A low temperature sintered high Q×f value Al2Mo 3+x O 12+3x Microwave dielectric ceramic material and preparation method thereof

Abstract

The present invention relates to a low temperature sintered high Q×f value Al2Mo 3+x O 12+3x Microwave dielectric ceramic material and preparation method thereof, the preparation method comprising: S1, Al2O3 original powder and MoO3 original powder according to the chemical formula Al2Mo 3+x O 12+3x The ingredients are mixed to obtain a mixed powder, wherein 0.02≤x≤0.06; S2, the mixed powder is subjected to a first planetary ball milling and sieving in sequence, and the sieved powder is pre-calcined to obtain a pre-calcined powder; S3, the pre-calcined powder is subjected to a second planetary ball milling, drying and bonding granulation to obtain a ceramic raw material; S4, the ceramic raw material is pressed into shape and subjected to debinding, and after debinding, sintered at 775-825°C for 4-6 hours to obtain Al2Mo 3+ x O 12+3x Microwave dielectric ceramic materials. This method forms Al2Mo 3+ x O 12+3x The low-temperature solid solution phase reduces the lattice loss, and the microwave dielectric ceramics obtained have a very excellent Q×f value while ensuring a low dielectric constant, which increases the corresponding research basis for low-firing, low-dielectric, and low-loss materials and broadens the selection range of low-dielectric-constant LTCC microwave dielectric ceramics.

Description

Technical Field

[0001] The present invention belongs to the field of electronic ceramics and their manufacturing, and specifically relates to a low temperature sintered high Q×f value Al2Mo 3+ x O 12+3x Microwave dielectric ceramic material and preparation method thereof. Background Art

[0002] Microwave dielectric ceramics are materials that perform specific functions in the 300MHz to 300GHz range. They can be used to manufacture key electronic components such as dielectric filters, substrates, and dielectric antennas. As the operating frequency of communication equipment continues to increase, signal delays are becoming increasingly pronounced, increasing system losses and heat generation, and gradually deteriorating system stability. Low dielectric constants can reduce the cross-coupling losses between the material and electrodes and increase the transmission rate of electrical signals. Excellent quality factors can reduce system losses and improve the material's frequency-selective properties. Their importance has garnered widespread attention due to the enormous demand for technologies such as 5G mobile communications and the Internet of Things.

[0003] Low-temperature co-fired ceramic (LTCC) technology is a novel multi-layer substrate process. LTCC technology enables the packaging of three essential components, along with various other passive devices, within a multi-layer wiring substrate. This technology offers high thermal conductivity, low loss, high stability, and high integration, characteristics not found in traditional PCBs. LTCC technology has become the leading passive integration technology available today. Currently, my country's research in microwave dielectric ceramics is gradually approaching that of developed countries. The development of new microwave dielectric ceramic materials and novel microwave components with independent intellectual property rights is of strategic importance to enhancing my country's national competitiveness in the electronic information sector. Therefore, it is essential to prepare materials with low dielectric constants and high Q×f values ​​suitable for low-temperature sintering.

[0004] Desintering high-temperature materials with low dielectric constants and high Q×f values ​​is an important method in current research. However, it is difficult to do so without seriously deteriorating microwave performance, and the temperature reduction is limited. For example, silicate ceramics have low dielectric constants and excellent Q×f values. It is reported that (Mg 0.925 Ca 0.075 )2SiO4 ceramics dielectric properties at 1425℃ / 3h are: dielectric constant ε r is 7.2, and the Q×f value is 199800GHz (26GHz) (tanδ=1.3×10 -4 ), frequency temperature coefficient τ fThe value is -33ppm / °C. However, the generally high sintering temperature of this ceramic increases energy consumption and hinders its application in the LTCC field. Modifying existing low-temperature sintering materials to improve their microwave performance is an effective approach. Given this, designing an improved low-k microwave dielectric ceramic with a high Q×f value and lower loss without increasing cost is a significant challenge. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a low temperature sintered high Q×f value Al2Mo 3+x O 12+3x Microwave dielectric ceramic material and preparation method thereof. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] The embodiment of the present invention provides a low temperature sintered high Q×f value Al2Mo 3+x O 12+3x A method for preparing a microwave dielectric ceramic material comprises the following steps:

