Barium titanate-barite composite material, and preparation method and application thereof

Abstract

The application provides a barium titanate-baryte composite material and a preparation method and application thereof, and belongs to the technical field of electronic materials.The barium titanate-baryte composite material comprises 20-30.5% of barium titanate, 35-45% of first barium sulfate, 25-35% of second barium sulfate, a coupling agent, 0.5-2% of nano silicon dioxide and 0.5-2% of nano aluminum oxide; and the coupling agent is a titanate coupling agent or a silane coupling agent.The barium titanate-baryte composite material has high dielectric constant, excellent radiation resistance, good mechanical strength, economy and construction convenience, and is particularly suitable for fields such as building decoration, industrial protection and electronic components, and is especially suitable for occasions requiring high dielectric constant and radiation resistance, such as radiation shielding plates, dielectric materials of electronic devices and the like.

Description

Technical Field

[0001] This invention relates to the field of electronic materials technology, and in particular to a barium titanate-barite composite material, its preparation method, and its application. Background Technology

[0002] With continuous technological advancements and increasingly complex application environments, the performance requirements for materials are constantly rising, especially in the construction, industrial, and electronics fields. Materials that combine high dielectric constants with radiation resistance have become an urgent market demand. Traditional radiation protection materials, such as barium titanate, barite, and lead plates, while demonstrating certain advantages in their respective applications, also face their limitations and cannot fully meet the diverse needs of modern applications.

[0003] Barium titanate, due to its high dielectric constant and low dielectric loss, is widely used in capacitors, piezoelectric elements, and electromagnetic shielding materials. However, its high production cost and susceptibility to degradation in high-radiation environments hinder its widespread adoption in large-scale applications. Furthermore, barium titanate is typically produced as powder or in bulk, making it difficult to maintain surface smoothness and aesthetics in large-area applications, increasing construction complexity and cost. Barite, due to its high density and excellent radiation resistance, is widely used in X-ray shielding and nuclear industry protection. However, its low dielectric constant limits its use in electronic applications requiring high dielectric properties. In addition, barite is relatively fragile, making it difficult to achieve a smooth and flat surface, often requiring additional surface treatment, which increases processing costs and reduces construction efficiency. Lead plates, due to their high density and excellent radiation shielding capabilities, are widely used in the medical and nuclear industries. However, lead plates are heavy and difficult to install, especially in large-area applications, resulting in extremely high transportation and installation costs. Furthermore, the toxicity of lead poses a potential threat to the environment and human health, which not only limits its application but also necessitates the use of additional decorative overlays to enhance the aesthetics of lead sheets in many cases, further increasing cost and complexity.

[0004] Therefore, although the aforementioned traditional materials have certain advantages in some specific applications, they have obvious shortcomings when facing modern requirements for multifunctionality, environmental protection, and economy. Summary of the Invention

[0005] The purpose of this invention is to provide a barium titanate-barite composite material, its preparation method and application, wherein the barium titanate-barite composite material meets the requirements of high performance, functionality, environmental protection and economy.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a barium titanate-barite composite material, comprising the following raw materials in weight percentages:

[0008] Barium titanate 20-30.5%, barium sulfate monosulfate 35-45%, barium sulfate disulfate 25-35%, coupling agent, nano silica 0.5-2%, nano alumina 0.5-2%;

[0009] The first barium sulfate has an average particle size of 4–5 μm and a maximum particle size of ≤27 μm; the second barium sulfate has an average particle size of 3–4.5 μm and a maximum particle size of ≤24 μm.

[0010] The coupling agent is a titanate coupling agent or a silane coupling agent;

[0011] When the coupling agent is a titanate coupling agent, the mass percentage of the titanate coupling agent is 1-3%;

[0012] When the coupling agent is a silane coupling agent, the mass percentage of the silane coupling agent is 0.5% to 2%.

[0013] Preferably, the titanate coupling agent includes one or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, tetraoctyl titanate, and tetraphenyl titanate.

[0014] Preferably, the silane coupling agent comprises one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, epoxypropyltrimethoxysilane, and propyltriethoxysilane isocyanate.

[0015] This invention provides a method for preparing the barium titanate-barite composite material described in the above technical solution, comprising the following steps:

[0016] Barium titanate, barium sulfate I, barium sulfate II, coupling agent, nano-silica and nano-alumina were ball-milled to obtain a mixture.

[0017] The mixture is spray-granulated to obtain spherical material;

[0018] The spherical material is pressed into shape using an isostatic pressing method to obtain a blank.

[0019] The preform is sintered in a protective atmosphere to obtain a barium titanate-barite composite material.

[0020] Preferably, the ball milling mixing time is 2-4 hours and the rotation speed is 150-200 rpm.

[0021] Preferably, the conditions for spray granulation include: a feed rate of 10-20 mL / min and a spray drying temperature of 120-150 °C.

