Low-cost ultralow dielectric microwave dielectric ceramic material and preparation method thereof

Abstract

The invention relates to the technical field of electronic ceramics, in particular to a low-cost ultra-low dielectric microwave dielectric ceramic material and a preparation method thereof.The low-cost ultra-low dielectric microwave dielectric ceramic material comprises, by mass, 4.1% of MgO, 36.4% of H2SiO3, 31.5% of Al2O3 and 28% of talc, talcum powder and Al2O3, H2SiO3 and MgO with the purity larger than or equal to 99% serve as initial raw materials, the microwave dielectric material Mg2.15 Al4Si5O18.15 is prepared through a solid-phase sintering method, and the microwave dielectric ceramic material is prepared through a microwave sintering method. The microwave performance of the material is excellent, the dielectric constant epsilon r is 3.82-4.42, the quality factor Q * f is 36653-64628 GHz, and the temperature coefficient of resonance frequency tau f is-26.02--24.80 ppm / DEG C. The ultra-low dielectric microwave dielectric ceramic material adopts talc to replace part of a silicon raw material and a magnesium raw material, the content of the silicon raw material and the magnesium raw material is greatly reduced, compared with the silicon raw material and the magnesium raw material, the talc is extremely low in cost, and the cost is low. The raw material cost is reduced, the preparation is easy, and great commercial potential is achieved. In addition, the added value of talc is improved, and development of related industries is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic ceramics, and in particular to a low-cost ultra-low dielectric microwave dielectric ceramic material and a preparation method thereof. Background Art

[0002] With the continuous upgrading of communication technology, my country's demand for microwave dielectric materials is increasing. Microwave dielectric ceramics refer to ceramics used as dielectric materials in microwave (300MHz~300GHz) frequency band circuits and perform one or more functions. They are key basic materials in modern communication technology and are widely used in microwave components such as dielectric resonators, filters, dielectric substrates, dielectric waveguide circuits, microwave capacitors, duplexers, antennas, etc.

[0003] Among them, low dielectric constant microwave dielectric materials can reduce signal transmission delay and reduce coupling crossover between conductors. As circuit integration and wiring density continue to increase, requirements for ultra-low dielectric materials are put forward. Most of the ultra-low dielectric ceramic materials reported so far are silicon-based materials, including Mg 2.15 Al4Si5O 18.15 This material has a high preparation cost because it contains a large amount of Mg and Si elements. Summary of the invention

[0004] The purpose of the present invention is to provide a low-cost ultra-low dielectric microwave dielectric ceramic material and a preparation method thereof, aiming to solve the problem that the existing ultra-low dielectric ceramic materials contain a large amount of Mg and Si elements and have a high preparation cost.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a low-cost ultra-low dielectric microwave ceramic material, comprising the following components in a mass ratio: MgO 4.1%, H2SiO3 36.4%, Al2O3 31.5% and talc 28%.

[0006] In a second aspect, the present invention further provides a low-cost method for preparing an ultra-low dielectric microwave ceramic material, which is applied to a low-cost ultra-low dielectric microwave ceramic material as described in the first aspect above, and is characterized in that it comprises the following steps:

[0007] Weighing talc, Al2O3, H2SiO3 and MgO powders and putting them into a ball mill, and adding anhydrous ethanol to the ball mill for the first wet grinding to obtain a powder slurry;

[0008] The powder slurry is placed in a drying oven for drying to obtain dried powder;

[0009] The dried powder is sieved using a sieve, and the sieved powder is placed in a muffle furnace for pre-calcination to obtain a pre-calcined powder;

[0010] Cooling the pre-calcined powder, and adding the anhydrous ethanol to perform secondary wet grinding to obtain a secondary powder slurry;

[0011] The secondary powder slurry is dried and granulated, and pressed to form a ceramic green body, and the ceramic green body is sintered to obtain an ultra-low dielectric microwave dielectric ceramic material.

[0012] The mass ratio of the anhydrous ethanol to the mixed powder of talc, Al2O3, H2SiO3 and MgO is 1:1, and the first wet grinding lasts for 4 hours.

[0013] The drying temperature of the powder slurry and the secondary powder slurry is in the range of 85 to 100° C., and the duration of the first wet grinding and the second wet grinding is 4 hours.

