Niobate-based ceramic material with rod-like microstructure and preparation method of niobate-based ceramic material

Abstract

The invention belongs to the technical field of electronic materials, and particularly relates to a niobate-based ceramic material with a rod-like microstructure and a preparation method of the niobate-based ceramic material. According to the invention, B2O3 is added in the sintering process, so that a liquid phase environment with relatively strong fluidity can be provided under a high-temperature condition, and the growth of crystal grains can be accelerated; tiW is doped in a liquid phase environment to generate an induction effect on a specific crystal face, directional growth regulation and control of material crystal grains are achieved through cooperation of TiW and B2O3, and meanwhile, B2O3 can reduce the sintering temperature and can form ceramic at a low temperature. Finally, the ZnNb1.96 (TiW) 0.04 O6 microwave dielectric ceramic with a rodlike microstructure is prepared by sintering at 850-950 DEG C by adopting a solid phase method and utilizing a synergistic effect of doping B2O3 and TiW, and the trend is further aggravated along with the increase of the B2O3 content and the improvement of the liquid phase quantity, so that a more obvious rodlike grain structure is formed in a sample. And a basis is provided for the application of the rod-like microstructure ZnNb < 1.96 > (TiW) < 0.04 > O6 microwave dielectric ceramic.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic materials, and in particular relates to a niobate-based ceramic material with a rod-shaped microstructure and a preparation method thereof. Background Art

[0002] Among all microwave dielectric ceramic materials, niobate ceramics not only have low dielectric loss but also possess an intermediate dielectric constant. Therefore, they have broad application potential in high-frequency and high-reliability devices, especially in multilayer ceramic capacitors, filters, antennas, resonant cavities and other fields, and have become a research hotspot in recent years.

[0003] Typically, niobate-based ceramic materials prepared by the solid-phase method generally present irregular granular shapes, with ceramic particles closely arranged and distributed. Because the solid-phase method relies on high-temperature diffusion and reaction of solid reactants, its atomic migration rate is much lower than that of liquid or gas phase systems. This slow diffusion process makes it difficult to precisely control the anisotropy of crystal growth. Solid-phase reactions usually require high temperatures (>1200°C) to promote diffusion, but high temperatures accelerate Ostwald ripening, leading to grain merging and size increase. Therefore, it is very difficult to obtain niobate ceramics with special morphologies such as rods and needles.

[0004] In particular, the unique rod-shaped microstructure gives such materials many unique advantages and expands their application range. For example, the microstructure of rod-shaped grains can improve the strength of the material. The interlocking rod-shaped grains form a strong network that can effectively disperse stress, thereby improving the mechanical strength of the material. At the same time, the rod-shaped structure is usually accompanied by a high porosity, which makes the material highly permeable and can be applied in unique scenarios. For example, in the field of microwave absorption applications, the rod-shaped structure significantly improves the microwave absorption performance of the material by optimizing the impedance matching and multi-scale loss mechanism of electromagnetic waves. For example, Sijian Liu, Mengyu Dai, Yujun Jia, Jiaying Ti, et al. (Electromagnetic wave-absorbing of polymer derived rod-like ZrB2 ultrahigh-temperature ceramic composites. Journal of the European Ceramic Society 2024, 44: 7668-7679.) prepared rod-shaped ZrB2 and its composite materials, whose strong absorption is caused by the strong loss and multiple scattering of electromagnetic waves by the rod-shaped network structure.

[0005] These advantages and wide range of applications make rod-shaped niobate-based ceramics of significant research and application value in modern materials science and engineering. However, the ability to produce niobate ceramics with microstructures using conventional solid-state methods remains a significant unresolved challenge. In particular, the ability to produce niobate ceramics with micron- or even nanometer-scale rod-shaped microstructures at low temperatures (<1000°C) through the use of low-temperature sintering techniques would significantly expand the material's adaptability to diverse processing conditions. Summary of the Invention