[0022] Preferably, the particle size of the spherical material is 100–300 μm.

[0023] Preferably, the pressing conditions include: a pressure of 250–350 MPa, a mold temperature of 20–40°C, and a time of 10–15 min.

[0024] Preferably, the sintering temperature is 1250–1350°C, and the holding time is 4–6 hours; the protective atmosphere includes nitrogen or argon.

[0025] This invention provides the application of the barium titanate-barite composite material described in the above technical solution or the barium titanate-barite composite material prepared by the preparation method described in the above technical solution in the fields of building decoration, industrial protection or electronic components.

[0026] This invention provides a barium titanate-barite composite material. The invention uses barium titanate and barium sulfate of different specifications as main raw materials, combining barium titanate with barite. Through reasonable proportioning and the addition of auxiliary materials, the high performance and economical production of the composite material are ensured. The components in the barium titanate-barite composite material of this invention work synergistically to ensure the high performance and economy of the composite material. Barium titanate, as the main raw material, provides a high dielectric constant and low dielectric loss, improving the material's performance in electronic components. The first barium sulfate, with its larger particle size and high purity, enhances radiation resistance and mechanical strength, while the second barium sulfate, with its finer particle size, improves the material's density and mechanical stability. The titanate coupling agent enhances the interfacial bonding of the composite material by reacting with the barium titanate surface, while the silane coupling agent improves the adhesion of barium sulfate to other components through chemical bonding. Nano-silica and alumina further improve the material's mechanical properties and heat resistance. The synergistic effect of the components described above in this invention not only endows the material with excellent dielectric and radiation resistance properties, but also enhances its mechanical strength and production economy, while ensuring ease of construction and suitability for large-scale applications. Therefore, this invention significantly improves the dielectric constant, dielectric loss, and radiation resistance of the material by adding barium titanate. The combination of barium titanate and barite significantly improves the electrical properties and interfacial bonding of the material.

[0027] The barium titanate-barite composite material of the present invention has high dielectric constant, excellent radiation resistance, good mechanical strength, economy and ease of construction. It is particularly suitable for building decoration, industrial protection, electronic components and other fields, especially for occasions that require high dielectric constant and radiation resistance, such as radiation shielding plates and dielectric materials for electronic devices.

[0028] The barium titanate-barite composite material of this invention can be made into large-size plates of 400×800mm. The surface is precisely shaped and polished, resulting in good flatness and aesthetics, making it suitable for large-area paving like ceramic tiles. This invention combines high performance with aesthetics, not only improving radiation resistance but also effectively reducing production costs. While maintaining high performance, it achieves the dual requirements of surface flatness and aesthetics, simplifies the construction process, and can meet a variety of application needs.

[0029] The barium titanate-barite composite material of this invention offers convenient construction due to its ability to be manufactured into large-size plates. After precision molding and polishing, the surface is smooth and suitable for large-area installation, reducing adjustment work. Furthermore, the material's high mechanical strength and density ensure it is not easily cracked or damaged during installation, reducing construction difficulty. Its good dimensional stability means the polished surface requires no additional treatment, simplifying the construction process. Simultaneously, compared to traditional radiation shielding materials such as lead plates, the composite material is lighter, facilitating transportation and installation, further improving construction efficiency. Therefore, compared to traditional materials, the barium titanate-barite composite material of this invention exhibits significant advantages in functionality, environmental friendliness, and ease of construction, providing a more extensive and cost-effective solution for modern building and industrial applications, and possessing great market application prospects. Detailed Implementation

[0030] This invention provides a barium titanate-barite composite material, comprising the following raw materials in weight percentages:

[0031] Barium titanate 20-30.5%, barium sulfate monosulfate 35-45%, barium sulfate disulfate 25-35%, coupling agent, nano silica 0.5-2%, nano alumina 0.5-2%;

[0032] The first barium sulfate has an average particle size of 4–5 μm and a maximum particle size of ≤27 μm; the second barium sulfate has an average particle size of 3–4.5 μm and a maximum particle size of ≤24 μm.

[0033] The coupling agent is a titanate coupling agent or a silane coupling agent;

[0034] When the coupling agent is a titanate coupling agent, the mass percentage of the titanate coupling agent is 1-3%;

[0035] When the coupling agent is a silane coupling agent, the mass percentage of the silane coupling agent is 0.5% to 2%.

[0036] Unless otherwise specified, all raw materials or reagents used in this invention are commercially available products well known in the art.

[0037] The raw materials for preparing the barium titanate-barite composite material provided by the present invention, by mass percentage, include 20-30.5% barium titanate, preferably 22-28%, and more preferably 24-25%. The barium titanate described in the present invention has a high dielectric constant and can be polarized under an external electric field, thereby improving the dielectric properties of the composite material while maintaining low dielectric loss.

