A multi-element mineral microwave dielectric ceramic material and a preparation method thereof

Abstract

The application discloses a kind of multi-element mineral microwave dielectric ceramic materials and preparation method thereof, multi-element mineral microwave dielectric ceramic materials, by the following weight fraction raw materials sintering is obtained: 192~224 parts black talc, 160~192 parts wollastonite, 8~12 parts MgO, 4~8 parts SnO2, 2~4 parts kaolin tailings.Preparation method includes the following steps: broken fine sieving, obtain black talc powder, wollastonite powder and kaolin tailings powder;Take black talc powder and MgO powder, ball milling is mixed;Add wollastonite powder, continue ball milling;Drying, calcination, heat preservation, with furnace cooling;The obtained powder and proportionally weighed SnO2 powder, kaolin tailings powder, ball milling is uniformly mixed, drying;After powder preparation blank, sintering.The application improves the microwave dielectric properties of ceramic material, selects kaolin tailings powder as sintering additive, reduces sintering temperature under the premise of not reducing ceramic dielectric properties.

Description

Technical Field

[0001] This invention pertains to ceramic materials and their preparation methods, specifically a multi-element mineral microwave dielectric ceramic material and its preparation method. Background Technology

[0002] Microwave dielectric materials play a vital role in global technological development, with a wide range of applications, including the Internet of Things (IoT), radio broadcasting, GPS, and satellite television. The rapid development of modern communication technologies such as IoT, satellite broadcasting, and smart transportation has driven the optimization of microwave dielectric material performance and product diversification. Recent research shows that low-loss microwave dielectric ceramics can enhance the miniaturization and integration of microwave devices by reducing the size of components such as filters, oscillators, and antennas, leading to significant breakthroughs in microwave communication technology.

[0003] The CaMgSi2O6 ceramic system has a low dielectric constant (ε). r =7~8), suitable for millimeter-wave communication, and can also be used as a substrate material for microwave integrated circuits. However, its relatively low quality factor, poor temperature stability, and high sintering temperature hinder the further application of CaMgSi2O6 ceramics in scientific and commercial fields. Therefore, how to further reduce the dielectric loss of the CaMgSi2O6 ceramic system and effectively adjust the τ of the ceramic material is a key issue. f Reducing the dielectric constant, lowering the sintering temperature, and maintaining a low dielectric constant have become critical technical issues that urgently need to be addressed. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a multi-component mineral microwave dielectric ceramic material with good dielectric stability and no impurity phases. Another purpose of this invention is to provide a convenient and controllable method for preparing multi-component mineral microwave dielectric ceramic materials that can reduce the sintering temperature.

[0005] Technical solution: The multi-mineral microwave dielectric ceramic material of the present invention is obtained by sintering the following raw materials in parts by weight: 192-224 parts black talc, 160-192 parts wollastonite, 8-12 parts MgO, 4-8 parts SnO2, and 2-4 parts kaolin tailings.

[0006] Furthermore, the main phase of the multi-mineral microwave dielectric ceramic material is CaMgSi2O6, and the secondary phase is Mg2SiO4, with the main phase accounting for 68-74% of the mass and the secondary phase accounting for 26-32% of the mass.

[0007] Furthermore, the relative permittivity of the multi-mineral microwave dielectric ceramic material is 9.12–10.52, the quality factor is 73473–84624 GHz, and the temperature coefficient of the resonant frequency is -7 to -12 ppm / ℃.

[0008] The preparation method of the above-mentioned multi-mineral microwave dielectric ceramic material includes the following steps:

[0009] Step S1: Crush, grind and sieve the black talc, wollastonite and kaolin tailings respectively to obtain black talc powder, wollastonite powder and kaolin tailings powder.

[0010] Step S2: Weigh out black talc powder and MgO powder according to the proportion, and mix them by ball milling;

[0011] Step S3: Add wollastonite powder to the product obtained in step S2 and continue ball milling;

[0012] Step S4: Dry the product obtained in step S3, calcine it, keep it warm, and cool it in the furnace.

