High-dielectric yttrium iron garnet ferrite material and preparation method thereof

Abstract

The invention belongs to the field of electronic information functional materials and microelectronic devices, and provides a high-dielectric yttrium iron garnet ferrite material and a preparation method thereof, the chemical formula of the high-dielectric yttrium iron garnet ferrite material is Y < 2.1-x > Bi < 0.9 > Ca < x > Zr < x > Fe < 5-x > O < 12 >, and x is greater than or equal to 0.15 and less than or equal to 0.25. The performance of the YIG ferrite material is regulated and controlled through Bi < 3 + >-Ca < 2 + >-Zr < 4 + > ion combined substitution, the relative dielectric constant epsilon r of a traditional yttrium iron garnet ferrite material is increased to 18-23, the saturation magnetization 4 pi Ms is 1680-1950 Gs, meanwhile, the ferromagnetic resonance line width delta H is finally kept at a small value of 40-80 Oe, and the ferrite material has a wide application prospect. The development of miniaturization, light weight and high integration of microwave devices is facilitated; the material is rich in raw materials, low in cost and beneficial to industrial application, and has important application prospects in the fields of microwave communication, radar systems, satellite communication and the like.

Description

Technical Field

[0001] The present invention belongs to the field of electronic information functional materials and microelectronic devices, and specifically provides a high-dielectric yttrium iron garnet ferrite material and a preparation method thereof, which are applied to small and lightweight microwave gyromagnetic ferrite devices such as circulators / isolators required by radar systems, 5G communication devices, etc. Background Art

[0002] Due to its unique and excellent properties, such as low ferromagnetic resonance linewidth, low dielectric loss, high resistivity, high Curie temperature, etc., yttrium iron garnet ferrite material has become the core material for the design of microwave band devices. With the development of 5G communication, radar and future 6G technologies, the demand for small and lightweight microwave ferrite devices, the gyromagnetic YIG material with high dielectric constant and low loss is the key material to meet this development demand.

[0003] According to the microwave transmission theory, when electromagnetic waves propagate in a dielectric material, the following relationship exists between the dielectric wavelength and the dielectric constant:

[0004]

[0005] where ε r is the microwave dielectric constant of the material, ε0 is the vacuum dielectric constant, μ0 is the vacuum permeability, and λ0 is the wavelength of electromagnetic waves in vacuum. According to the above formula, the relationship between the wavelength of electromagnetic waves in the medium and the dielectric constant of the material can be obtained. Therefore, the key to reducing the size of microwave devices and realizing their miniaturization lies in increasing the dielectric constant of the material. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-dielectric yttrium iron garnet ferrite material and a preparation method thereof, which can increase the microwave dielectric constant from the traditional 13 - 15 to 18 - 23 to meet the requirements of small and lightweight microwave gyromagnetic ferrite devices.

[0007] To achieve the above invention purpose, the technical scheme adopted by the present invention is as follows:

[0008] A high-dielectric yttrium iron garnet ferrite material, the chemical formula of the high-dielectric yttrium iron garnet ferrite material is expressed as Y 2.1-x Bi 0.9 Ca x Zr x Fe 5-x O 12 , 0.15 ≤ x ≤ 0.25.

[0009] As a preferred embodiment, the high-dielectric yttrium iron garnet ferrite material has a garnet structure and is formed by sintering raw materials Y2O3, Bi2O3, CaCO3, Fe2O3 and ZrO2 at 1120 °C.

[0010] As a preferred embodiment, the relative dielectric constant ε of the high-dielectric yttrium iron garnet ferrite material r is 18 - 23, the saturation magnetization 4πM s is 1680 - 1950 Gs, and the ferromagnetic resonance linewidth ΔH is 40 - 80 Oe.

