Preparation method of yttrium iron garnet ferrite with high medium saturation magnetization

Abstract

A method for preparing high-dielectric, moderately saturated magnetized yttrium iron garnet ferrite belongs to the field of microwave and magnetic materials technology. This invention utilizes a method that substitutes the dodecahedral Y-site in the garnet structure. 3+ Octahedral and tetrahedral Fe 3+ The formulation and secondary granulation process result in a material with moderate saturation magnetization (1050G < 4πMs < 1250G), suitable for low-frequency microwave ferrite devices. It also possesses high dielectric constant ε' > 20, low ferromagnetic resonance linewidth ΔH ≤ 24Oe, and low dielectric loss tanδ. ε <1×10 ‑4 This can reduce the design size of the device, which is beneficial for the miniaturization and weight reduction of microwave ferrite devices.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave and magnetic materials, and particularly relates to a preparation method of a high-dielectric-constant medium-saturation-magnetization yttrium iron garnet ferrite. BACKGROUND

[0002] In recent years, with the rapid development of 5G communication technology, microwave ferrite devices show a trend of miniaturization and integration. How to design and manufacture small, low-cost and high-performance microwave ferrite devices has become an urgent problem to be solved. Traditional yttrium iron garnet ferrite has low loss and high resistivity, and is widely used in microwave ferrite devices such as circulators, phase shifters and isolators. However, due to its low dielectric constant, it is difficult to meet the urgent needs of the development of current microwave ferrite devices. Therefore, how to prepare yttrium iron garnet ferrite with high dielectric constant has become a key problem that must be solved for the further development of microwave ferrite devices.

[0003] CN116409988A disclosed a high-dielectric-constant medium-saturation-magnetization garnet ferrite material on April 12, 2023, with the chemical formula Bi a Ca b Y c Zr d V e Fe 5-d-e-δ O 12 , wherein 0≤a≤1.2, 0≤b≤1.46, 0.34≤c≤1.8, 0≤d≤0.45, 0≤e≤0.505, 0≤δ≤0.3, and δ is the iron deficiency. The dielectric constant of the garnet ferrite material is 23-25, and it also has medium saturation magnetization (1050-1250G), low ferromagnetic resonance line width (as low as 30Oe), low dielectric loss (as low as 2.0x10 -4 , and Curie temperature up to 205℃. Although the material has a high dielectric constant, the ferromagnetic resonance line width is high, the dielectric loss is high, and the sintering process is complex, requiring multiple holding at high temperature and a long holding time after reaching the sintering temperature.

[0004] CN114477995B disclosed a medium-saturation-magnetization power-type high-dielectric-constant garnet material on February 23, 2022, belonging to the field of microwave ferrite materials, with the chemical formula Bi a Ca b Dy c Y 3-a-b-c Fe 5-d-e-f-g-h-δ Zr d V e Sn f In g Sb h O 12Where 1.0≤a≤1.7, 1≤b≤2, 0≤c≤0.2, 0≤d≤0.7, 0≤e≤0.7, 0≤f≤0.3, 0≤g≤0.2, 0≤h≤0.1, and δ represents the iron deficiency. This garnet ferrite material has a dielectric constant of 25-26 and also exhibits moderate saturation magnetization (1050-1250G), with a ferromagnetic resonance linewidth as low as 23Oe. Although the material has good magnetic properties, the introduction of rare earth ions into the formulation increases the material cost. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by proposing a method for preparing yttrium iron garnet ferrite with high dielectric strength and moderate saturation magnetization. This invention utilizes a method that substitutes the dodecahedral Y-site in the garnet structure. 3+ Octahedral and tetrahedral Fe 3+ The formulation and secondary granulation process result in a material with moderate saturation magnetization (1050G < 4πMs < 1250G), suitable for low-frequency microwave ferrite devices. It also possesses high dielectric constant (ε' > 20), low ferromagnetic resonance linewidth (ΔH ≤ 24Oe), and low dielectric loss (tanδ). ε <1×10 -4 This can reduce the design size of the device, which is beneficial for the miniaturization and weight reduction of microwave ferrite devices.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing high dielectric medium yttrium iron garnet ferrite includes the following steps:

[0008] Step 1, Raw material pretreatment:

[0009] Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 were used as raw materials. The raw materials were placed in an oven and dried at 100℃ for 6 hours.

