A full active scandium acid salt for an impregnated diffusion cathode and a method for preparing the same
Patent Information
- Application Number
- CN202611011947.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-08
- Publication Date
- 2026-09-25
AI Technical Summary
然而，Al、Ca的掺入不可避免稀释发射面上Ba-Sc-O活性原子层的覆盖率，限制了电子发射（Seif M N, Zhou Q, Liu X, et al. A Review of Sc-containing "Scandate" Thermionic Cathodes[J]. 2022.DOI:10.48550/arXiv.2202.04745）；同时，工作过程中随着Ba的持续扩散与消耗，易生成稳定的BaAl2O4等贫钡相
[0019]1、本发明提出了一种浸渍扩散阴极用全活性物质钪酸盐及其制备方法，结构式为Ba2ScCuO4.4，其浸渍后实际有效浸渍活性物质中只含全活性的钡钪化合物，并且钪分布均匀且含量高，所得浸渍阴极具有低温大电流密度发射的特性，且发射均匀性优异，950 ℃下的直流发射电流密度至少达到10.0 A/cm2，相比于浸渍高温固相法制备的(Ba,Ca)2ScAlO5钪铝酸盐阴极在950 ℃下4.90 A/cm2的直流发射电流密度，其电流密度提高了1倍；
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of impregnated cathode materials, specifically relating to a scandium salt, a fully active material for impregnated diffusion cathodes, and its preparation method. Background Technology
[0002] Vacuum electronic devices have wide applications in the civilian sector, and their core electron sources often employ thermionic cathodes, which offer advantages such as high emission current density and high reliability. With the continuous improvement of device performance requirements, higher demands are being placed on the emission capabilities of thermionic cathodes. Among various cathode types, scandium-containing diffused cathodes are considered the most promising thermionic cathodes to meet the needs of high-frequency, high-power microwave devices. Among these, impregnated scandium-barium-tungsten cathodes have attracted widespread attention due to their advantages such as low-temperature high emission characteristics and simple manufacturing process.
[0003] Impregnated cathodes are prepared by impregnating a molten active material into a porous tungsten matrix. The emission performance of the cathode largely depends on the active material. Early and widely used impregnating active materials are barium aluminates with low melting points, commonly including the 532, 411, and 612 series (the numbers correspond to the molar ratios of BaO, CaO, and Al2O3, respectively). Later research incorporated 1–16 wt.% Sc2O3 into aluminates to prepare scandium-containing aluminates. Compared to undoped aluminate cathodes, scandium-containing aluminate-impregnated cathodes can achieve high emission currents at lower operating temperatures, meeting the stringent requirements of high-frequency, high-power devices while significantly reducing device thermal load. To further improve emission uniformity and other issues, researchers have developed a single-phase, high-scandium-content scandium salt (Ba,Ca)2ScAlO5 as the impregnating active material, significantly improving cathode performance. While a unified explanation for the working mechanism of scandium cathodes remains elusive, the prevailing view is that a Ba-Sc-O atomic layer forms on the emission surface, which is believed to lower the work function of the cathode emission surface, thereby improving emission performance. However, the BaO-Sc2O3 binary oxide phase diagram shows that Ba2Sc2O5 in barium scandium oxides is thermodynamically unstable, while Ba3Sc4O9 and BaSc2O4 have excessively high melting points, making them unsuitable for direct use as impregnation active materials. Therefore, researchers have introduced Al and Ca to form a multi-component oxide to balance suitable melting points and structural stability. However, the incorporation of Al and Ca inevitably dilutes the coverage of the Ba-Sc-O active atom layer on the emitting surface, limiting electron emission (Seif MN, Zhou Q, Liu X, et al. A Review of Sc-containing "Scandate" Thermionic Cathodes[J]. 2022.DOI:10.48550 / arXiv.2202.04745). Simultaneously, during operation, with the continuous diffusion and consumption of Ba, stable barium-depleted phases such as BaAl2O4 are easily generated. This reduces the utilization rate of Ba in the active material and also clogs the pores of the tungsten matrix, blocking the diffusion of internal Ba / Sc to the emitting surface, leading to a decline in cathode performance and lifetime. Summary of the Invention
[0004] To address the technical problems existing in the prior art, the present invention provides a scandium salt for impregnating diffusion cathodes, which is a fully active material and its preparation method. After impregnation, the tungsten substrate of the cathode contains only barium scandium compounds, and has the characteristics of low-temperature high current density emission and long working life.