[0011] The second object of the present invention is to provide a method for preparing a high-dielectric yttrium iron garnet ferrite material, comprising the following steps:

[0012] Step 1: Weigh Y2O3, Bi2O3, CaCO3, Fe2O3, and ZrO2 as raw materials according to the stoichiometric ratio of the chemical formula Y 2.1-x Bi 0.9 Ca x Zr x Fe 5-x O 12 , where 0.15 ≤ x ≤ 0.25, to obtain a mixed raw material A;

[0013] Step 2: Wet ball-mill the mixed raw material A weighed in Step 1. Place the raw material A and the ball-milling medium in a ball mill for ball milling to obtain a first mixed slurry B;

[0014] Step 3: Dry the first mixed slurry B obtained in Step 2, and then grind and screen the dried mixed material to obtain a dry first mixed powder C;

[0015] Step 4: Calcinate the first mixed powder C obtained in Step 3 at 850 °C for 6 hours to cause the first mixed powder C to undergo a pre-calcination reaction and obtain a pre-calcined powder D;

[0016] Step 5: Wet ball-mill the pre-calcined powder D obtained in Step 4. Place the pre-calcined powder D, the ball-milling medium, and a dispersant in a ball mill for ball milling to obtain a second mixed slurry E;

[0017] Step 6: Dry, grind, granulate, and screen the second mixed slurry E obtained in Step 5, and then press the collected particles to form a green body;

[0018] Step 7: Place the green body obtained in Step 6 in a vacuum sintering furnace and sinter it at a temperature of 1120 °C in a vacuum environment for 6 hours to prepare a Y 2.1-x Bi 0.9 Ca x Zr x Fe 5-x O 12 high-dielectric yttrium iron garnet ferrite material.

[0019] As a preferred embodiment, in Steps 2 and 5, wet ball milling is carried out in an oxidation atmosphere using non-polar solvent toluene as a dispersant and zirconia balls as a ball milling medium; wherein, the mass ratio of powder: non-polar solvent: zirconia balls is 1: 1.8: 6, the rotational speed of the ball mill is 260 rad / min, and the ball milling time is 12 to 14 hours.

[0020] As a preferred embodiment, in Steps 3 and 6, the drying temperature of the slurry is 130 °C.

[0021] As a preferred embodiment, in Step 4, the temperature change rate of calcination is 2 °C / min.

[0022] As a preferred embodiment, in Step 6, the granulating agent is polyvinyl alcohol solution PVA, and the mass fraction of the PVA solution is 8%; in the sieving step, the particles formed after granulation are sieved, and the powder particles between 40 mesh and 100 mesh are collected.

[0023] As a preferred embodiment, in Step 7, first evacuate to (3-5) × 10 -2 Torr, and the heating rate is 1.7-2 °C / min; the specific sintering curve is: first heat up to 100 °C at 1.7 °C / min, during which the moisture in the material is discharged, then heat up to 300 °C at 2 °C / min and keep it at this temperature for 2 hours for degumming, then heat up to 1120 °C at 2 °C / min and keep it for 6 hours, cool down to 800 °C at 2 °C / min, and then cool naturally to room temperature.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The present invention provides a high-dielectric yttrium iron garnet ferrite material. By jointly substituting Bi 3+ -Ca 2+ -Zr 4+ ions, the performance of the YIG ferrite material is regulated. The relative dielectric constant ε of the traditional yttrium iron garnet ferrite material r is increased to 18-23, the saturation magnetization intensity 4πM s is 1680-1950 Gs, and at the same time the ferromagnetic resonance linewidth ΔH finally also remains at a relatively small value of 40-80 Oe, which is conducive to the development of microwave devices in the direction of miniaturization, light weight and high integration; in addition, the present invention also provides a preparation method for the high-dielectric yttrium iron garnet ferrite material, which has rich raw materials and low cost, is conducive to industrial application, and has important application prospects in the fields of microwave communication, radar systems, satellite communication, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1This is the micrograph of the high-dielectric yttrium iron garnet ferrite material prepared in Examples 1 to 3 of the present invention. Among them, (a) is Example 1, (b) is Example 2, and (c) is Example 3. Detailed implementation manners

[0027] To make the objectives, technical solutions and beneficial effects of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0028] The embodiment provides a high-dielectric yttrium iron garnet ferrite material, and the chemical formula of the high-dielectric yttrium iron garnet ferrite material is expressed as Y 2.1-x Bi 0.9 Ca x Zr x Fe 5-x O 12 , 0.15 ≤ x ≤ 0.25.

[0029] The high-dielectric yttrium iron garnet ferrite material has a garnet structure and is formed by sintering raw materials Y2O3, Bi2O3, CaCO3, Fe2O3 and ZrO2 at 1120 °C.