[0006] In response to the above-mentioned problems or deficiencies, and to solve the problems in preparing existing rod-shaped niobate-based ceramic materials, the present invention provides a niobate-based ceramic material with a rod-shaped microstructure and a preparation method thereof. The present invention combines TiW doping with B2O3 to provide a liquid phase environment during the sintering process to produce an inductive effect on the specific crystal planes of the niobium zinc structure, thereby achieving directional growth control of the material grains, thereby obtaining a rod-shaped orthorhombic niobate ceramic material. Specifically, the present invention prepares xwt.% B2O3+(1-x)wt.% ZnNb by a traditional solid-phase reaction method. 1.96 (TiW) 0.04 O6 (0<x≤30) ceramic material, ZnNb 1.96 (TiW) 0.04 O6 is successfully sintered at 850-950℃, while ZnNb 1.96 (TiW) 0.04 The grains of O6 ceramic material show obvious rod-like characteristics, accompanied by the directional growth of more grains.

[0007] A method for preparing a niobate-based ceramic material having a rod-shaped microstructure comprises the following steps:

[0008] Step 1: The analytically pure raw materials B2O3, ZnO, TiO2, Nb2O5 and WO3 were mixed according to the formula of xwt.%B2O3+(1-x)wt.%ZnNb 1.96 (TiW) 0.04 Prepare materials in proportion O6 (0<x≤30).

[0009] Step 2: ball mill the raw materials prepared in step 1, mix them evenly, dry and grind them, dry them at 80°C to 120°C, and then pass them through a 40-120 mesh sieve.

[0010] Step 3: pre-sinter the ball-milled powder obtained in step 2 at 700° C.-800° C. for 2-4 hours at a heating rate of 1° C. / min-2° C. / min to obtain a pre-sintered material.

[0011] Step 4: The pre-sintered material obtained in step 3 is subjected to secondary ball milling. After the ball milling is completed, the slurry is dried and ground to obtain xwt.% B2O3+(1-x)wt.% ZnNb1.96 (TiW) 0.04 O6 (0<x≤30) powder.

[0012] Step 5: Add PVA aqueous solution as a binder to the powder obtained in step 4 to form granules, and press them at a pressure of 18 MPa to 20 MPa and a holding time of 2 min to 3 min to obtain an embryo body.

[0013] Step 6: Sinter the molded body obtained in step 5 at 850-950°C with a heating rate of 1°C / min to 2°C / min and a holding time of 4h to 6h; and allow it to cool naturally to obtain ZnNb with a rod-like microstructure. 1.96 (TiW) 0.04 O6 niobate-based ceramic material.

[0014] Furthermore, 5≤x≤20.

[0015] Furthermore, the ball milling in step 2 is performed at a rotation speed of 250 r / min to 300 r / min, and the time is 8 h to 12 h.

[0016] Furthermore, the concentration of the PVA aqueous solution in step 4 is 8 to 12 wt%.

[0017] Furthermore, the sintering temperature in step 6 is 900°C.

[0018] Furthermore, a niobate-based ceramic material with a rod-shaped microstructure is prepared using the above method.

[0019] Furthermore, the above-mentioned niobate-based ceramic material with a rod-shaped microstructure is applied in the field of microwave absorption to improve the microwave absorption performance of the material.

[0020] In summary, the present invention provides a niobate ceramic material with a rod-shaped microstructure and a preparation method thereof, wherein ZnNb is prepared by a solid phase method through batching, primary ball milling, pre-sintering, secondary ball milling, granulation and sintering. 1.96 (TiW) 0.04 O6 microwave dielectric ceramics. The present invention adds B2O3 during the sintering process, which can provide a liquid phase environment with strong fluidity under high temperature conditions and accelerate the growth of grains. Combined with the doping of TiW in the liquid phase environment, it produces an induction effect on specific crystal planes. The two work together to achieve the directional growth control of the material grains. At the same time, B2O3 can reduce the sintering temperature so that the sample can be formed into porcelain at a lower temperature and ZnNb 1.96 (TiW) 0.04 The O6 grains are rod-shaped. Finally, the present invention uses the synergistic effect of B2O3 and TiW doping to achieve ZnNb 1.96 (TiW) 0.04As the B2O3 content increases, the increase in the amount of liquid phase further exacerbates this trend, resulting in the formation of a more significant rod-shaped grain structure inside the sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a process flow chart for preparing materials of the present invention.