[0005] The technical solution adopted in this invention is as follows:
[0006] A scandium salt, a fully active material for impregnating diffusion cathodes, has the structural formula Ba2ScCuO. 4.4 .
[0007] A method for preparing scandium salt, a fully active material for impregnated diffusion cathodes, involves mixing raw materials of Ba, Sc, and Cu in a molar ratio of 2:1:1, and then synthesizing the structure Ba2ScCuO via a high-temperature solid-state reaction. 4.4 The impregnation diffusion cathode uses scandium, a fully active material.
[0008] Furthermore, the impregnated diffusion cathode is coated around the cathode substrate with a fully active material scandate, and impregnated in a hydrogen furnace at 1500~1700 °C. After the impregnated diffusion cathode is melted with the fully active material scandate, Cu is reduced and separated by hydrogen, and Ba and Sc are impregnated into the cathode substrate to obtain a fully active material impregnated cathode.
[0009] Furthermore, the cathode substrate is a tungsten cathode substrate.
[0010] Furthermore, the hydrogen furnace immersion time is 3 to 5 minutes.
[0011] Furthermore, the specific process of the high-temperature solid-phase reaction is as follows: after the raw materials are mixed, they are pressed into sheets, placed in a muffle furnace, heated to 1000~1600 ℃, sintered for more than 300 minutes, and after cooling, they are ground to obtain scandium salt, a fully active material for impregnating diffusion cathodes.
[0012] Furthermore, the heating rate is 5 °C / min.
[0013] Furthermore, the pressing conditions are as follows: the pressure gauge pointer of the tablet press is controlled at 30 MPa and maintained for more than 10 minutes to ensure that the tablet-shaped mixed raw materials are compacted and that the powder particles are in full contact.
[0014] Furthermore, the specific mixing process is as follows: each raw material is added to the dispersant, stirred to obtain a dispersion, allowed to stand until the supernatant and precipitate are clearly separated into layers, and then dried to obtain the mixed raw materials.
[0015] Furthermore, the dispersant is anhydrous ethanol.
[0016] Furthermore, the concentration of the dispersion is 0.1–0.4 g / ml.
[0017] Furthermore, the drying temperature is 60–80 °C, and the duration is at least 12 hours, to ensure that the dispersant in the dispersion is completely evaporated.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0019] 1. This invention proposes a fully active material scandate for impregnating diffusion cathodes and its preparation method, with the structural formula Ba2ScCuO. 4.4The impregnated cathode contains only fully active barium-scandium compounds in its effective impregnating material, with uniform scandium distribution and high content. This results in an impregnated cathode exhibiting low-temperature, high-current-density emission characteristics and excellent emission uniformity, with a DC emission current density of at least 10.0 A / cm² at 950 °C. 2 Compared to the (Ba,Ca)₂ScAlO₅ scandium aluminate cathode prepared by the high-temperature solid-state impregnation method, which has an efficiency of 4.90 A / cm at 950 °C, this method significantly improves performance. 2 The DC emission current density is increased by 1 time;
[0020] 2. The impregnated diffusion cathode is synthesized using scandium salt, a fully active material, at 1000-1600 °C. The preparation process is simple, fully compatible with existing impregnated cathodes, and impregnation can be achieved below 1700 °C. It has the advantages of low cost, good processability, and easy mass production. During the hydrogen furnace impregnation process, Cu element is reduced and then separated, and the active material impregnated into the cathode substrate is entirely barium scandium compound. It has the advantages of high effective active material coverage, no working residue, and long working life when the cathode is working. It is suitable for various microwave vacuum electronic devices, such as klystrons, traveling wave tubes, gyrotrons, and magnetrons, and can also be used in space ion thrusters.