[0010] Step 2, Weighing:

[0011] According to the chemical formula Y 3-x-y-z-2a Bi x Ca y+z+2a Zr y Sn z V a Fe 5-y-z-a O 12 Calculate and weigh the raw materials Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 after step 1 treatment according to the stoichiometric ratio; where 1.0≤x≤1.3, 0.1≤y≤0.6, 0.1≤z≤0.6, and 0≤a≤0.7.

[0012] Step 3, primary ball milling:

[0013] The powder weighed in step 2 is added to deionized water and a dispersant for primary ball milling, the ball mill speed is 200-210 rpm, and the ball milling time is 4-15 h;

[0014] Step 4, pre-sintering:

[0015] The primary ball-milled material obtained in step 3 is dried and then pre-sintered at a temperature of 800-900 °C for 4-10 h;

[0016] Step 5, secondary ball milling:

[0017] The pre-sintered material obtained in step 4 is added to deionized water for secondary ball milling, the secondary ball milling time is 10-20 h, and the ball mill speed is 200-210 rpm;

[0018] Step 6, primary granulation:

[0019] The secondary ball-milled material obtained in step 5 is dried and then added to a binder for primary granulation;

[0020] Step 7, primary pre-pressing:

[0021] The powder obtained in step 6 is pressed into a green body at 5 MPa, and the green body is placed in an oven for drying;

[0022] Step 8, secondary granulation:

[0023] The green body obtained in step 7 is ground and added to a binder for secondary granulation;

[0024] Step 9, secondary pre-forming:

[0025] The powder obtained in step 8 is pressed into a green body at 5 MPa, the green body is ground and passed through a 40-mesh sieve;

[0026] Step 10, forming:

[0027] The powder obtained in step 9 is pressed into a green body at 110 MPa;

[0028] Step 11, sintering:

[0029] The green body obtained in step 10 is sintered at a temperature of 1020-1060 °C for more than 10 h, and then naturally cooled to room temperature to obtain the yttrium iron garnet ferrite material.

[0030] Further, the purity of each raw material in step 1 is as follows: Y2O3 purity 99.99%, Fe2O3 purity 99.6%, CaCO3 purity 99.11%, SnO2 purity 99.84%, Bi2O3 purity 99%, ZrO2 purity 99%, and V2O5 purity 99%.

[0031] Further, in step 3, the mass ratio of balls, material, deionized water and dispersant is (3.5-3.7):1:(0.8-0.9):0.002.

[0032] Further, in step 4, the pre-burning process is a segmented pre-burning process, and the specific process is as follows: starting from room temperature, the temperature is raised to 200℃ for 2h, then the temperature is raised to the target pre-burning temperature (800-900℃) at a temperature raising rate of 2℃ / min, and the temperature is kept constant, and then the temperature is naturally lowered after the temperature keeping is finished.

[0033] Further, in step 5, the mass ratio of balls, material and deionized water is 3.5:1:0.8, and no dispersant is added.

[0034] Further, the adhesive in steps 6 and 8 is a polyvinyl alcohol (PVA) aqueous solution with a concentration of 5wt%-15wt%, and the mass of the adhesive added in steps 6 and 8 is the same, which is 4.0wt% of the mass of the secondary ball-milled material.

[0035] Further, in step 7, the oven temperature is 120℃, and the drying time is 1h.