[0014] Among them, the sieve is a 80-mesh sieve, the pre-calcination temperature is 1250°C, the calcination time is 2 hours, the drying and granulation uses 30% polymethyl methacrylate solution as a binder, the sintering temperature is 1390°C to 1420°C, and the time is 3 hours.

[0015] The invention discloses a low-cost ultra-low dielectric microwave ceramic material. The microwave dielectric material Mg is prepared by solid phase sintering using talcum powder and Al2O3, H2SiO3 and MgO with a purity of ≥99% as initial raw materials. 2.15 Al4Si5O 18.15 , the microwave performance of the material is relatively excellent: dielectric constant ε r is 3.82~4.42, the quality factor Q×f is 36653~64628GHz, and the resonant frequency temperature coefficient τ f The ultra-low dielectric microwave ceramic material uses talc to replace part of the silicon raw material and magnesium raw material, which greatly reduces the content of silicon raw material and magnesium raw material. Compared with silicon raw material and magnesium raw material, talc has extremely low cost, reduces the cost of raw materials and is easy to prepare, and has great commercial potential. In addition, it increases the added value of talc and drives the development of related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The present invention provides a flow chart of a method for preparing a low-cost ultra-low dielectric microwave ceramic material. DETAILED DESCRIPTION

[0018] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0019] In a first aspect, the present invention provides a low-cost ultra-low dielectric microwave ceramic material, comprising the following components in a mass ratio: MgO 4.1%, H2SiO3 36.4%, Al2O3 31.5% and talc 28%.

[0020] In the embodiment of the present invention, talcum powder and Al2O3, H2SiO3 and MgO with a purity of ≥99% are used as initial raw materials to prepare the microwave dielectric material Mg by solid phase sintering method. 2.15 Al4Si5O 18.15 , the microwave performance of the material is relatively excellent: dielectric constant ε r is 3.82~4.42, the quality factor Q×f is 36653~64628GHz, and the resonant frequency temperature coefficient τ f The ultra-low dielectric microwave ceramic material uses talc to replace part of the silicon raw material and magnesium raw material, which greatly reduces the content of silicon raw material and magnesium raw material. Compared with silicon raw material and magnesium raw material, talc has extremely low cost, reduces the cost of raw materials and is easy to prepare, and has great commercial potential. In addition, it increases the added value of talc and drives the development of related industries.

[0021] See also Figure 1 In a second aspect, the present invention further provides a low-cost method for preparing an ultra-low dielectric microwave ceramic material, which is applied to a low-cost ultra-low dielectric microwave ceramic material as described in the first aspect above, and is characterized in that it comprises the following steps:

[0022] S1: weighing talc, Al2O3, H2SiO3 and MgO powders and putting them into a ball mill, and adding anhydrous ethanol to the ball mill for the first wet grinding to obtain a powder slurry;

[0023] In the embodiment of the present invention, the mass ratio of the added anhydrous ethanol to the mass ratio of the talc, Al2O3, H2SiO3 and MgO powder is 1:1, and the duration of the first wet grinding is 6 hours.

[0024] S2: placing the powder slurry in a drying oven for drying to obtain dried powder;

[0025] In the embodiment of the present invention, the drying treatment temperature ranges from 85 to 100°C.

[0026] S3 uses a sieve to sieve the dried powder, and puts the sieved powder into a muffle furnace for pre-calcination to obtain a pre-calcined powder;

[0027] In the embodiment of the present invention, a sieve of 80 mesh is used for sieving, the pre-burning temperature in the muffle furnace is 1250° C., and the calcination time is 2 hours.

[0028] S4: cooling the pre-calcined powder, and adding the anhydrous ethanol to perform secondary wet grinding to obtain a secondary powder slurry;

[0029] In the embodiment of the present invention, after the pre-calcined powder is cooled to room temperature using a cooling device, the anhydrous ethanol is added to perform a second wet grinding, and the ball milling time is 4 hours.

[0030] S5: drying and granulating the secondary powder slurry, pressing to form a ceramic green body, and sintering the ceramic green body to obtain an ultra-low dielectric microwave dielectric ceramic material.

[0031] In the embodiment of the present invention, during the drying and granulation process, 30% polymethyl methacrylate solution is used as a binder, the drying temperature ranges from 85 to 100° C., the green body sintering temperature is 1390° C. to 1420° C., and the sintering time is 3 hours.