[0021] 3. The structure of the scandate salt used as the fully active material for the impregnation diffusion cathode described in this invention is Ba2ScCuO4.4. Although first transition metals (such as Co, Ni, etc.) can also form isomorphic compounds with Ba and Sc and achieve metal phase separation during hydrogen reduction impregnation, except for Cu, the other metals are prone to alloying with the tungsten matrix at the impregnation or operating temperature, resulting in incomplete separation of reduction products and penetration into the grain interior along the tungsten grain boundaries, thereby damaging the pore structure and mechanical strength of the matrix, severely deteriorating the emission performance of the cathode, and limiting its engineering application. Attached Figure Description
[0022] Figure 1 Scandium salt Ba2ScCuO, a fully active material for impregnated diffusion cathodes prepared in Example 1 of this invention. 4.4 Powder X-ray diffraction pattern;
[0023] Figure 2 Scandium salt Ba2ScCuO, a fully active material for impregnated diffusion cathodes prepared in Example 1 of this invention. 4.4 X-ray diffraction pattern of the remaining powder after impregnation;
[0024] Figure 3 Ba2ScCuO impregnated in Example 1 of this invention 4.4 A double logarithmic graph of DC emission current density (A / cm2) versus voltage (V) for a fully active scandium cathode;
[0025] Figure 4 Ba2ScCuO impregnated in Example 1 of this invention 4.4 The emission current (in mA) of a fully active scandium cathode under constant anode and cathode high voltage and filament heating current as a function of time (in × 10⁻¹⁰) 2 (hour) data chart;
[0026] Figure 5 The powder X-ray diffraction pattern of scandium aluminate (Ba,Ca)2ScAlO5 for impregnated diffusion cathode prepared in Comparative Example 1 is shown.
[0027] Figure 6 This is a double logarithmic graph showing the DC emission current density (A / cm2) versus voltage (V) of the (Ba,Ca)2ScAlO5 scandium aluminate cathode impregnated in Comparative Example 1.
[0028] Figure 7 Scandium salt Ba2ScCuO, a fully active material for impregnated diffusion cathodes prepared in Example 2 of this invention. 4.4 Powder X-ray diffraction pattern;
[0029] Figure 8 Ba2ScCuO impregnation in Example 2 of this invention 4.4 DC emission current density of fully active scandium cathode (unit: A / cm²) 2 A log-log plot of voltage (in V) versus voltage.
[0030] Figure 9 Scandium salt Ba2ScCuO, a fully active material for impregnated diffusion cathodes prepared in Example 3 of this invention. 4.4 Powder X-ray diffraction pattern. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.
[0032] Example 1
[0033] This embodiment prepares a scandium salt, a fully active material for impregnating diffusion cathodes, with the structural formula Ba2ScCuO. 4.4 Specifically, it includes the following steps:
[0034] Step A1: Weigh the raw materials BaCO3, CuO and Sc2O3 according to the molar ratio BaCO3:CuO:Sc2O3 = 4:2:1;
[0035] Step A2: Place all the raw materials weighed in step A1 into a beaker and add an appropriate amount of anhydrous ethanol as a dispersant. The anhydrous ethanol should completely submerge the raw materials. Stir with a glass rod to disperse evenly. The stirring should not be too vigorous to avoid splashing the raw materials onto the beaker wall. If any raw materials splash onto the beaker wall, rinse immediately with anhydrous ethanol. Stir for 10-20 minutes until there are no particles to be felt, and obtain a dispersion with a concentration of 0.1-0.4 g / ml.
[0036] Step A3: Let the dispersion obtained in step A2 stand for about 1 hour until the upper layer of solution is clear. Place the layered solution into a drying oven and set the drying temperature range to 60~80 ℃. Dry for about 12 hours to ensure that the anhydrous ethanol in the raw material is completely evaporated to obtain the mixed raw material.