[0013] Step S5: The powder obtained in step S4, SnO2 powder and kaolin tailings powder weighed in proportion are ball-milled and mixed evenly, and then dried.

[0014] Step S6: Take out the powder obtained in step S5, prepare the powder into a blank, and sinter it to obtain a multi-mineral microwave dielectric ceramic material.

[0015] Furthermore, in step S1, the particle size of the black talc, wollastonite, and kaolin tailings after crushing, grinding, and sieving is less than 45 μm.

[0016] Furthermore, in step S2, the particle size of MgO is 1–5 μm, the ball milling is wet ball milling, the ball milling speed is 150–200 r / min, and the ball milling time is 3–5 h. Wet ball milling makes the material easier to grind, improves grinding efficiency, and results in better material uniformity.

[0017] Furthermore, in step S3, the ball milling is a wet ball milling process, with a milling speed of 250–300 r / min and a milling time of 16–24 h.

[0018] Further, in step S4, the calcination temperature is 750–900℃, and the holding time is 1–3 hours. Preferably, the heating rate is 3℃ / min. If the calcination temperature is below 750℃, the powder contains the raw material phase, which is prone to the formation of impurity phases during subsequent sintering; if the calcination temperature is above 900℃, the powder particle size becomes larger, and the reactivity decreases during subsequent sintering.

[0019] Furthermore, in step S5, the ball milling is a wet ball milling process, the ball milling speed is 200-250 r / min, and the ball milling time is 8-12 h; the particle size of the SnO2 is 5-20 μm, and the particle size of the kaolin tailings powder is less than 25 μm.

[0020] Further, in step S6, the sintering temperature is 1050–1150℃, and after sintering, the temperature is held for 4–6 hours, then cooled to 500–600℃ at a rate of 5–10℃ / min, followed by furnace cooling. Preferably, the heating rate is 3℃ / min. If the sintering temperature is below 1050℃, the ceramic material lacks sufficient sintering kinetics, resulting in decreased density and reduced performance. If the sintering temperature is above 1150℃, abnormal grain growth occurs, and the grains are coated during growth, leading to increased porosity, decreased density, and reduced performance.

[0021] Preparation Principle: This invention introduces MgO additives into black talc and wollastonite, which can compensate for the insufficient Mg content in the mineral materials. Since black talc is mainly composed of Mg and Si oxides, the premixing of MgO with black talc ensures that Mg2SiO4 appears in the final product as a secondary phase, thereby ensuring that the main crystalline phase of the final ceramic product is (CaMgSi2O6 + Mg2SiO4), thus significantly reducing the dielectric loss of the material. 4+ The introduction of (SnO2) can partially replace Si in CaMgSi2O6 and Mg2SiO4. 4+ The distortion degree of the oxygen octahedron at the B site was adjusted, thereby improving the temperature coefficient τ of the resonant frequency of the ceramic material. f .

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0023] 1. MgO and SnO2 were selected as additives to improve the microwave dielectric properties of ceramic materials, including improving the quality factor and adjusting the temperature coefficient of the resonant frequency to near zero. Kaolin tailings powder was selected as a sintering aid to reduce the sintering temperature of ceramic materials without reducing the dielectric properties of ceramics.

[0024] 2. Using wollastonite and black talc as the main raw materials, a low-cost microwave dielectric ceramic material with CaMgSi2O6 and Mg2SiO4 coexisting was prepared.

[0025] 3. By using a two-stage ball milling process, black talc and MgO are fully premixed before being combined with wollastonite to prevent the appearance of impurity phases after the ceramic powder is calcined, thereby ensuring the stability of the dielectric properties of the ceramic material. Attached Figure Description

[0026] Figure 1The image shows the XRD pattern of the multi-component mineral microwave dielectric ceramic material prepared in Example 3 of this invention.

[0027] Figure 2 This is a SEM image of the multi-mineral microwave dielectric ceramic material prepared in Example 3 of the present invention.

[0028] Figure 3 This is a SEM image of the multi-mineral microwave dielectric ceramic material prepared in Comparative Example 1 of the present invention.