[0007] S1, Al2O3 original powder and MoO3 original powder according to the chemical formula Al2Mo 3+x O 12+3x The ingredients are batched to obtain a mixed powder, wherein 0.02≤x≤0.06;

[0008] S2, sequentially subjecting the mixed powder to a first planetary ball milling and sieving, and pre-calcining the sieved powder to obtain a pre-calcined powder;

[0009] S3, subjecting the pre-calcined powder to a second planetary ball milling, drying and bonding granulation to obtain ceramic raw material;

[0010] S4, pressing the ceramic raw material into shape and debinding, and sintering at 775-825° C. for 4-6 hours to obtain Al2Mo 3+x O 12+3x Microwave dielectric ceramic materials.

[0011] In one embodiment of the present invention, step S2 includes:

[0012] The mixed powder is placed in a ball mill, and subjected to a first planetary ball milling for 6 to 8 hours under the action of a first grinding medium to obtain a mixed slurry;

[0013] Drying the mixed slurry, and sieving the dried powder through a 60-100 mesh sieve to obtain the sieved powder;

[0014] The sieved powder is pre-calcined in an atmosphere at 650-700° C. for 2-4 hours to obtain the pre-calcined powder.

[0015] In one embodiment of the present invention, the first grinding medium includes zirconium balls and alcohol;

[0016] During the first planetary ball milling, the mass ratio of the mixed powder, zirconium balls and alcohol is 1:5:2-5.

[0017] In one embodiment of the present invention, step S3 includes:

[0018] The calcined powder is placed in a ball mill, and subjected to a second planetary ball milling for 4 to 6 hours under the action of a second grinding medium to obtain a ball-milled material;

[0019] The ball-milled material is dried, and a binder is added to the dried powder for granulation to obtain the ceramic raw material.

[0020] In one embodiment of the present invention, the second grinding medium comprises zirconium balls and alcohol;

[0021] During the second planetary ball milling, the mass ratio of the calcined powder, zirconium balls and alcohol is 1:5:3-5.

[0022] In one embodiment of the present invention, the adhesive comprises 50% by mass of an acrylic acid solution.

[0023] In one embodiment of the present invention, step S4 includes:

[0024] pressing the ceramic raw material into a shape to obtain a pressed material;

[0025] Placing the pressed material in a sintering device, heating the sintering device to 400-450° C. at a heating rate of 2-5° C. / min and keeping the temperature for 2-4 hours to debind the pressed material;

[0026] The sintering equipment is heated to 775-825°C at a heating rate of 2-5°C / min and kept at this temperature for 4-6 hours to sinter the debinded material to obtain the Al2Mo 3+x O 12+3x Microwave dielectric ceramic materials.

[0027] Another embodiment of the present invention provides a low temperature sintered high Q×f value Al2Mo 3+x O 12+3x The microwave dielectric ceramic material is prepared by the preparation method described in the above embodiment, wherein the Al2Mo 3+x O 12+3x The crystal structure of the microwave dielectric ceramic material is a pure phase monoclinic crystal structure, wherein 0.02≤x≤0.06.

[0028] In one embodiment of the present invention, when x=0.04 and the sintering temperature is 775°C, Al2Mo 3.04 O 12.12 The dielectric constant of microwave dielectric ceramic material is 6.19 and the dielectric loss is 2.64×10 -4 , the Q×f value is 53076GHz, the resonant frequency f=14.011GHz, and the frequency temperature coefficient is -47.60ppm / ℃.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The method of the present invention is guided by the formation rules of solid solution, and the original powders of Al2O3 and MoO3 are prepared according to the chemical formula Al2Mo 3+x O 12+3x Under the premise of not introducing foreign ions, the non-stoichiometric ratio design of "Mo excess" for the high-valence Mo position is used to form Al2Mo 3+x O 12+3x The low-temperature solid solution phase reduces the lattice loss, and the microwave dielectric ceramics obtained have a very excellent Q×f value while ensuring a low dielectric constant, which increases the corresponding research basis for low-firing, low-dielectric, and low-loss materials, and will add a material system with greater potential to the LTCC application field, broadening the selection range of low-dielectric-constant LTCC microwave dielectric ceramics. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A low temperature sintered high Q×f value Al2Mo 3+x O 12+3x Schematic diagram of the process for preparing microwave dielectric ceramic materials;