[0037] Step A4: Grind the mixed raw materials obtained in step A3 thoroughly to make the powder particles finer and more uniform. Use a tablet press to press the powder particles into round tablets with a diameter of 12 mm. The pressure gauge pointer of the tablet press should be kept at around 30 MPa for more than 10 minutes to ensure that the mixed raw material round tablets are compacted and that the powder particles are in full contact.
[0038] Step A5: Place the mixed raw material discs obtained in Step A4 into a high-temperature muffle furnace for sintering to carry out a high-temperature solid-state reaction. The heating and cooling rate of the high-temperature sintering is 5 °C / min. Sinter at 1200 °C for 400 minutes. After sintering, remove and cool, then grind into powder to obtain scandium salt Ba2ScCuO, a fully active material for impregnated diffusion cathodes. 4.4 .
[0039] The fully active material scandium salt Ba2ScCuO for impregnated diffusion cathodes obtained in this embodiment 4.4 Powder X-ray diffraction analysis was performed under the following conditions: sampling time 0.5 seconds, sampling step width 0.02°, and Bragg diffraction angle range of 10°–60°. The results were then obtained as follows: Figure 1 The X-ray diffraction data shown were obtained using phase analysis software and data from the International Data Center for Diffraction of Ba2ScCuO. 4.4 (PDF card number 43-0218) Comparison of diffraction patterns shows that the sintered product obtained in this example is a single-phase Ba2ScCuO. 4.4 .
[0040] Based on the fully active material scandium salt Ba2ScCuO for impregnated diffusion cathodes obtained in this embodiment... 4.4 The specific process for preparing an impregnated cathode is as follows:
[0041] Step B1: Preparation of porous tungsten matrix
[0042] Tungsten-copper rods with a porosity of 23%–28% were processed into cylinders with a diameter of 3.0 mm and a thickness of 3.5 mm. The cylinders were then immersed in concentrated nitric acid for chemical copper removal. The nitric acid was replaced every 12 hours. Before replacing the nitric acid, the cylinders were cleaned with anhydrous ethanol. The cylinders were then dried in an oven at 60–80 °C and weighed until there was no change in mass and the nitric acid solution became colorless and transparent, thus obtaining a tungsten matrix. The tungsten matrix was then subjected to high-temperature vacuum copper removal at 1400 °C. After waiting for 1 hour, the tungsten matrix was allowed to cool to below 300 °C. This heating and cooling process was repeated 3–5 times until no copper metal vapor evaporated, thus obtaining a porous tungsten matrix.
[0043] Step B2, Hot Wire Preparation
[0044] Tungsten wire is wound on a special shaping mold and shaped at high temperature. Then, an alumina coating of about 0.5 mm thickness is electrophoretically applied to its surface, and then high-temperature sintering is performed to densify the coating to obtain a hot wire.
[0045] Step B3: Preparation of molybdenum support
[0046] According to the design drawings, the molybdenum rod is processed into a sleeve. After degreasing, pickling and drying, it is placed in a high-temperature tungsten mesh hydrogen furnace for purification to obtain the molybdenum support.
[0047] Step B4: Preparation of hot wire assembly
[0048] The porous tungsten substrate obtained in step B1 is brazed with the molybdenum support obtained in step B3 at a high temperature of 1995 °C. Then, the hot wire obtained in step B2 is placed into the molybdenum support cylinder, filled with alumina powder, and then sintered at a high temperature of 1700 °C to obtain the hot wire assembly.
[0049] Step B5: Salt soaking
[0050] The impregnated diffusion cathode obtained in this embodiment is made of scandium salt Ba2ScCuO. 4.4 The cathode was coated around a porous tungsten substrate and then placed in a high-temperature tungsten mesh hydrogen furnace for high-temperature impregnation at 1700 °C. The residue in the crucible after impregnation diffusion was ground into powder and subjected to powder X-ray diffraction analysis. The diffraction data acquisition conditions were: sampling time 0.5 seconds, sampling step width 0.02°, and Bragg diffraction angle range of 15°~65°. This yielded the following results: Figure 2 The X-ray diffraction data shown were obtained using phase analysis software and the data of Ba(OH)2(H2O) (PDF card number 78-1831) and Ba6Sc6O, which are included in the International Diffraction Data Center. 15 (PDF card number 27-0040) Comparison of diffraction spectra shows that the effective active materials actually impregnated into the tungsten matrix in this embodiment are Ba(OH)2(H2O) and Ba6Sc6O.15 It contains no metallic elements other than barium and scandium.
