Milling effect on the microwave properties of Ba2Ti9O20 investigated by EMP technique

• Published in: Journal of the European Ceramic Society Vol. 27; no. 8-9; pp. 3069 - 3073
• Main Authors: CHEN, Yi-Chun, HONG, Tsung-Hsuan, CHENG, Hsiu-Fung, CHANG, Chi-Ben, LEOU, Keh-Chyang, LIN, I.-Nan
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 2007
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Electrotechnical and electronic ceramics; Exact sciences and technology; Technical ceramics; Scanning electron microscopy; Electrical properties; Barium Titanium Oxides Mixed; Dielectric properties; Grinding(comminution); Experimental study; Fabrication property relation; X ray diffraction; Oxide ceramics; BaO-TiO2; Mechanical treatment; Barium oxide; Milling; Evanescent microwave microscopy; Manufacturing; Titanium oxide; Electroceramics
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2006.11.070

The effects of milling on the microstructure and microwave properties of Ba2Ti9O20 materials were investigated by the evanescent microwave probe (EMP) technique. Although the reaction kinetics of the Ba2Ti9O20 materials was markedly enhanced by the high-energy-milling (HeM) process, the quality factor of the materials decreased with the milling time. SiO2-contamination due to the HeM process (with Si3N4 media) was presumed to be the main cause. SiO2-doped Ba2Ti9O20 samples were adopted to enhance and trace the SiO2 effect during HeM. The EMP investigation of the microwave dielectric properties of the local region for the Ba2Ti9O20 samples indicated that lossy Si/Ti-containing phases were expelled by the Ba2Ti9O20 grains, which is particularly obvious in the as-sintered sample surface. Si-contamination induced the abnormal grain growth phenomenon, which, in turn, degraded the microwave dielectric quality factor of the Ba2Ti9O20 materials. 10 refs.