Cold sintering ZnO based varistor ceramics with controlled grain growth to realize superior breakdown electric field. Issue 1 (January 2021)

• Record Type: Journal Article
• Authors: Zhao, Xuetong; Liang, Jie; Sun, Jianjie; Guo, Jing; Dursun, Sinan; Wang, Ke; Randall, Clive A.
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 1(2021)
• Page Start: 430
• Page End: 435
• Publication Date: 2021-01
• Subjects: Varistors -- Cold sintering -- Submicron-/nano-ceramics -- Grain boundaries -- High breakdown field; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2020.09.023
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Controlling the grain growth and grain boundary morphology is of great importance in the manipulation of electrical properties of electro-ceramics. However, it has been a challenge to achieve dense varistor ceramics with grain sizes in submicrons and nanometers using conventional thermal sintering at high temperatures. Here we present a strategy to fabricate dense ZnO based ceramics with controlled grain growth and thin grain boundaries using cold sintering process (CSP). With CSP, the sintering temperature of ZnO based ceramics dramatically drops from 1100 °C to 300 °C. The Bi2 O3, Mn2 O3, and CoO dopants suppress the grain growth of ZnO under CSP conditions, and Bi-rich intergranular films (2−5 nm) can be observed along grain boundaries. The cold sintered ZnO-Bi2 O3 -Mn2 O3 -CoO ceramic shows a non-linear coefficient of 33.5, and a superior breakdown electric field of 3550 V/mm. This work thus demonstrates that CSP is a promising technique for designing new submicron-/nano-ceramics with superior performances.