A method for preparing petal-shaped nanometer dysprosium oxide

Abstract

The application belongs to the technical field of capacitor materials, and particularly relates to a preparation method of petal-shaped nano dysprosium oxide. A surfactant is added into a soluble dysprosium salt solution and stirred uniformly; a urea solution is added dropwise to generate a precipitate; and the petal-shaped nano dysprosium oxide is obtained through a hydrothermal reaction. The petal-shaped nano dysprosium oxide doped into an MLCC capacitor can reduce dielectric loss, and the effect of improving the performance of a barium titanate-based substrate ceramic capacitor is achieved.

Description

Technical Field

[0001] This invention belongs to the field of capacitor material preparation technology, and specifically relates to a method for preparing petal-shaped nano-dysprosium oxide. Background Technology

[0002] Rare earth elements are known as "industrial gold" because of their excellent photoelectric and electromagnetic properties. They can be combined with other materials to form a wide variety of new materials with different properties. Their most significant function is to greatly improve the quality and performance of other products.

[0003] Multilayer ceramic capacitors (MLCCs) are the most widely produced and used capacitors in electronic devices. MLCCs have advantages such as small size, low price, good high-frequency characteristics, low dielectric loss, and high temperature and high voltage resistance, making them suitable for a wide range of applications. They are also suitable for automated surface mount production, helping to save internal space in electronic products, and have become the most widely used capacitor product. High dielectric constant and low loss are the technical indicators that MLCC development has always pursued. The level of dielectric loss directly determines the energy consumption of the capacitor during use. Higher dielectric loss leads to more heat generation during device operation and significantly reduces the device's lifespan.

[0004] Dysprosium oxide possesses high thermal stability and electromagnetic interference resistance. Appropriate doping with barium titanate can enhance the dielectric temperature stability and electrical conductivity of dielectric ceramics, improving product performance and reliability. The small radius Dy ions can simultaneously replace Ba²⁺ and Ti⁴⁺, and co-doping can form stable composite ions that are difficult to oxidize even in a pure oxygen atmosphere. This effectively reduces the number of oxygen holes and restricts oxygen movement, making Dy one of the most effective elements for improving the lifespan of MLCCs. Currently, while commonly used dysprosium oxide can improve the lifespan of dielectric ceramic capacitors, it is difficult to reduce dielectric loss simultaneously. Additional doping is required to control dielectric loss. However, the more additives used, the more factors affect the capacitor's electrical performance, making it more difficult to control the insulation resistivity, thermal conductivity, thermal stability, and chemical stability of the ceramic capacitor.

[0005] Chinese patent CN115246653A discloses a nano-dysprosium oxide with an average particle size of 20-60 nm and a specific surface area of ​​100-250 m². 2 ·g -1 The patented nano-dysprosium oxide has a large specific surface area, high surface energy, and high surface atomic activity, which will significantly reduce the melting point of the nanoparticles. MLCC ceramic powder requires strict control of the calcination temperature; an excessively low melting point will greatly affect the electrical performance and thermal stability of the powder formulation. Therefore, this invention provides a petal-shaped nano-dysprosium oxide, which, when doped into MLCC capacitors, can reduce dielectric loss and achieve the effect of improving the performance of barium titanate-based ceramic capacitors. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing petal-shaped nano-dysprosium oxide. The nano-dysprosium oxide prepared by this method can be doped into MLCC capacitors to reduce dielectric loss and improve the electrical performance of MLCC capacitors.

[0007] The technical solution adopted in this invention is as follows:

[0008] A method for preparing petal-shaped nano-dysprosium oxide specifically includes the following steps:

[0009] (1) Prepare a soluble dysprosium salt solution with a concentration controlled at 0.1-0.3 mol / L;

[0010] The soluble dysprosium salt is dysprosium chloride (DyCl3) or dysprosium nitrate (Dy(NO3)3).

[0011] (2) Prepare a surfactant solution by dissolving a surfactant of 1-2% of the theoretical mass of dysprosium oxide in hot water above 90°C and adding it to a soluble dysprosium salt solution under a water bath at 85°C-90°C and stirring until homogeneous.

[0012] The mass ratio of the surfactant to hot water is 1-2:100; the surfactant is one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and lauramide propyl betaine.