[0032] In order to better understand the present technical solution, the following embodiments are provided for further explanation:

[0033] Embodiment 1:

[0034] Using talc powder as the only raw material, microwave dielectric ceramic materials are prepared by solid phase sintering. The specific implementation steps are as follows:

[0035] S01 Weigh a certain amount of talc, Al2O3, H2SiO3 and MgO powders, add anhydrous ethanol with a mass ratio of 1:1 and ball mill for 6 hours at a speed of 350 rpm;

[0036] S02: placing the powder slurry obtained in step S01 into a drying oven and drying it at 85°C;

[0037] S03: placing the powder sieved in step S02 into a muffle furnace, pre-calcining at 1250° C., and keeping the temperature for 2 hours;

[0038] S04: The powder calcined in step S03 is added with anhydrous ethanol in a mass ratio of 1:1 for a second ball milling, the ball milling time is 4 hours, and the rotation speed is 300 rpm;

[0039] S05: placing the powder slurry obtained in step S04 into a drying oven, drying at 85° C., using a 30% polymethyl methacrylate solution as a binder for granulation, passing through an 80-mesh sieve, and then using a tablet press to press into a ceramic green body;

[0040] S06: sintering the green body of step S05 at 1390° C. for 3 hours;

[0041] S07 The microwave dielectric properties of the prepared samples were tested by network analyzer. r =3.82, Q×f=36653GHz, τ f =-24.80ppm / ℃. Specific embodiment 2:

[0043] The implementation steps are as follows:

[0044] Using talc powder as the only raw material, microwave dielectric ceramic materials are prepared by solid phase sintering. The specific implementation steps are as follows:

[0045] S11: Weigh a certain amount of talc, Al2O3, H2SiO3 and MgO powders, add anhydrous ethanol in a mass ratio of 1:1 and perform ball milling for 6 hours at a speed of 350 rpm;

[0046] S12: placing the powder slurry obtained in step S11 into a drying oven and drying it at 85°C;

[0047] S13: placing the powder sieved in step S12 into a muffle furnace, pre-calcining at 1250° C., and keeping the temperature for 2 hours;

[0048] S14: the powder calcined in step S13 is added with anhydrous ethanol in a mass ratio of 1:1 and ball-milled for a second time for 4 hours at a rotation speed of 300 rpm;

[0049] S15: putting the powder slurry obtained in step S14 into a drying oven, drying it at 85° C., using 30% polymethyl methacrylate solution as a binder to granulate it, passing it through an 80-mesh sieve, and then using a tablet press to press it into a ceramic green body;

[0050] S16: sintering the green body of step S15 at 1400° C. for 3 hours;

[0051] S17 The microwave dielectric properties of the prepared samples were tested by network analyzer. r =4.20, Q×f=39941GHz, τ f =-24.83ppm / ℃. Specific embodiment 3:

[0053] The implementation steps are as follows:

[0054] Using talc powder as the only raw material, microwave dielectric ceramic materials are prepared by solid phase sintering. The specific implementation steps are as follows:

[0055] S31 Weigh a certain amount of talc, Al2O3, H2SiO3 and MgO powders, add anhydrous ethanol in a mass ratio of 1:1 and perform ball milling for 6 hours at a speed of 350 rpm;

[0056] S32: placing the powder slurry obtained in step S31 into a drying oven and drying at 85° C.;

[0057] S33: placing the sieved powder in step S32 into a muffle furnace, pre-burning at 1250° C., and keeping the temperature for 2 hours;

[0058] S34: the powder calcined in step S33 is added with anhydrous ethanol in a mass ratio of 1:1 and ball-milled for a second time for 4 hours at a rotation speed of 300 rpm;

[0059] S35: putting the powder slurry obtained in step S34 into a drying oven, drying it at 85° C., using 30% polymethyl methacrylate solution as a binder to granulate it, passing it through an 80-mesh sieve, and then using a tablet press to press it into a ceramic green body;

[0060] S36: sintering the green body of step S35 at 1410° C. for 3 hours;

[0061] S37 The microwave dielectric properties of the prepared samples were tested by network analyzer. r =4.42, Q×f=64628GHz, τ f =-25.18ppm / ℃. Specific embodiment 4:

