Microwave dielectric properties of Ba6-3xLa8+2x(Ti1-zZrz)18O54（x=2/3） ceramics
来源期刊：JOURNAL OF RARE EARTHS2010年第3期
论文作者：高旭芳 丘泰
文章页码：411 - 415
摘 要：Zr substitution for Ti was investigated to modify the dielectric properties of Ba6-3xLa8+2xTi18O54（x=2/3） ceramics.A single-phase solid solution with tungstenbronze-like structure was formed in the range of 0<z<0.2 in Ba6-3xLa8+2x（Ti1-zZrz）18O54 ceramics.As Zr content exceeded this range,a secondary phase of Ba2ZrO4 was detected.This is correlated with the decrease of tolerance factor.As Zr content increased,there was an expansion of the b-axis and c-axis,and increase in the cell volume.Incorporation of small levels of Zr into the structure led to a significant increase in Q·f values,from 2053 to 6665 GHz,a decrease in dielectric constant（εr） from 107.4 to 79.6 and the temperature coefficient of resonant frequency（τf） slightly improved.The maximum value of Q·f（6665 GHz,f=4.83 GHz） was achieved while εr was 79.6 and τf was 109.83×10-6 oC-1 for z=0.1.Microstructure studies with SEM indicated that the ceramics with larger and homogenous columnar grains had high Q·f value.
高旭芳，丘泰
College of Materials Science and Engineering,Nanjing University of Technology
摘 要：Zr substitution for Ti was investigated to modify the dielectric properties of Ba6-3xLa8+2xTi18O54（x=2/3） ceramics.A single-phase solid solution with tungstenbronze-like structure was formed in the range of 0<z<0.2 in Ba6-3xLa8+2x（Ti1-zZrz）18O54 ceramics.As Zr content exceeded this range,a secondary phase of Ba2ZrO4 was detected.This is correlated with the decrease of tolerance factor.As Zr content increased,there was an expansion of the b-axis and c-axis,and increase in the cell volume.Incorporation of small levels of Zr into the structure led to a significant increase in Q·f values,from 2053 to 6665 GHz,a decrease in dielectric constant（εr） from 107.4 to 79.6 and the temperature coefficient of resonant frequency（τf） slightly improved.The maximum value of Q·f（6665 GHz,f=4.83 GHz） was achieved while εr was 79.6 and τf was 109.83×10-6 oC-1 for z=0.1.Microstructure studies with SEM indicated that the ceramics with larger and homogenous columnar grains had high Q·f value.
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