CN117125972A - High-power low-loss NiCuZn microwave ferrite material and preparation method thereof - Google Patents

Abstract

The invention discloses a high-power low-loss NiCuZn microwave ferrite material and a preparation method thereof, belonging to the technical field of microwave ferrite material preparation. By carrying out fast relaxation of ionic Co ²⁺ And Ho ³⁺ Substitution, not only introducing fast relaxation ions to shorten relaxation time, but also refining grains, for improving spin wave linewidth delta H _k A dual effect is created that enables the material to withstand higher peak powers. At the same time, over a certain amount of Ho ³⁺ Substitution to make the host lattice in an iron-deficient state, thereby inhibiting Fe ²⁺ And related electron transfer mechanism, to reduce tan delta _ε The dielectric property of the NiCuZn microwave ferrite is improved. The high-power low-loss NiCuZn microwave ferrite prepared by the inventionBulk saturation magnetization 4 pi M _s Stable at 4.9kGs +/-5%, and has smaller ferromagnetic resonance linewidth delta H: 120-235 Oe, lower dielectric loss tan delta _ε ：≤3.81×10 ^‑4 Spin wave linewidth Δh _k Within 24.8-33.0 Oe, has a line width delta H of Gao Zixuan waves _k Low ferroresonance linewidth Δh and lower dielectric loss tan delta _ε 。

Description

High-power low-loss NiCuZn microwave ferrite material and preparation method thereof

Technical Field

The technology belongs to the technical field of microwave ferrite material preparation, and particularly relates to a high-power low-loss NiCuZn microwave ferrite material and a preparation method thereof.

Background

With the vigorous development of communication technology, there are demands for higher frequency band, faster propagation speed, lower signal delay, etc. on signal propagation. The signal frequency is improved, so that the attenuation of the signal is greatly increased, and under the development background that the communication and detection technology is advanced towards the directions of beyond visual range and miniaturization at present, such as carrier-borne, airborne, satellite-borne radars, 5G base stations and the like, the advantages of miniaturization, high power and low loss are all needed to be simultaneously considered. A large number of transmit-receive components (T/R components) are required in phased array radars and 5G base stations, each requiring a circulator/isolator in each for signal shunt isolation, matching between the microwave system antenna and the transmitterThe gain is improved. The performance of the circulator is critical for the T/R component, and the saturation induction of the circulator is 4 pi M for the core ferrite material applied to the circulator _s Determines the frequency of device operation, low dielectric loss tan delta _ε And the ferromagnetic resonance line width delta H can reduce the insertion loss of the circulator, and the high spin wave line width delta H _k The maximum bearing power of the device can be improved, so that the requirement of high power is met.

Ni-based spinel ferrite has a high Curie temperature T _c Can work in high temperature severe environment and simultaneously has the saturation magnetization of 4pi.M _s High (up to 5200 Gs) and can be applied to high frequency, but the charged particles are easy to move due to the fact that the oxygen ion gap is not completely occupied by cations, so that the dielectric loss tan delta is generated _ε The ferromagnetic resonance linewidth Δh is larger, resulting in larger losses. At present, research on Ni-series spinel ferrite materials mainly focuses on how to reduce microwave and dielectric loss, but the urgent requirement of high power of transceiver components is that spin wave linewidth delta H needs to be improved _k To improve the high power characteristics of the materials and devices. However, the ferromagnetic resonance linewidth Δh characterizing the loss performance of the microwave ferrite material and the spin linewidth Δh characterizing the high power characteristics of the material _k Is mutually conflicting and restricted, and needs to improve the spin wave linewidth delta H _k Effectively suppressing the ferroresonance linewidth deltah at the same time.