[0030] The relative dielectric constant ε of the high-dielectric yttrium iron garnet ferrite material r is 18 to 23, the saturation magnetization intensity 4πM s is 1680 to 1950 Gs, and the ferromagnetic resonance linewidth ΔH is 40 to 80 Oe.

[0031] Example 1

[0032] This example provides a high-dielectric yttrium iron garnet ferrite material, expressed as Y 1.95 Bi 0.9 Ca 0.15 Zr 0.15 Fe 4.85 O 12 , and is specifically prepared by the following steps:

[0033] Step 1: Weigh a total of 40 g of raw materials LY2O3, Bi2O3, CaCO3, Fe2O3, ZrO2 according to the stoichiometric ratio of the molecular formula Y 1.95 Bi 0.9 Ca 0.15 Zr0.15Fe 4.85 O 12 , and the purity of the raw materials is greater than 99%;

[0034] Step 2: Wet ball-mill the mixed raw material A weighed in Step 1. Place the raw material A and the ball-milling medium in a ball mill for ball milling. The specific process is as follows: Use a non-polar solvent such as toluene as a dispersant and zirconia balls as the ball-milling medium, and carry out the process in an oxidizing atmosphere. Among them, the mass ratio of powder: non-polar solvent: zirconia balls is 1:1.8:6, the rotational speed of the ball mill is 260 rad / min, and the ball-milling time is 12 hours to obtain the first mixed slurry B;

[0035] Step 3: Dry the first mixed slurry B obtained in Step 2 at 130 °C, then grind the dried mixed material, and then perform screening treatment through a 100-mesh standard sieve to obtain the dried first mixed powder C;

[0036] Step 4: Calcinate the first mixed powder C obtained in Step 3 at 850 °C for 6 hours, and the temperature change rate is 2 °C / min, so that the first mixed powder undergoes a pre-burning reaction to obtain the pre-burned powder D;

[0037] Step 5: Wet ball-mill the pre-burned powder D obtained in Step 4. Place the pre-burned powder D and the ball-milling medium in a ball mill for ball milling; the specific process is as follows: Use a non-polar solvent such as toluene as a dispersant and zirconia balls as the ball-milling medium, or carry out the process in an oxidizing atmosphere. Among them, the mass ratio of powder: non-polar solvent: zirconia balls is 1:1.8:6, the rotational speed of the ball mill is 260 rad / min, and the ball-milling time is 14 hours to obtain the second mixed slurry E;

[0038] Step 6: After drying the second mixed slurry E obtained in Step 5 at 130 °C, grind it, then add a PVA solution with a mass fraction of 8% for granulation, sieve it using a standard sieve, collect the powder particles between 40 mesh and 100 mesh, and then press the collected particles into ring-shaped and cylindrical green compacts;

[0039] Step 7: Place the green compact obtained in Step 6 in a vacuum sintering furnace, first evacuate to (3 - 5)×10 -2 Torr, and the heating rate is 1.7 - 2 °C / min. The specific sintering curve is as follows: First, heat up to 100 °C at a rate of 1.7 °C / min. During this process, the moisture in the material is discharged. Then, heat up to 300 °C at a rate of 2 °C / min and hold at this temperature for 2 hours for degumming. Subsequently, heat up to 1120 °C at a rate of 2 °C / min and hold for 6 hours, cool down to 800 °C at a rate of 2 °C / min, and then naturally cool to room temperature to obtain the Y 1.95 Bi 0.9 Ca 0.15 Zr0.15Fe 4.85 O 12 high-dielectric yttrium iron garnet ferrite material.

[0040] Example 2

[0041] This embodiment provides a high-dielectric yttrium iron garnet ferrite material, denoted as Y 1.9 Bi 0.9 Ca 0.2 Zr 0.2 Fe 4.8 O 12 , and it is specifically prepared by the following steps:

[0042] Step 1: According to the stoichiometric ratio of the molecular formula Y 1.9 Bi 0.9 Ca 0.2 Zr 0.2 Fe 4.8 O 12 , weigh a total of 40 g of raw materials LY2O3, Bi2O3, CaCO3, Fe2O3, and ZrO2, and the purity of the raw materials is greater than 99%;

