CN-121974691-A - Temperature-stable ultralow-loss orthogonal calcium-based microwave dielectric ceramic and preparation method thereof

Abstract

The invention relates to the technical field of ceramic materials, and discloses a temperature-stable ultralow-loss orthogonal calcium-based microwave dielectric ceramic and a preparation method thereof, wherein the composition chemical formula of the ceramic is CaSc 2 O 4 . The preparation method comprises the steps of firstly weighing CaCO 3 and Sc 2 O 3 powder according to a certain proportion, mixing, then sequentially carrying out wet grinding and drying, presintering for 4-8 hours under the condition that the temperature is 1200 ℃ in an air atmosphere, obtaining presintering powder, carrying out secondary ball milling, drying, adding a binder, granulating, pressing and forming, and finally sintering for 4-8 hours in the air atmosphere of 1525-1575 ℃ to obtain the product. The CaSc 2 O 4 microwave dielectric ceramic prepared at 1550 ℃ has an ultrahigh Q multiplied by f value (124607 GHz), a near-zero resonant frequency temperature coefficient (-9.6 ppm/°C) and a lower dielectric constant (19), and is widely used for manufacturing microwave devices such as various dielectric antenna substrates, resonators, filters and the like.

Inventors

• ZHANG SIJIN
• ZHANG SIYING
• HE CHONGKANG
• FANG WEISHUANG
• YANG YANG
• TANG YING
• QIN YUANDONG
• FANG LIANG

Assignees

• 桂林理工大学
• 广西新未来信息产业股份有限公司

Dates

Publication Date

20260505

Application Date

20260225

Claims (7)

1. 1. The temperature-stable ultralow-loss orthogonal calcium-based microwave dielectric ceramic material has a chemical formula of CaSc 2 O 4 and is single-phase ceramic, and is characterized in that the microwave dielectric ceramic material realizes the near-zero resonant frequency temperature coefficient while ultralow dielectric loss through the cooperative regulation and control of Ca-O bond and Sc-O bond, and the preparation method of the microwave dielectric ceramic material comprises the following steps: (1) Weighing CaCO 3 and Sc 2 O 3 powder with purity of more than 99.9% to obtain original powder; (2) Stirring and mixing the original powder, sequentially carrying out first wet grinding treatment and first drying treatment to obtain dried powder, and presintering for 4-8 hours under the condition that the temperature is 1200 ℃ in an air atmosphere to obtain presintered powder; (3) And (3) performing secondary wet ball milling and secondary drying on the presintered powder, adding a binder for granulating, pressing and forming, and finally sintering for 4-8 hours in an air atmosphere at 1525-1575 ℃ to obtain the orthogonal calcium-based microwave dielectric ceramic.
2. 2. The temperature-stabilized ultra-low loss, orthogonal calcium-based microwave dielectric ceramic of claim 1, wherein in step (1), the molar ratio of CaCO 3 to Sc 2 O 3 is 1:1.
3. 3. The temperature-stable ultralow-loss orthogonal calcium-based microwave dielectric ceramic according to claim 2, wherein the first wet milling treatment time is 6-12 hours, and the ball milling medium adopted in the first wet milling process is absolute ethyl alcohol.
4. 4. The temperature-stable ultralow-loss orthogonal calcium-based microwave dielectric ceramic according to claim 3, wherein in the step (3), the ball milling medium adopted by the second wet ball milling is absolute ethyl alcohol, the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and the added mass of the binder accounts for 3% of the total mass of the original powder.
5. 5. The temperature-stabilized ultra-low loss, orthogonal calcium-based microwave dielectric ceramic of claim 4, wherein in step (3), the sintering temperature is 1550 ℃.
6. 6. The temperature-stable ultralow-loss orthogonal calcium-based microwave dielectric ceramic according to claim 5, wherein the prepared CaSc 2 O 4 microwave dielectric ceramic has a stacking rate of 63.31%.
7. 7. The application of the microwave dielectric ceramic as claimed in claim 6, wherein the microwave dielectric ceramic is applied to the preparation of microwave components of microwave dielectric antenna substrates or resonators or filters, and the components have the advantages of small leakage current, low aging speed and the like.