[0051] Step B6: Cathode Surface Cleaning Treatment
[0052] The residual salt on the surface of the impregnated cathode obtained in step B5 was removed using a carbide cutting tool, and then the surface was polished and purified to obtain the final impregnated cathode, which was used as the test cathode.
[0053] The electron emission performance of the impregnated cathode obtained in this embodiment was measured, specifically as follows:
[0054] Step C1: Pretreatment of the impregnated cathode
[0055] While ensuring the vacuum level is always better than 4.0×10 -5 Under the condition of Pa, the filament current is adjusted to heat the impregnated cathode obtained in this embodiment to 1150 ℃; then the anode voltage is adjusted to 1000~1100 V to electrically activate the impregnated cathode. After the emission current is stable, the temperature of the impregnated cathode is adjusted to 1100 ℃ to age the impregnated cathode for 20~30 min to complete the pretreatment process.
[0056] Step C2, I-V characteristic test
[0057] First, the impregnated cathode was installed in the diode test system inside the quartz bell jar. Then, the temperature of the impregnated cathode was adjusted to the predetermined test temperature (850 ℃, 900 ℃, 950 ℃, 1000 ℃, and 1030 ℃, respectively). Next, the anode voltage was adjusted at equal intervals. After the emission current stabilized, the anode voltage and emission current data were recorded. During the test, the vacuum degree was always better than 1.0 × 10⁻⁶. -6 Pa, because the use of DC mode will produce an electron cooling effect, the surface temperature of the immersed cathode will decrease. Therefore, temperature compensation is used to measure the cathode electron emission during the test to obtain the volt-ampere characteristic data.
[0058] Step C3, Deviation point current density J div The determination
[0059] According to the electron flow law in the ideal diode model, in the full space charge limited region (FSCL region), the following condition is satisfied: J = pU 1.5 Where J is the cathode emission current density, U is the anode voltage, and p is a constant;
[0060] Plotting the volt-ampere characteristic data obtained in step C2 on a double logarithmic coordinate system, as shown below. Figure 3 The impregnated Ba2ScCuO shown 4.4The DC emission current density versus voltage of the fully active scandium cathode is plotted in a double logarithmic coordinate system. The current densities at 850 ℃, 900 ℃, 950 ℃, 1000 ℃, and 1030 ℃ were determined using a method deviating from the space charge confinement region, and were found to be 4.4 A / cm². 2 6.3 A / cm 2 11.9 A / cm 2 14.1 A / cm 2 18.1 A / cm 2 This demonstrates the characteristics of low-temperature, high-current-density emission.
[0061] Step C4: Emission lifetime test of the impregnated cathode in a diode system within a bell jar
[0062] First, the inflection point temperature was determined based on the underheating curve at the target lifetime emission current density (set to 5 A / cm² in this experiment), and the operating temperature of the impregnated cathode was set 50 °C above the inflection point. Then, the anode and cathode high voltages were adjusted to achieve the expected emission current (357 mA for a 3 mm cathode at this emission current density), while compensating for the cooling effect caused by the emitted electrons. After the system stabilized, the anode and cathode high voltages and filament current were fixed, and the emission current was continuously monitored over time to obtain... Figure 4 The emission lifetime characteristics of scandium cathodes impregnated with Ba2ScCuO4.4 fully active material in quartz bell-jar diode systems. The end-of-life criterion is typically defined as the decay of the cathode emission current to 90% of its initial value. Under this standard, the scandium cathode impregnated with Ba2ScCuO4.4 fully active material operated continuously for 1100 hours at a relatively high DC emission current density without reaching its lifespan limit, demonstrating its advantage of long service life.