Many efforts have been made by researchers in the field to solve the above problems:

the chemical formula of the NiCuZn spinel ferrite material disclosed in Chinese patent CN 115180935A is Ni _{1-x- y} Zn _x Cu _y Mn _z Fe _2-z-δ O ₄ Wherein delta is the iron deficiency, and the additive is Li ₂ CO ₃ And V ₂ O ₅ Sintering at 850-920 deg.c for 5-10 hr to obtain saturated magnetization 4 pi M _s 4410-4620 Gs, dielectric loss tan delta _ε Is 3.5 to 4.2X10 ^-4 The line width delta H of the ferromagnetic resonance is 109-165 Oe, and the line width delta H of the spin wave of the material _k 15.6-16.3 Oe, while Curie temperature T _c Greater than 320 ℃.

Chinese patentThe chemical formula of the NiCuZn spinel ferrite material disclosed in CN 114702310A is as follows: ni (Ni) _1-a-d+e-g Zn _a In _b Dy _c Co _d Sn _e Mn _f Cu _g Fe _{2-b-c-2e-f-δ} O ₄ Wherein delta is the iron deficiency, and researchers adjust Co in NiCuZn ferrite ²⁺ And Dy ³⁺ Is sintered at 1100 ℃ for 4 hours to lead the saturation magnetization of the material to be 4 pi M _s 4520Gs, dielectric loss tan delta _ε Is 3.2X10 ^-4 The line width delta H of the ferromagnetic resonance is 146Oe, and the line width delta H of the spin wave of the material _k 37.5Oe was reached with a Curie temperature Tc of 475 ℃.

Based on the above, the invention provides a high-power low-loss NiCuZn microwave ferrite material and a preparation method thereof. The material has higher saturation magnetic induction intensity 4 pi M _s Low dielectric loss tan delta _ε Higher spin wave linewidth ΔH _k And a suitable ferroresonance linewidth Δh.

Disclosure of Invention

The core idea of the invention is that Co is usually adopted in NiCuZn microwave ferrite ²⁺ The fast relaxation ion substitution is carried out, the relaxation time is shortened, and the spin wave linewidth delta H of the material is improved _k But with Co added ²⁺ Generally, the material enters the crystal lattice completely, and the microstructure (grain size and grain boundary characteristics) is not affected, so that the effect of regulating the spin wave linewidth is limited. While Ho is added into the main formula ₂ O ₃ On the one hand, ho likewise has fast relaxation properties ³⁺ Part of the material enters spinel octahedral gaps, so that the relaxation time is shortened, and the delta H of the material can be improved _k At the same time part Ho ³⁺ Will be with Fe ³⁺ Combining to produce another phase of HoFeO ₃ Inhibiting the progress of solid phase reaction, inhibiting the growth of crystal grains, refining crystal grains, and leading the line width delta H of spin waves to be _k Increasing. More importantly, ho ³⁺ With Fe ³⁺ Combining to produce another phase of HoFeO ₃ Can lead the main crystal lattice to be in an iron deficiency state, thereby inhibiting Fe ²⁺ And related electron transfer mechanism, to increase resistivity ρ and reduce dielectric loss tan delta _ε Improving the dielectric of NiCuZn microwave ferriteElectrical properties.

The technical scheme adopted by the invention is as follows: the high-power low-loss NiCuZn microwave ferrite material is characterized in that the spinel ferrite comprises a main formula and an additive, and the chemical formula is as follows: ni (Ni) _1-a-b Cu _a Zn _b Co _c Ho _d Fe _{2-c- d} O ₄ Wherein a is more than or equal to 0.05 and less than or equal to 0.40,0.10, b is more than or equal to 0.70,0.01 and c is more than or equal to 0.06,0.01 and d is more than or equal to 0.10;

the mass percentage of the additive is calculated as oxide as follows: 0.05 to 0.20 weight percent of Bi ₂ O ₃ ，0.05～0.20wt％CaO，0.05～0.20wt％BaTiO ₃ ；