[0013] (3) Prepare a urea solution by dissolving urea in hot water at 85°C or above, with a concentration of 0.05-0.2 mol / L; slowly add the urea solution dropwise into the soluble dysprosium salt solution under 85°C water bath conditions until the pH value is between 6 and 7, and a precipitate is formed.

[0014] (4) Pour the above reaction system into a reaction vessel, heat at 120°C and stir for 8-10 hours;

[0015] (5) Remove the liquid and wash it with deionized water at 90°C or higher;

[0016] (6) After the purity of the filter cake reaches 4N5 (99.995%), calcine it at 900-1000℃ for 4 hours;

[0017] (7) The calcined dysprosium oxide is pulverized to obtain petal-shaped nano-dysprosium oxide.

[0018] The nano-dysprosium oxide powder prepared by this invention has an average particle size of 30-40 nm and a specific surface area of ​​19-25 m². 2 / g.

[0019] The nano-dysprosium oxide doped by the present invention is used to prepare MLCC capacitors.

[0020] Furthermore, the doping amount of the nano-dysprosium oxide is 2-3 wt.%.

[0021] The nano-dysprosium oxide doping of the present invention into the MLCC capacitor can reduce its dielectric loss and achieve the effect of improving the performance of barium titanate-based ceramic capacitors. Attached image description:

[0022] Figure 1 The image shows the SEM morphology of the nano-dysprosium oxide prepared in Example 1.

[0023] Figure 2 The image shows the SEM morphology of the nano-dysprosium oxide prepared in Example 2.

[0024] Figure 3 The image shows the SEM morphology of the nano-dysprosium oxide prepared in Example 3.

[0025] Figure 4 The image shows the SEM morphology of the nano-dysprosium oxide prepared in Example 4.

[0026] Figure 5 SEM image of nano-dysprosium oxide prepared in Comparative Example 1;

[0027] Figure 6 SEM image of the nano-dysprosium oxide prepared in Comparative Example 2;

[0028] Figure 7 SEM image of the nano-dysprosium oxide prepared in Comparative Example 3;

[0029] Figure 8 SEM image of the nano-dysprosium oxide prepared in Comparative Example 4;

[0030] Figure 9 The image shows the SEM morphology of the nano-dysprosium oxide prepared in Comparative Example 5. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] Example 1

[0033] Prepare 5.36 L of a 0.1 mol / L DyCl3 solution. Dissolve 1 g of sodium dodecyl sulfate in 100 g of hot water above 90°C and pour the solution into the DyCl3 solution. Stir well under an 85°C water bath. Dissolve and dilute urea to 0.2 mol / L with hot water above 85°C and slowly add it dropwise to the DyCl3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel and heat at 120°C for 8 hours with stirring. Remove the solution and filter. Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 900°C for 4 hours. Pulverize the calcined dysprosium oxide to obtain an average particle size of 30-40 nm and a particle size of 22.08 μm. 2 / g of nano-dysprosium oxide powder, SEM image Figure 1 As shown.

[0034] Example 2

[0035] Prepare 2.68 L of a 0.2 mol / L DyCl3 solution. Dissolve 1 g of sodium dodecylbenzenesulfonate in 100 g of hot water above 90°C and pour it into the DyCl3 solution. Stir well under an 85°C water bath. Dissolve and dilute urea to 0.1 mol / L with hot water above 85°C and slowly add it dropwise to the DyCl3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel, heat and react at 120°C for 9 hours, then remove the solution and filter. Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 950°C for 4 hours. Pulverize the calcined dysprosium oxide to obtain an average particle size of 30-40 nm and a BET of 19.88 μm. 2 / g of nano-dysprosium oxide powder, SEM image Figure 2 As shown.

[0036] Example 3

[0037] Prepare 1.78 L of a 0.3 mol / L DyCl3 solution. Dissolve 1 g of lauramidopropyl betaine in 100 g of hot water above 90°C and pour it into the DyCl3 solution. Stir well under an 85°C water bath. Dissolve and dilute urea to 0.1 mol / L with hot water above 85°C and slowly add it dropwise to the DyCl3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel and heat and stir at 120°C for 10 hours. Remove the solution and filter it. Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 1000°C for 4 hours. Pulverize the calcined dysprosium oxide to obtain an average particle size of 30-40 nm and a particle size of 21.06 μm. 2 / g of nano-dysprosium oxide powder, SEM image Figure 3 As shown.

