Method for preparing scandium lutetium co-doped zirconia ceramic ultrafine powder by using sol-gel method and application of scandium lutetium co-doped zirconia ceramic ultrafine powder
By employing the sol-gel method and stepwise drying and calcination processes, uniform mixing and fine particle size of scandium-lutetium co-doped zirconia ceramic powder were achieved, solving the problems of component segregation and agglomeration, improving the stability and conductivity of the electrolyte, and reducing the preparation cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN INST OF TECH
- Filing Date
- 2026-02-13
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies make it difficult to achieve uniform mixing of scandium-lutetium co-doped zirconia ceramic powder at the molecular/atomic level, leading to component segregation and powder agglomeration, which affects the stability and conductivity of the electrolyte.
By employing a sol-gel method combined with stepwise drying and programmed calcination, uniform mixing of Sc, Lu, and Zr ions is achieved at the molecular level, thereby inhibiting powder agglomeration and grain growth, and producing ultrafine powder with uniform particle size.
Scandium-lutetium co-doped zirconia ceramic ultrafine powder with uniform composition, fine particle size, and good dispersibility was obtained, which improved the chemical stability and conductivity of the electrolyte and reduced the preparation cost and energy consumption.
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Figure CN122010561A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of advanced ceramic material preparation technology, specifically to a method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method. Background Technology
[0002] Zirconia (ZrO2)-based ceramics are key electrolyte materials for SOFCs due to their high-temperature ionic conductivity and good chemical stability. Pure ZrO2 has low ionic conductivity, and its crystal phase undergoes a transformation with temperature from monoclinic (<1175℃), tetragonal (1175~2370℃), to cubic (>2370℃). 3+ ,Sc 3+ It can introduce oxygen vacancies into its crystal lattice and stabilize the high-temperature cubic phase to medium-low temperature, thereby obtaining the applicable oxygen ion conductivity.
[0003] Among many dopants, scandium (Sc) 3+ Due to the difference in ionic radius (0.087 nm) and zirconium ion (Zr) 4+ The closest 0.084 nm chromatic ion density (C0) found in Sc2O3-doped zirconium oxide (ScSZ) exhibits the highest oxygen ion conductivity. However, studies have confirmed that the 10 mol% Sc2O3-doped zirconium oxide (10ScSZ) with the optimal conductivity undergoes a reversible phase transition from the cubic (c-phase) to the rhombohedral (β-phase) at approximately 600°C. This phase transition leads to abrupt changes in conductivity and induces microcracks during thermal cycling, severely threatening the long-term reliability of the electrolyte.
[0004] To suppress the harmful phase transition of 10ScSZ, existing technologies have proposed strategies involving the introduction of a second-phase stabilizer. Cerium oxide (CeO2) has been widely studied due to its fluorite structure and ability to broaden the stability range of cubic phases, leading to co-doped systems such as 10Sc1CeSZ. Notably, in the Sc2O3-CeO2-ZrO2 system, the 10Sc1CeSZ composition (i.e., doped with 10 mol% Sc2O3 and 1 mol% CeO2) has reportedly exhibited one of the highest known oxygen ion conductivities. The addition of CeO2 does indeed enhance the peak conductivity and further improve phase stability. However, this approach introduces new and more difficult technical challenges: in the strongly reducing atmosphere of the SOFC anode side, Ce... 4+ Easily reduced to Ce 3+ This process, accompanied by lattice expansion and the generation of additional oxygen vacancies, can disrupt the integrity of the electrolyte structure and may cause harmful electronic conductivity, leading to accelerated battery performance degradation.
[0005] Therefore, there is an urgent need in this field for a novel co-dopermeable that can effectively stabilize the cubic phase structure of ScSZ and maintain high chemical stability in a reducing atmosphere. Trivalent lutetium ions (Lu) 3+ Because its ionic radius (approximately 0.085 nm) is similar to that of Zr. 4 + Highly matched (better match than Ce) 4+ At a density of 0.087 nm, Lu₂O₃ can theoretically reduce lattice strain more effectively and enhance phase structure stability. Furthermore, Lu₂O₃ exhibits stable valence states over a wide oxygen partial pressure range and is not easily reduced, thus potentially overcoming the shortcomings of Ce-based dopants. Therefore, scandium-lutetium (Sc-Lu) co-doping can be considered a highly promising technical solution to address the dual challenges of phase instability and chemical reduction instability in ScSZ-based electrolytes.