A preparation method of a high-power low-loss NiCuZn microwave ferrite material comprises the following steps:

step 1, batching: according to chemical formula Ni _1-a Cu _a Zn _b Co _c Ho _d Fe _2-c-d O ₄ Wherein a is more than or equal to 0.05 and less than or equal to 0.40,0.10, b is more than or equal to 0.05 and less than or equal to 0.70,0.01 and c is more than or equal to 0.06,0.01 and d is more than or equal to 0.10, d=0.00 in the comparative example, and various raw materials are calculated and weighed, wherein the raw materials are NiO, cuO, znO, co ₂ O ₃ 、Fe ₂ O ₃ 、Ho ₂ O ₃ ；

Step 2, ball milling for the first time: placing the initial powder, the zirconium balls and the dispersing agent obtained in the step 1 into a ball mill, and uniformly mixing for 1-7 h to obtain primary ball milling slurry;

step 3, presintering: drying the slurry obtained in the step 2, sieving with a 30-60 mesh sieve to prepare powder, and then placing the powder into a sintering furnace for presintering at 800-1000 ℃ for 1-5 h to obtain presintering powder;

step 4 doping: the presintered powder obtained in the step 3 is prepared into powder through a sieve with 30-60 meshes, and additives are added, wherein the additives are calculated according to the mass percentage of main components and are as follows: 0.05 to 0.20 weight percent of Bi ₂ O ₃ ，0.05～0.20wt％CaO，0.05～0.20wt％BaTiO ₃ ；

Step 5, secondary ball milling: placing the powder, the zirconium balls and the dispersing agent obtained in the step 4 into a ball mill, and uniformly mixing for 3-9 hours to obtain secondary ball milling slurry;

and 6, granulating: drying the ball milling slurry obtained in the step 5, sieving with a 30-60 mesh sieve to prepare powder, adding an adhesive for granulating to obtain granulated particles;

and 7, molding: placing the particles obtained in the step 6 into a mould for pressing, wherein the forming pressure is 100-250 MPa, and the pressure maintaining time is 10-30 s, so as to obtain a green body of the material;

step 8, sintering: and (3) placing the blank obtained by pressing in the step (7) into a sintering furnace to be sintered in air, wherein the sintering temperature is 1000-1100 ℃, and the heat preservation time is 2-6 hours, so as to obtain the NiCuZn ferrite material.

Step 9, testing: and (3) testing the magnetic property of the sample obtained in the step (8): saturation magnetization of material (4. Pi.M _s ) Ferromagnetic resonance linewidth (ΔH) was tested using the American Lake Shore 8604 type VSM test at 9.3GHz using the American Agilent N5227A vector network analyzer, spin wave linewidth (ΔH) _k ) The dielectric constant (. Epsilon.') and dielectric loss (. Tan. Delta.) were measured using a 3Mb-27A spin wave test system _ε ) By using cylindrical TM ₀₁₀ The resonant cavity was measured at 9.3 GHz.

The final technical indexes of the NiCuZn microwave ferrite material prepared by the invention are as follows:

saturation magnetization 4 pi M _s ：4.9kGs±5％；

Ferromagnetic resonance linewidth Δh: 120-235 Oe

Spin wave line ΔH _k ：24.8～33.0Oe；

Dielectric loss tan delta _ε ：≤3.81×10 ^-4

Compared with the prior art, the invention has the following beneficial effects:

the high-power low-loss NiCuZn microwave ferrite provided by the invention is prepared by performing fast relaxation on ion Co ²⁺ And Ho ³⁺ Substitution, not only introducing fast relaxation ions to shorten relaxation time, but also refining grains, for improving spin wave linewidth delta H _k A dual effect is created that enables the material to withstand higher peak powers. At the same time, over a certain amount of Ho ³⁺ Substitution to make the host lattice in an iron-deficient state, thereby inhibiting Fe ²⁺ And related electron transfer mechanism, to reduce tan delta _ε The dielectric property of the NiCuZn microwave ferrite is improved. The saturation magnetization intensity of the high-power low-loss NiCuZn microwave ferrite prepared by the invention is 4 pi M _s Stable at 4.9kGs +/-5%, and has smaller ferromagnetic resonance linewidth delta H: 120-235 Oe, lower dielectric loss tan delta _ε ：≤3.81×10 ^-4 Spin wave linewidth Δh _k Within 24.8-33.0 Oe, has a line width delta H of Gao Zixuan waves _k Low ferroresonance linewidth Δh and lower dielectric loss tan delta _ε 。

Drawings

FIG. 1 is an X-ray diffraction chart of comparative example 1 and examples 1 to 4.