[0036] Further, in step 11, the specific process of sintering is as follows: starting from room temperature, the temperature is raised to 400℃ for 2h 40min, and the temperature is kept constant for 1h; then the temperature is raised to 800℃ for 4h, and the temperature is kept constant for 2h; then the temperature is raised to 900℃ for 1h, and the temperature is kept constant for 2h; finally, the temperature is raised to the sintering temperature at a temperature raising rate of 1.5℃ / min, and the temperature is kept constant for more than 10h, and then the temperature is naturally lowered after the temperature keeping is finished.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] The preparation method of the yttrium iron garnet ferrite provided by the present application has the following advantages: the preparation process is secondary granulation, the material granulation effect is good, the adhesive is mixed uniformly, the material has good magnetic properties, has a medium saturation magnetization (1050G ε <1×10 -4 ) and a high Curie temperature (T c(>200℃), which can effectively solve the problems of miniaturization and integration of current microwave ferrite devices; at the same time, it adopts a formula without rare earth ion substitution, resulting in lower overall cost. Attached Figure Description

[0039] Figure 1 The image shows the XRD results of the phase analysis of the ferrite material in Example 1.

[0040] Figure 2 The image shows the SEM results of the phase analysis of the ferrite material in Example 1.

[0041] Figure 3 The image shows the XRD results of the phase analysis of the ferrite material in Example 2.

[0042] Figure 4 The image shows the SEM results of the phase analysis of the ferrite material in Example 2.

[0043] Figure 5 The image shows the XRD results of the phase analysis of the ferrite material in Example 3.

[0044] Figure 6 The image shows the SEM results of the phase analysis of the ferrite material in Example 3. Detailed Implementation

[0045] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0046] Example 1

[0047] A method for preparing high dielectric medium yttrium iron garnet ferrite includes the following steps:

[0048] Step 1, Raw material pretreatment:

[0049] Using Y2O3 with a purity of 99.99%, Fe2O3 with a purity of 99.6%, CaCO3 with a purity of 99.11%, SnO2 with a purity of 99.84%, Bi2O3 with a purity of 99%, ZrO2 with a purity of 99%, and V2O5 with a purity of 99% as raw materials, the raw materials were placed in an oven and dried at 100℃ for 6 hours.

[0050] Step 2, Weighing:

[0051] According to the chemical formula Y 3-x-y-z-2a Bi x Ca y+z+2a Zr y Sn z V a Fe 5-y-z-a O 12The Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 raw materials after step 1 treatment were calculated and weighed according to the stoichiometric ratio, wherein x = 1.0, y = 0.3, z = 0.45, a = 0.35;

[0052] Step 3, primary ball milling:

[0053] The powder weighed in step 2 was added to deionized water and a dispersant for primary ball milling, and the mass ratio of ball:powder:deionized water:dispersant was 3.7:1:0.9:0.002, the ball mill speed was 210 rpm, and the ball milling time was 6 h;

[0054] Step 4, pre-sintering:

[0055] After drying the primary ball-milled material obtained in step 3, pre-sintering was performed at a temperature of 820°C for 4 h;

[0056] Step 5, secondary ball milling:

[0057] The pre-sintered material obtained in step 4 was added to deionized water for secondary ball milling, and the secondary ball milling time was 15 h at a ball mill speed of 210 rpm;

[0058] Step 6, primary granulation:

[0059] The secondary ball-milled material obtained in step 5 was dried and added to a binder for primary granulation;

[0060] Step 7, primary pre-pressing:

[0061] The powder obtained in step 6 was pressed into a green body at 5 MPa, and the green body was placed in an oven for drying;

[0062] Step 8, secondary granulation:

[0063] The green body obtained in step 7 was ground and added to a binder for secondary granulation;

[0064] Step 9, secondary pre-forming:

[0065] The powder obtained in step 8 was pressed into a green body at 5 MPa, the green body was ground and passed through a 40-mesh sieve;

[0066] Step 10, forming:

[0067] The powder obtained in step 9 was pressed into a green body at 110 MPa;

[0068] Step 11, sintering:

[0069] Sintering the green body obtained in step 10, the sintering process is: from room temperature to 400℃ for 2h 40min, holding for 1h; then to 800℃ for 4h, holding for 2h; then to 900℃ for 1h, holding for 2h; finally to the sintering temperature 1060℃ at a heating rate of 1.5℃ / min, holding for 10h or more, and then naturally cooling down, to obtain the yttrium iron garnet ferrite material

[0070] Example 2

[0071] A method for preparing a yttrium iron garnet ferrite with high medium saturation magnetization, comprising the following steps:

[0072] Step 1, raw material pretreatment:

[0073] Y2O3 with a purity of 99.99%, Fe2O3 with a purity of 99.6%, CaCO3 with a purity of 99.11%, SnO2 with a purity of 99.84%, Bi2O3 with a purity of 99%, ZrO2 with a purity of 99% and V2O5 with a purity of 99% are used as raw materials, and the raw materials are placed in an oven for drying, with a temperature of 100℃ and a time of 6h;

[0074] Step 2, weighing:

[0075] According to the stoichiometric ratio of the chemical formula Y 3-x-y-z-2a Bi x Ca y+z+2a Zr y Sn z V a Fe 5-y-z-a O 12 , the Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 raw materials treated in step 1 are calculated and weighed; wherein x=1.0, y=0.45, z=0.1, a=0.5;

[0076] Step 3, first ball milling:

[0077] The powder weighed in step 2 is added to deionized water and a dispersant for first ball milling, with a mass ratio of ball:powder:deionized water:dispersant of 3.7:1:0.9:0.002, a ball mill speed of 200rpm and a ball milling time of 5h;

[0078] Step 4, pre-sintering:

[0079] After drying the first ball milled material obtained in step 3, pre-sintering is performed at a temperature of 800℃ for 4h;

[0080] Step 5, second ball milling:

[0081] The pre-calcined material obtained in step 4 was added to deionized water for secondary ball milling. The secondary ball milling time was 15 hours and the ball mill speed was 200 rpm.

[0082] Step 6, Primary granulation:

[0083] Dry the secondary ball milling material obtained in step 5, add a binder and granulate it once.

[0084] Step 7, First Pre-compression:

[0085] The powder obtained in step 6 is pressed into a green body at 5 MPa, and the green body is placed in an oven to dry.

[0086] Step 8, Secondary granulation:

[0087] The green body obtained in grinding step 7 is granulated again by adding an adhesive.

[0088] Step 9, Secondary Pre-forming:

[0089] The powder obtained in step 8 is pressed into a green body at 5 MPa, the green body is ground and passed through a 40-mesh sieve;

[0090] Step 10, Shaping:

[0091] The powder obtained in step 9 is pressed into a green body at 110 MPa;

[0092] Step 11, Sintering:

[0093] The green body obtained in step 10 was sintered. The sintering process was as follows: starting from room temperature, the temperature was increased to 400℃ over 2 hours and 40 minutes, and held for 1 hour; then, after 4 hours, the temperature was increased to 800℃ and held for 2 hours; then, after another hour, the temperature was increased to 900℃ and held for 2 hours; finally, the temperature was increased to the sintering temperature of 1060℃ at a rate of 1.5℃ / min and held for more than 10 hours. After the holding period, the temperature was allowed to drop naturally to obtain the yttrium iron garnet ferrite material.

[0094] Example 3

[0095] A method for preparing high dielectric medium yttrium iron garnet ferrite includes the following steps:

[0096] Step 1, Raw material pretreatment:

[0097] Using Y2O3 with a purity of 99.99%, Fe2O3 with a purity of 99.6%, CaCO3 with a purity of 99.11%, SnO2 with a purity of 99.84%, Bi2O3 with a purity of 99%, ZrO2 with a purity of 99%, and V2O5 with a purity of 99% as raw materials, the raw materials were placed in an oven and dried at 100℃ for 6 hours.

[0098] Step 2, Weighing:

[0099] According to the stoichiometric ratio of chemical formula Y 3-x-y-z-2a Bi x Ca y+z+2a Zr y Sn z V a Fe 5-y-z-a O 12 The Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 raw materials after step 1 treatment are calculated and weighed according to the stoichiometric ratio of chemical formula Y; wherein x = 1.0, y = 0.3, z = 0.3, a = 0.35;

[0100] Step 3, primary ball milling:

[0101] The powder weighed in step 2 is added to deionized water and a dispersant for primary ball milling, and the mass ratio of ball:powder:deionized water:dispersant is 3.7:1:0.9:0.002, the ball mill speed is 210 rpm, and the ball milling time is 6h;

[0102] Step 4, pre-sintering:

[0103] The primary ball-milled material obtained in step 3 is dried and then pre-sintered, and the pre-sintering temperature is 820°C and the holding time is 4h;

[0104] Step 5, secondary ball milling:

[0105] The pre-sintered material obtained in step 4 is added to deionized water for secondary ball milling, and the secondary ball milling time is 15h and the ball mill speed is 210 rpm;

[0106] Step 6, primary granulation:

[0107] The secondary ball-milled material obtained in step 5 is dried and added to a binder for primary granulation;

[0108] Step 7, primary pre-pressing:

[0109] The powder obtained in step 6 is pressed into a green body at 5MPa, and the green body is dried in an oven;

[0110] Step 8, secondary granulation:

[0111] The green body obtained in step 7 is ground and added to a binder for secondary granulation;

[0112] Step 9, secondary pre-forming:

[0113] The powder obtained in step 8 is pressed into a green body at 5MPa, the green body is ground and passed through a 40 mesh sieve;

[0114] Step 10, forming:

[0115] The powder obtained in step 9 is pressed into a green body at 110 MPa;

[0116] Step 11, sintering:

[0117] The green body obtained in step 10 is sintered by the following process: from room temperature, it is heated to 400℃ for 2h 40min, and then heated to 800℃ for 4h, and then heated to 900℃ for 1h, and then heated to a sintering temperature of 1050℃ at a heating rate of 1.5℃ / min, and then kept at 1050℃ for 10h or more, and then naturally cooled to obtain the yttrium iron garnet ferrite material

[0118] Comparative Example 1

[0119] Step 1, pretreatment of raw materials:

[0120] Y2O3 with a purity of 99.99%, Fe2O3 with a purity of 99.6%, CaCO3 with a purity of 99.11%, SnO2 with a purity of 99.84%, Bi2O3 with a purity of 99%, ZrO2 with a purity of 99%, and V2O5 with a purity of 99% are used as raw materials, and the raw materials are placed in an oven and dried at a temperature of 100℃ for 6h;

[0121] Step 2, weighing:

[0122] According to the stoichiometric ratio of the chemical formula Y 3-x-y-z-2a Bi x Ca y+z+2a Zr y Sn z V a Fe 5-y-z-a O 12 , the Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 raw materials treated in step 1 are calculated and weighed; wherein x = 1.0, y = 0.3, z = 0.3, a = 0.35;

[0123] Step 3, first ball milling:

[0124] The powder weighed in step 2 is added to deionized water and a dispersant for first ball milling, and the mass ratio of ball: material: deionized water: dispersant is 3.7: 1: 0.9: 0.002, the ball mill speed is 210 rpm, and the ball milling time is 6h;

[0125] Step 4, pre-sintering:

[0126] After the first ball milling material obtained in step 3 is dried, it is pre-sintered at a pre-sintering temperature of 820℃ for 4h;

[0127] Step 5, second ball milling:

[0128] The pre-sintering material obtained in step 4 is added with deionized water for secondary ball milling, the secondary ball milling time is 15 h, and the rotation speed of the ball mill is 210 rpm;

[0129] Step 6, granulation:

[0130] The secondary ball milling material obtained in step 5 is dried, and 8wt% of a binder is added for granulation, and the granulated material is sieved through a 40-mesh sieve;

[0131] Step 7, pre-pressing:

[0132] The powder obtained in step 6 is pressed into a green body at 5 MPa, the green body is ground and sieved through a 40-mesh sieve;

[0133] Step 8, forming:

[0134] The powder obtained in step 7 is pressed into a green body at 110 MPa;

[0135] Step 9, sintering:

[0136] The green body obtained in step 8 is sintered, the sintering temperature is 1050℃, and the holding time is more than 10 h.