[0029] Figure 4 The image shows the XRD pattern of the multi-component mineral microwave dielectric ceramic material prepared in Comparative Example 4 of this invention. Detailed Implementation

[0030] Unless otherwise specified, all materials, reagents, and instruments used in the following examples are commercially available. Experimental methods not specifically described in the examples are generally performed under standard conditions or as recommended by the manufacturer. The specific compositions of black talc powder, wollastonite, and kaolin tailings are shown in Table 1 below. The particle size of MgO is 1–5 μm.

[0031] Table 1. Composition of black talc powder, wollastonite, and kaolin tailings

[0032] sample <![CDATA[SiO2]]> CaO MgO <![CDATA[Fe2O3]]> <![CDATA[Al2O3]]> <![CDATA[Na2O]]> Loss on ignition Black talc 65.64 0.19 23.39 0.05 0.48 0.38 5.79 Wollastonite 49.81 37.67 1.12 0.29 0.26 0.11 10.74 Kaolin tailings 72.86 1.52 2.12 1.14 12.04 4.04 6.28

[0033] Example 1

[0034] A method for preparing a multi-mineral microwave dielectric ceramic material includes the following steps:

[0035] Step S1: Crush, grind and sieve the black talc, wollastonite and kaolin tailings respectively, so that the average particle size of the black talc and wollastonite powder is 40μm and the average particle size of the kaolin tailings powder is 20μm.

[0036] Step S2: Weigh 19.2g of black talc powder, 19.2g of wollastonite powder, and 0.8g of analytical grade MgO powder. Premix the black talc powder and MgO powder by ball milling at a speed of 150r / min for 3h.

[0037] Step S3: Pause the ball mill and remove the milling jar. Add wollastonite powder to the milling jar and continue milling at a speed of 250 r / min for 16 h.

[0038] Step S4: Dry the product obtained in step S3, place it in a muffle furnace and calcine it at 750°C for 1 hour, with a heating rate of 3°C / min, and then cool it with the furnace.

[0039] Step S5: Weigh 0.5g of analytical grade SnO2 powder and 0.3g of kaolin tailings powder. Mix the calcined powder with SnO2 and kaolin tailings powder and wet ball mill at 200r / min for 8h, then dry. The average particle size of SnO2 and kaolin tailings powder is 20μm.

[0040] Step S6: Take out the powder obtained in step S5, press it into a compact, and sinter it in a high-temperature muffle furnace. The sintering temperature is 1050℃, the heating rate is 3℃ / min, the holding time is 4h, and then the temperature is reduced to 500℃ at a rate of 5℃ / min. Then the furnace is cooled to obtain a multi-mineral microwave dielectric ceramic material.

[0041] The phase content (by mass ratio) of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is: CaMgSi2O6 accounts for 68.0%, and Mg2SiO4 accounts for 32.0%. The relative permittivity of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is 9.92, the quality factor is 79231 GHz, and the temperature coefficient of resonant frequency is -12 ppm / ℃.

[0042] Example 2

[0043] A method for preparing a multi-mineral microwave dielectric ceramic material includes the following steps:

[0044] Step S1: Crush, grind and sieve the black talc, wollastonite and kaolin tailings respectively, so that the average particle size of the black talc and wollastonite powder is 40μm and the average particle size of the kaolin tailings powder is 20μm.

[0045] Step S2: Weigh 20.0g of black talc powder, 18.4g of wollastonite powder, and 1.0g of analytical grade MgO powder. Premix the black talc powder and MgO powder by ball milling at a speed of 175r / min for 4h.

[0046] Step S3: Pause the ball mill and remove the milling jar. Add wollastonite powder to the milling jar and continue milling at a speed of 275 r / min for 18 hours.

[0047] Step S4: Dry the product obtained in step S3, place it in a muffle furnace and calcine it at 800°C for 2 hours, with a heating rate of 3°C / min, and then cool it with the furnace.

[0048] Step S5: Weigh 0.4g of analytical grade SnO2 powder and 0.2g of kaolin tailings powder. Mix the calcined powder with SnO2 and kaolin tailings powder and wet ball mill at 225r / min for 9h, then dry. The average particle size of SnO2 is 5μm, and the average particle size of kaolin tailings powder is 20μm.