[0006] However, the realization of high-performance Sc-Lu co-doped zirconium oxide materials is highly dependent on powder preparation technology. Traditional solid-state methods are difficult to achieve atomic-scale uniform doping; while wet chemical methods such as co-precipitation are available, they require extremely high process control and are prone to component segregation and severe powder agglomeration. The insufficient microscopic uniformity of the powders prepared by these methods negates the theoretical advantages brought by co-doping design. Therefore, developing a synthesis method that can achieve highly uniform mixing of Sc, Lu, and Zr ions at the molecular / atomic level and precisely control the particle size and morphology of the powder has become a prerequisite for obtaining the expected high-performance Sc-Lu SZ electrolyte materials. Summary of the Invention
[0007] The purpose of this invention is to address the problems of poor component uniformity, large grain size, wide distribution, severe hard agglomeration, and low conductivity of ceramic powders used in existing solid oxide fuel cell electrolytes, and to provide a method and application for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method.
[0008] This invention provides a sol-gel preparation method that is relatively simple in process, produces uniform components, and effectively inhibits agglomeration and excessive grain growth. This invention achieves uniform mixing of components at the molecular level, effectively inhibiting hard agglomeration of powder and abnormal grain growth, resulting in ultrafine powders with fine grains and uniform particle size distribution. The method is simple, requires low synthesis temperature and no pressure, and is relatively low in cost.
[0009] A method for preparing scandium-lutetium co-doped zirconium oxide ceramic ultrafine powder using the sol-gel method is specifically carried out according to the following steps:
[0010] 1. Preparation of precursor solution: According to the target product (ZrO2) 1-x-y (Sc2O3) x (Lu2O3) yThe stoichiometric ratio of zirconium source, scandium nitrate, and lutetium nitrate, with x = 0.01~0.10 and y = 0.005~0.10, is weighed and added together to glacial acetic acid. The mixture is heated and stirred until completely dissolved, and then naturally cooled to room temperature to obtain a clear solution.
[0011] 2. Formation of a stable sol: Under continuous stirring, ethylene glycol is added to the clear solution, and stirring is continued until the mixture is homogeneous, resulting in a uniform and transparent sol.
[0012] 3. Stepwise drying: First, dry the sol at a low temperature, then increase the temperature to continue drying, and obtain a dry gel;
[0013] IV. Calcination treatment: The dry gel is ground and then subjected to heat treatment, which shall be carried out by one of the following two methods:
[0014] A. Two-step calcination method: First, raise the temperature to 300℃~500℃ and hold it; then, continue to raise the temperature to 700℃~900℃ and hold it. After calcination, cool it with the furnace.
[0015] B. Two-stage calcination method: First, raise the temperature to 300℃~500℃ and hold it at that temperature. Then, cool it to room temperature with the furnace and remove it for grinding. Raise the ground powder to 700℃~900℃ and hold it at that temperature. After calcination, cool it with the furnace to obtain scandium-lutetium co-doped zirconia ceramic ultrafine powder.
[0016] The beneficial effects of this invention are:
[0017] I. The sol-gel method used in this invention is beneficial for achieving uniform mixing of ions at the molecular scale, effectively avoiding component segregation, and laying the foundation for obtaining high-purity single cubic phase solid solutions.
[0018] Second, this invention effectively suppresses hard agglomeration and abnormal grain growth through optimized step-by-step drying and programmed calcination processes, resulting in powders with fine particle size, uniform distribution, and good dispersibility.
[0019] Third, the entire process of this invention does not require complex equipment or high pressure conditions, the main crystallization temperature is significantly lower than that of the traditional solid-state method, and it has low energy consumption, strong controllability, and good repeatability.
[0020] This invention can obtain a scandium-lutetium co-doped zirconium oxide ceramic ultrafine powder. Attached Figure Description
[0021] Figure 1 The images show the XRD patterns of 10Sc1LuSZ ceramic powders calcined at different temperatures in Examples 1 to 6.
