Preparation method of spinel with high entropy and double optimization of configuration entropy and grain boundary segregation energy
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LUOYANG INST OF SCI & TECH
- Filing Date
- 2026-01-15
- Publication Date
- 2026-06-05
AI Technical Summary
Existing high-entropy spinel preparation technologies suffer from problems such as single-index optimization, grain boundary impurity enrichment, and poor overall performance synergy, making it difficult to meet the requirements for use in harsh high-temperature environments.
Using pentagonal metal oxides with a purity of ≥99.9% as raw materials, the dual index design of configuration entropy and grain boundary segregation energy was carried out by CALPHAD method, and combined with a two-step sintering process, grain boundary purification treatment was achieved, including forming, densification and grain boundary optimization. EBSD electron backscatter diffraction technology was used to monitor grain boundary characteristics in real time.
The prepared high-entropy spinel material exhibits an erosion rate of <0.1mm/100h at 1650℃, a permeability of <, a thermal shock cycle life of >1500 cycles (ΔT=800℃), a fracture toughness of ≥, and a material performance consistency deviation of <3%, making it suitable for harsh environments such as glass melting furnace linings.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of refractory ceramic materials technology, and in particular to a method for preparing high-entropy spinel with dual optimization of configuration entropy and grain boundary segregation energy. Background Technology
[0002] High-entropy spinel, as a novel type of multi-element solid solution ceramic material, exhibits great application potential in harsh environments such as glass melting furnaces and high-temperature reaction equipment due to its high lattice stability and excellent corrosion resistance resulting from the synergistic effect of multiple elements. However, existing high-entropy spinel preparation technologies still have significant shortcomings, making it difficult to meet the stringent requirements for comprehensive performance in industrial settings.
[0003] Patent document CN202310731599 discloses a preparation process for spinel-type high-entropy oxides. The process optimizes lattice stability by adjusting the element ratio. However, it adopts a conventional single sintering process and lacks a targeted grain boundary purification design. The grain boundary segregation energy cannot be effectively controlled, making it difficult to balance the thermal shock stability and low permeability of the material. This makes it unsuitable for scenarios such as glass melting furnace linings that need to withstand drastic temperature changes and melt penetration.
[0004] Patent document CN115594497A discloses a magnetic high-entropy ceramic and its preparation method. It improves the stability of the material by regulating the configuration entropy through the combination of multiple metal ions. However, this technology only focuses on optimizing the single index of configuration entropy and does not consider the influence of grain boundary segregation energy on the material properties. This results in the easy accumulation of impurity phases and high defect density at grain boundaries. During long-term service at high temperatures, grain boundary cracking is likely to occur, and the corrosion resistance is insufficient.
[0005] Patent document CN113501709B uses a hydrothermal method to prepare high-entropy oxide materials. Although the microstructure has been improved through process optimization, the correlation between configuration entropy and grain boundary performance has not been established. Furthermore, the materials prepared by the hydrothermal method have low density (<95%) and are prone to structural failure under high-temperature corrosion environments, which limits their large-scale industrial application.
[0006] Patent document CN202410665618 discloses a method for preparing high-entropy ceramic films, which achieves grain boundary densification by controlling the heating rate. However, it does not specify the quantitative design standard for configuration entropy, nor does it precisely control the grain boundary segregation energy, resulting in poor material performance consistency and difficulty in meeting the requirements of large industrial components.
[0007] In summary, existing technologies generally suffer from technical pain points such as "single index optimization, lack of grain boundary regulation, and poor overall performance synergy." There is an urgent need for a dual-optimization preparation scheme that takes into account both configuration entropy and grain boundary segregation energy, so as to simultaneously improve the corrosion resistance, low permeability, and thermal shock stability of high-entropy spinel, and solve the problem of short lifespan and easy failure of traditional materials under high temperature and harsh environments. Summary of the Invention
[0008] The purpose of this invention is to provide a method for preparing high-entropy spinel with dual optimization of configuration entropy and grain boundary segregation energy, which solves the problems of single index optimization, grain boundary impurity enrichment, and difficulty in simultaneously achieving high-temperature corrosion resistance and thermal shock stability in existing high-entropy spinel preparation technologies. This invention adopts a solid-state sintering process, which has the advantages of low cost, controllable operation, and easy large-scale production. The high-entropy spinel prepared can be used in high-temperature erosion environments such as glass melting furnace linings.
