DC bias characteristics of BaTi0.65Zr0.35O3 with additives (Gd2O3, SiO2, MgO) for multilayer ceramic capacitors. Issue 18 (15th December 2020)

• Record Type: Journal Article
• Authors: Wang, Sea-Fue; Hsu, Yung-Fu; Chang, Chun-Wei; Lai, Bo-Cheng; Li, Jian-Hua; Lai, Yuan-Cheng
• Is Part Of: Ceramics international. Volume 46:Issue 18(2020)Part A
• Page Start: 28227
• Page End: 28236
• Publication Date: 2020-12-15
• Subjects: Dielectric properties -- X7T -- BaTiO3 -- Formulation -- Microstructure -- DC bias; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.07.323
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In this study, BaTi0.65 Zr0.35 O3 -2 mol% MgO ceramics with various amounts of Gd2 O3 and SiO2 additives were prepared via a solid-state reaction method. The densification temperature of the BaTi0.65 Zr0.35 O3 -2 mol%, MgO-2 mol%, and SiO2 ceramic was 1275 °C, with the addition of less than 2.0 mol% Gd2 O3 . The Gd 3+ ions preferentially replaced the A-site ions. The densification temperature was reduced to 1225 °C, and the grain size of the ceramics was grown significantly up to 2.96 μm for 2 mol% Gd2 O3, in addition to the formation of a trace amount of Ba2 GdZrO5.5 . There was a significant decline in the value of tanδ, and the electrical resistivity was increased by almost an order of magnitude due to the decrease in the V O concentration and the larger grain size. When the Gd2 O3 content exceeded 2 mol%, the Gd 3+ ions entered the B-site positions. For 5 mol% Gd2 O3, the densification temperature is increased to over 1350 °C, the grain size reduced to 0.84 μm, and the value of tanδ is increased and the electrical resistivity is decreased as a result of the increasing V O concentration. The temperature coefficient of capacitance curves shows a nearly linear relationship between temperature and negative temperature coefficient and rotate counter-clockwise with an increase in Gd2 O3 and SiO2 content. The BaTi0.65 Zr0.35 O3 -2 mol% MgO-2 mol% SiO2 ceramics had a dielectric constant of 871 at room temperature, which decreased to 417 for 5 mol% Gd2 O3 . The dielectric constant of the BaTi0.65 Zr0.35 O3 -2 mol% MgO ceramics, with and without the 2 mol% SiO2 additive, steadily declined by 10.2% at a bias field of 2.5 KV/mm. The magnitude of change in the dielectric constant has reduced significantly to 1.33% for the 5 mol% Gd2 O3 additive.