[0032] Figure 2 Al2Mo sintered at 775℃ with different amounts of x 3+x O 12+3x XRD patterns of ceramics;

[0033] Figure 3 SEM morphology of the sample sintered at 775℃. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0035] Example 1

[0036] In order to solve the problem of low Q×f value of low-firing and low-dielectric materials at present, and to obtain higher Q×f value under the premise of ensuring low sintering temperature, this embodiment adopts Al2Mo3O 12The non-stoichiometric ratio of the ceramic was modified to provide an Al2Mo2O3 that can be sintered at low temperature and has excellent microwave dielectric properties. 3+x O 12+3x (0.02≤x≤0.06) microwave dielectric ceramic material, which has great application potential in the field of electronic communications.

[0037] See Figure 1 , Figure 1 A low temperature sintered high Q×f value Al2Mo 3+x O 12+3x Schematic diagram of the preparation process of microwave dielectric ceramic materials. 3+x O 12+3x The microwave dielectric ceramic material is prepared by solid phase reaction, and the preparation method includes the following steps:

[0038] S1, Al2O3 original powder and MoO3 original powder according to the chemical formula Al2Mo 3+x O 12+3x The ingredients are batched to obtain a mixed powder, wherein 0.02≤x≤0.06.

[0039] Specifically, according to the chemical formula Al2Mo 3+x O 12+3x Calculate the mass ratio of Al2O3 and MoO3 for batching.

[0040] S2. The mixed powder is subjected to a first planetary ball milling and sieving in sequence, and the sieved powder is pre-calcined to obtain pre-calcined powder.

[0041] Specifically, the mixed powder prepared in step S1 is first placed in a ball mill, and a first grinding medium is selected. A first planetary ball milling is performed under the action of the first grinding medium for 6-8 hours to obtain a mixed slurry. The first grinding medium comprises zirconium balls and alcohol; accordingly, the mass ratio of the mixed powder, zirconium balls, and alcohol during the first planetary ball milling is 1:5:2-5.

[0042] After the ball milling is completed, the mixed slurry is placed in an oven to dry, and the dried powder is sieved through a 60-100 mesh sieve, and the powder sieved out of the sieve is retained as the sieved powder. Through sieving, the particle size of the powder is refined and uniform.

[0043] Thereafter, the sieved powder is pre-calcined in an atmosphere at 650 to 700° C. for 2 to 4 hours to obtain a pre-calcined powder.

[0044] S3, subjecting the pre-calcined powder to a second planetary ball milling, drying and bonding granulation to obtain ceramic raw material.

[0045] Specifically, the calcined powder obtained in step S2 is first re-charged into a ball mill and subjected to a second planetary ball milling for 4-6 hours under the action of a second grinding medium to obtain a ball-milled material. The second grinding medium comprises zirconium balls and alcohol. Accordingly, during the second planetary ball milling, the mass ratio of calcined powder, zirconium balls, and alcohol is 1:5:3-5.

[0046] Then, the ball milled material is placed in an oven for drying, and a binder is added to the dried powder for granulation to obtain ceramic raw material. The binder comprises an acrylic acid aqueous solution with a mass percentage of 50%.

[0047] S4, pressing the ceramic raw material into shape and debinding, sintering at 775-825℃ for 4-6 hours to obtain Al2Mo 3+x O 12+3x Microwave dielectric ceramic materials.