Description

Temperature-stable ultralow-loss orthogonal calcium-based microwave dielectric ceramic and preparation method thereof Technical Field The invention relates to the technical field of ceramic materials, in particular to a temperature-stable ultralow-loss orthogonal calcium-based microwave dielectric ceramic and a preparation method thereof. Background The microwave dielectric ceramic (MWDC) is ceramic which is applied to a microwave frequency band (300 MHz-300 GHz) circuit as a dielectric material and can perform one or more functions of microwave waveguide, shielding, resonance and the like, is a key basic material in the technical fields of modern communication such as microwave communication, high-speed high-frequency circuit substrates, satellite positioning navigation systems, radar detection and the like, and is widely used as a resonator, a filter, a dielectric substrate, a dielectric guided wave loop and the like. The rapid development of modern mobile communication promotes the rapid development of various microwave mobile communication terminal devices to the directions of miniaturization, light weight, multifunction and low cost. With the deep application of the 5G and 6G technologies, the microwave communication technology extends to millimeter wave bands, and the microwave dielectric ceramic filter material needs to have 1a low dielectric constant (epsilon r) to reduce delay and improve the transmission rate of electric signals and 2 a low dielectric loss (Q×f, the dielectric filter generally needs to have Q×f not less than 100000 GHz) to improve the selectivity of the working frequency of the device and reduce the energy consumption of the device. 3. The near zero resonant frequency temperature coefficient (-10 ppm/°C≤τ f≤ + ppm/°C) ensures circuit temperature stability. Therefore, microwave dielectric ceramic materials with low dielectric constants (dielectric constants epsilon r < 20) and high quality factors and near zero are being researched and researched by researchers at home and abroad in recent years. To meet the above objective, chen Junji et al reported for the first time that the dielectric properties of the orthogonal structure SrIn 2O4 microwave dielectric ceramic (ε r = 12.3,Q×f = 96,900 GHz,τf = -61.6 ppm/°c), which attracts attention of a large number of researchers with its high quality factor, however its larger negative τ ƒ cannot meet the needs of practical applications. Subsequently a series of binary Rare Earth (RE) oxides AB 2O4 (a=sr, ba; b=sm, eu, ho, yb, Y, er, tm) microwave ceramic systems were reported one after the other, and it was found that the complete substitution of In by rare earth ions of different radii shifted the τ f value In the positive direction, but at the same time resulted In a significant decrease In the quality factor (q×f value) (< 90000 GHz), for example SrSm2O4（εr = 18.16,Q×f = 40646 GHz,τf = -17.6 ppm/°C）,SrY2O4（εr = 14.78,Q×f = 84090 GHz,τf = -14.98 ppm/°C）,SrEu2O4（εr = 20.1,Q×f = 28,963 GHz,τf = -9.9 ppm/°C）,SrEr2O4（εr = 14.44,Q×f = 23271 GHz,τf = -21.5 ppm/°C）,BaSm2O4（εr = 10.99,Q×f = 54598 GHz,τf = -25.4 ppm/°C）. Zhou Huanfu et al Sr 1+xY2O4+x (x=0.2) series ceramic prepared by non-stoichiometry had a high quality factor (ε r =15.41, q×f= 112375 GHz), but its τ f value (τ f = -17.44 ppm/°c) remained largely negative. they further prepared Sr 0.98Y2O4.02+2wt%CaTiO3 ceramics by adding positive resonant frequency temperature coefficient compensator CaTiO 3 to obtain near zero values (τ f =0 ppm/°c) but with a substantial decrease in quality factor (qxf= 51004 GHz), while the process resulted in the obtained ceramics being heterogeneous, prone to defects at the phase boundaries, impurity segregation or amorphous phase, each phase distribution needs to be controlled accurately, process repeatability is strictly required, and performance consistency is challenging. Therefore, compared with the prior art, the performance regulation strategy of the orthogonal calcium-based ceramic at present can lead to optimization of a certain parameter, and meanwhile, the other parameter is often deteriorated, and three performance parameters are difficult to regulate and control simultaneously, so that the application requirements of a millimeter wave frequency band (30-300 GHz) and a terahertz frequency band (0.1-1 THz) with higher frequency cannot be completely met. When the microwave dielectric ceramic is used for preparing electronic components, the low dielectric constant, the high quality factor and the near-zero resonance frequency temperature coefficient are met, the application problems of electricity leakage, aging and the like are also required to be considered, and if the resistivity is low, the aging of the components is easily accelerated, and even serious consequences such as cracking, burning, explosion and the like occur. Disclosure of Invention Based on the problems of the background technology, the invention aims to provide a single-ph