CN-118063203-B - High-power low-loss Li-based microwave ferrite for LTCC and preparation method

Abstract

A high-power low-loss Li-based microwave ferrite for LTCC and a preparation method thereof belong to the technical field of electronic ceramics. According to the content ：Li 2 CO 3 11.80～12.24mol％,ZnO19.87～20.41mol％,TiO 2 10.78～11.08mol％,Mn 3 O 4 0.39～2.65mol％,Co 3 O 4 0.04～0.58mol％,Fe 2 O 3 54.70～56.18mol％,Bi 2 O 3 0.09mol％. of the ferrite calculated according to the respective standard substance, the high valence Mn ions are introduced into the Li-based microwave ferrite to change the grain size distribution of the ferrite, especially the small grain ratio is increased to improve the spin wave linewidth, and on the basis of grain refinement, a proper amount of Co ions with rapid relaxation characteristic are introduced to further improve the spin wave linewidth of the ferrite.

Inventors

• JIA LIJUN
• LI HONGWEI
• YANG MINGCHAO
• CHEN ZHIHAO

Assignees

• 电子科技大学

Dates

Publication Date

20260505

Application Date

20240226

Claims (1)

1. 1. The preparation method of the high-power low-loss Li-based microwave ferrite for the LTCC is characterized by comprising the following steps of: step 1, weighing: taking Li 2 CO 3 、ZnO、TiO 2 、Mn 3 O 4 、Co 3 O 4 、Fe 2 O 3 、Bi 2 O 3 as a raw material, and weighing the raw material according to the content Li 2 CO 3 11.80~12.24 mol%,ZnO 19.87~20.41mol%,TiO 2 10.78~11.08mol%,Mn 3 O 4 0.39~2.65mol%,Co 3 O 4 0.04~0.58mol%,Fe 2 O 3 54.70~56.18mol%,Bi 2 O 3 0.09mol% of each standard substance; Step 2, ball milling for the first time: Performing primary ball milling on the raw materials weighed in the step 1, wherein the rotating speed of the ball mill is 250r/min, and the ball milling time is 4h; step 3, presintering: Drying and sieving the primary ball milling slurry obtained in the step 2, presintering for 2-3 hours in an oxygen atmosphere at 750-850 ℃, cooling to room temperature along with a furnace after the presintering is completed, and taking out to obtain a Li-based microwave ferrite presintering material; Step 4, secondary ball milling: Performing secondary ball milling on the Li-based microwave ferrite pre-sintered material obtained in the step 3, wherein the rotating speed of the ball mill is 250r/min, the ball milling time is 6h, and drying the slurry after the ball milling is completed; step 5, molding: Sieving the secondary ball milling material obtained in the step 4, adding a polyvinyl alcohol adhesive for granulating, and pressing into a green body sample by using a hydraulic press; Step 6, sintering: Placing the green body sample obtained in the step 5 into a sintering furnace, heating to 600 ℃, preserving heat for 1-2 h to remove glue, heating to the sintering temperature of 880 ℃, preserving heat for 2-3h, cooling to 600 ℃ after sintering, and finally naturally cooling to room temperature along with the furnace to obtain the Li-based microwave ferrite.

