterized in that, In step 2), the ligand b is selected from at least one of butanedione, acetylacetone, acetic acid, and ethyl acetoacetate; The total amount of metal elements in the aluminum and yttrium sources is in a molar ratio of 1:0.2-5 to ligand b.

4. The method according to claim 1 or 2, characterized in that, In step 3), the dripping rate is 0.5-5 drops / s; The total amount of metal elements in the aluminum and yttrium sources is in a molar ratio of 1:0.2-3 to deionized water.

5. The method according to claim 1 or 2, characterized in that, In step 4), the hafnium source is selected from at least one of ethanol hafnium, n-propanol hafnium, and tert-butanol hafnium; The amount of hafnium source fed into the source, converted to an Al:Hf molar ratio of 5:0.1-1, is 1:

1. The solvent c is selected from at least one of methanol, n-propanol, isopropanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, and ethylene glycol butyl ether; The ligand d is selected from at least one of butanedione, acetylacetone, acetic acid, and ethyl acetoacetate; The ratio of ligand d is such that the molar ratio of Hf element to ligand d is 1:0.2-5; The deionized water ratio is such that the molar ratio of Hf element to deionized water is 1:0.2-3; The drip rate is 0.5-5 drops / s.

6. A multiphase yttrium aluminum garnet ceramic precursor prepared by the method of any one of claims 1-5.

7. The solid-state multiphase yttrium aluminum garnet ceramic precursor according to claim 6, characterized in that, The softening point of the solid multiphase yttrium aluminum garnet ceramic precursor is 120-150°C.

8. The application of the multiphase yttrium aluminum garnet ceramic precursor as described in claim 6 or 7 in the preparation of YAG-HfO2 continuous ceramic fibers.

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