[0063] The implementation steps are as follows:

[0064] Using talc powder as the only raw material, microwave dielectric ceramic materials are prepared by solid phase sintering. The specific implementation steps are as follows:

[0065] S41 Weigh a certain amount of talc, Al2O3, H2SiO3 and MgO powders, add anhydrous ethanol in a mass ratio of 1:1 and perform ball milling for 6 hours at a speed of 350 rpm;

[0066] S42: placing the powder slurry obtained in step S41 into a drying oven and drying at 85° C.;

[0067] S43: placing the powder sieved in step S42 into a muffle furnace, pre-calcining at 1250° C., and keeping the temperature for 2 hours;

[0068] S44: the powder calcined in step S43 is added with anhydrous ethanol in a mass ratio of 1:1 and ball-milled for a second time, the ball-milling time is 4 hours, and the rotation speed is 300 rpm;

[0069] S45: putting the powder slurry obtained in step S44 into a drying oven, drying it at 85° C., using 30% polymethyl methacrylate solution as a binder to granulate it, passing it through an 80-mesh sieve, and then using a tablet press to press it into a ceramic green body;

[0070] S46: sintering the green body of step S45 at 1420° C. for 3 hours;

[0071] S47 The microwave dielectric properties of the prepared samples were tested by network analyzer. r =4.42, Q×f=42307GHz, τ f =-26.02ppm / ℃.

[0072] Examples composition Sintering temperature <![CDATA[ε r ]]> Q×f(GHz) <![CDATA[τ f (ppm / ℃)]]> 1 <![CDATA[Mg 2.15 Al4Si5O 18.15 ]]> 1390℃ 3.82 36653 -24.80 2 <![CDATA[Mg 2.15 Al4Si5O 18.15 ]]> 1400℃ 4.20 39941 -25.13 3 <![CDATA[Mg 2.15 Al4Si5O 18.15 ]]> 1410℃ 4.42 64628 -25.20 4 <![CDATA[Mg 2.15 Al4Si5O 18.15 ]]> 1420℃ 4.42 42307 -26.02

[0073] The above disclosure is only a preferred embodiment of a low-cost ultra-low dielectric microwave dielectric ceramic material and a preparation method thereof of the present invention. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A low-cost ultra-low dielectric microwave ceramic material, characterized in that: The invention comprises the following components in the following mass ratios: MgO 4.1%, H2SiO3 36.4%, Al2O3 31.5% and talc 28%.

2. A low-cost method for preparing ultra-low dielectric microwave ceramic materials, applied to a low-cost ultra-low dielectric microwave ceramic material as claimed in claim 1, characterized in that: The following steps are involved: Weighing talc, Al2O3, H2SiO3 and MgO powders and putting them into a ball mill, and adding anhydrous ethanol to the ball mill for the first wet grinding to obtain a powder slurry; The powder slurry is placed in a drying oven for drying to obtain dried powder; The dried powder is sieved using a sieve, and the sieved powder is placed in a muffle furnace for pre-calcination to obtain a pre-calcined powder; Cooling the pre-calcined powder, and adding the anhydrous ethanol to perform secondary wet grinding to obtain a secondary powder slurry; The secondary powder slurry is dried and granulated, and pressed to form a ceramic green body, and the ceramic green body is sintered to obtain an ultra-low dielectric microwave dielectric ceramic material.

3. A low-cost method for preparing ultra-low dielectric microwave ceramic materials as claimed in claim 2, characterized in that: The mass ratio of the anhydrous ethanol to the mixed powder of talc, Al2O3, H2SiO3 and MgO is 1:1, and the first wet grinding lasts for 4 hours.

4. A low-cost method for preparing ultra-low dielectric microwave ceramic materials as claimed in claim 2, characterized in that: The drying temperature range of the powder slurry and the secondary powder slurry is 85-100° C., and the duration of the first wet grinding and the second wet grinding is 4 hours.

5. A low-cost method for preparing ultra-low dielectric microwave ceramic materials as claimed in claim 2, characterized in that: The sieve is a 80-mesh sieve, the pre-sintering temperature is 1250° C., the calcining time is 2 hours, the drying granulation uses a 30% polymethyl methacrylate solution as a binder, the sintering temperature is 1390° C. to 1420° C., and the time is 3 hours.

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