[0022] Figure 2 These are the XRD patterns of the ceramic materials of Examples 1 to 4.

[0023] Figure 3 These are SEM images of the ceramic materials of Examples 1 to 4.

[0024] Figure 4 This is the SEM image of the comparative example ceramic material. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] Comparative Example:

[0027] A ZnNb 1.96 (TiW) 0.04 Preparation method of O6 niobate ceramic material (such as Figure 1 ), comprising the following steps:

[0028] Step 1: Use analytical grade ZnO (99%), TiO2 (99%), Nb2O5 (99.5%), WO3 (99.8%). All raw materials are produced by Shanghai Maclin. 1.96 (TiW) 0.04 The composition of O6 was weighed and mixed.

[0029] Step 2: Place the mixed raw materials into a planetary ball mill and perform wet ball milling using deionized water and anhydrous ethanol as solvents and agate beads as ball milling media. The raw materials are mixed at a mass ratio of material: deionized water: balls of 1:1:1.5, the ball mill speed is 250 r / min, and the ball milling time is 9 h. The mixture is then dried at 100° C., ground, and passed through a 40-mesh sieve.

[0030] Step 3: pre-sinter the ball-milled powder obtained in step 2 at 800° C. for 4 h at a heating rate of 2° C. / min to obtain a pre-sintered material.

[0031] Step 4: The pre-sintered material is subjected to a second ball milling process, using the same wet ball milling method as in step 2. After the ball milling is completed, the obtained slurry is dried in an oven at 100° C. and ground to obtain a powder.

[0032] Step 5: Add PVA aqueous solution (concentration of 9 wt%) to the powder mixed in step 4 as a binder for granulation. The amount of binder used is 12 ml. The sieving process is: 40 mesh and 100 mesh in turn, and take the particles between 40 mesh and 100 mesh; then press the obtained particles into shape at 20 MPa, and hold the pressure for 2 minutes.

[0033] Step 6: Sinter the embryo formed by pressing in step 5 at 1100° C., with a heating rate of 2° C. / min and a holding time of 4 hours; and allow it to cool naturally to obtain the ceramic material.

[0034] The zinc-niobium-titanium-tungsten microwave ceramic material prepared in this comparative example was tested, and its SEM image is as follows: Figure 4 As shown in the figure, it can be seen that the sample grains are obviously granular.

[0035] Example 1:

[0036] A method for preparing a niobate ceramic material having a rod-like microstructure (such as Figure 1 ), comprising the following steps:

[0037] Step 1: Use analytical grade B2O3 (99%), ZnO (99%), TiO2 (99%), Nb2O5 (99.5%), WO3 (99.8%), all raw materials are produced by Shanghai Macklin, according to 5wt.% B2O3 + 95wt.% ZnNb 1.96 (TiW) 0.04 The composition of O6 was weighed and mixed.

[0038] Step 2: Place the mixed raw materials into a planetary ball mill and perform wet ball milling using deionized water and anhydrous ethanol as solvents and agate beads as ball milling media. The raw materials are mixed at a mass ratio of material: deionized water: balls of 1:1:1.5, the ball mill speed is 250 r / min, and the ball milling time is 9 h. The mixture is then dried at 100° C., ground, and passed through a 40-mesh sieve.

[0039] Step 3: pre-sinter the ball-milled powder obtained in step 2 at 800° C. for 4 h at a heating rate of 2° C. / min to obtain a pre-sintered material.

[0040] Step 4: The pre-sintered material is subjected to a second ball milling process, using the same wet ball milling method as in step 2. After the ball milling is completed, the obtained slurry is dried in an oven at 100° C. and ground to obtain a powder.

[0041] Step 5: Add PVA aqueous solution (concentration of 9 wt%) to the powder mixed in step 4 as a binder for granulation. The amount of binder used is 12 ml. The sieving process is: 40 mesh and 100 mesh in turn, and take the particles between 40 mesh and 100 mesh; then press the obtained particles into shape at 20 MPa, and hold the pressure for 2 minutes.