[0022] Figure 2 The graph shows the calculated grain size results of 10Sc1LuSZ ceramic powders at different calcination temperatures in Examples 4 to 6.
[0023] Figure 3 The graph shows the calculated crystallinity results of 10Sc1LuSZ ceramic powders at different calcination temperatures in Examples 1 to 7.
[0024] Figure 4 The morphology and color changes of 10Sc1LuSZ ceramic powders at different calcination temperatures are shown in Examples 1 to 6.
[0025] Figure 5 XRD patterns of ceramic powders with different lutetium doping concentrations in Examples 1, 8, and 9;
[0026] Figure 6 The particle size distribution diagrams of 10Sc1LuSZ ceramic powders obtained by laser particle size analysis in Examples 10 to 12 are shown.
[0027] Figure 7 The conductivity-temperature relationship curves are shown for the 10Sc0.5LuSZ ceramic obtained by calcining the 10Sc0.5LuSZ powder prepared in Example 13 at 1450℃ and the 10Sc1CeSZ ceramic obtained by calcining the commercial 10Sc1CeSZ powder at 1450℃. Detailed Implementation
[0028] Specific Implementation Method 1: This implementation method is a method for preparing scandium-lutetium co-doped zirconium oxide ceramic ultrafine powder using the sol-gel method, specifically completed according to the following steps:
[0029] 1. Preparation of precursor solution: According to the target product (ZrO2) 1-x-y (Sc2O3) x (Lu2O3) y The stoichiometric ratio of zirconium source, scandium nitrate, and lutetium nitrate, with x = 0.01~0.10 and y = 0.005~0.10, is weighed and added together to glacial acetic acid. The mixture is heated and stirred until completely dissolved, and then naturally cooled to room temperature to obtain a clear solution.
[0030] 2. Formation of a stable sol: Under continuous stirring, ethylene glycol is added to the clear solution, and stirring is continued until the mixture is homogeneous, resulting in a uniform and transparent sol.
[0031] 3. Stepwise drying: First, dry the sol at a low temperature, then increase the temperature to continue drying, and obtain a dry gel;
[0032] IV. Calcination treatment: The dry gel is ground and then subjected to heat treatment, which shall be carried out by one of the following two methods:
[0033] A. Two-step calcination method: First, raise the temperature to 300℃~500℃ and hold it; then, continue to raise the temperature to 700℃~900℃ and hold it. After calcination, cool it with the furnace.
[0034] B. Two-stage calcination method: First, raise the temperature to 300℃~500℃ and hold it at that temperature. Then, cool it to room temperature with the furnace and remove it for grinding. Raise the ground powder to 700℃~900℃ and hold it at that temperature. After calcination, cool it with the furnace to obtain scandium-lutetium co-doped zirconia ceramic ultrafine powder.
[0035] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the zirconium source mentioned in step one is zirconium oxynitrate or zirconium nitrate. The other steps are the same as in Specific Implementation Method One.
[0036] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the concentration of the zirconium source in the clarified solution described in step one is 0.3 mol / L to 1 mol / L. The other steps are the same as in Specific Implementation Method One or Two.
[0037] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the mass fraction of glacial acetic acid in step one is 99.5% to 99.9%; and the mass fraction of ethylene glycol in step two is 99% to 99.8%. The other steps are the same as in Specific Implementation Methods One to Three.
[0038] Specific Implementation Method Five: The difference between this implementation method and Specific Implementation Methods One to Four is that the volume ratio of glacial acetic acid in step one to ethylene glycol in step two is (1.5~3.5):1. The other steps are the same as in Specific Implementation Methods One to Four.
[0039] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: in step one, the heating and stirring temperature is 60℃~80℃, the heating and stirring speed is 150r / min~300r / min, and the heating and stirring time is 10min~15min; in step two, the stirring speed is 150r / min~300r / min, and the stirring time is 15min~60min. Other steps are the same as in Specific Implementation Methods One to Five.
[0040] Specific Implementation Method Seven: The difference between this implementation method and Specific Implementation Methods One to Six is that in step three, the sol is first dried at 40°C for 48 to 96 hours, and then dried at 60°C for 72 to 168 hours to obtain a dry gel. The other steps are the same as in Specific Implementation Methods One to Six.