[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0010] Use materials with a purity of ≥99.9%. Using pentagonal metal oxides as raw materials, the composition was designed with dual indices of configuration entropy and grain boundary segregation energy through the CALPHAD method, and grain boundary purification was achieved by combining a two-step sintering process.
[0011] The specific steps are as follows:
[0012] Step 1: Component Space Design: Based on the CALPHAD thermodynamic calculation method, the space was drawn and analyzed using FactSage software. Isothermal phase diagram of the pentaceous system at 1600℃; simulation results show that the system has a broad spinel solid solution single-phase region dominated by high entropy effect at this temperature; to achieve the dual optimization objectives of configuration entropy and grain boundary segregation energy: ΔSconf≥1.5R, grain boundary segregation energy≥1.8eV, A content of 40-60 wt% is used as the core of the design; within this range, the remaining... The four oxides were allocated in equimolar ratios to ensure maximum configuration entropy, and thermodynamic simulations were used to verify that they met the above dual-index optimization conditions.
[0013] Step 2: Raw material pretreatment: Select raw materials with a purity ≥ 99.9%. The powder is accurately weighed according to the component ratio determined in step one. The weighed mixed powder is placed in a planetary ball mill, and 50-60 mL of anhydrous ethanol is added as a dispersion medium. The ball milling speed is controlled at 200-300 r / min, the ball-to-powder ratio is 10:1-15:1, and the ball milling time is 2-4 h. After the powder is mixed evenly, it is placed in an 80℃ oven to dry for 4 h. The dried powder is passed through a 200-300 mesh standard sieve to remove agglomerated particles.
[0014] Step 3: Molding process: Add 5-8 wt% polyvinyl alcohol binder to the sieved mixed powder and stir thoroughly until the binder and powder are evenly mixed. Then, use cold isostatic pressing or compression molding to press the blank into the target shape under a pressure of 150-200 MPa. After molding, test the density of the blank to ensure that the density of the blank is ≥2.8 g / cm³.
[0015] Step 4: Two-step sintering: The formed green body is placed in a high-temperature sintering furnace and heated to 1600℃ at a heating rate of 5-8℃ / min, and held for 1-2 hours to complete densification sintering; then, it is cooled to 1400℃ at a cooling rate of 3-5℃ / min and held for 10-15 hours to perform grain boundary optimization treatment.
[0016] Step 5: Post-processing: After sintering, the furnace is naturally cooled to room temperature at a rate of 3-5℃ / min. After the blank is removed, the surface is polished with a diamond grinder to remove the surface oxide layer and impurities, thus obtaining this configuration entropy-grain boundary segregation energy dual-optimized high-entropy spinel.
[0017] In step four, a two-step sintering process is employed: the shaped green body is placed in a high-temperature sintering furnace and heated to 1600℃ at a heating rate of 5-8℃ / min, and held at that temperature for 1-2 hours to complete the densification sintering. This high-temperature stage aims to achieve overall densification, with all cations participating in diffusion to eliminate large-sized pores.
[0018] Subsequently, the temperature was lowered to 1400℃ at a rate of 3-5℃ / min and held for 10-15 hours for grain boundary optimization. This stage focuses on adjusting the grain boundary structure, mainly by ions with strong diffusion capabilities (such as... , , Ions with weaker diffusion ability (such as ions) undergo directional migration and rearrangement in the grain boundary region, while ions with weaker diffusion ability (such as ions) migrate and rearrange in a more directional manner in the grain boundary region. , This process primarily stabilizes the interior of the grains. By maintaining a temperature that inhibits grain growth for an extended period, it provides the kinetic conditions for atomic diffusion and structural relaxation at grain boundaries, promoting the transition of high-energy grain boundaries to a low-energy stable state and effectively eliminating intrinsic point defects and micropores at the grain boundaries. During sintering, the distribution of grain boundary characteristics is monitored in real time using EBSD electron backscatter diffraction technology, and sintering parameters are adjusted to ensure a grain boundary CSL model matching rate ≥85%.
[0019] The main crystalline phase of this invention is High-entropy spinel solid solution, fracture toughness ≥ At 1650℃, the erosion rate is <0.1mm / 100h, and the permeability is < Thermal shock cycle life >1500 cycles (ΔT=800℃).