[0042] Step 6: Sinter the embryo formed by pressing in step 4 at 900° C., with a heating rate of 2° C. / min and a holding time of 4 hours; and allow it to cool naturally to obtain the ceramic material.

[0043] The zinc-niobium-titanium-tungsten microwave ceramic material prepared in this embodiment was tested, wherein the X-ray diffraction pattern is as follows: Figure 2 As shown in the figure, the microwave dielectric ceramic material ZnNb prepared in this embodiment 1.96 (TiW) 0.04 O6 has good crystallinity, indicating that B2O3 can effectively reduce the sintering temperature. In addition, SEM images such as Figure 3 As shown in (a), it can be seen from the figure that the sample grains are different from the granularity of ZnNbTiT ceramics ( Figure 4 ), ZnNb in this embodiment 1.96 (TiW) 0.04 The grains of O6 sample are rod-shaped.

[0044] Example 2:

[0045] A method for preparing a niobate ceramic material having a rod-like microstructure (such as Figure 1 ), comprising the following steps:

[0046] Step 1: Using analytical grade B2O3 (99%), ZnO (99%), TiO2 (99%), Nb2O5 (99.5%), and WO3 (99.8%), all raw materials are produced by Shanghai Macklin, according to 10wt.% B2O3 + 90wt.% ZnNb 1.96 (TiW) 0.04 The composition of O6 was weighed and mixed.

[0047] Step 2: Place the mixed raw materials into a planetary ball mill and perform wet ball milling using deionized water and anhydrous ethanol as solvents and agate beads as ball milling media. The raw materials are mixed at a mass ratio of material: deionized water: balls of 1:1:1.5, the ball mill speed is 250 r / min, and the ball milling time is 9 h. The mixture is then dried at 100° C., ground, and passed through a 40-mesh sieve.

[0048] Step 3: pre-sinter the ball-milled powder obtained in step 2 at 800° C. for 4 h at a heating rate of 2° C. / min to obtain a pre-sintered material.

[0049] Step 4: The pre-sintered material is subjected to a second ball milling process, using the same wet ball milling method as in step 2. After the ball milling is completed, the obtained slurry is dried in an oven at 100° C. and ground to obtain a powder.

[0050] Step 5: Add PVA aqueous solution (concentration of 9 wt%) to the powder mixed in step 4 as a binder for granulation. The amount of binder used is 12 ml. The sieving process is: 40 mesh and 100 mesh in turn, and take the particles between 40 mesh and 100 mesh; then press the obtained particles into shape at 20 MPa, and hold the pressure for 2 minutes.

[0051] Step 6: Sinter the embryo formed by pressing in step 4 at 900° C., with a heating rate of 2° C. / min and a holding time of 4 hours; and allow it to cool naturally to obtain the ceramic material.

[0052] The zinc-niobium-titanium-tungsten microwave ceramic material prepared in this embodiment was tested, wherein the X-ray diffraction pattern is as follows: Figure 2 As shown in the figure, the microwave dielectric ceramic material ZnNb 1.96 (TiW) 0.04 O6 has good crystallinity, which shows that B2O3 can effectively reduce the sintering temperature; in addition, the SEM images such as Figure 3 As shown in (b), it can be seen from the figure that the sample grains are different from the granularity of ZnNbTiT ceramics ( Figure 4 ), ZnNb in this embodiment 1.96 (TiW) 0.04 The grains of O6 sample are rod-shaped.

[0053] Example 3:

[0054] A method for preparing a niobate ceramic material having a rod-like microstructure (such as Figure 1 ), comprising the following steps:

[0055] Step 1: Use analytical grade B2O3 (99%), ZnO (99%), TiO2 (99%), Nb2O5 (99.5%), WO3 (99.8%), all raw materials are produced by Shanghai Macklin, according to 15wt.% B2O3 + 85wt.% ZnNb 1.96 (TiW) 0.04 The composition of O6 was weighed and mixed.

[0056] Step 2: Place the mixed raw materials into a planetary ball mill and perform wet ball milling using deionized water and anhydrous ethanol as solvents and agate beads as ball milling media. The raw materials are mixed at a mass ratio of material: deionized water: balls of 1:1:1.5, the ball mill speed is 250 r / min, and the ball milling time is 9 h. The mixture is then dried at 100° C., ground, and passed through a 40-mesh sieve.