[0041] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: in step fourA, the temperature is first raised to 300℃~500℃ at a heating rate of 1℃ / min~5℃ / min and held for 1h~3h; subsequently, the temperature is further raised to 700℃~900℃ at a heating rate of 2℃ / min~6℃ / min and held for 2h~4h. After calcination, the furnace is cooled. The other steps are the same as in Specific Implementation Methods One to Seven.
[0042] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: in step four B, the temperature is first raised to 300℃ to 500℃ at a heating rate of 1℃ / min to 5℃ / min, held for 1h to 3h, and then cooled to room temperature in the furnace before being removed and ground. The ground powder is then heated again from room temperature to 700℃ to 900℃ at a heating rate of 2℃ / min to 6℃ / min, held for 2h to 4h, and cooled in the furnace after calcination to obtain scandium-lutetium co-doped zirconia ceramic ultrafine powder. Other steps are the same as in Specific Implementation Methods One to Eight.
[0043] Specific Implementation Method 10: This implementation method uses scandium-lutetium co-doped zirconia ceramic ultrafine powder as an electrolyte for solid oxide fuel cells.
[0044] The embodiments of the present invention will be described in detail below. The following embodiments are implemented based on the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.
[0045] Example 1: A method for preparing scandium-lutetium co-doped zirconium oxide ceramic ultrafine powder using the sol-gel method, specifically comprising the following steps:
[0046] 1. Preparation of precursor solution: According to the target product (ZrO2) 0.89 (Sc2O3) 0.1 (Lu2O3) 0.01 The stoichiometric ratio of zirconium source, scandium nitrate and lutetium nitrate (i.e. 10Sc1LuSZ) was measured and added together to glacial acetic acid with a mass fraction of 99.8%. The solution was heated and stirred for 15 minutes in a water bath at 70°C and a stirring speed of 200 r / min. The solution was then naturally cooled to room temperature to obtain a clear solution.
[0047] 2. Formation of a stable sol: Under continuous stirring at 200 r / min, 99.5% ethylene glycol by mass was added to the clear solution, and stirring was continued at 200 r / min for 30 min to obtain a homogeneous and transparent sol.
[0048] The volume ratio of glacial acetic acid in step one to ethylene glycol in step two is 2.5:1;
[0049] 3. Stepwise drying: The sol is first dried at 40℃ for 48h~96h, and then dried at 60℃ for 120h to obtain a dry gel;
[0050] IV. Calcination treatment: The dry gel was ground into fine powder using an agate mortar and pestle. The ground dry gel powder was placed in an alumina crucible and then placed in a muffle furnace. The temperature was increased from room temperature to 300℃ at a rate of 1℃ / min and held at this temperature for 60 minutes. After the holding time was completed, the sample was allowed to cool naturally to room temperature with the furnace to obtain 10Sc1LuSZ powder.
[0051] Example 2: The difference between this example and Example 1 is that in step four, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 300°C at a rate of 1°C / min and held at this temperature for 60 minutes. Subsequently, without cooling, the temperature is increased from 300°C to 400°C at a rate of 2°C / min and held at 400°C for 60 minutes. After calcination, the powder is allowed to cool naturally to room temperature to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0052] Example 3: The difference between this example and Example 1 is that in step four, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 300°C at a rate of 1°C / min and held at this temperature for 60 minutes. Subsequently, without cooling, the temperature is increased from 300°C to 500°C at a rate of 2°C / min and held at 500°C for 60 minutes. After calcination, the powder is allowed to cool naturally to room temperature to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0053] Example 4: The difference between this example and Example 1 is that in step four, the dry gel is ground into a fine powder using an agate mortar and pestle. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 300°C at a rate of 1°C / min and held at this temperature for 60 minutes. Subsequently, without cooling, the temperature is increased from 300°C to 600°C at a rate of 2°C / min and held at 600°C for 60 minutes. After calcination, the powder is allowed to cool naturally to room temperature in the furnace to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0054] Example 5: The difference between this example and Example 1 is that in step four, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 300°C at a rate of 1°C / min and held at this temperature for 60 minutes. Subsequently, without cooling, the temperature is increased from 300°C to 700°C at a rate of 2°C / min and held at 700°C for 60 minutes. After calcination, the powder is allowed to cool naturally to room temperature to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0055] Example 6: The difference between this example and Example 1 is that in step four, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 300°C at a rate of 1°C / min and held at this temperature for 60 minutes. Subsequently, without cooling, the temperature is increased from 300°C to 800°C at a rate of 2°C / min and held at 800°C for 60 minutes. After calcination, the powder is allowed to cool naturally to room temperature to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0056] Example 7: The difference between this example and Example 1 is that in step four, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 300°C at a rate of 1°C / min and held at this temperature for 60 minutes. Subsequently, without cooling, the temperature is increased from 300°C to 750°C at a rate of 2°C / min and held at 750°C for 60 minutes. After calcination, the powder is naturally cooled to room temperature with the furnace to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0057] Example 8: The difference between this example and Example 5 is that in step one, the target product (ZrO2) is... 0.895 (Sc2O3) 0.1 (Lu2O3) 0.005 The zirconium source, scandium nitrate, and lutetium nitrate were weighed according to the stoichiometric ratio of 10Sc0.5LuSZ; step four yielded 10Sc0.5LuSZ powder. Other steps and parameters were the same as in Example 1.