[0020] The high-entropy spinel preparation method with dual optimization of configuration entropy and grain boundary segregation energy provided by this invention has the following advantages compared with the prior art: First, it breaks through the limitations of single configuration entropy optimization and establishes a dual-index synergistic control system of configuration entropy and grain boundary segregation energy, effectively reducing grain boundary defects and improving the comprehensive performance of materials; Second, it adopts a unique two-step sintering process to simultaneously achieve compaction of the green body and optimization of the grain boundary structure, overcoming the problem of grain boundary defect control; Third, the process route is mature and controllable, the raw materials are readily available, the production cost is low, and it is suitable for industrial mass production; Fourth, the prepared high-entropy spinel has an erosion rate of <0.1mm / 100h at a high temperature of 1650℃ and a thermal shock cycle life of >1500 cycles (ΔT=800℃), which can meet the use requirements of harsh working conditions such as glass melting furnace lining.
[0021] The beneficial effects of this invention are as follows:
[0022] 1. Excellent overall performance: Through dual optimization of configurational entropy and grain boundary segregation energy, the prepared high-entropy spinel exhibits an erosion rate of <0.1mm / 100h and a permeability of < at a high temperature of 1650℃. Thermal shock cycle life > 1500 cycles (ΔT = 800℃), fracture toughness ≥ This solves the problem that existing materials have outstanding single properties but insufficient overall performance.
[0023] 2. High process stability: The quantitative standards for key process nodes such as composition range and sintering parameters have been clearly defined. Mature powder metallurgy and sintering technologies are adopted, which are easy to scale up production and the material performance consistency deviation is <3%.
[0024] 3. Wide range of applications: The product has excellent high temperature corrosion resistance, low permeability and thermal shock stability, and can be directly applied to harsh environments such as glass melting furnace lining and high temperature reactor lining. Its service life is more than 3 times longer than that of traditional materials, which greatly reduces maintenance costs.
[0025] 4. Outstanding technological innovation: Breaking through the traditional design approach of optimizing a single index, it establishes a dual optimization system of configuration entropy and grain boundary segregation energy, providing a new technical path for improving the performance of high-entropy ceramic materials. Detailed Implementation
[0026] The present invention will be further described in detail below with reference to specific embodiments. The embodiments of the present invention provide a method for preparing high-entropy spinel with dual optimization of configuration entropy and grain boundary segregation energy for glass melting furnace linings, using spinel with a purity ≥99.9%. Using pentagonal metal oxides as raw materials, the composition was designed with dual indices of configuration entropy and grain boundary segregation energy through the CALPHAD method, and grain boundary purification was achieved by combining a two-step sintering process, ultimately producing high-entropy spinel ceramics that meet the requirements for use as linings in glass melting furnaces.
[0027] Example 1:
[0028] Step 1: Component Design The calculated configuration entropy ΔSconf = 1.7R and grain boundary segregation energy = 2.0eV.
[0029] Step 2: Raw material pretreatment: Select raw materials with a purity ≥ 99.9%. The powder is accurately weighed according to the component ratio determined in step one. The weighed mixed powder is placed in a planetary ball mill, and 50 mL of anhydrous ethanol is added as a dispersion medium. The ball milling speed is controlled at 300 r / min, the ball-to-powder ratio is 15:1, and the ball milling time is 2 h. After the powder is mixed evenly, it is placed in an 80℃ oven to dry for 4 h. The dried powder is passed through a 200-mesh standard sieve to remove agglomerated particles.
[0030] Step 3: Molding process: Add 5 wt% polyvinyl alcohol binder to the sieved mixed powder and stir thoroughly until the binder and powder are evenly mixed. Then, use cold isostatic pressing or compression molding to press the blank into the target shape under a pressure of 200 MPa. The density of the blank after molding is 3.13 g / cm³.
[0031] Step 4: Two-step sintering: The formed green body is placed in a high-temperature sintering furnace and heated to 1600℃ at a heating rate of 5℃ / min, and held for 1 hour to complete the densification sintering; then, it is cooled to 1400℃ at a cooling rate of 3℃ / min and held for 15 hours to perform grain boundary optimization treatment.
[0032] Step 5: Post-processing: After sintering, the blank is naturally cooled to room temperature at a rate of 3℃ / min. After the blank is removed, the surface is polished with a diamond grinder to remove the surface oxide layer and impurities, thus obtaining this configuration entropy-grain boundary segregation energy dual-optimized high-entropy spinel.
[0033] Example 2:
[0034] Step 1, Component Design: Based on the CALPHAD method, determine the component proportions. , The calculated configuration entropy ΔSconf = 1.6R and grain boundary segregation energy = 1.9eV.
