A novel low‐permittivity LiAl0.98(Zn0.5Si0.5)0.02O2‐based microwave dielectric ceramics for LTCC application

• Published in: International journal of applied ceramic technology Vol. 17; no. 2; pp. 745 - 750
• Main Authors: Lan, Xue‐Kai, Li, Jie, Wang, Fei, Wang, Xiaohong, Lu, Wen‐Zhong, Hu, Ming-Zhe, Lei, Wen
• Format: Journal Article
• Language: English
• Published: Malden Wiley Subscription Services, Inc 01.03.2020
• Subjects: Calcium titanate; Ceramics; Chemical compatibility; dielectric materials/properties; Dielectric properties; electroceramics; Low temperature; Morphology; Organic chemistry; Phase composition; Sintering
• ISSN: 1546-542X; 1744-7402
• DOI: 10.1111/ijac.13368

Phase composition, morphology, and microwave dielectric properties of (1−x) LiAl0.98(Zn0.5Si0.5)0.02O2 + x CaTiO3 (0.05 ≤ x ≤ 0.20) materials synthesized via the solid state reaction method were investigated. All these densified materials were obtained at a sintering temperature of 1150°C. All compositions showed a major LiAlO2 phase that was accompanied by a minor CaTiO3 phase. The εr value increased gradually from 10.88 to 11.60, whereas the Q × f value remarkably decreased from 33 251 GHz to 13 511 GHz. The τf value changes from −85 ppm/°C to 212 ppm/°C, thereby indicating that CaTiO3 could effectively adjust this value. HBO3‐doping was used to further decrease the sintering temperature to 900°C. The optimum value was obtained at 7 wt.% HBO3 doped with microwave dielectric properties of εr = 9.39, Q × f = 10 224 GHz, and τf = −7.8 ppm/°C. This material also exhibited chemical compatibility with silver, making it a candidate for low temperature co‐fired ceramics applications.