[0049] Step S6: Take out the powder obtained in step S5, press it into a compact, and sinter it in a high-temperature muffle furnace. The sintering temperature is 1100℃, the heating rate is 3℃ / min, the holding time is 5h, and then the temperature is reduced to 550℃ at a rate of 8℃ / min. Then the furnace is cooled to obtain a multi-mineral microwave dielectric ceramic material.

[0050] The phase content (by mass ratio) of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is: CaMgSi2O6 accounts for 70.5%, and Mg2SiO4 accounts for 29.5%. The relative permittivity of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is 9.52, the quality factor is 82156GHz, and the temperature coefficient of resonant frequency is -11ppm / ℃.

[0051] Example 3

[0052] A method for preparing a multi-mineral microwave dielectric ceramic material includes the following steps:

[0053] Step S1: Crush, grind and sieve the black talc, wollastonite and kaolin tailings respectively, so that the average particle size of the black talc and wollastonite powder is 40μm and the average particle size of the kaolin tailings powder is 20μm.

[0054] Step S2: Weigh 20.8g of black talc powder, 17.2g of wollastonite powder, and 0.8g of analytical grade MgO powder. Premix the black talc powder and MgO powder by ball milling at a speed of 200r / min for 5h.

[0055] Step S3: Pause the ball mill and remove the ball mill jar. Add wollastonite powder to the ball mill jar and continue ball milling at a speed of 300 r / min for 20 h.

[0056] Step S4: Dry the product obtained in step S3, place it in a muffle furnace and calcine it at 850°C for 3 hours, with a heating rate of 3°C / min, and then cool it with the furnace.

[0057] Step S5: Weigh 0.8g of analytical grade SnO2 powder and 0.4g of kaolin tailings powder. Mix the calcined powder with SnO2 and kaolin tailings powder and wet ball mill at 250r / min for 10h, then dry. The average particle size of SnO2 is 15μm, and the average particle size of kaolin tailings powder is 20μm.

[0058] Step S6: Take out the powder obtained in step S5, press it into a compact, and sinter it in a high-temperature muffle furnace. The sintering temperature is 1150℃, the heating rate is 3℃ / min, the holding time is 6h, and then the temperature is reduced to 600℃ at a rate of 10℃ / min. Then the furnace is cooled to obtain a multi-mineral microwave dielectric ceramic material.

[0059] The phase content (by mass ratio) of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is: CaMgSi2O6 accounts for 71.6%, and Mg2SiO4 accounts for 28.4%. The relative permittivity of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is 9.12, the quality factor is 84624 GHz, and the temperature coefficient of resonant frequency is -7 ppm / ℃.

[0060] Example 4

[0061] A method for preparing a multi-mineral microwave dielectric ceramic material includes the following steps:

[0062] Step S1: Crush, grind and sieve the black talc, wollastonite and kaolin tailings respectively, so that the average particle size of the black talc and wollastonite powder is 40μm and the average particle size of the kaolin tailings powder is 20μm.

[0063] Step S2: Weigh 21.6g of black talc powder, 16.2g of wollastonite powder, and 1.2g of analytical grade MgO powder. Premix the black talc powder and MgO powder by ball milling at a speed of 175r / min for 4h.

[0064] Step S3: Pause the ball mill and remove the milling jar. Add wollastonite powder to the milling jar and continue milling at a speed of 275 r / min for 22 h.

[0065] Step S4: Dry the product obtained in step S3, place it in a muffle furnace and calcine it at 900°C for 2 hours, with a heating rate of 3°C / min, and then cool it with the furnace.

[0066] Step S5: Weigh 0.6g of analytical grade SnO2 powder and 0.4g of kaolin tailings powder. Mix the calcined powder with SnO2 and kaolin tailings powder and wet ball mill at 225r / min for 11h, then dry. The average particle size of SnO2 is 10μm, and the average particle size of kaolin tailings powder is 20μm.