[0058] Example 9: The difference between this example and Example 5 is that in step one, the target product (ZrO2) is... 0.885 (Sc2O3) 0.1 (Lu2O3) 0.015The zirconium source, scandium nitrate, and lutetium nitrate were weighed according to the stoichiometric ratio of 10Sc1.5LuSZ; step four yielded 10Sc1.5LuSZ powder. Other steps and parameters were the same as in Example 1.
[0059] Example 10: The difference between this example and Example 1 is that in step four, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 350°C at a rate of 1°C / min and held at this temperature for 60 minutes. Subsequently, without cooling, the temperature is increased from 350°C to 700°C at a rate of 2°C / min and held at 700°C for 120 minutes. After calcination, the powder is allowed to cool naturally to room temperature to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0060] Example 11: The difference between this example and Example 1 is that in step four, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 350°C at a rate of 1°C / min and held at this temperature for 60 minutes. Subsequently, without cooling, the temperature is increased from 350°C to 800°C at a rate of 2°C / min and held at 800°C for 120 minutes. After calcination, the powder is allowed to cool naturally to room temperature to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0061] Example 12: The difference between this example and Example 1 is that a two-stage calcination method is used in step four. Specifically, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 350°C at a rate of 1°C / min and held at this temperature for 60 minutes. Afterward, the furnace is cooled to room temperature, and the sample is removed and ground again. The powder, after being ground again, is heated from room temperature to 800°C at a rate of 2°C / min and held at 800°C for 120 minutes. After calcination, the furnace is allowed to cool naturally to room temperature to obtain 10Sc1LuSZ powder. All other steps and parameters are the same as in Example 1.
[0062] Example 13: The difference between this example and Example 8 is that a two-stage calcination method is used in step four. Specifically, the dry gel is ground into a fine powder using an agate mortar. The ground dry gel powder is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased from room temperature to 350°C at a rate of 1°C / min and held at this temperature for 60 minutes. Afterward, the furnace is cooled to room temperature, and the sample is removed and ground again. The powder, after being ground again, is heated from room temperature to 800°C at a rate of 2°C / min and held at 800°C for 120 minutes. After calcination, the furnace is allowed to cool naturally to room temperature to obtain 10Sc0.5LuSZ powder. All other steps and parameters are the same as in Example 1.
[0063] The above embodiments (1-11) further demonstrate the parameter flexibility of the two-step calcination method in this invention. Embodiments 10 and 11, by increasing the calcination temperature of the first step to 350°C and combining it with different final temperatures (700°C or 800°C), provide more options for controlling the organic matter decomposition and crystal nucleation process. Embodiments 12 and 13 specifically demonstrate a feasible process of two-step calcination (i.e., intermediate cooling and grinding followed by final calcination), which helps to further break down the initial agglomerates before final high-temperature crystallization, potentially yielding powders with better dispersibility.
[0064] Figure 1 The images show the XRD patterns of 10Sc1LuSZ ceramic powders calcined at different temperatures in Examples 1 to 6.