[0048] Specifically, first, the ceramic raw material obtained in step S3 is pressed into shape to obtain a pressed material. Then, the pressed material is placed in a sintering device; then, the sintering device is heated to 400-450°C at a heating rate of 2-5°C / min and kept at this temperature for 2-4 hours to debind the pressed material; then, the sintering device is heated to 775-825°C at a heating rate of 2-5°C / min and kept at this temperature for 4-6 hours to sinter the debinded material to obtain Al2Mo 3+x O 12+3x Microwave dielectric ceramic materials.

[0049] Furthermore, a microwave dielectric ceramic material with a high Q×f value was prepared by the above preparation method. The general chemical formula of the microwave dielectric ceramic material is Al2Mo 3+x O 12+3x , where 0.02≤x≤0.06. Al2Mo 3+x O 12+3x Crystal structure of microwave dielectric ceramic materials and Al2Mo3O 12 The crystal structures of the two are consistent, both of which are pure phase monoclinic structures.

[0050] Specifically, when x=0.04 and the sintering temperature is 775℃, Al2Mo 3.04 O 12.12 The dielectric constant of microwave dielectric ceramic material is 6.19 and the dielectric loss is 2.64×10 -4 , the Q×f value is 53076GHz, the resonant frequency f=14.011GHz, and the frequency temperature coefficient is -47.60ppm / ℃.

[0051] The method of the present invention is guided by the formation rules of solid solution, and the original powders of Al2O3 and MoO3 are prepared according to the chemical formula Al2Mo 3+x O 12+3x Under the premise of not introducing foreign ions, the non-stoichiometric ratio design of "Mo excess" for the high-valence Mo position is carried out to increase the proportion of MoO3 and form Al2Mo 3+x O 12+3x The low-temperature solid solution phase reduces the lattice loss, and the microwave dielectric ceramics obtained have a very excellent Q×f value while ensuring a low dielectric constant, which increases the corresponding research basis for low-firing, low-dielectric, and low-loss materials, and will add a material system with greater potential to the LTCC application field, broadening the selection range of low-dielectric-constant LTCC microwave dielectric ceramics.

[0052] Example 2

[0053] Based on the first embodiment, this embodiment is to conduct a low temperature sintered high Q × f value Al2Mo 3+x O 12+3x The preparation method of microwave dielectric ceramic material is further described in detail.

[0054] The preparation method comprises the steps of:

[0055] S1, Al2O3 original powder and MoO3 original powder according to the chemical formula Al2Mo 3+x O 12+3x (x=0.02-0.06) to prepare the ingredients and obtain a mixed powder.

[0056] As shown in Table 1, when x = 0.02, the mass of Al2O3 is 31.932g, and the mass of MoO3 is 68.068g, which is recorded as Example No. 1; when x = 0.03, the mass of Al2O3 is 31.860g, and the mass of MoO3 is 68.140g, which is recorded as Example No. 2; when x = 0.04, the mass of Al2O3 is 31.788g, and the mass of MoO3 is 68.212g, which is recorded as Example No. 3; when x = 0.05, the mass of Al2O3 is 31.717g, and the mass of MoO3 is 68.283g, which is recorded as Example No. 4; when x = 0.06, the mass of Al2O3 is 31.646g, and the mass of MoO3 is 68.354g, which is recorded as Example No. 5.

[0057] S2. The mixed powder prepared in step S1 is placed in a ball mill, and zirconium balls and alcohol are selected as the first grinding media. A first planetary ball milling is performed for 8 hours at a mass ratio of mixed powder: zirconium balls: alcohol of 1:5:2. After the ball milling is completed, the mixed slurry is placed in an oven to dry and then sieved with an 80-mesh screen. The sieved powder is pre-calcined in an atmosphere at 700°C for 4 hours to obtain a pre-calcined powder.

[0058] S3. The calcined powder prepared in step S2 is subjected to a second planetary ball milling for 6 hours according to a mass ratio of calcined powder: zirconium balls: alcohol of 1:5:2. After the ball-milled material is dried, 50% by mass of acrylic acid solution is added to the dried powder as a binder to granulate the dried powder to obtain ceramic raw material.