[0057] Step 3: pre-sinter the ball-milled powder obtained in step 2 at 800° C. for 4 h at a heating rate of 2° C. / min to obtain a pre-sintered material.

[0058] Step 4: The pre-sintered material is subjected to a second ball milling process, using the same wet ball milling method as in step 2. After the ball milling is completed, the obtained slurry is dried in an oven at 100° C. and ground to obtain a powder.

[0059] Step 5: Add PVA aqueous solution (concentration of 9 wt%) to the powder mixed in step 4 as a binder for granulation. The amount of binder used is 12 ml. The sieving process is: 40 mesh and 100 mesh in turn, and take the particles between 40 mesh and 100 mesh; then press the obtained particles into shape at 20 MPa, and hold the pressure for 2 minutes.

[0060] Step 6: Sinter the embryo formed by pressing in step 4 at 900° C., with a heating rate of 2° C. / min and a holding time of 4 hours; and allow it to cool naturally to obtain the ceramic material.

[0061] The zinc-niobium-titanium-tungsten microwave ceramic material prepared in this embodiment was tested, wherein the X-ray diffraction pattern is as follows: Figure 2 As shown in the figure, the microwave dielectric ceramic material ZnNb 1.96 (TiW) 0.04 O6 has good crystallinity, which shows that B2O3 can effectively reduce the sintering temperature; in addition, the SEM images such as Figure 3 As shown in (c), it can be seen from the figure that the sample grains are different from the granularity of ZnNbTiT ceramics ( Figure 4 ), ZnNb in this embodiment 1.96 (TiW) 0.04 The grains of O6 sample are rod-shaped.

[0062] Example 4:

[0063] A method for preparing a niobate ceramic material having a rod-like microstructure (such as Figure 1 ), comprising the following steps:

[0064] Step 1: Using analytical grade B2O3 (99%), ZnO (99%), TiO2 (99%), Nb2O5 (99.5%), and WO3 (99.8%), all raw materials are produced by Shanghai Macklin, according to 20wt.% B2O3 + 80wt.% ZnNb 1.96 (TiW) 0.04 The composition of O6 was weighed and mixed.

[0065] Step 2: Place the mixed raw materials into a planetary ball mill and perform wet ball milling using deionized water and anhydrous ethanol as solvents and agate beads as ball milling media. The raw materials are mixed at a mass ratio of material: deionized water: balls of 1:1:1.5, the ball mill speed is 250 r / min, and the ball milling time is 9 h. The mixture is then dried at 100° C., ground, and passed through a 40-mesh sieve.

[0066] Step 3: pre-sinter the ball-milled powder obtained in step 2 at 800° C. for 4 h at a heating rate of 2° C. / min to obtain a pre-sintered material.

[0067] Step 4: The pre-sintered material is subjected to a second ball milling process, using the same wet ball milling method as in step 2. After the ball milling is completed, the obtained slurry is dried in an oven at 100° C. and ground to obtain a powder.

[0068] Step 5: Add PVA aqueous solution (concentration of 9 wt%) to the powder mixed in step 4 as a binder for granulation. The amount of binder used is 12 ml. The sieving process is: 40 mesh and 100 mesh in turn, and take the particles between 40 mesh and 100 mesh; then press the obtained particles into shape at 20 MPa, and hold the pressure for 2 minutes.

[0069] Step 6: Sinter the embryo formed by pressing in step 4 at 900° C., with a heating rate of 2° C. / min and a holding time of 4 hours; and allow it to cool naturally to obtain the ceramic material.

[0070] The zinc-niobium-titanium-tungsten microwave ceramic material prepared in this embodiment was tested, wherein the X-ray diffraction pattern is as follows: Figure 2 As shown in the figure, the microwave dielectric ceramic material ZnNb 1.96 (TiW) 0.04 O6 has good crystallinity, indicating that B2O3 can effectively reduce the sintering temperature. In addition, SEM images such as Figure 3 As shown in (d), it can be seen from the figure that the sample grains are different from the granularity of ZnNbTiT ceramics ( Figure 4 ), ZnNb in this embodiment 1.96 (TiW) 0.04The grains of the O6 sample are rod-shaped. The grains of the sample grow further and show more obvious rod-shaped characteristics, accompanied by the directional growth of more grains.