[0065] from Figure 1 It can be seen that the ceramic powders of Examples 1 to 3 all exhibit the characteristic of not being fully crystallized. The cubic phase Fm-3m characteristic peak of the ceramic powder of Example 4 was not completely separated. The 10ScSZ ceramic powder prepared in Examples 5 and 6 has a cubic phase crystal structure with a space group of Fm-3m.
[0066] Figure 2 , Figure 3 Showing based on Figure 1 The variation of grain size and crystallinity with increasing calcination temperature, calculated from XRD data. For example... Figures 2-3 As shown;
[0067] Figure 2 The graph shows the calculated grain size results of 10Sc1LuSZ ceramic powders at different calcination temperatures in Examples 4 to 6.
[0068] Figure 3 The graph shows the calculated crystallinity results of 10Sc1LuSZ ceramic powders at different calcination temperatures in Examples 1 to 7.
[0069] from Figures 2-3It can be seen that as the calcination temperature increases from 600℃ to 800℃, the average grain size of the powder increases from about 9.8nm to about 19.7nm, and the crystallinity increases significantly, reaching more than 93.16% at 750℃. This proves that the method of the present invention can prepare highly crystalline nanocrystalline powder at relatively low temperatures (700-900℃).
[0070] Figure 4 The morphology and color changes of 10Sc1LuSZ ceramic powders at different calcination temperatures are shown in Examples 1 to 6.
[0071] Figures 1-4 In the examples, 300℃ is Example 1, 400℃ is Example 2, 500℃ is Example 3, 600℃ is Example 4, 700℃ is Example 5, 800℃ is Example 6, and 750℃ is Example 7.
[0072] Figure 5 X-ray diffraction (XRD) patterns of 10ScxLuSZ powders with different Lu2O3 doping concentrations (e.g., y=0.005, 0.01, 0.015 corresponding to Examples 8, 1, and 9) prepared using the method of this invention are shown. Figure 5 As shown;
[0073] Figure 5 XRD patterns of ceramic powders with different lutetium doping concentrations in Examples 1, 8, and 9;
[0074] Figure 5 10Sc1LuSZ is Example 1, 10Sc0.5LuSZ is Example 8, and 10Sc1.5LuSZ is Example 9; Figure 5 The results show that within the specified doping range, all samples maintain a single cubic fluorite phase without the formation of any impurity phases, indicating that the method of the present invention has good adaptability to changes in composition and can obtain a series of structurally stable powders.
[0075] Figure 6 The particle size distribution diagrams of 10Sc1LuSZ ceramic powder obtained by laser particle size analysis in Examples 10 to 12 are shown in Table 1; Table 1 shows the corresponding statistical results of D10, D50 and D90.
[0076] Figure 6 Example 10 is a two-step calcination method at 700℃, Example 11 is a two-step calcination method at 800℃, and Example 12 is a two-stage calcination method at 800℃.
[0077] from Figure 6As can be seen, the particle size of 10Sc1LuSZ ceramic powder obtained under different calcination processes all exhibit a bimodal distribution. The concentration of particle size distribution is evaluated using the (D90-D10) / (2×D50) value; a smaller value indicates a more uniform distribution. As shown in Table 1, the powder obtained by calcination at 800℃ using a two-step calcination method (Example 11) has the smallest distribution index (2.17) and the most uniform particle size distribution. Calcination at 800℃ using a double calcination method (Example 12) yielded the finest median particle size (D50 = 0.459 μm) and the highest specific surface area. Furthermore, the powder specific surface area of Example 11 (11440 m²) is also high. 2 The kg was significantly higher than that of Example 10 (4047m). 2 / kg), indicating that increasing the calcination temperature helps to obtain finer and more active powders.
[0078] Figure 7 Table 2 shows the electrical conductivity comparison between 10Sc0.5LuSZ ceramics prepared from 10Sc0.5LuSZ powder (prepared by double calcination at 800°C) in Example 13 and sintered at 1450°C, and ceramics prepared from commercially available 10Sc1CeSZ ceramic powder (purchased from Daiichi Rare Element Chemical Industry Co., Ltd. (DKK) of Japan) sintered using the same process (1450°C) at different temperature ranges.
