Effect of TiO2 Doping on the Structure and Microwave Dielectric Properties of Cordierite Ceramics |
| |
Authors: | Song Wu Kaixin Song Peng Liu Huixing Lin Fangfang Zhang Peng Zheng Huibin Qin |
| |
Affiliation: | 1. College of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, China;2. Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China |
| |
Abstract: | The (1?x)Mg2Al4Si5O18–xTiO2 |(1?x)MAS‐xT| (0 ≤ x ≤ 0.35) cordierite ceramics are fabricated by solid‐state reaction method for obtaining near‐zero temperature coefficient of resonant frequency (τf). The XRD and SEM results show that (1?x)MAS‐xT (0 ≤ x ≤ 0.10) ceramics exhibit single cordierite solid solution, whereas as 0.15 ≤ x ≤ 0.35, present composite phases of Mg2Al4Si5O18 solution and TiO2. Rietveld refinements of XRD data suggest that the (Si4Al2)O18] hexagonal shape in cordierite structure happens to alternate change from nonsymmetrical hexagonal rings to almost centrosymmetrical equilateral rings as x increases to 0.10 comparing to that of x = 0. As Ti4+ ions squeeze into the (Si4Al2)O18] rings structure, the orientation and shapes of the rings begin to rotate and expand from initial state of 1–20] (x = 0) to near 210] direction (x = 0.10), and then continue to expand toward close to 110] direction (x = 0.25). Due to centrosymmetry adjustment of (Si4Al2)O18] hexagonal rings and of other microstructure factors improvement, the (1?x)MAS‐xT (x = 0.10) cordierite solution achieves optimum quality factor Qf: εr = 6.3, Qf = 55 400 GHz (17.6 GHz), τf = ?21 ppm/°C. The (1?x)MAS‐xT (x = 0.25) composites obtain a near‐zero temperature coefficient of resonance frequency: εr = 6.8, Qf = 37 800 GHz (18.4 GHz), τf = ?0.2 ppm/°C. |
| |
Keywords: | |
|
|