[0059] S4, the ceramic raw material obtained in step S3 is pressed into shape, and then the binder is removed at 450°C at a heating rate of 2°C / min for 2 hours, and then the temperature is increased to 775-825°C at a heating rate of 3°C / min and kept at this temperature for 6 hours to obtain low-temperature sintered Al2Mo 3+x O 12 Microwave dielectric ceramic materials.

[0060] Furthermore, Al2Mo with x=0.02, 0.03, 0.04, 0.05, and 0.06 were prepared by the above preparation method. 3+x O 12 Microwave dielectric ceramic materials. x is the corresponding Al2Mo when different amounts 3+x O 12 The composition and sintering temperature of microwave dielectric ceramic materials are shown in Table 1.

[0061] Table 1

[0062]

[0063] See Figure 2 , Figure 2 Al2Mo sintered at 775℃ with different amounts of x 3+x O 12+3x XRD patterns of ceramics, with PDFNo.89–8579 as the standard sample. Figure 2 It can be seen that the XRD patterns of the sintered samples are all Al2Mo3O 12 phase, no other phases were retrieved, indicating that the formation of Al2Mo 3+x O 12+3x The crystal structure is pure phase Al2Mo3O 12 crystal structure.

[0064] See Figure 3 , Figure 3 The SEM morphology of the sample sintered at 775℃. Figure 3 It can be seen that the samples sintered at 775℃ are relatively dense, and no obvious pores are found. When x=0.04, the grains of the sintered samples are evenly distributed and of uniform size. As the x value increases to x=0.05 or decreases to x=0.03, dozens of micron grains appear and are unevenly distributed. As x increases or decreases further, the grain distribution becomes relatively uniform.

[0065] Specifically, when the amount of x is different, Al2Mo is sintered at 775℃. 3+x O 12 The microwave dielectric properties of microwave dielectric ceramic materials are shown in Table 2.

[0066] Table 2

[0067]

[0068] As can be seen from the table data, in Example 3, that is, when x = 0.04, the ceramic material sintered at 775 ° C achieved the maximum Q × f value. This is because the temperature at this time is most suitable for grain growth. When the temperature is lower, the surface cannot be fully dense. When the temperature rises, some grains will overgrow, resulting in uneven grain distribution. Porosity and unevenness will both lead to increased losses. When x = 0.04 is the middle value, the dielectric constant shows a trend of first decreasing and then increasing towards both sides. The Q × f value also shows the same trend of change. That is, Example 3 sintered at 775 ° C with x = 0.04 achieves the maximum Q × f value of 53076 GHz. At the same time, the dielectric constant remains at a low value of 6.19, which is closely related to grain growth. Combined with the SEM image, it can be seen that the sample with x = 0.04 has a dense surface morphology, sufficient grain growth, and the corresponding dielectric loss is minimal.

[0069] In this embodiment, by adding Al2Mo 3+x O 12+3x The proportion of MoO3 in the Al2MoO3 has successfully increased its Q×f value under the premise of ensuring a lower sintering temperature and a lower dielectric constant, making the Al2Mo 3+x O 12+3x Ceramics have better microwave performance, which greatly enhances their potential for application in LTCC technology.

[0070] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0071] Although the present application is described herein with reference to exemplary embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by examining the drawings, the disclosure, and the appended claims in the course of practicing the claimed application. In the claims, the word "comprising" does not exclude other components or steps. The fact that different dependent claims recite certain measures does not mean that these measures cannot be combined to produce advantageous effects.