[0137] Comparative Example 2

[0138] Step 1, pretreatment of raw materials:

[0139] Y2O3 with a purity of 99.99%, Fe2O3 with a purity of 99.6%, CaCO3 with a purity of 99.11%, SnO2 with a purity of 99.84%, Bi2O3 with a purity of 99%, ZrO2 with a purity of 99%, and V2O5 with a purity of 99% are used as raw materials, and the raw materials are dried in an oven at a temperature of 100℃ for 6 h;

[0140] Step 2, weighing:

[0141] According to the stoichiometric ratio of the chemical formula Y 3-x-y-z-2a Bi x Ca y+z+2a Zr y Sn z V a Fe 5-y-z-a O 12 , the Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3, and ZrO2 raw materials treated in step 1 are calculated and weighed; wherein x = 1.0, y = 0.45, z = 0.1, and a = 0.5;

[0142] Step 3, primary ball milling:

[0143] The weighed powder of step 2 is added to deionized water and a dispersant for primary ball milling, the mass ratio of ball:powder:deionized water:dispersant is 3.7:1:0.9:0.002, the rotation speed of the ball mill is 200 rpm, and the ball milling time is 5 h;

[0144] Step 4, pre-sintering:

[0145] After drying the primary ball-milled material of step 3, pre-sintering is performed at a temperature of 800℃ for 4 h;

[0146] Step 5, secondary ball milling:

[0147] The pre-sintered material of step 4 is added to deionized water for secondary ball milling, the secondary ball milling time is 15 h, and the rotation speed of the ball mill is 200 rpm;

[0148] Step 6, granulation:

[0149] The secondary ball-milled material of step 5 is dried, and 8wt% of a binder is added for granulation, and the granulated material is sieved through a 40-mesh sieve;

[0150] Step 7, pre-pressing:

[0151] The powder of step 6 is pressed into a green body at a pressure of 5 MPa, the green body is ground and sieved through a 40-mesh sieve;

[0152] Step 8, forming:

[0153] The powder of step 7 is pressed into a green body at a pressure of 110 MPa;

[0154] Step 9, sintering:

[0155] The green body of step 8 is sintered at a temperature of 1060℃ for more than 10 h.

[0156] Comparative Example 3

[0157] Step 1, raw material pretreatment:

[0158] Purity 99.99% Y2O3, purity 99.6% Fe2O3, purity 99.11% CaCO3, purity 99.84% SnO2, purity 99% Bi2O3, purity 99% ZrO2, and purity 99% V2O5 are used as raw materials, and the raw materials are dried in an oven at a temperature of 100℃ for 6 h;

[0159] Step 2, weighing:

[0160] According to the chemical formula Y 3-x-y-z-2a Bi x Ca y+z+2a Zr y Sn zV a Fe 5-y-z-a O 12 The raw materials of Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 after step 1 were calculated and weighed according to the stoichiometric ratio of x: y: z: a = 1.0: 0.3: 0.3: 0.35, wherein x = 1.0, y = 0.3, z = 0.3, a = 0.35;

[0161] Step 3, primary ball milling:

[0162] The powder weighed in step 2 was added to deionized water and a dispersant for primary ball milling, and the mass ratio of ball: powder: deionized water: dispersant was 3.7: 1: 0.9: 0.002, the ball mill speed was 210 rpm, and the ball milling time was 6h;

[0163] Step 4, pre-sintering:

[0164] After drying the primary ball-milled material obtained in step 3, pre-sintering was performed at a temperature of 820℃ for 4h;

[0165] Step 5, secondary ball milling:

[0166] The pre-sintered material obtained in step 4 was added to deionized water for secondary ball milling, and the secondary ball milling time was 15h, and the ball mill speed was 210 rpm;

[0167] Step 6, granulation:

[0168] The secondary ball-milled material obtained in step 5 was dried, and a binder was added at a weight percentage of 8wt% for granulation, and the granulated material was sieved through a 40 mesh sieve;

[0169] Step 7, pre-pressing:

[0170] The powder obtained in step 6 was pressed into a green body at a pressure of 5MPa, the green body was ground and sieved through a 40 mesh sieve;

[0171] Step 8, shaping:

[0172] The powder obtained in step 7 was shaped by pressing at a pressure of 110MPa;

[0173] Step 9, sintering:

[0174] The green body obtained in step 8 was sintered at a temperature of 1050℃ for more than 10h.

[0175] The properties of the samples prepared in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1.