[0035] Step 2: Raw material pretreatment: Select raw materials with a purity ≥ 99.9%. The powder is accurately weighed according to the component ratio determined in step one. The weighed mixed powder is placed in a planetary ball mill, and 60 mL of anhydrous ethanol is added as a dispersion medium. The ball milling speed is controlled at 200 r / min, the ball-to-powder ratio is 10:1, and the ball milling time is 4 h. After the powder is mixed evenly, it is placed in an 80℃ oven to dry for 4 h. The dried powder is passed through a 230 mesh standard sieve to remove agglomerated particles.
[0036] Step 3: Molding Process: Add 8 wt% polyvinyl alcohol binder to the sieved mixed powder and stir thoroughly until the binder and powder are uniformly mixed. Then, use cold isostatic pressing or compression molding to press the green body into the target shape under a pressure of 180 MPa. The density of the green body after molding is 2.95 g / cm³. 3 ;
[0037] Step 4: Two-step sintering: The formed green body is placed in a high-temperature sintering furnace and heated to 1600℃ at a heating rate of 7℃ / min, and held for 2 hours to complete the densification sintering; then, it is cooled to 1400℃ at a cooling rate of 4℃ / min and held for 10 hours to perform grain boundary optimization treatment.
[0038] Step 5: Post-processing: After sintering, the blank is naturally cooled to room temperature at a rate of 4℃ / min. After the blank is removed, the surface is polished with a diamond grinder to remove the surface oxide layer and impurities, thus obtaining this configuration entropy-grain boundary segregation energy dual-optimized high-entropy spinel.
[0039] Example 3:
[0040] Step 1: Component Design The calculated configuration entropy ΔSconf = 1.5R and grain boundary segregation energy = 1.8eV.
[0041] Step 2: Raw material pretreatment: Select raw materials with a purity ≥ 99.9%. The powder is accurately weighed according to the component ratio determined in step one. The weighed mixed powder is placed in a planetary ball mill, and 55 mL of anhydrous ethanol is added as a dispersion medium. The ball milling speed is controlled at 280 r / min, the ball-to-powder ratio is 13:1, and the ball milling time is 3 h. After the powder is mixed evenly, it is placed in an 80℃ oven to dry for 4 h. The dried powder is passed through a 300-mesh standard sieve to remove agglomerated particles.
[0042] Step 3: Molding process: Add 6 wt% polyvinyl alcohol binder to the sieved mixed powder and stir thoroughly until the binder and powder are evenly mixed. Then, use cold isostatic pressing or compression molding to press the blank into the target shape under a pressure of 150 MPa. The density of the blank after molding is 2.88 g / cm³.
[0043] Step 4: Two-step sintering: The formed green body is placed in a high-temperature sintering furnace and heated to 1600℃ at a heating rate of 8℃ / min, and held for 1 hour to complete the densification sintering; then, it is cooled to 1400℃ at a cooling rate of 5℃ / min and held for 13 hours to perform grain boundary optimization treatment.
[0044] Step 5: Post-processing: After sintering, the blank is naturally cooled to room temperature at a rate of 5℃ / min. After the blank is removed, the surface is polished with a diamond grinder to remove the surface oxide layer and impurities, thus obtaining this configuration entropy-grain boundary segregation energy dual-optimized high-entropy spinel.
[0045] Comparative Example 1 (Single configuration entropy optimization, no grain boundary purification)
[0046] 1. Composition design: Same as in Example 1, configuration entropy ΔSconf = 1.6R, grain boundary segregation energy not controlled.
[0047] 2. Raw material pretreatment - molding process: Same as in Example 1.
[0048] 3. Sintering process: A single sintering process is adopted, which involves holding at 1600℃ for 4 hours and then directly cooling to room temperature, without the 1400℃ grain boundary purification step.
[0049] 4. Post-treatment: Grinding to remove the surface oxide layer.
[0050] Comparative Example 2 (Preparation of conventional ternary spinel)
[0051] 1. Component design: Traditional Ternary spinel, without configurational entropy and grain boundary segregation energy optimization.
[0052] 2. Raw material pretreatment - molding process: Same as in Example 1.
[0053] 3. Sintering process: Hold at 1500℃ for 3 hours, then cool directly.
[0054] 4. Post-treatment: Grinding to remove the surface oxide layer.
