Temperature-stable BaLiF3 microwave ceramics for LTCC applications with the addition of SrTiO3 and LiF

IF 1.8 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

International Journal of Applied Ceramic Technology Pub Date : 2025-04-25 DOI:10.1111/ijac.15153

H. Zheng, L. M. Huang, J. J. Bian

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引用次数: 0

Abstract

Although BaLiF₃ ceramic has a high quality-factor at microwave frequencies (Q × f value = ∼83000 GHz) coupled with a low sintering temperature (750°C/2 h), its high negative temperature coefficient of resonant frequency (τ_f = ∼ −70 ppm/°C) prevents practical applications. In the present paper, we employed SrTiO₃ as a second phase (7 mol%) to tune the negative τ_f value to near zero (∼2.5 ppm/°C) and added a small amount of LiF (4 mol%) to reduce the sintering temperature to ∼800°C. Sintering in the N₂ atmosphere has a beneficial effect on the density, while it has a detrimental impact on the Q × f value of the sintered body due to the partial reduction of Ti⁴⁺ in the SrTiO₃ (SrTi⁴⁺_1-_xTi³⁺_xO_3-_xF_x) and F-vacancies in the BaLiF₃ (BaLiF_3-x)_. The 0.93BaLiF₃ +0.07SrTiO₃ composite with 4 mol% LiF addition exhibits excellent combined microwave dielectric properties (ε_r= 14, Q × f = 55 000 GHz, and τ_f= −3 ppm/°C), coupled with low sintering temperature (785°C/3 h) and good cofiring chemical compatibility with silver, which is a promising candidate for LTCC applications.

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添加SrTiO3和LiF的用于LTCC应用的温度稳定的BaLiF3微波陶瓷

虽然BaLiF3陶瓷在微波频率下具有高质量因子（Q × f值= ~ 83000 GHz）和低烧结温度（750°C/2 h），但其谐振频率的高负温度系数（τf = ~ - 70 ppm/°C）阻碍了实际应用。在本文中，我们采用SrTiO3作为第二相（7 mol%）将负τf值调整到接近零（~ 2.5 ppm/°C），并添加少量的LiF （4 mol%）将烧结温度降低到~ 800°C。在N2气氛下烧结有利于密度的提高，但由于SrTiO3中的Ti4+部分还原（SrTi4+1-xTi3+xO3-xFx）和BaLiF3中的f空位（BaLiF3-x），对烧结体的Q × f值有不利影响。添加4 mol% LiF的0.93BaLiF3 +0.07SrTiO3复合材料具有优异的复合微波介电性能（εr = 14, Q × f = 55 000 GHz, τf =−3 ppm/°C），烧结温度低（785°C/3 h），与银具有良好的共烧化学相容性，是LTCC应用的理想候选材料。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Applied Ceramic Technology 工程技术-材料科学：硅酸盐

CiteScore

3.90

自引率

9.50%

发文量

280

审稿时长

4.5 months

期刊介绍： The International Journal of Applied Ceramic Technology publishes cutting edge applied research and development work focused on commercialization of engineered ceramics, products and processes. The publication also explores the barriers to commercialization, design and testing, environmental health issues, international standardization activities, databases, and cost models. Designed to get high quality information to end-users quickly, the peer process is led by an editorial board of experts from industry, government, and universities. Each issue focuses on a high-interest, high-impact topic plus includes a range of papers detailing applications of ceramics. Papers on all aspects of applied ceramics are welcome including those in the following areas: Nanotechnology applications; Ceramic Armor; Ceramic and Technology for Energy Applications (e.g., Fuel Cells, Batteries, Solar, Thermoelectric, and HT Superconductors); Ceramic Matrix Composites; Functional Materials; Thermal and Environmental Barrier Coatings; Bioceramic Applications; Green Manufacturing; Ceramic Processing; Glass Technology; Fiber optics; Ceramics in Environmental Applications; Ceramics in Electronic, Photonic and Magnetic Applications;