[0038] Example 4

[0039] Prepare 5.36 L of a 0.1 mol / L Dy(NO3)3 solution. Dissolve 0.5 g sodium dodecyl sulfate and 0.5 g lauramide propyl betaine in 100 g of hot water above 90°C, then pour the solution into the Dy(NO3)3 solution and stir well in an 85°C water bath. Dissolve and dilute urea to 0.2 mol / L in hot water above 85°C, then slowly add it dropwise to the Dy(NO3)3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel, heat and stir at 120°C for 9 hours, then remove the solution and filter. Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 900°C for 4 hours. Pulverize the calcined dysprosium oxide to obtain an average particle size of 30-40 nm and a BET of 19.2 μm. 2 / g of nano-dysprosium oxide powder, SEM image Figure 4 As shown.

[0040] Comparative Example 1

[0041] Prepare 1.07 L of a 0.5 mol / L DyCl3 solution. Dissolve 1 g of sodium dodecyl sulfate in 100 g of hot water above 90°C and pour the solution into the DyCl3 solution. Stir well under an 85°C water bath. Dissolve and dilute urea to 0.2 mol / L with hot water above 85°C and slowly add it dropwise to the DyCl3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel, heat and stir at 120°C for 8 hours. Remove the solution and filter. Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 900°C for 4 hours. Crush the calcined dysprosium oxide to obtain an average particle size of 20-30 nm, but the particle agglomeration is severe. (BET: 16.18m) 2 / g of nano-dysprosium oxide powder, SEM image Figure 5 As shown.

[0042] Comparative Example 2

[0043] Prepare 5.36 L of a 0.1 mol / L DyCl3 solution. Dissolve 2 g of sodium dodecyl sulfate in 100 g of hot water above 90°C and pour the solution into the DyCl3 solution. Stir well under an 85°C water bath. Dissolve and dilute urea to 0.2 mol / L with hot water above 85°C and slowly add it dropwise to the DyCl3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel and heat at 120°C for 8 hours with stirring. Remove the solution and filter (there will be a lot of foam during filtration). Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 900°C for 4 hours. Crush the calcined dysprosium oxide to obtain an average particle size of 20-30 nm (BET: 12.36 μm). 2 / g of nano-dysprosium oxide powder showed significant particle agglomeration, as indicated by SEM. Figure 6 As shown.

[0044] Comparative Example 3

[0045] Prepare 5.36 L of a 0.1 mol / L DyCl3 solution. Dissolve 1 g of sodium dodecyl sulfate in 100 g of hot water above 90°C and pour the solution into the DyCl3 solution. Stir well under an 85°C water bath. Dissolve and dilute urea to 0.5 mol / L with hot water above 85°C and slowly add it dropwise to the DyCl3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel and heat at 120°C for 8 hours with stirring. Remove the solution and filter. Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 900°C for 4 hours. Pulverize the calcined dysprosium oxide to obtain an average particle size of 30-40 nm and a BET value of 15.41 μm. 2 / g of nano-dysprosium oxide powder, SEM image Figure 7 As shown.

[0046] Comparative Example 4

[0047] Prepare 2.68 L of a 0.2 mol / L DyCl3 solution. Dissolve 1 g of sodium dodecylbenzenesulfonate in 100 g of hot water above 90°C and pour it into the DyCl3 solution. Stir well under an 85°C water bath. Dissolve and dilute urea to 0.1 mol / L with hot water above 85°C and slowly add it dropwise to the DyCl3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel, heat and react at 120°C for 4 hours, then remove the solution and filter. Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 950°C for 4 hours. Pulverize the calcined dysprosium oxide to obtain an average particle size of 30-40 nm and a BET of 22.35 μm. 2 / g of nano-dysprosium oxide powder, SEM image Figure 8 As shown.