FIG. 2 is a back-scattered electron microscopic image of the sintered body obtained at 1030℃in comparative example 1.

FIG. 3 is a back-scattered electron microscopic image of the sintered body obtained at 1030℃in example 1.

FIG. 4 is a back-scattered electron microscopic image of the sintered body obtained at 1030℃in example 2.

FIG. 5 is a back-scattered electron microscopic image of the sintered body obtained at 1030℃in example 3.

FIG. 6 is a back-scattered electron microscopic image of a sintered body obtained at 1030℃in example 4.

Description of the embodiments

The invention will be further illustrated with reference to examples.

The main phase structure of the high-power low-loss NiCuZn microwave ferrite is a spinel structure, the spinel ferrite comprises a main formula and an additive, and the chemical general formula is as follows: ni (Ni) _1-a-b Cu _a Zn _b Co _c Ho _d Fe _2-c-d O ₄ Wherein a is more than or equal to 0.05 and less than or equal to 0.40,0.10, b is more than or equal to 0.70,0.01 and c is more than or equal to 0.06,0.01 and d is more than or equal to 0.10.

The mass percentage of the main formula of the additive is calculated as oxide: 0.05 to 0.20 weight percent of Bi ₂ O ₃ ，0.05～0.20wt％CaO，0.05～0.20wt％BaTiO ₃ 。

The preparation method comprises the following steps:

(1) And (3) batching: the raw materials are calculated and weighed according to chemical formula, and the raw materials are analytically pure NiO, cuO, znO, co ₂ O ₃ 、Fe ₂ O ₃ 、Ho ₂ O ₃ ；

The main formulations of examples 1 to 4 and comparative example 1 are shown in the following table:

	a	b	c	d
					example 1	0.1	0.4	0.015	0.01
Example 2	0.1	0.4	0.015	0.02
					Example 3	0.1	0.4	0.015	0.03
Example 4	0.1	0.4	0.015	0.04
					Comparative example 1	0.1	0.4	0.015	0.00

(2) Ball milling for the first time: placing the initial powder, the zirconium balls and the dispersing agent obtained in the step (1) into a ball mill, and uniformly mixing for 3 hours to obtain primary ball milling slurry;

(3) Presintering: drying the slurry obtained in the step (2), sieving with a 40-mesh sieve to prepare powder, and then placing the powder into a sintering furnace for presintering at 900 ℃ for 2.5 hours to obtain presintering powder;

(4) Doping: the presintered powder obtained in the step (3) is prepared into powder through a sieve with 30-60 meshes, and additives are added, wherein the additives are calculated according to the mass percentage of main components and are as follows: 0.05wt% Bi ₂ O ₃ ，0.15wt％CaO，0.20wt％BaTiO ₃ ；

(5) Secondary ball milling: placing the powder, the zirconium balls and the dispersing agent obtained in the step (4) into a ball mill, and uniformly mixing for 6 hours to obtain secondary ball milling slurry;

(6) Granulating: drying the ball-milling slurry obtained in the step (5), sieving with a 40-mesh sieve to prepare powder, adding an adhesive, and granulating to obtain granulated particles;

(7) And (3) forming: placing the particles obtained in the step (6) into a mould for pressing, wherein the forming pressure is 200MPa, and the pressure maintaining time is 20s, so as to obtain a green body of the material;