[0072] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A low temperature sintered high Q×f value Al2Mo 3+x O 12+3x A method for preparing a microwave dielectric ceramic material, characterized in that: Including steps: S1, Al2O3 original powder and MoO3 original powder according to the chemical formula Al2Mo 3+x O 12+3x The ingredients are batched to obtain a mixed powder, wherein 0.02≤x≤0.06; S2, sequentially subjecting the mixed powder to a first planetary ball milling and sieving, and pre-calcining the sieved powder to obtain a pre-calcined powder; S3, subjecting the pre-calcined powder to a second planetary ball milling, drying and bonding granulation to obtain ceramic raw material; S4, pressing the ceramic raw material into shape and debinding, and sintering at 775-825° C. for 4-6 hours to obtain Al2Mo 3+x O 12+3x Microwave dielectric ceramic material; wherein the Al2Mo 3+x O 12+3x The crystal structure of microwave dielectric ceramic materials is a pure phase monoclinic crystal structure.

2. The low temperature sintered high Q×f value Al2Mo according to claim 1 3+x O 12+3x A method for preparing a microwave dielectric ceramic material, characterized in that: Step S2 includes: The mixed powder is placed in a ball mill, and subjected to a first planetary ball milling for 6 to 8 hours under the action of a first grinding medium to obtain a mixed slurry; Drying the mixed slurry, and sieving the dried powder through a 60-100 mesh sieve to obtain the sieved powder; The sieved powder is pre-calcined in an atmosphere at 650-700° C. for 2-4 hours to obtain the pre-calcined powder.

3. The low temperature sintered high Q×f value Al2Mo according to claim 2 3+x O 12+3x A method for preparing a microwave dielectric ceramic material, characterized in that: The first grinding medium includes zirconium balls and alcohol; During the first planetary ball milling, the mass ratio of the mixed powder, zirconium balls and alcohol is 1:5:2-5.

4. The low temperature sintered high Q×f value Al2Mo according to claim 1 3+x O 12+3x A method for preparing a microwave dielectric ceramic material, characterized in that: Step S3 includes: The calcined powder is placed in a ball mill, and subjected to a second planetary ball milling for 4 to 6 hours under the action of a second grinding medium to obtain a ball-milled material; The ball-milled material is dried, and a binder is added to the dried powder for granulation to obtain the ceramic raw material.

5. The low temperature sintered high Q×f value Al2Mo according to claim 4 3+x O 12+3x A method for preparing a microwave dielectric ceramic material, characterized in that: The second grinding medium includes zirconium balls and alcohol; During the second planetary ball milling, the mass ratio of the calcined powder, zirconium balls and alcohol is 1:5:3-5.

6. The low temperature sintered high Q×f value Al2Mo according to claim 4 3+x O 12+3x A method for preparing a microwave dielectric ceramic material, characterized in that: The adhesive includes 50% by mass of an acrylic acid solution.

7. The low temperature sintered high Q×f value Al2Mo according to claim 1 3+x O 12+3x A method for preparing a microwave dielectric ceramic material, characterized in that: Step S4 includes: pressing the ceramic raw material into a shape to obtain a pressed material; Placing the pressed material in a sintering device, heating the sintering device to 400-450° C. at a heating rate of 2-5° C. / min and keeping the temperature for 2-4 hours to debind the pressed material; The sintering equipment is heated to 775-825°C at a heating rate of 2-5°C / min and kept at this temperature for 4-6 hours to sinter the debinded material to obtain the Al2Mo 3+x O 12+3x Microwave dielectric ceramic materials.

8. A low temperature sintered high Q×f value Al2Mo 3+x O 12+3x Microwave dielectric ceramic material, characterized in that Prepared by the preparation method according to any one of claims 1 to 7, the Al2Mo 3+x O 12+3x The crystal structure of the microwave dielectric ceramic material is a pure phase monoclinic crystal structure, wherein 0.02≤x≤0.

06.

9. The low temperature sintered high Q×f value Al2Mo according to claim 8 3+x O 12+3x Microwave dielectric ceramic material, characterized in that When x=0.04 and sintering temperature is 775℃, Al2Mo 3.04 O 12.12 The dielectric constant of microwave dielectric ceramic material is 6.19 and the dielectric loss is 2.64×10 -4 , the Q×f value is 53076GHz, the resonant frequency f=14.011GHz, and the frequency temperature coefficient is -47.60ppm / ℃.

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