[0063] Comparative Example 1
[0064] This comparative example prepared a scandium aluminate for impregnating diffusion cathodes, with the structural formula (Ba,Ca)₂ScAlO₅. The preparation method differed from Example 1 only in that the raw materials and ratio in step A1 were adjusted to "BaCO₃:Al(OH)₃:Sc₂O₅". 3: "CaCO3=4.4:1.8:1.1:1.4", the sintering temperature in step A5 is adjusted to "1450 ℃", and the holding time is adjusted to "300 min"; the other steps are exactly the same.
[0065] The impregnated diffusion cathode obtained in this comparative example was ground into powder using scandium aluminate (Ba,Ca)₂ScAlO₅, and powder X-ray diffraction analysis was performed. The diffraction data acquisition conditions were: sampling time 0.5 seconds, sampling step width 0.02°, and Bragg diffraction angle range of 8°~65°. The results were as follows... Figure 5The X-ray diffraction data shown can be compared with the diffraction pattern of (Ba,Ca)2ScAlO5 (PDF card number 43-0078) already included in the International Diffraction Data Center using phase analysis software. It can be seen that the sintered product obtained in this comparative example is a single-phase (Ba,Ca)2ScAlO5.
[0066] The impregnated diffusion cathode obtained in this comparative example was prepared using scandium aluminate (Ba,Ca)2ScAlO5, and the preparation process was exactly the same as that in Example 1.
[0067] The electron emission performance of the impregnated cathode obtained in this comparative example was measured using the same procedures as in Example 1, with performance tested only at 950 °C and 1000 °C, yielding the following results. Figure 6 The double logarithmic plot of DC emission current density versus voltage for the (Ba,Ca)₂ScAlO₅ scandium aluminate cathode shown is used to determine the current densities at 950 °C and 1000 °C using the method of deviating from the space charge confinement region; these densities are 4.90 A / cm². 2 and 11.6 A / cm 2 .
[0068] Comparing the electron emission performance of the impregnated cathodes obtained in Example 1 and Comparative Example 1, it can be seen that the impregnated diffusion cathode prepared in Example 1 uses scandium salt Ba2ScCuO, which is a fully active material. 4.4 The cathode exhibits higher current density emission characteristics at the same test temperature, demonstrating the superior performance of the fully active scandium salt Ba2ScCuO prepared in Example 1. 4.4 The advantages.
[0069] Compared to the multiphase scandium aluminate of Comparative Example 1, the fully active scandium salt Ba2ScCuO prepared in Example 1... 4.4 After impregnation, the actual effective impregnated active material contains only barium scandium compounds. Scandium is evenly distributed in the active material, resulting in excellent emission uniformity.
[0070] Example 2
[0071] This embodiment prepares a scandium salt, a fully active material for impregnating diffusion cathodes, with the structural formula Ba2ScCuO. 4.4 The preparation method is the same as in Example 1, except that the sintering temperature in step A5 is adjusted to "1600 ℃"; the other steps are exactly the same.
[0072] The fully active material scandium salt Ba2ScCuO for impregnated diffusion cathodes obtained in this embodiment 4.4 Powder X-ray diffraction analysis was performed under the following conditions: sampling time 0.5 seconds, sampling step width 0.02°, and Bragg diffraction angle range of 10°–60°. The results were then obtained as follows: Figure 7The X-ray diffraction data shown were obtained using phase analysis software and data from the International Data Center for Diffraction of Ba2ScCuO. 4.4 (PDF card number 43-0218) Comparison of diffraction patterns shows that the sintered product obtained in this example is a single-phase Ba2ScCuO. 4.4 .
[0073] Based on the fully active material scandium salt Ba2ScCuO for impregnated diffusion cathodes obtained in this embodiment... 4.4 The impregnated cathode was prepared in the same manner as in Example 1.