[0038] The raw materials for preparing the barium titanate-barite composite material provided by the present invention, by weight percentage, include 35-45% barium sulfate, more preferably 38-40%.

[0039] In this invention, the average particle size of the first barium sulfate is 4-5 μm, and the maximum particle size is ≤27 μm.

[0040] In this invention, the barium sulfate content in the first barium sulfate is preferably ≥90wt%, the whiteness of the first barium sulfate is preferably 83-84%, more preferably 83.8%, and the pseudo-specific gravity is preferably 0.65-0.75 g / cm³. 3 More preferably, it is 0.69 g / cm³. 3 .

[0041] This invention does not specifically limit the source of the first barium sulfate; any commercially available product meeting the aforementioned purity level, as well as those well-known in the art, is acceptable. In the embodiments of this invention, the first barium sulfate is specifically GY-1250, manufactured by Jiangxi Guangyuan Chemical Co., Ltd. The first barium sulfate of this invention has high barium content and excellent whiteness, while also possessing high density and good X-ray shielding effect, which can enhance the electrical properties and radiation resistance of the material, especially in applications requiring high density and high purity. Furthermore, the larger particle size and high purity of the first barium sulfate contribute to improving the overall mechanical strength and stability of the composite material, as well as its radiation shielding performance.

[0042] The raw materials for preparing the barium titanate-barite composite material provided by the present invention, by weight percentage, include 25-35% barium sulfate, preferably 27-32%, and more preferably 29-30%.

[0043] In this invention, the average particle size of the second barium sulfate is 3 to 4.5 μm, and the maximum particle size is ≤24 μm.

[0044] In this invention, the barium sulfate content in the second barium sulfate is preferably ≥90wt%, the whiteness of the second barium sulfate is preferably 85-86%, more preferably 85.4%, and the pseudo-specific gravity is preferably 0.65-0.75 g / cm³. 3 More preferably, it is 0.68 g / cm³. 3 .

[0045] This invention does not specifically limit the source of the second barium sulfate; any commercially available product meeting the aforementioned purity level, as well as those well-known in the art, is acceptable. In the embodiments of this invention, the specific product is barium sulfate (GY-2500) from Jiangxi Guangyuan Chemical Co., Ltd. The second barium sulfate of this invention, with its fine particle size and good particle size distribution, enhances the material's density and mechanical strength. In this invention, the second barium sulfate has a fine particle size and uniform particle size distribution. These fine particles can effectively fill the tiny voids in the material, significantly improving the material's density and reducing porosity. By improving the material's density, the overall mechanical strength of the composite material is enhanced, making it more durable and stable, particularly suitable for applications requiring high strength and surface smoothness.

[0046] The raw materials for preparing the barium titanate-barite composite material provided by the present invention, by weight percentage, include a coupling agent; the coupling agent is a titanate coupling agent or a silane coupling agent.

[0047] When the coupling agent is a titanate coupling agent, the mass percentage of the titanate coupling agent is 1-3%, preferably 2-2.8%, and more preferably 2.2-2.5%. The titanate coupling agent preferably includes one or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, tetraoctyl titanate, and tetraphenyl titanate. When the titanate coupling agent is two or more of the above, the present invention does not have a special limitation on the ratio of different types of titanate coupling agents, and any ratio is acceptable. The present invention utilizes titanate coupling agents to improve the interfacial bonding force between barium titanate and other inorganic components. The titanate coupling agent can react with the surface of barium titanate, bonding with titanium ions through chemical bonds to form a chemically bonded layer at the material interface. This improved interfacial bonding force helps to enhance the mechanical properties of the composite material, such as compressive strength and flexural strength. Reaction mechanism: In a humid environment, the titanate coupling agent can undergo hydrolysis to form a titanium oxide layer. This layer can improve the adhesion and interaction force between barium titanate and barium sulfate, ultimately enhancing the overall structure of the composite material.

[0048] When the coupling agent is a silane coupling agent, the mass percentage of the silane coupling agent is 0.5-2%, preferably 1.0-1.5%. The silane coupling agent preferably includes one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane (APTES), vinyltriethoxysilane (VTES), epoxypropyltrimethoxysilane (GPTMS), and isocyanate-propyltriethoxysilane (IPTES). When the silane coupling agent is two or more of the above, the present invention does not have a special limitation on the ratio of different types of silane coupling agents, and any ratio is acceptable. The present invention utilizes silane coupling agents as bridging materials, which can connect inorganic components (barium sulfate, barium titanate) to an organic matrix through silicon-oxygen bonds. The silane coupling agent reacts with the surface of the inorganic material to form chemical bonds, thereby improving the interfacial bonding force between the inorganic material and other components. Reaction mechanism: Silane coupling agents hydrolyze on the material surface to form silanol groups, which then undergo a condensation reaction with the surface of barium sulfate or barium titanate to form strong silicon-oxygen bonds. This chemical reaction can enhance the interfacial strength of composite materials, thereby improving the mechanical properties and radiation resistance of the materials.