[0067] Step S6: Take out the powder obtained in step S5, press it into a compact, and sinter it in a high-temperature muffle furnace. The sintering temperature is 1100℃, the heating rate is 3℃ / min, the holding time is 5h, and then the temperature is reduced to 550℃ at a rate of 8℃ / min. Then the furnace is cooled to obtain a multi-mineral microwave dielectric ceramic material.

[0068] The phase content (by mass ratio) of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is: CaMgSi2O6 accounts for 72.9%, and Mg2SiO4 accounts for 27.1%. The relative permittivity of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is 10.31, the quality factor is 78482GHz, and the temperature coefficient of resonant frequency is -9ppm / ℃.

[0069] Example 5

[0070] A method for preparing a multi-mineral microwave dielectric ceramic material includes the following steps:

[0071] Step S1: Crush, grind and sieve the black talc, wollastonite and kaolin tailings respectively, so that the average particle size of the black talc and wollastonite powder is 40μm and the average particle size of the kaolin tailings powder is 20μm.

[0072] Step S2: Weigh 22.4g of black talc powder, 16.0g of wollastonite powder, and 1.0g of analytical grade MgO powder. Premix the black talc powder and MgO powder by ball milling at a speed of 150r / min for 3h.

[0073] Step S3: Pause the ball mill and remove the ball mill jar. Add wollastonite powder to the ball mill jar and continue ball milling at a speed of 250 r / min for 24 hours.

[0074] Step S4: Dry the product obtained in step S3, place it in a muffle furnace and calcine it at 850°C for 1 hour, with a heating rate of 3°C / min, and then cool it with the furnace.

[0075] Step S5: Weigh 0.4g of analytical grade SnO2 powder and 0.2g of kaolin tailings powder. Mix the calcined powder with SnO2 and kaolin tailings powder and wet ball mill at 200r / min for 12h, then dry. The average particle size of SnO2 is 10μm, and the average particle size of kaolin tailings powder is 20μm.

[0076] Step S6: Take out the powder obtained in step S5, press it into a compact, and sinter it in a high-temperature muffle furnace. The sintering temperature is 1050℃, the heating rate is 3℃ / min, the holding time is 4h, and then the temperature is reduced to 500℃ at a rate of 5℃ / min. Then the furnace is cooled to obtain a multi-mineral microwave dielectric ceramic material.

[0077] The phase content (by mass ratio) of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is: CaMgSi2O6 accounts for 74.0%, and Mg2SiO4 accounts for 26.0%. The relative permittivity of the multi-component mineral microwave dielectric ceramic material obtained in this embodiment is 10.52, the quality factor is 73473GHz, and the temperature coefficient of resonant frequency is -11ppm / ℃.

[0078] Comparative Example 1

[0079] Black talc, wollastonite, and kaolin tailings were crushed and refined to a particle size of less than 45 μm for black talc and wollastonite powder, and less than 25 μm for kaolin tailings powder. 20.8 g of black talc powder, 17.2 g of wollastonite powder, and 0.8 g of analytical grade MgO powder were weighed. The black talc powder was ball-milled at 200 r / min for 5 hours using a wet ball mill. The milling was then paused, and the mill jar was removed. Wollastonite powder was added back into the mill jar, and ball milling continued at 300 r / min for 20 hours. The dried powder was then calcined in a muffle furnace at 850℃ for 3 hours. After calcination, the powder was ball-milled again at 250 r / min for 10 hours using a wet ball mill. After ball milling and drying, the powder is pressed into a compact and then sintered in a high-temperature muffle furnace at a temperature of 1050℃ for 6 hours. The temperature is then reduced to 600℃ at a rate of 10℃ / min and then cooled with the furnace to obtain microwave dielectric ceramic material. The phase content of the ceramic material (by mass ratio) is: CaMgSi2O6 accounts for 72.5%, and Mg2SiO4 accounts for 27.5%.