[0071] As can be seen from the above specific embodiments, the present invention is based on zinc niobate ceramic materials. By using B2O3 during sintering, it provides a liquid phase environment under high temperature conditions. Combined with TiW doping in the liquid phase environment to produce an induction effect on specific crystal planes, the two synergistically achieve directional growth of material grains. At the same time, B2O3 can lower the sintering temperature, so that the zinc niobate-based ceramic material can be formed at 850-950°C and its morphology presents a distinct rod-like structure.

[0072] In addition, it can be seen from the corresponding pictures of the examples that: with the increase of B2O3 content, the increase of liquid phase further exacerbates this trend, resulting in the formation of a more significant rod-shaped grain structure inside the sample. This further illustrates that B2O3 provides a liquid phase environment with strong fluidity under high temperature conditions and can accelerate the growth of grains. Combined with TiW doping in the liquid phase environment, it can produce an inductive effect on specific crystal planes. The two work together to achieve the directional growth control of the material grains. At the same time, B2O3 can reduce the sintering temperature so that the sample can be porcelainized at a lower temperature and ZnNb 1.96 (TiW) 0.04 The crystal grains of O6 are rod-shaped. 1.96 (TiW) 0.04 It provides a basis for the application of O6 microwave dielectric ceramics.

Claims

1. A method for preparing a niobate-based ceramic material having a rod-shaped microstructure, characterized in that: The following steps are involved: Step 1: The analytically pure raw materials B2O3, ZnO, TiO2, Nb2O5 and WO3 were mixed according to the ratio of xwt.%B2O3+(1-x)wt.%ZnNb 1.96 (TiW) 0.04 O6, 0<x≤30 proportion preparation; Step 2: After ball milling and mixing the raw materials prepared in step 1, the mixture is dried, ground, dried at 80°C to 120°C, and then passed through a 40-120 mesh sieve; Step 3, pre-calcining the ball-milled powder obtained in step 2 at 700°C-800°C, holding time 2-4h, and heating rate 1°C / min-2°C / min to obtain a pre-calcined material; Step 4: The pre-sintered material obtained in step 3 is subjected to secondary ball milling. After the ball milling is completed, xwt.% B2O3+(1-x)wt.% ZnNb is obtained after drying and grinding. 1.96 (TiW) 0.04 O6 powder; Step 5: Add PVA aqueous solution as a binder to the powder obtained in step 4 to form granules, and press them at a pressure of 18 MPa to 20 MPa and a holding time of 2 min to 3 min to obtain an embryo body; Step 6: Sinter the molded body obtained in step 5 at 850-950°C with a heating rate of 1°C / min to 2°C / min and a holding time of 4h to 6h; and allow it to cool naturally to obtain ZnNb with a rod-like microstructure. 1.96 (TiW) 0.04 O6 niobate-based ceramic material.

2. The method for preparing the niobate-based ceramic material having a rod-shaped microstructure according to claim 1, wherein: Said 5≤x≤20.

3. The method for preparing the niobate-based ceramic material having a rod-shaped microstructure according to claim 1, wherein: The ball milling process in step 2 is performed at a rotation speed of 250 to 300 r / min and a time of 8 to 12 hours.

4. The method for preparing a niobate-based ceramic material having a rod-shaped microstructure according to claim 1, wherein: The concentration of the PVA aqueous solution in step 4 is 8-12 wt %.

5. The method for preparing the niobate-based ceramic material having a rod-shaped microstructure according to claim 1, wherein: The sintering temperature in step 6 is 900°C.

6. A niobate-based ceramic material having a rod-shaped microstructure, characterized in that: The method is prepared by any one of claims 1 to 5.

7. The niobate-based ceramic material having a rod-shaped microstructure according to claim 6, wherein: Used in the field of microwave absorption to improve the microwave absorption performance of materials.

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