[0079] from Figure 7 As shown in Table 2, the 10Sc0.5LuSZ ceramic prepared in this invention exhibits excellent oxygen ion conductivity in the temperature range of 750-850℃, and the conductivity increases significantly with increasing temperature, conforming to the typical Arrhenius law. Particularly at 850℃, its conductivity reaches 134.7 mS / cm, which is very close to the level of commercially available 10Sc1CeSZ materials (139.4 mS / cm), achieving a relative performance of approximately 97%.
[0080] Table 1
[0081]
[0082] Table 2
[0083]
Claims
1. A method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method, characterized in that... The method is specifically implemented according to the following steps:
1. Preparation of precursor solution: According to the target product (ZrO2) 1-x-y (Sc2O3) x (Lu2O3) y The stoichiometric ratio of zirconium source, scandium nitrate, and lutetium nitrate, with x = 0.01~0.10 and y = 0.005~0.10, is weighed and added together to glacial acetic acid. The mixture is heated and stirred until completely dissolved, and then naturally cooled to room temperature to obtain a clear solution.
2. Formation of a stable sol: Under continuous stirring, ethylene glycol is added to the clear solution, and stirring is continued until the mixture is homogeneous, resulting in a uniform and transparent sol.
3. Stepwise drying: First, dry the sol at a low temperature, then increase the temperature to continue drying, and obtain a dry gel; IV. Calcination treatment: The dry gel is ground and then subjected to heat treatment, which shall be carried out by one of the following two methods: A. Two-step calcination method: First, raise the temperature to 300℃~500℃ and hold it; then, continue to raise the temperature to 700℃~900℃ and hold it. After calcination, cool it with the furnace. B. Two-stage calcination method: First, raise the temperature to 300℃~500℃ and hold it at that temperature. Then, cool it to room temperature with the furnace and remove it for grinding. Raise the ground powder from room temperature to 700℃~900℃ and hold it at that temperature. After calcination, cool it with the furnace to obtain scandium-lutetium co-doped zirconia ceramic ultrafine powder.
2. The method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method according to claim 1, characterized in that... The zirconium source mentioned in step one is zirconium oxynitrate or zirconium nitrate.
3. The method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method according to claim 1, characterized in that... The concentration of the zirconium source in the clarified solution described in step one is 0.3 mol / L to 1 mol / L.
4. The method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method according to claim 1, characterized in that... The mass fraction of glacial acetic acid in step one is 99.5%~99.9%; the mass fraction of ethylene glycol in step two is 99%~99.8%.
5. The method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method according to claim 1, characterized in that... The volume ratio of glacial acetic acid in step one to ethylene glycol in step two is (1.5~3.5):
1.
6. The method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method according to claim 1, characterized in that... The heating and stirring temperature in step one is 60℃~80℃, the heating and stirring speed is 150r / min~300r / min, and the heating and stirring time is 10min~15min; the stirring speed in step two is 150r / min~300r / min, and the stirring time is 15min~60min.
7. The method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method according to claim 1, characterized in that... In step three, the sol is first dried at 40°C for 48-96 hours, and then dried at 60°C for 72-168 hours to obtain a dry gel.
8. The method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method according to claim 1, characterized in that... In step 4A, the temperature is first raised to 300℃~500℃ at a heating rate of 1℃ / min~5℃ / min and held for 1h~3h; then, the temperature is raised to 700℃~900℃ at a heating rate of 2℃ / min~6℃ / min and held for 2h~4h. After calcination, the furnace is cooled.
9. A method for preparing scandium-lutetium co-doped zirconia ceramic ultrafine powder using the sol-gel method according to claim 1, characterized in that... In step 4B, the temperature is first raised to 300℃~500℃ at a heating rate of 1℃ / min~5℃ / min, held for 1h~3h, then cooled to room temperature in the furnace and ground. The ground powder is then heated again from room temperature to 700℃~900℃ at a heating rate of 2℃ / min~6℃ / min, held for 2h~4h, and cooled in the furnace after calcination to obtain scandium-lutetium co-doped zirconia ceramic ultrafine powder.
10. The application of the scandium-lutetium co-doped zirconium oxide ceramic ultrafine powder prepared by the method according to any one of claims 1 to 9, characterized in that... The scandium-lutetium co-doped zirconia ceramic ultrafine powder is used as an electrolyte for solid oxide fuel cells.