[0080] Comparative Example 2

[0081] Black talc, wollastonite, and kaolin tailings were crushed and refined to a particle size of less than 45 μm for black talc and wollastonite powder, and less than 25 μm for kaolin tailings powder. 20.8 g of black talc powder, 17.2 g of wollastonite powder, and 0.8 g of analytical grade MgO powder were weighed. The black talc powder and MgO powder were premixed and wet ball-milled at 200 r / min for 5 h. The ball milling was then paused, and the milling jar was removed. Wollastonite powder was added back into the milling jar, and ball milling continued at 300 r / min for 20 h. The dried powder was then calcined in a muffle furnace at 850℃ for 3 h. 0.8 g of analytical grade SnO2 powder and 0.4 g of kaolin tailings powder were weighed. The calcined powder was mixed with the SnO2 powder and wet ball-milled at 250 r / min for 10 h. After ball milling and drying, the powder was pressed into a compact and then sintered in a high-temperature muffle furnace at a temperature of 1150℃ for 6 hours. The temperature was then reduced to 600℃ at a rate of 10℃ / min and then cooled with the furnace to obtain microwave dielectric ceramic material. The phase content of the ceramic material (by mass ratio) was: CaMgSi2O6 accounted for 72.0% and Mg2SiO4 accounted for 28.0%.

[0082] Comparative Example 3

[0083] Black talc, wollastonite, and kaolin tailings were crushed and refined to a particle size of less than 45 μm for black talc and wollastonite powder, and less than 25 μm for kaolin tailings powder. 20.8 g of black talc powder, 17.2 g of wollastonite powder, and 0.8 g of analytical grade MgO powder were weighed. The black talc powder was ball-milled at 200 r / min for 5 hours using a wet ball mill. The milling was then paused, and the mill jar was removed. Wollastonite powder was added back into the mill jar, and the milling continued at 300 r / min for 20 hours. The dried powder was then calcined in a muffle furnace at 850℃ for 3 hours. 0.8 g of analytical grade SnO2 powder and 0.4 g of kaolin tailings powder were weighed. The calcined powder was mixed with the kaolin tailings powder and wet-milled at 250 r / min for 10 hours. After ball milling and drying, the powder was pressed into a compact and then sintered in a high-temperature muffle furnace at a temperature of 1050℃ for 6 hours. The temperature was then reduced to 600℃ at a rate of 10℃ / min and then cooled with the furnace to obtain microwave dielectric ceramic material. The phase content of the ceramic material (by mass ratio) was: CaMgSi2O6 accounted for 72.2%, and Mg2SiO4 accounted for 27.8%.

[0084] Comparative Example 4

[0085] Black talc, wollastonite, and kaolin tailings were crushed and refined to a particle size of less than 45 μm for black talc and wollastonite powder, and less than 25 μm for kaolin tailings powder. 20.8 g of black talc powder, 17.2 g of wollastonite powder, 0.8 g of analytical grade MgO powder, 0.8 g of analytical grade SnO2 powder, and 0.4 g of kaolin tailings powder were weighed and mixed using a wet ball mill. The mixture was first ball-milled at 200 r / min for 5 hours, and then wet-milled at 300 r / min for 20 hours. The dried powder was then calcined in a muffle furnace at 850℃ for 3 hours. The calcined powder was then wet-milled at 250 r / min for 10 hours. After ball milling and drying, the powder was pressed into a compact and sintered in a high-temperature muffle furnace at 1150℃ for 6 hours. Then, it was cooled to 600℃ at a rate of 10℃ / min and then cooled with the furnace to obtain microwave dielectric ceramic material. The phase content of the ceramic material (by mass ratio) is as follows: Ca2MgSi2O7 accounts for 41.6%, CaMgSi2O6 accounts for 30.1%, Mg2SiO4 accounts for 22.3%, CaSiO3 accounts for 2.7%, MgSiO3 accounts for 2.3%, and SiO2 accounts for 1.0%.

[0086] Table 2. Material properties obtained from each embodiment and comparative example.