(8) Sintering: placing the blank obtained by pressing in the step (7) into a sintering furnace to be sintered in air, wherein the sintering temperature is 1030 ℃, 1050 ℃ and 1070 ℃ respectively, and the heat preservation time is 3 hours, so as to obtain NiCuZn ferrite sintered bodies of examples 1-4 and comparative example 1;

the saturation magnetization of the material was tested (4. Pi.M _s ) And coercivity (H) _c ) Ferromagnetic resonance linewidth (ΔH) was tested using the American Lake Shore 8604 type VSM test at 9.3GHz using the American Agilent N5227A vector network analyzer, spin wave linewidth (ΔH) _k ) The dielectric constant (. Epsilon.') and dielectric loss (. Tan. Delta.) were measured using a 3Mb-27A spin wave test system _ε ) By using cylindrical TM ₀₁₀ The resonant cavity was measured at 9.3 GHz.

Experiment and data

The results of the electromagnetic property tests of the NiCuZn microwave ferrite materials prepared according to examples 1 to 4 and comparative example 1 are shown in table 1.

Comparison of Properties of the materials of Table 1

Comparison of the comparative examples with the examples can be seen: with Ho ³⁺ The density of the sintered body gradually increases due to the increase in the ion content due to Ho ³⁺ Ion compared with Fe ³⁺ Ions have a higher molar mass; saturation magnetization 4 pi M _s Gradually decrease, ho ³⁺ The ions combine with Fe ions in the main crystal phase to form HoFeO ₃ The hetero-phase, which causes the main crystal phase to be in an iron-deficiency state, and the molecular magnetic moment in the ferrite to be reduced, so that the saturation magnetization is 4 pi M _s Gradually lowering; ferromagnetic resonance linewidth ΔH gradually increases, part Ho ³⁺ The ions enter the crystal lattice, and in rare earth ions Ho ³⁺ Under the action of spin-orbit coupling, magnetocrystalline anisotropy constant K ₁ Increase in anisotropy induced width ΔH _a An increase, resulting in an increase in the ferromagnetic resonance linewidth Δh; an increase in the content and concentration of fast relaxing ions promotes relaxationThe time tau is reduced, which is beneficial to spin wave linewidth delta H _k Increase at the same time Ho ³⁺ Grain refinement after ion increase also leads to spin wave linewidth ΔH _k Increasing; a small amount of Ho ³⁺ Ion substitutes Fe ³⁺ The ions occupy octahedral sites (B sites), and the iron-deficient state of the host lattice suppresses Fe ²⁺ Is generated by (1), electrons in Fe ²⁺ And Fe (Fe) ³⁺ The probability of transition between the two is reduced, leading to an increase in the resistivity ρ, the dielectric loss tan delta _ε And (3) lowering.

Compared with the embodiments of the Chinese patent CN 115180935A, the invention has higher saturation induction (4 pi M _s Not less than 4736 Gs), higher spin linewidth (ΔH _k 24.8 Oe) and lower dielectric losses (up to 1.34×10 minimum ^-4 ) The method comprises the steps of carrying out a first treatment on the surface of the Compared with examples 1 and 2 of Chinese patent CN 114702310A, the sintered body obtained in example 4 of the invention at 1030 ℃ has higher saturation induction (4 pi M _s =48131 Gs), higher spin linewidth (Δh _k =33.0 Oe), lower dielectric loss (tan δ _ε ＝2.05×10 ^-4 ) A lower sintering temperature; compared with example 3 of Chinese patent CN 114702310A, the sintered body obtained in example 2 of the invention at 1030 ℃ has higher saturation induction (4 pi M _s =4894 Gs), higher spin linewidth (Δh _k =25.9 Oe) and lower sintering temperature, the sintered body obtained in example 3 of the present invention had a higher spin wave linewidth (Δh) at 1070 ℃ _k =29.0 Oe) and lower sintering temperatures; compared with example 4 of Chinese patent CN 114702310A, the sintered bodies obtained in examples 1 and 2 of the invention at 1070 ℃ have higher saturation induction (4 pi M _s ∈ 4931 Gs), lower dielectric loss (tan δ _ε ≦2.6×10 ^-4 ) And lower sintering temperatures.