[0049] The raw materials for preparing the barium titanate-barite composite material provided by this invention, by mass percentage, include 0.5-2% nano-silica, preferably 0.8-1.8%, more preferably 1-1.5%, and the particle size of the nano-silica is preferably 20-40 nm, more preferably 30 nm. This invention utilizes nano-silica to improve the mechanical strength, density, and radiation resistance of the material. Due to its extremely small particle size, nano-silica can fill the tiny pores in the material, thereby improving the density and mechanical strength. It can also enhance the radiation resistance of the material through interaction with other components (such as barium titanate and barium sulfate).

[0050] The raw materials for preparing the barium titanate-barite composite material provided by this invention, by mass percentage, include 0.5-2% nano-alumina, preferably 1-1.5%; the particle size of the nano-alumina is preferably 30-50 nm, more preferably 40-45 nm. This invention utilizes nano-alumina to further enhance the mechanical properties and thermal stability of the material. Nano-alumina possesses excellent heat resistance and mechanical properties, enhancing the high-temperature resistance of the composite material while improving its hardness and strength. Its interaction with barium titanate and barium sulfate ensures the material remains stable even at high temperatures.

[0051] This invention achieves the following effects by rationally combining barium titanate, barium sulfate of different particle sizes, coupling agents, and nanofillers (such as silica and alumina):

[0052] High dielectric constant: The addition of barium titanate gives the composite material a high dielectric constant, making it suitable for use as a dielectric material.

[0053] Radiation resistance: The synergistic effect of barium sulfate (especially high-density barium sulfate) and nanofillers greatly improves the radiation resistance of the material, making it suitable for use in radiation shielding plates.

[0054] Mechanical strength and density: By controlling the particle size distribution of barium sulfate and adding nanofillers, the composite material has higher mechanical strength and density, ensuring its stability under high load conditions.

[0055] Economy and ease of construction: By rationally proportioning various raw materials, the composite material of the present invention not only achieves a high level of performance, but also has a relatively low production cost. In particular, the material can be processed into large-area flat panels, making it simple and easy to construct.

[0056] This invention provides a method for preparing the barium titanate-barite composite material described in the above technical solution, comprising the following steps:

[0057] Barium titanate, barium sulfate I, barium sulfate II, coupling agent, nano-silica and nano-alumina were ball-milled to obtain a mixture.

[0058] The mixture is spray-granulated to obtain spherical material;

[0059] The spherical material is pressed into shape using an isostatic pressing method to obtain a blank.

[0060] The preform is sintered in a protective atmosphere to obtain a barium titanate-barite composite material.

[0061] In this invention, before ball milling, barium titanate, barium sulfate I, and barium sulfate II are preferably vacuum dried in a vacuum drying oven to remove moisture from the raw materials and prevent the formation of bubbles or pores during molding and sintering; the vacuum drying temperature is preferably 100°C and the time is preferably 4 hours.

[0062] In this invention, the ball milling time is preferably 2-4 hours, more preferably 2.5-3 hours, and the rotation speed is preferably 150-200 rpm, more preferably 160-180 rpm. In this invention, the ball milling method is preferably dry ball milling. During ball milling, ethanol (5 wt% of the total material) is preferably added as a dispersant to improve the uniformity of the powder.

[0063] In this invention, the spray granulation is preferably carried out using a spray granulator; the spray granulation conditions preferably include: a feed rate of 10-20 mL / min, more preferably 12-15 mL / min, and a spray drying temperature of 120-150℃, preferably 130-140℃; the particle size of the spherical material is preferably 100-300 μm, more preferably 120-250 μm, more preferably 150-200 μm, and even more preferably 160-180 μm.

[0064] After the spray granulation is completed, the resulting powder particles are left to stand at room temperature for 24 hours to ensure the uniformity and stability of the particles, which helps to improve the effect of subsequent pressing and molding.

[0065] In this invention, the pressing conditions include: a pressure of 250–350 MPa, more preferably 300–320 MPa; a mold temperature of 20–40°C; and a time of 10–15 min, preferably 12–13 min. This invention preferably uses an isostatic press for pressing, ensuring the density and uniformity of the sheet material under the above pressing conditions.

[0066] In this invention, during the pressing and molding process, there is no special limitation on the pressing and molding size; it can be adjusted according to actual needs. In the embodiments of this invention, the mold used specifically presses and molds a blank with a size of 412×824mm (considering a 3% shrinkage rate).

[0067] 1. Ensure finished product dimensions meet requirements: During pressing, the blank size is 412×824mm. Considering the shrinkage characteristics of the material during sintering, the post-sintering size is expected to be 400×800mm. This shrinkage rate of approximately 3% is based on the material's coefficient of thermal expansion and the optimized sintering process, ensuring the final finished product dimensions meet the expected standard specifications. This dimensional accuracy is crucial for laying and installation in practical applications, especially for large-area laying.