[0048] Comparative Example 5

[0049] Prepare 2.68 L of a 0.2 mol / L DyCl3 solution. Dissolve 1 g of sodium dodecylbenzenesulfonate in 100 g of hot water above 90°C and pour it into the DyCl3 solution. Stir well under an 85°C water bath. Dissolve and dilute urea to 0.1 mol / L with hot water above 85°C and slowly add it dropwise to the DyCl3 solution until the pH value is fixed between 6 and 7. Pour the precipitate into a reaction vessel, heat and react at 120°C for 9 hours with stirring. Remove the solution and filter. Wash the filter cake with hot water above 90°C until the purity is 99.995%. Calcinate at 1100°C for 4 hours. Pulverize the calcined dysprosium oxide to obtain an average particle size of 30-40 nm and a BET of 10.9 μm. 2 / g of nano-dysprosium oxide powder showed significant agglomeration, as indicated by SEM. Figure 9 As shown.

[0050] Application Example 1

[0051] The nano-dysprosium oxide prepared in Examples 1-4 and Comparative Examples 1-5 was used to prepare MLCCBLOCK.

[0052] The raw materials used to prepare the BLOCK were a mixed powder of BaCO3, TiO2, V2O5, SiO2, Dy2O3, Y2O3, Gd2O3, Mn2O3, Nb2O5, and Sm2O3. The powder was ground, dried, granulated, pressed into ingots, calcined in an atmosphere furnace, silver-coated, and tin-plated. The prepared BLOCK was then subjected to DF testing.

[0053] Table 1. Effects of different morphologies and amounts of nano-dysprosium oxide on dielectric loss (DF) of MLC Blocks

[0054]

[0055] As shown in the table, the nano-dysprosium oxide prepared according to this invention, when added to MLCC capacitors at an amount between 2-3 wt.%, reduces dielectric loss; however, adding more or less than this range increases dielectric loss. Examples 2, 3, and 4 respectively confirm the practical performance of this invention. Comparative Examples 1-5 demonstrate that the electrical performance of other morphologies of nano-dysprosium oxide is inferior to that of the petal-shaped nano-dysprosium oxide prepared according to this invention.

Claims

1. A method for preparing petal-shaped nano-dysprosium oxide, characterized in that, Specifically, the following steps are included: (1) Provide a soluble dysprosium salt solution with a concentration of 0.1-0.3 mol / L; provide a surfactant solution, wherein the surfactant solution is prepared by dissolving the surfactant in hot water at a temperature ≥90℃, wherein the mass ratio of the surfactant to the hot water is 1-2:100, and the mass of the surfactant is 1-2% of the theoretical yield of dysprosium oxide; (2) Under water bath conditions of 85℃~90℃, the surfactant solution is added to the soluble dysprosium salt solution and stirred evenly; (3) Provide a urea solution with a concentration of 0.05-0.2 mol / L; add the urea solution dropwise to a soluble dysprosium salt solution until the pH value is fixed between 6 and 7, and a precipitate is formed; (4) Heat the reaction system of step (3) at 120°C and stir for 8-10 hours; (5) Filter, wash, calcinate, and pulverize. The calcination temperature is 900-1000℃ and the calcination time is 4h. The resulting powder is petal-shaped nano-dysprosium oxide. The specific surface area of ​​the petal-shaped nano-dysprosium oxide is 19–25 m². 2 / g; The petal-shaped nano-dysprosium oxide is used as a dopant to prepare multilayer ceramic capacitors.

2. The method for preparing petal-shaped nano-dysprosium oxide according to claim 1, characterized in that, The soluble dysprosium salt is dysprosium chloride or dysprosium nitrate.

3. The method for preparing petal-shaped nano-dysprosium oxide according to claim 1, characterized in that, The surfactant is one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and lauramidopropyl betaine.

4. The method for preparing petal-shaped nano-dysprosium oxide according to claim 1, characterized in that, The urea solution is prepared by dissolving urea in hot water at a temperature ≥85℃.

5. The method for preparing petal-shaped nano-dysprosium oxide according to claim 1, characterized in that, The washing process involves using deionized water at a temperature above 90°C until the filter cake purity reaches 99.995%.

6. The application of the petal-shaped nano-dysprosium oxide prepared by the method according to any one of claims 1 to 5, characterized in that, The petal-shaped nano-dysprosium oxide is used as a dopant to prepare multilayer ceramic capacitors.

7. The application of the petal-shaped nano-dysprosium oxide according to claim 6, characterized in that, The doping amount of the petal-shaped nano-dysprosium oxide is 2-3 wt%.

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