FIG. 1 shows that the main crystal phases of comparative example 1 and examples 1 to 4 are spinel structures, and that HoFeO gradually appears in the examples as the substitution amount of Ho ions increases ₃ And (3) impurity phase.

FIGS. 2 to 6 show back-scattered electron microscopic images of NiCuZn ferrite, in which the elements having higher atomic numbers are in the imagesThe high brightness of the ferrite is achieved, and part of Ho element is found to be HoFeO outside NiCuZn ferrite grains ₃ The morphological enrichment of the crystals further demonstrates that the impurity phase present in the examples is HoFeO ₃ Thereby playing a role of blocking the growth of NiCuZn ferrite grains in the solid phase reaction, reducing the grain size D, simultaneously leading the main crystal phase to be in an iron-deficiency state, inhibiting Fe ²⁺ Is generated such that the resistivity ρ increases.

Claims (2)

1. The high-power low-loss NiCuZn microwave ferrite material is characterized in that the spinel ferrite comprises a main formula and an additive, and the chemical formula is as follows: ni (Ni) _1-a-b Cu _a Zn _b Co _c Ho _d Fe _2-c-d O ₄ Wherein a is more than or equal to 0.05 and less than or equal to 0.40,0.10, b is more than or equal to 0.70,0.01 and c is more than or equal to 0.06,0.01 and d is more than or equal to 0.10.

The mass percentage of the additive is calculated as oxide as follows: 0.05 to 0.20 weight percent of Bi ₂ O ₃ ，0.05～0.20wt％CaO，0.05～0.20wt％BaTiO ₃ ；

2. The preparation method of the high-power low-loss NiCuZn microwave ferrite material as claimed in claim 1, comprising the following steps:

step 1, batching: according to chemical formula Ni _1-a Cu _a Zn _b Co _c Ho _d Fe _2-c-d O ₄ Wherein a is more than or equal to 0.05 and less than or equal to 0.40,0.10, b is more than or equal to 0.05 and less than or equal to 0.70,0.01 and c is more than or equal to 0.06,0.01 and d is more than or equal to 0.10, d=0.00 in the comparative example, and various raw materials are calculated and weighed, wherein the raw materials are NiO, cuO, znO, co ₂ O ₃ 、Fe ₂ O ₃ 、Ho ₂ O ₃ ；

Step 2, ball milling for the first time: placing the initial powder, the zirconium balls and the dispersing agent obtained in the step 1 into a ball mill, and uniformly mixing for 1-7 h to obtain primary ball milling slurry;

step 3, presintering: drying the slurry obtained in the step 2, sieving with a 30-60 mesh sieve to prepare powder, and then placing the powder into a sintering furnace for presintering at 800-1000 ℃ for 1-5 h to obtain presintering powder;

step 4 doping: the presintered powder obtained in the step 3 is prepared into powder through a sieve with 30-60 meshes, and additives are added, wherein the additives are calculated according to the mass percentage of main components and are as follows: 0.05 to 0.20 weight percent of Bi ₂ O ₃ ，0.05～0.20wt％CaO，0.05～0.20wt％BaTiO ₃ ；

Step 5, secondary ball milling: placing the powder, the zirconium balls and the dispersing agent obtained in the step 4 into a ball mill, and uniformly mixing for 3-9 hours to obtain secondary ball milling slurry;

and 6, granulating: drying the ball milling slurry obtained in the step 5, sieving with a 30-60 mesh sieve to prepare powder, adding an adhesive for granulating to obtain granulated particles;

and 7, molding: placing the particles obtained in the step 6 into a mould for pressing, wherein the forming pressure is 100-250 MPa, and the pressure maintaining time is 10-30 s, so as to obtain a green body of the material;

step 8, sintering: and (3) placing the blank obtained by pressing in the step (7) into a sintering furnace to be sintered in air, wherein the sintering temperature is 1000-1100 ℃, and the heat preservation time is 2-6 hours, so as to obtain the NiCuZn ferrite material.