[0068] 2. Ensuring Material Density and Strength: During sintering, the green body undergoes rearrangement and densification of its microstructure, resulting in a reduction in size. By controlling the initial size of the green body, it is possible to ensure that the material is dense and free of pores after sintering, thereby improving its mechanical strength and radiation resistance. A finished product size smaller than the green body size indicates that the material has achieved a good densification effect during sintering, which helps to improve its mechanical properties and durability.

[0069] Therefore, ensuring that the sintered size is smaller than the green body size not only reflects the normal shrinkage characteristics of the material, but also ensures the mechanical strength, density and dimensional accuracy of the finished product, making it suitable for large-scale industrial applications.

[0070] After the pressing and molding process is completed, the present invention preferably demolds the material. Compressed air is used to assist in demolding to avoid damage to the surface of the sheet or stress concentration.

[0071] In this invention, the sintering temperature is preferably 1250–1350°C, more preferably 1300°C, and the holding time is preferably 4–6 hours, more preferably 5 hours. The protective atmosphere preferably includes nitrogen or argon to avoid oxidation or uneven chemical reactions at high temperatures. The above sintering conditions ensure uniform sintering of the plate inside and out, forming a dense microstructure.

[0072] After the sintering is completed, the present invention preferably cools down to room temperature to reduce warping or cracking caused by thermal stress; the cooling rate is preferably 5-8°C / h, more preferably 6-8°C / h.

[0073] During the sintering process, the plates are placed on a support frame or a high-temperature plate to prevent bending or deformation due to their own weight, thus ensuring the flatness and stability of the plates.

[0074] After sintering, the present invention preferably performs surface polishing and dimensional trimming on the obtained sheet material in sequence to ensure that the sheet material dimensions meet the requirements. The present invention preferably uses a water polishing machine to polish the surface of the sheet material to ensure the flatness and smoothness of the surface, and the surface polishing is preferably performed using 800-1000 grit sandpaper.

[0075] This invention preferably employs precision cutting technology to trim the sheet metal. During the cutting process, the tool linear speed and cooling water usage are controlled to prevent cracks or thermal deformation, ensuring the final dimensions meet the required specifications. The preferred tool linear speed is 20–30 m / min, and the feed rate is 0.1–0.5 mm / s to ensure cutting accuracy and surface quality. The preferred cooling water flow rate is 10–20 L / min, the preferred water pressure is 0.5–1 MPa, and the preferred water temperature is 15–25°C to effectively cool the cutting area and prevent overheating and material damage. This invention controls the above cutting parameters to ensure efficient and precise cutting, avoiding cracks and thermal damage.

[0076] The present invention preferably determines the sintered size based on actual application requirements and material performance optimization; in the embodiments of the present invention, it is specifically 400×800mm. The sintered size is determined according to the following methods: 1) Application field requirements: The 400×800mm plate size conforms to the standard specifications in the fields of building decoration and industrial protection. This size is suitable for large-area laying, such as for radiation shielding panels or wall decoration materials, which can effectively reduce the number of splicing times and improve construction efficiency. In addition, this size is also convenient for transportation and installation, and is suitable for industrial production and on-site construction. 2) Balance of material performance: By controlling the sintered size, the balance between thickness, density, mechanical strength and flatness of the plate can be ensured. The dimensional changes during the sintering process are closely related to the compactness and uniformity of the material. Selecting this size can ensure that the material maintains good surface smoothness and stability while ensuring mechanical strength and radiation resistance. 3) Processing and production feasibility: The 400×800mm size can be efficiently produced in current industrial equipment. The dimensional tolerance of the finished product is controlled by precision cutting technology to meet strict quality standards. Furthermore, this size also facilitates subsequent precision polishing and finishing, ensuring that the material surface achieves ideal flatness. Therefore, the 400×800mm size standard is determined based on multiple factors such as application requirements, material performance optimization, and production feasibility, ensuring that the material performs well in practical applications.

[0077] This invention provides applications of the barium titanate-barite composite material described in the above-described technical solutions or the barium titanate-barite composite material prepared by the preparation method described in the above-described technical solutions in the fields of building decoration, industrial protection, or electronic components. This invention does not specifically limit the methods for these applications; the barium titanate-barite composite material can be used in the aforementioned fields according to methods well-known in the art.

[0078] The barium titanate-barite composite material described in this invention is particularly suitable for applications requiring high dielectric constant and radiation resistance, such as radiation shielding plates and dielectric materials for electronic devices.

[0079] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0080] In the following examples, the first barium sulfate is commercially available barium sulfate (GY-1250) from Jiangxi Guangyuan Chemical Co., Ltd.; the second barium sulfate is commercially available barium sulfate (GY-2500) from Jiangxi Guangyuan Chemical Co., Ltd., and the specific parameters are shown in Table 1.