[0043] Step 2: Wet ball mill the mixed raw material A weighed in Step 1. Place the raw material A and the ball milling medium in a ball mill for ball milling. The specific process is as follows: Use a non-polar solvent such as toluene as a dispersant and zirconia balls as the ball milling medium, or carry out the ball milling in an oxidizing atmosphere. Among them, the mass ratio of powder: non-polar solvent: zirconia balls is 1:1.8:6, the rotation speed of the ball mill is 260 rad / min, and the ball milling time is 12 hours to obtain the first mixed slurry B;

[0044] Step 3: Dry the first mixed slurry B obtained in Step 2 at 130 °C, then grind the dried mixed material, and then screen it through a 100-mesh standard sieve to obtain the dried first mixed powder C;

[0045] Step 4: Calcinate the first mixed powder C obtained in Step 3 at 850 °C for 6 hours, and the temperature change rate is 2 °C / min to cause the first mixed powder to undergo a pre-calcination reaction to obtain the pre-calcined powder D;

[0046] Step 5: Wet ball mill the pre-calcined powder D obtained in Step 4. Place the pre-calcined powder D and the ball milling medium in a ball mill for ball milling; the specific process is as follows: Use a non-polar solvent such as toluene as a dispersant and zirconia balls as the ball milling medium, or carry out the ball milling in an oxidizing atmosphere. Among them, the mass ratio of powder: non-polar solvent: zirconia balls is 1:1.8:6, the rotation speed of the ball mill is 260 rad / min, and the ball milling time is 14 hours. Obtain the second mixed slurry E;

[0047] Step 6: The second mixed slurry E obtained in Step 5 is dried at 130 °C and then ground. Subsequently, a PVA solution with a mass fraction of 8% is added for granulation, and then it is sieved using a standard sieve. The powder particles between 40 mesh and 100 mesh are collected. Subsequently, the collected particles are pressed into ring-shaped and cylindrical green compacts;

[0048] Step 7: The green compact obtained in Step 6 is placed in a vacuum sintering furnace. First, it is evacuated to (3 - 5)×10 -2 Torr, and the heating rate is 1.7 - 2 °C / min. The specific sintering curve is as follows: First, it is heated to 100 °C at a rate of 1.7 °C / min. During this process, the moisture in the material is discharged. Then, it is heated to 300 °C at a rate of 2 °C / min and held at this temperature for 2 hours for degumming. Subsequently, it is heated to 1120 °C at a rate of 2 °C / min and held for 6 hours, cooled to 800 °C at a rate of 2 °C / min, and then naturally cooled to room temperature to obtain Y 1.9 Bi 0.9 Ca 0.2 Zr 0.2 Fe 4.8 O 12 high-dielectric yttrium iron garnet ferrite material.

[0049] Example 3

[0050] This example provides a high-dielectric yttrium iron garnet ferrite material, denoted as Y 1.85 Ca 0.25 Bi 0.9 Zr 0.25 Fe 4.75 O 12 , which is specifically prepared by the following steps:

[0051] Step 1: According to the stoichiometric ratio of the molecular formula Y 1.85 Ca 0.25 Bi 0.9 Zr 0.25 Fe 4.75 O 12 , 40 g of raw materials LY2O3, Bi2O3, CaCO3, Fe2O3, and ZrO2 are weighed. The purity of the raw materials is greater than 99%;

[0052] Step 2: The mixed raw material A weighed in Step 1 is wet ball-milled. The raw material A and the ball-milling medium are placed in a ball mill for ball-milling. The specific process is as follows: A non-polar solvent such as toluene is used as a dispersant, and zirconia balls are used as the ball-milling medium, or it is carried out in an oxidizing atmosphere. Among them, the mass ratio of the powder: non-polar solvent: zirconia balls is 1:1.8:6. The rotation speed of the ball mill is 260 rad / min, and the ball-milling time is 12 hours to obtain the first mixed slurry B;

[0053] Step 3: Dry the first mixed slurry B obtained in Step 2 at 130°C, then grind the dried mixed material, and then perform screening through a 100-mesh standard sieve to obtain a dry first mixed powder C;

[0054] Step 4: Calcinate the first mixed powder C obtained in Step 3 at 850°C for 6 hours, with a temperature change rate of 2°C / min, so that the first mixed powder undergoes a pre-calcination reaction to obtain a pre-calcined powder D;