Description

High-power low-loss Li-based microwave ferrite for LTCC and preparation method Technical Field The invention belongs to the technical field of electronic ceramics, and particularly relates to a high-power low-loss Li-based microwave ferrite for LTCC and a preparation method thereof. Background With the development of phased array radar systems toward miniaturization, integration and multifunction, phase shifters, a key device, are required to have lower insertion loss, higher peak power and faster response speed. Li-based ferrite has the advantages of high rectangle degree, high saturation magnetization (4pi M s), high Curie temperature (T c), low ferromagnetic resonance line width (delta H) and the like, and is used as an excellent candidate material for a microwave ferrite phase shifter. In order to meet the requirements of miniaturization and integration of microwave ferrite devices, the research work on lithium ferrite is mainly focused on the following two aspects, namely 1) reducing the sintering temperature of ferrite to be close to 900 ℃ by introducing additives such as low-melting-point oxide, glass and the like so as to realize matching co-firing with silver electrodes, and 2) improving the problems of serious dielectric loss and magnetic loss performance degradation of the lithium ferrite sintered at low temperature by ion substitution. Furthermore, microwave ferrite devices for high power applications should have high power handling capabilities in addition to requiring low electromagnetic losses. Therefore, the combination of the spin wave linewidth, dielectric loss, magnetic loss and other properties of the Li-based ferrite material under the low-temperature sintering condition is an urgent problem to be solved. The invention patent with the application number 202010379833.9 discloses a high-power torque ferrite material for a Ku wave band and a preparation method thereof, and the invention obtains a spin wave line width delta H k maximum value of a sample under a 1000 ℃ sintering condition by changing the substitution amount of Zn 2+ and Ti 4+ ions in Li ferrite and assisting with auxiliaries such as Bi 2O3、V2O5, wherein the maximum value of the spin wave line width delta H k is 3.88Oe, the ferromagnetic resonance line width delta H is as low as 298Oe, the dielectric loss tangent tan delta ε is as low as 5.7X10. 10 -4, the sintering temperature of the material prepared by the invention is higher, the material cannot be compatible with an LTCC technology, the spin wave line width delta H k is lower, and the microwave magnetic loss delta H is higher. The invention patent with the application number 202110372118.7 discloses a narrow-linewidth LTCF gyromagnetic substrate material and a preparation method thereof, wherein the substitution amount of Zn 2+、Ti4+ ions in Li ferrite is changed, meanwhile, B 2O3-ZnO-Bi2O3 (BZB) glass auxiliary agent and Bi 2O3 oxide are added, ferrite samples with the delta H of 90Oe are obtained under the sintering condition of 900 ℃, but the tan delta ε is as high as 6.5X10 -4, the low magnetic loss and the low dielectric loss cannot be simultaneously achieved, and the delta H k parameter is not shown. The invention patent with the application number 201811483879.4 discloses a spinel Li ferrite material for a lock phase shifter from an X band to a millimeter wave band, which is characterized in that Zn 2+、Ti4+、Mg2+、Cu2+、Co2+、Bi3+ and Mn 2+ plasmas are combined to replace Li ferrite, a spin wave line width delta H k of a sample is up to 10.0Oe under the sintering condition of 980 ℃, a ferromagnetic resonance line width delta H is as low as 145Oe, a dielectric loss tangent tan delta ε is as low as 2.3X10 -4, the sintering temperature and the spin wave line width are further optimized, bi 2O3 auxiliary agents are added in ."Effect of Bi2O3contents on magnetic and electromagnetic properties of LiZnMn ferrite ceramics[J],Eur.Ceram.Soc.42(2022)3463–3472" articles, low magnetic loss (delta H= -158 Oe) and low dielectric loss (tan delta ε＝～5.49×10-4) are obtained through sintering at 1075 ℃, the spin wave line width is only ～1.87Oe."Low-temperature sintering and ferrimagnetic properties of LiZnTiMn ferrites with Bi2O3–Nb2O5 eutectic mixture[J],J.Mater.Sci.Mater.Electron.33(2022)20162–20169" added with Bi 2O3–Nb2O5 composite auxiliary agents, and lower magnetic loss (delta H= 161 Oe) is realized under the sintering condition of 920 ℃, and the spin wave line width parameters are not reported. In summary, none of the above patents and articles simultaneously obtain a Li-based ferrite material with Gao Zixuan wave width and low microwave loss under the condition of low-temperature sintering (less than or equal to 900 ℃), and a better solution is needed in the face of the requirements of microwave ferrite devices in LTCC integration technology on high power bearing capacity and low electromagnetic loss. Disclosure of Invention The invention aims to solve the problem that the h