[0081] Table 1 Performance parameters of first barium sulfate GY-1250 and second barium sulfate GY-2500

[0082]

[0083]

[0084] Example 1

[0085] The raw materials for preparing the barium titanate-barite composite material provided in this embodiment, by weight percentage, are:

[0086] Barium titanate (BaTiO3): 28wt%; Barium sulfate I: 40wt%; Barium sulfate II: 27wt%; Titanate coupling agent (tetrabutyl titanate): 2wt%; Nano silica: 1wt% (particle size 20nm); Nano alumina: 2wt% (particle size 30nm).

[0087] The preparation method of barium titanate-barite composite material is as follows: barium titanate, barium sulfate I and barium sulfate II are vacuum dried in a vacuum drying oven at 100℃ for 4 hours. The dried barium titanate, barium sulfate, titanate coupling agent, nano silica (particle size of 20nm) and nano alumina (particle size of 30nm) are mixed in a ball mill in proportion for 3 hours at a speed of 180 rpm to obtain a uniform mixture. The obtained mixture is then spray-granulated by a spray granulator at a feed rate of 15mL / min and a spray drying temperature of 130℃ to obtain spherical particles with a particle size of 150μm. The obtained spherical particles are then allowed to stand at room temperature for 24 hours.

[0088] The isostatic pressing method was adopted, the mold temperature was 40℃, and the spherical particles were pressed into shape with a pressure of 300MPa. The initial mold size was 412×824mm, the molding time was 12min, and compressed air was used to assist in demolding to obtain the blank.

[0089] The blank is placed on a support frame and then placed in a sintering furnace. Sintering is carried out in a nitrogen protective atmosphere at a sintering temperature of 1300℃ for 5 hours. After sintering, the blank is cooled to room temperature at a rate of 6℃ / h. The surface is then polished using 800-grit sandpaper and a water polishing machine. The blank is then precisely cut to achieve a plate size of 400×800mm.

[0090] Example 2

[0091] The raw materials for preparing the barium titanate-barite composite material provided in this embodiment, by weight percentage, are:

[0092] Barium titanate (BaTiO3): 25wt%; Barium sulfate I: 40wt%; Barium sulfate II: 30wt%; Titanate coupling agent (tetrabutyl titanate): 2wt%; Nano silica: 1wt% (particle size 30nm); Nano alumina: 2wt% (particle size 40nm).

[0093] Preparation method:

[0094] Barium titanate, barium sulfate I, and barium sulfate II were vacuum dried in a vacuum drying oven at 100°C for 4 hours. Then, barium titanate, barium sulfate, and titanate coupling agent, nano-silica (particle size 30 nm), and nano-alumina (particle size 40 nm) were mixed in a ball mill in a certain proportion for 3 hours at a speed of 180 rpm to obtain a uniform mixture.

[0095] The obtained mixture was spray granulated using a spray granulator with a feed rate of 15 mL / min and a spray drying temperature of 130℃ to obtain spherical particles with a particle size of 150 μm. The spherical particles were then left to stand at room temperature for 24 h.

[0096] The isostatic pressing method was adopted, the mold temperature was 40℃, and the spherical particles were pressed into shape with a pressure of 300MPa. The initial mold size was 412×824mm, the molding time was 12min, and compressed air was used to assist in demolding to obtain the blank.

[0097] The blank is placed on a support frame and then placed in a sintering furnace. Sintering is carried out in a nitrogen protective atmosphere at a temperature of 1300℃ for 5 hours. After sintering, the blank is cooled to room temperature at a rate of 6℃ / h. The surface is then polished using 800-grit sandpaper and a water polishing machine. Finally, it is precisely cut to a standard size of 400×800mm.

[0098] Example 3

[0099] The raw materials for preparing the barium titanate-barite composite material provided in this embodiment, by weight percentage, are:

[0100] Barium titanate (BaTiO3): 30.5 wt%; Barium sulfate disulfide: 35 wt%; Barium sulfate disulfide: 29 wt%; Silane coupling agent (γ-aminopropyltriethoxysilane): 2.0 wt%; Nano silica: 2 wt% (particle size 40 nm); Nano alumina: 1.5 wt% (particle size 50 nm);

[0101] Preparation method:

[0102] Barium titanate, barium sulfate I, and barium sulfate II were vacuum dried in a vacuum drying oven at 100°C for 4 hours. The dried barium titanate and barium sulfate were then mixed with silane coupling agent, nano-silica (particle size 40 nm), and nano-alumina (particle size 50 nm) in a ball mill in a certain proportion for 3 hours at a speed of 180 rpm to obtain a homogeneous mixture.

[0103] The obtained mixture was spray granulated using a spray granulator with a feed rate of 20 mL / min and a spray drying temperature of 150 °C to obtain spherical particles with a particle size of 200 μm. The spherical particles were then left to stand at room temperature for 24 h.