[0055] Step 5: Perform wet ball milling on the pre-calcined powder D obtained in Step 4, and place the pre-calcined powder D and the ball milling medium in a ball mill for ball milling; the specific process is as follows: Use a non-polar solvent such as toluene as a dispersant and zirconia balls as the ball milling medium, or perform it in an oxidizing atmosphere. Among them, the mass ratio of powder: non-polar solvent: zirconia balls is 1:1.8:6, the rotation speed of the ball mill is 260 rad / min, and the ball milling time is 14 hours. Obtain a second mixed slurry E;

[0056] Step 6: Dry the second mixed slurry E obtained in Step 5 at 130°C and then grind it, then add a PVA solution with a mass fraction of 8% for granulation, then use a standard sieve for screening, collect the powder particles between 40 meshes and 100 meshes, and then press the collected particles into ring-shaped and cylindrical green compacts;

[0057] Step 7: Place the green compact obtained in Step 6 in a vacuum sintering furnace, first evacuate to (3 - 5)×10 -2 Torr, and the heating rate is 1.7 - 2°C / min. The specific sintering curve is as follows: First, heat up to 100°C at a rate of 1.7°C / min, during which the moisture in the material is discharged, then heat up to 300°C at a rate of 2°C / min and hold at this temperature for 2 hours for debinding, then heat up to 1120°C at a rate of 2°C / min and hold for 6 hours, cool down to 800°C at a rate of 2°C / min, and then naturally cool to room temperature to obtain a Y 1.85 Ca 0.25 Bi 0.9 Zr 0.25 Fe 4.75 O 12 high-dielectric yttrium iron garnet ferrite material.

[0058] Perform microscopic morphology, magnetic properties, and microwave dielectric properties tests on the Y 1.85 Ca 0.25 Bi 0.9 Zr 0.25 Fe 4.75 O 12 high-dielectric yttrium iron garnet ferrite materials prepared in the above Examples 1 to 3. The SEM images are as Figure 1 shown, and the test results of magnetic properties and microwave dielectric properties are shown in Table 1.

[0059] Table 1

[0060] Number Chemical composition <![CDATA[ε r > <![CDATA[4πM s (Gs)]]> ΔH (Oe) Example 1 <![CDATA[Y 1.95 Bi 0.9 Ca 0.15 Zr 0.15 Fe 4.85 O 12 > 18.89 1679 275 Example 2 <![CDATA[Y 1.9 Bi 0.9 Ca 0.2 Zr 0.2 Fe 4.8 O 12 > 19.61 1760 120 Example 3 <![CDATA[Y 1.85 Ca 0.25 Bi 0.9 Zr 0.25 Fe 4.75 O 12 > 19.93 1920 80

[0061] From Figure 1 It can be seen that when the doping amount of Zr 4+ ions is x = 0.15, the grains are mainly large grains, mixed with many small grains, and the grain distribution is extremely uneven. As the doping amount of Zr 4+ ions increases, the grains gradually become finer. When the doping amount reaches x = 0.20, the small grains become the main grains, and the grain distribution is basically uniform, with only a small number of large-sized grains remaining. When the doping amount x = 0.25, the grains are completely refined, all being small grains, the grain distribution is uniform, the grain boundaries are obvious, and the sintering is dense.

[0062] As can be seen from Table 1, the present invention effectively improves the dielectric constant and saturation magnetization of yttrium iron garnet ferrite materials. Among them, in Example 3, Y 1.85 Ca 0.25 Bi 0.9 Zr 0.25 Fe 4.75 O 12 The dielectric constant of the high-dielectric yttrium iron garnet ferrite material is the largest, being 19.93, the saturation magnetization is also the largest, being 1920 Gs, and the ferromagnetic resonance linewidth also remains at a relatively low value, being 80 Oe.

[0063] In summary, the present invention provides a high-dielectric yttrium iron garnet ferrite material and a preparation method thereof. By jointly substituting Bi 3+ -Ca 2+ -Zr 4+ ions, the performance of the YIG ferrite material is regulated, and the relative dielectric constant ε r of the traditional yttrium iron garnet ferrite material is increased to 19.9, the saturation magnetization 4πM s is 1920 Gs, and at the same time, the ferromagnetic resonance linewidth ΔH finally remains at a relatively small value of 80 Oe, which is beneficial to the development of microwave devices in the direction of miniaturization, lightweight, and high integration.