[0087]

[0088] Table 1 shows the microwave dielectric properties and sintering properties of the multi-component mineral ceramic materials in Examples 1-5 under different formulations and processing conditions. Among them, the ceramic sample prepared in Example 3 has the lowest relative permittivity, the highest quality factor, a near-zero temperature coefficient of resonant frequency, and the lowest sintering temperature, making it the optimal example. The phase composition is as follows: Figure 1 As shown, the main phase is CaMgSi2O6, and the secondary phase is Mg2SiO4. Compared with Example 3, Comparative Example 1 prepared ceramic samples without the addition of MgO, SnO2, and kaolin tailings, as shown. Figure 2 (Example 3) and Figure 3 As shown in Comparative Example 1, the ceramic material prepared in Comparative Example 1 has poor density and many pores, resulting in poor dielectric and sintering properties. Comparative Example 2 prepared a ceramic sample without the addition of kaolin tailings, which exhibited poor sintering properties. Comparative Example 3 prepared a ceramic sample without the addition of MgO and SnO2, which showed generally poor dielectric properties. Comparative Example 4 did not employ a two-stage ball milling process to fully premix the black talc and MgO before combining them with wollastonite, leading to changes in the phase composition, such as... Figure 4 As shown, both dielectric and sintering properties decrease significantly.

Claims

1. A method for preparing a multi-component mineral microwave dielectric ceramic material, characterized in that, Includes the following steps: Step S1: Crush, grind and sieve the black talc, wollastonite and kaolin tailings respectively to obtain black talc powder, wollastonite powder and kaolin tailings powder; Step S2: Weigh out black talc powder and MgO powder according to the proportion, and mix them by ball milling; Step S3: Add wollastonite powder to the product obtained in step S2 and continue ball milling; Step S4: Dry the product obtained in step S3, calcine it, keep it warm, and cool it in the furnace. Step S5: The powder obtained in step S4, SnO2 powder and kaolin tailings powder weighed in proportion are ball-milled and mixed evenly, and then dried. Step S6: Take out the powder obtained in step S5, prepare the powder into a blank and sinter it to obtain a multi-mineral microwave dielectric ceramic material. The multi-mineral microwave dielectric ceramic material is obtained by sintering the following raw materials in parts by weight: 192-224 parts black talc, 160-192 parts wollastonite, 8-12 parts MgO, 4-8 parts SnO2, and 2-4 parts kaolin tailings. The main phase of the multi-mineral microwave dielectric ceramic material is CaMgSi2O6, and the secondary phase is Mg2SiO4, wherein the main phase accounts for 68-74% of the mass and the secondary phase accounts for 26-32% of the mass.

2. The method for preparing a multi-component mineral microwave dielectric ceramic material according to claim 1, characterized in that: The relative permittivity of the multi-mineral microwave dielectric ceramic material is 9.12~10.52, the quality factor is 73473~84624GHz, and the temperature coefficient of resonant frequency is -7~-12ppm / ℃.

3. The method for preparing a multi-component mineral microwave dielectric ceramic material according to claim 1, characterized in that: In step S1, the particle size of the black talc, wollastonite, and kaolin tailings after crushing, grinding, and sieving is less than 45 μm.

4. The method for preparing a multi-component mineral microwave dielectric ceramic material according to claim 1, characterized in that: In step S2, the particle size of MgO is 1~5μm, the ball milling is wet ball milling, the ball milling speed is 150~200r / min, and the ball milling time is 3~5h.

5. The method for preparing a multi-component mineral microwave dielectric ceramic material according to claim 1, characterized in that: In step S3, the ball milling is a wet ball milling process, with a milling speed of 250-300 r / min and a milling time of 16-24 h.

6. The method for preparing a multi-component mineral microwave dielectric ceramic material according to claim 1, characterized in that: In step S4, the calcination temperature is 750–900℃, and the holding time is 1–3 hours.

7. The method for preparing a multi-component mineral microwave dielectric ceramic material according to claim 1, characterized in that: In step S5, the ball milling is a wet ball milling process, with a milling speed of 200-250 r / min and a milling time of 8-12 h; the particle size of SnO2 is 5-20 μm, and the particle size of kaolin tailings powder is less than 25 μm.

8. The method for preparing a multi-component mineral microwave dielectric ceramic material according to claim 1, characterized in that: In step S6, the sintering temperature is 1050~1150℃, and after sintering, the temperature is held for 4~6 hours, and then the temperature is reduced to 500~600℃ at a rate of 5~10℃ / min, followed by furnace cooling.

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