[0104] The isostatic pressing method was adopted, the mold temperature was 40℃, and the spherical particles were pressed into shape with a pressure of 350MPa. The initial mold size was 412×824mm, the molding time was 15min, and compressed air was used to assist in demolding to obtain the blank.

[0105] The blank is placed on a support frame and then placed in a sintering furnace. Sintering is carried out in a nitrogen protective atmosphere at a temperature of 1300℃ for 4 hours. After sintering, the blank is cooled to room temperature at a rate of 5℃ / h. The surface is then polished with 800-grit sandpaper and precisely cut into 400×800mm plates.

[0106] Example 4

[0107] The raw materials for preparing the barium titanate-barite composite material provided in this embodiment, by weight percentage, are:

[0108] Barium titanate (BaTiO3): 22wt%; Barium sulfate I: 45wt%; Barium sulfate II: 27wt%; Titanate coupling agent (tetraethyl titanate): 2.2wt%; Nano silica: 1.8wt% (particle size 30nm); Nano alumina: 2wt% (particle size 45nm);

[0109] Preparation method:

[0110] Barium titanate, barium sulfate I and barium sulfate II were vacuum dried at 100°C for 4 hours. Then, barium titanate, barium sulfate, and titanate coupling agent, nano silica (30 nm particle size) and nano alumina (45 nm particle size) were mixed in a ball mill in a certain proportion for 2.5 hours at a speed of 170 rpm to obtain a uniform mixture.

[0111] The obtained mixture was spray granulated using a spray granulator with a feed rate of 12 mL / min and a spray drying temperature of 140℃ to obtain spherical particles with a particle size of 120 μm. The spherical particles were then left to stand at room temperature for 24 h.

[0112] The isostatic pressing method was adopted, the mold temperature was 40℃, and the spherical particles were pressed into shape with a pressure of 250MPa. The initial mold size was 412×824mm, the molding time was 10min, and compressed air was used to assist in demolding to obtain the blank.

[0113] The blank is placed on a support frame and then placed in a sintering furnace. Sintering is carried out in a nitrogen protective atmosphere at a temperature of 1300℃ for 6 hours. After sintering, the blank is cooled to room temperature at a rate of 5℃ / h. The surface is then polished using 800-grit sandpaper and a water polishing machine, and then precisely cut into finished products of 400×800mm.

[0114] Example 5

[0115] The raw materials for preparing the barium titanate-barite composite material provided in this embodiment, by weight percentage, are:

[0116] Barium titanate (BaTiO3): 24wt%; Barium sulfate I: 38wt%; Barium sulfate II: 32wt%; Silane coupling agent (γ-aminopropyltriethoxysilane): 2wt%; Nano silica: 2wt% (particle size 20nm); Nano alumina: 2wt% (particle size 30nm).

[0117] Preparation method:

[0118] Barium titanate, barium sulfate I and barium sulfate II were vacuum dried at 100°C for 4 hours. Then, barium titanate, barium sulfate, silane coupling agent, nano-silica (particle size 20 nm) and nano-alumina (particle size 30 nm) were mixed in a ball mill in a certain proportion for 2 hours at a speed of 160 rpm to obtain a uniform mixture.

[0119] The obtained mixture was spray granulated using a spray granulator with a feed rate of 15 mL / min and a spray drying temperature of 120℃ to obtain spherical particles with a particle size of 180 μm. The spherical particles were then left to stand at room temperature for 24 h.

[0120] The isostatic pressing method was adopted, the mold temperature was 40℃, and the spherical particles were pressed into shape with a pressure of 320MPa. The initial mold size was 412×824mm, the molding time was 13min, and compressed air was used to assist in demolding to obtain the blank.

[0121] The blank is placed on a support frame and then placed in a sintering furnace. Sintering is carried out in a nitrogen protective atmosphere at a temperature of 1300℃ for 5 hours. After sintering, the blank is cooled to room temperature at a rate of 6℃ / h. The surface is then polished with 800-grit sandpaper and precisely cut to a standard size of 400×800mm.

[0122] Performance testing

[0123] The products of Examples 1-5 were subjected to performance tests according to the following testing standards:

[0124] 1. GB / T 1409-2006 "Method for Measurement of Dielectric Constant and Loss Tangent of Electrical Insulation Materials": This standard specifies the method for measuring the dielectric constant and loss tangent of electrical insulation materials. It is widely used in the determination of dielectric properties of various composite materials and is applicable to barium titanate-barite composite materials.

[0125] 2. GB / T 5591.3-2018 Electrical Insulation Materials - Part 3: Test Methods: This standard provides test methods for insulation materials, especially detailing the test methods for dielectric loss, for the testing of electrical insulation materials.