[0064] The above is only the specific implementation manner of the present invention. Any feature disclosed in this specification, unless specifically described, can be replaced by other equivalent or similar-purpose alternative features; all the features disclosed, or all the steps in any method or process, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A high dielectric yttrium iron garnet ferrite material, characterized in that: The chemical formula of the high dielectric yttrium iron garnet ferrite material is Y 2.1-x Bi 0.9 Ca x Zr x Fe 5-x O 12 , 0.15≤x≤0.

25.

2. The high dielectric yttrium iron garnet ferrite material according to claim 1, characterized in that: The high dielectric yttrium iron garnet ferrite material has a garnet structure and is formed by sintering raw materials Y2O3, Bi2O3, CaCO3, Fe2O3 and ZrO2 at 1120°C.

3. The high dielectric yttrium iron garnet ferrite material according to claim 1, characterized in that: The relative dielectric constant ε of the high dielectric yttrium iron garnet ferrite material is r 18~23, saturation magnetization 4πM s It is 1680~1950Gs, and the ferromagnetic resonance linewidth ΔH is 40~80Oe.

4. The method for preparing the high dielectric yttrium iron garnet ferrite material according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Use Y2O3, Bi2O3, CaCO3, Fe2O3 and ZrO2 as raw materials, according to the molecular formula Y 2.1-x Bi 0.9 Ca x Zr x Fe 5-x O 12 The stoichiometric ratio is weighed, wherein 0.15≤x≤0.25, to obtain a mixed raw material A; Step 2, wet-milling the mixed raw material A weighed in step 1, placing the raw material A and the ball milling medium in a ball mill to obtain a first mixed slurry B; Step 3, drying the first mixed slurry B obtained in step 2, and then grinding and sieving the dried mixed material to obtain a dried first mixed powder C; Step 4, calcining the first mixed powder C obtained in step 3 at 850° C. for 6 hours to allow the first mixed powder C to undergo a pre-calcination reaction to obtain a pre-calcined powder D; Step 5, wet-milling the pre-burned powder D obtained in step 4, placing the pre-burned powder D, a ball milling medium, and a dispersant in a ball mill to obtain a second mixed slurry E; Step 6, drying, grinding, granulating, and sieving the second mixed slurry E obtained in step 5, and then pressing the collected particles to form a green body; Step 7: Place the green body obtained in step 6 in a vacuum sintering furnace and sinter at 1120°C for 6 hours in a vacuum environment to prepare Y 2.1-x Bi 0.9 Ca x Zr x Fe 5-x O 12 High dielectric yttrium iron garnet ferrite material.

5. The method for preparing the high dielectric yttrium iron garnet ferrite material according to claim 4, characterized in that: In step 2 and step 5, wet ball milling uses non-polar solvent toluene as dispersant and zirconium dioxide balls as ball milling media in an oxidizing atmosphere; wherein the mass ratio of powder: non-polar solvent: zirconium dioxide balls is 1:1.8:6, the ball mill speed is 260 rad / min, and the ball milling time is 12 and 14 hours.

6. The method for preparing the high dielectric yttrium iron garnet ferrite material according to claim 4, characterized in that: In step 3 and step 6, the slurry drying temperature is 130°C.

7. The method for preparing the high dielectric yttrium iron garnet ferrite material according to claim 4, characterized in that: In step 4, the temperature change rate of calcination is 2°C / min.

8. The method for preparing the high dielectric yttrium iron garnet ferrite material according to claim 4, characterized in that: In step 6, the granulating agent is polyvinyl alcohol solution PVA, and the mass fraction of the PVA solution is 8%; in the sieving step, the particles formed after granulation are sieved to collect powder particles between 40 mesh and 100 mesh.

9. The method for preparing a high dielectric yttrium iron garnet ferrite material according to claim 4, characterized in that: In step 7, first evacuate to (3-5)×10 -2 The specific sintering curve is: firstly, the temperature is increased to 100°C at 1.7°C / min, during which the moisture in the material is discharged, then the temperature is increased to 300°C at 2°C / min and kept at this temperature for 2 hours for debinding, then the temperature is increased to 1120°C at 2°C / min and kept at this temperature for 6 hours, then the temperature is decreased to 800°C at 2°C / min, and then naturally cooled to room temperature.

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