[0176] Table 1 Basic properties of samples of examples and comparative examples

[0177]

Claims

1. A method for preparing yttrium iron garnet ferrite with high dielectric and moderate saturation magnetization, characterized in that, Includes the following steps: Step 1, Raw material pretreatment: Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 were used as raw materials, and the raw materials were dried in an oven. Step 2, Weighing: According to the chemical formula Y 3-x-y-z-2a Bi x Ca y+z+2a Zr y Sn z V a Fe 5-y-z-a O 12 Calculate and weigh the raw materials Y2O3, Fe2O3, CaCO3, SnO2, V2O5, Bi2O3 and ZrO2 after step 1 treatment according to the stoichiometric ratio; where 1.0≤x≤1.3, 0.1≤y≤0.6, 0.1≤z≤0.6, and 0≤a≤0.

7. Step 3, First ball milling: The powder weighed in step 2 is ball-milled once, with a ball mill speed of 200-210 rpm and a ball milling time of 4-15 hours. Step 4, Preheating: After drying the primary ball milling material obtained in step 3, it is pre-fired at a temperature of 800-900℃ for 4-10 hours. Step 5, Secondary ball milling: The pre-calcined material obtained in step 4 is subjected to a second ball milling for 10-20 hours, with the ball mill speed being 200-210 rpm. Step 6, Primary granulation: Dry the secondary ball milling material obtained in step 5, add a binder and granulate it once. Step 7, First Pre-compression: The powder obtained in step 6 is pressed into a green blank, and the green blank is placed in an oven to dry. Step 8, Secondary granulation: The green body obtained in grinding step 7 is granulated again by adding an adhesive. Step 9, Secondary Pre-forming: The powder obtained in step 8 is pressed into a green body, the green body is ground and sieved; Step 10, Shaping: The powder obtained in step 9 is pressed into a green body; Step 11, Sintering: The green blank obtained in step 10 is sintered at a temperature of 1020-1060℃ for a holding time of more than 10 hours. After sintering, it is naturally cooled to room temperature to obtain the yttrium iron garnet ferrite material.

2. The method for preparing high-dielectric-content, moderately saturated magnetized yttrium iron garnet ferrite according to claim 1, characterized in that, In step 3, during the first ball milling, the mass ratio of ball:material:deionized water:dispersant is (3.5~3.7):1:(0.8~0.9):0.

002.

3. The method for preparing high-dielectric-content, moderately saturated magnetized yttrium iron garnet ferrite according to claim 1, characterized in that, In step 4, during pre-firing, the temperature is first raised from room temperature to 200℃ over 2 hours, then raised to the target pre-firing temperature of 800-900℃, and then kept at that temperature. After the holding period, the temperature is allowed to drop naturally.

4. The method for preparing high-dielectric-content, moderately saturated magnetized yttrium iron garnet ferrite according to claim 1, characterized in that, In step 5, during the secondary ball milling, the mass ratio of balls:material:deionized water is 3.5:1:0.8, and no dispersant is added.

5. The method for preparing high-dielectric-content, moderately saturated magnetized yttrium iron garnet ferrite according to claim 1, characterized in that, The adhesive in steps 6 and 8 is a polyvinyl alcohol aqueous solution with a concentration of 5wt%-15wt%; the mass of the adhesive added in steps 6 and 8 is the same, which is 4.0wt% of the mass of the secondary ball milling material.

6. The method for preparing high-dielectric-content, moderately saturated magnetized yttrium iron garnet ferrite according to claim 1, characterized in that, In step 7, the oven temperature is 120℃ and the drying time is 1 hour.

7. The method for preparing high-dielectric-content, moderately saturated magnetized yttrium iron garnet ferrite according to claim 1, characterized in that, The sintering process described in step 11 is as follows: starting from room temperature, the temperature is increased to 400℃ after 2 hours and 40 minutes, and held for 1 hour; then the temperature is increased to 800℃ after 4 hours, and held for 2 hours; then the temperature is increased to 900℃ after 1 hour, and held for 2 hours; finally, the temperature is increased to the sintering temperature at a rate of 1.5℃ / min, and held for more than 10 hours, and then the temperature is allowed to drop naturally after the holding period.

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