[0126] 3. GB / T 23913.1-2009 "Determination of Shielding Performance of Radiation Protection Shielding Materials": This standard covers the methods for determining the shielding performance of radiation protection materials, and is particularly applicable to the testing of the protective performance of shielding materials in X-ray and gamma-ray environments.

[0127] 4. GB / T 7314-2017 Metallic Materials - Compression Test at Room Temperature: This standard is applicable to the compression performance test of metallic materials and composite materials under room temperature conditions, and determines the compressive strength of the materials.

[0128] 5. GB / T 1449-2019 Test Method for Bending Properties of Fiber Reinforced Plastics: This standard is mainly used for testing the bending properties of fiber reinforced composite materials and is suitable for testing the bending properties of barium titanate-barite composite materials.

[0129] 6. GB / T 9966.3-2021 "Test Methods for Natural Stone - Part 3: Density and Water Absorption": This standard specifies the methods for determining the density and water absorption of stone materials, and is applicable to the determination of the density of composite materials.

[0130] 7. GB / T 23806-2020 "Determination of fracture toughness of engineering ceramics": This standard provides a method for determining the fracture toughness of engineering ceramic materials, and is widely used for fracture toughness testing of high-performance ceramics and composite materials.

[0131] The results are shown in Table 2.

[0132] Table 2 Product performance of Examples 1-5

[0133]

[0134]

[0135]

[0136] As shown in Table 2, the barium titanate-barite composite material of the present invention has high dielectric constant, excellent radiation resistance and good mechanical strength, and is suitable for occasions that require high dielectric constant and radiation resistance, such as radiation shielding plates and dielectric materials for electronic devices.

[0137] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A barium titanate-barite composite material for use in radiation shielding or electronic devices, characterized in that, The raw materials include the following ingredients in weight percentage: Barium titanate 20~30.5%, barium sulfate 1 35~45%, barium sulfate 25~35%, coupling agent, nano silica 0.5~2%, nano alumina 0.5~2%; The first barium sulfate has an average particle size of 4~5μm and a maximum particle size of ≤27μm; the second barium sulfate has an average particle size of 3~4.5μm and a maximum particle size of ≤24μm. The coupling agent is a titanate coupling agent or a silane coupling agent; When the coupling agent is a titanate coupling agent, the mass percentage of the titanate coupling agent is 1-3%; When the coupling agent is a silane coupling agent, the mass percentage of the silane coupling agent is 0.5-2%; The nano-silica has a particle size of 20-40 nm; the nano-alumina has a particle size of 30-50 nm. The preparation method of the barium titanate-barite composite material includes the following steps: Barium titanate, barium sulfate I, barium sulfate II, coupling agent, nano-silica and nano-alumina were ball-milled to obtain a mixture. The mixture is spray-granulated to obtain spherical material; The spherical material is pressed into shape using an isostatic pressing method to obtain a blank. The preform is sintered in a protective atmosphere to obtain a barium titanate-barite composite material. The particle size of the spherical material is 100~300μm; The pressing pressure is 250~350MPa; The sintering temperature is 1250~1350℃, and the holding time is 4~6h; the protective atmosphere includes nitrogen or argon.

2. The barium titanate-barite composite material according to claim 1, characterized in that, The titanate coupling agent includes one or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, tetraoctyl titanate, and tetraphenyl titanate.

3. The barium titanate-barite composite material according to claim 1, characterized in that, The silane coupling agent includes one or more of γ-aminopropyltriethoxysilane, vinyltriethoxysilane, epoxypropyltrimethoxysilane, and propyltriethoxysilane isocyanate.

4. The method for preparing the barium titanate-barite composite material according to any one of claims 1 to 3, characterized in that, Includes the following steps: Barium titanate, barium sulfate I, barium sulfate II, coupling agent, nano-silica and nano-alumina were ball-milled to obtain a mixture. The mixture is spray-granulated to obtain spherical material; The spherical material is pressed into shape using an isostatic pressing method to obtain a blank. The preform is sintered in a protective atmosphere to obtain a barium titanate-barite composite material. The particle size of the spherical material is 100~300μm; The pressing pressure is 250~350MPa; The sintering temperature is 1250~1350℃, and the holding time is 4~6h; the protective atmosphere includes nitrogen or argon.

5. The preparation method according to claim 4, characterized in that, The ball milling mixing time is 2-4 hours, and the rotation speed is 150-200 rpm.

6. The preparation method according to claim 4, characterized in that, The conditions for spray granulation include: a feed rate of 10-20 mL / min and a spray drying temperature of 120-150 °C.

7. The preparation method according to claim 4, characterized in that, The pressing and molding conditions include: mold temperature of 20~40℃ and time of 10~15min.

8. The application of the barium titanate-barite composite material according to any one of claims 1 to 3 or the barium titanate-barite composite material prepared by the preparation method according to any one of claims 4 to 7 in the field of radiation shielding or electronic devices.

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