[0074] The electron emission performance of the impregnated cathode obtained in this example was measured using the same steps as in Example 1, with performance tested only at temperatures of 850 °C, 900 °C, and 950 °C, yielding the following results: Figure 8 The impregnated Ba2ScCuO shown 4.4 The DC emission current density versus voltage plot of the fully active scandium cathode is shown in a double logarithmic graph. The current densities at 850 °C, 900 °C, and 950 °C are determined using the method of deviating from the space charge confinement region, and are 9.7 A / cm². 2 12.3 A / cm 2 and 15.9 A / cm 2 Compared to Comparative Example 1, the fully active substance scandate Ba2ScCuO prepared in this embodiment... 4.4 It exhibits higher current density emission characteristics at the same test temperature.
[0075] Example 3
[0076] This embodiment prepares a scandium salt, a fully active material for impregnating diffusion cathodes, with the structural formula Ba2ScCuO. 4.4 The preparation method is the same as in Example 1, except that the sintering temperature in step A5 is adjusted to "1000 ℃"; the other steps are exactly the same.
[0077] The fully active material scandium salt Ba2ScCuO for impregnated diffusion cathodes obtained in this embodiment 4.4 Powder X-ray diffraction analysis was performed under the following conditions: sampling time 0.5 seconds, sampling step width 0.02°, and Bragg diffraction angle range of 10°–60°. The results were then obtained as follows: Figure 9 The X-ray diffraction data shown were obtained using phase analysis software and data from the International Data Center for Diffraction of Ba2ScCuO. 4.4 (PDF card number 43-0218) Comparison of diffraction patterns shows that the sintered product obtained in this example is a single-phase Ba2ScCuO. 4.4 .
[0078] Example 4
[0079] This embodiment prepares a scandium salt, a fully active material for impregnating diffusion cathodes, with the structural formula Ba2ScCuO. 4.4 The preparation method is the same as in Example 1, except that the impregnation temperature in step B5 is adjusted to "1500 ℃"; all other steps are exactly the same.
[0080] It should be noted that this is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A scandium salt, a fully active material for impregnating diffusion cathodes, characterized in that, Its structural formula is Ba2ScCuO 4.4 .
2. A method for preparing scandium salt, a fully active material for impregnating diffusion cathodes, characterized in that, By mixing raw materials containing Ba, Sc, and Cu in a molar ratio of 2:1:1, and then synthesizing the structure Ba₂ScCuO through a high-temperature solid-state reaction, a product with the structural formula Ba₂ScCuO is formed. 4.4 The impregnation diffusion cathode uses scandium, a fully active material.
3. The method for preparing scandium salt, a fully active material for impregnated diffusion cathodes, according to claim 2, is characterized in that... The impregnated diffusion cathode is coated with scandium, a fully active material, around the cathode substrate and impregnated in a hydrogen furnace at 1500~1700 °C. After the impregnated diffusion cathode is melted with scandium, the Cu in it is reduced and separated by hydrogen, and Ba and Sc are impregnated into the cathode substrate to obtain a fully active material impregnated cathode.
4. The method for preparing scandium salt, a fully active material for impregnated diffusion cathodes, according to claim 3, is characterized in that... The cathode substrate is a tungsten cathode substrate.
5. The method for preparing scandium salt, a fully active material for impregnated diffusion cathodes, according to claim 4, is characterized in that... The hydrogen furnace immersion time is 3 to 5 minutes.
6. The method for preparing scandium salt, a fully active material for impregnated diffusion cathodes, according to claim 2, is characterized in that, The specific process of the high-temperature solid-phase reaction is as follows: after the raw materials are mixed, they are pressed into sheets, placed in a muffle furnace, heated to 1000~1600℃, sintered for more than 300 minutes, and after cooling, they are ground to obtain scandium salt, a fully active material for impregnating diffusion cathodes.
7. The method for preparing scandium salt, a fully active material for impregnated diffusion cathodes, according to claim 6, is characterized in that... The heating rate is 5 °C / min.
8. The method for preparing scandium salt, a fully active material for impregnated diffusion cathodes, according to claim 6, is characterized in that, The specific mixing process is as follows: each raw material is added to the dispersant, stirred to obtain a dispersion, allowed to stand until the supernatant and precipitate are clearly separated into layers, and then dried to obtain the mixed raw materials.