[0055] The performance test results are as follows:
[0056]
[0057] This invention successfully prepared high-entropy spinel materials with excellent comprehensive performance through a dual optimization design of configuration entropy and grain boundary segregation energy, combined with an innovative two-step sintering process. Performance test results show that the products of Examples 1-3 are significantly superior to the comparative examples in terms of high-temperature corrosion resistance, low permeability, thermal shock stability, and mechanical properties, verifying the effectiveness of the technical solution of this invention.
[0058] This invention overcomes the limitations of existing technologies that focus on single-index optimization, establishing a complete technical system of "dual-index component design - precise process control - grain boundary feature optimization." The prepared high-entropy spinel can meet the requirements of high-temperature and harsh environments such as glass melting furnace linings, extending equipment lifespan and reducing maintenance costs, thus possessing significant industrial application value and market prospects. Furthermore, the process route of this invention is mature, highly operable, and easily scalable, providing new technical support for the performance improvement and industrial application of high-entropy ceramic materials.
Claims
1. A method for preparing high-entropy spinel with dual optimization of configuration entropy and grain boundary segregation energy, characterized in that: Step 1: Component Space Design: Based on the CALPHAD thermodynamic calculation method, the space was drawn and analyzed using FactSage software. Isothermal phase diagram of a pentagonal system at 1600℃; Simulation results show that the system possesses a broad spinel solid solution single-phase region dominated by a high-entropy effect at the stated temperature; to achieve the dual optimization objectives of configuration entropy and grain boundary segregation energy: ΔSconf ≥ 1.5R, grain boundary segregation energy ≥ 1.8 eV, A content of 40-60 wt% is used as the core of the design; within this range, the remaining... , , , The four oxides were allocated in equimolar ratios to ensure maximum configuration entropy, and thermodynamic simulations were used to verify that they met the above dual-index optimization conditions. Step 2: Raw material pretreatment: Select raw materials with a purity ≥ 99.9%. The powder is accurately weighed according to the component ratio determined in step one. The weighed mixed powder is placed in a planetary ball mill, and anhydrous ethanol is added as a dispersion medium. The ball milling speed is controlled at 200-300 r / min, the ball-to-powder ratio is 10:1-15:1, and the ball milling time is 2-4 h. After the powder is mixed evenly, it is placed in an 80℃ oven to dry for 4 h. The dried powder is passed through a 200-300 mesh standard sieve to remove agglomerated particles. Step 3: Molding process: Add 5-8 wt% polyvinyl alcohol binder to the sieved mixed powder and stir thoroughly until the binder and powder are evenly mixed. Then press it into a blank of the target shape under a pressure of 150-200 MPa. Step 4: Two-step sintering: The formed green body is placed in a high-temperature sintering furnace and heated to 1600℃ at a heating rate of 5-8℃ / min, and held for 1-2 hours to complete densification sintering; then, it is cooled to 1400℃ at a cooling rate of 3-5℃ / min and held for 10-15 hours to perform grain boundary optimization treatment. Step 5: Post-processing: After sintering, the furnace is naturally cooled to room temperature at a rate of 3-5℃ / min. After the blank is removed, the surface is polished with a diamond grinder to remove the surface oxide layer and impurities, thus obtaining this configuration entropy-grain boundary segregation energy dual-optimized high-entropy spinel.
2. The method for preparing high-entropy spinel with dual optimization of configuration entropy and grain boundary segregation energy according to claim 1, characterized in that: The high-entropy spinel with dual optimization of configurational entropy and grain boundary segregation energy obtained in step five has the following main crystalline phase: High-entropy spinel solid solution.
3. The method for preparing high-entropy spinel with dual optimization of configuration entropy and grain boundary segregation energy according to claim 1, characterized in that: In step four, the distribution of grain boundary features is monitored in real time during the sintering process using EBSD electron backscatter diffraction technology. Adjusting sintering parameters to achieve a grain boundary CSL model matching rate of ≥85%.
4. The method for preparing high-entropy spinel with dual optimization of configuration entropy and grain boundary segregation energy according to claim 1, characterized in that: In step three, the pressing and forming process adopts cold isostatic pressing or die pressing, and the density of the formed blank is ≥2.8g / cm³.
5. The method for preparing high-entropy spinel with dual optimization of configuration entropy and grain boundary segregation energy according to claim 1, characterized in that: Step 2: Add 50-60 mL of anhydrous ethanol.