Ba_<6-3x>Sm_<8+2x>Ti_<18>O_<54> 固溶体の低温焼結化とマイクロ波誘電特性

概要

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Ba_<6-3x>Sm_<(8+2x)(1-y)>Ti_<18>O_<54-δ> {δ=3y (x+4)} ceramics were developed in this study to lower the sintering temperature as well as to maintain the excellent microwave dielectric properties of tungsten-bronze-type like Ba_<6-3x>Sm_<8+2x>Ti_<18>O_<54> solid solutions. Ba_<6-3x>Sm_<(8+2x)(1-y)>Ti_<18>O_<54-δ> ceramics were prepared by a slight change in the mixing composition from the solid solutions area to Ba_2Ti_9O_<20> direction on the BaO-Sm_2O_3-TiO_2 ternary phase diagram. Effects of compositional parameters x and y on the density of the sintered body and the microwave dielectric properties were investigated. Ba_4Sm_<9.15>Ti_<18>O_<53.72> (x=2/3,y=0.02) ceramics sintered at 1350℃ demonstrated the excellent properties including a high relative permittivity (ε_r=81), high quality factor (Q・f=10000GHz) and low temperature factor of resonant frequency (τ_f=-13 ppm/℃). These properties are almost equivalent to those obtained in Ba_4Sm_<9.33>Ti_<18>O_<54> (x=2/3) solid solutions which need higher fabricating temperatures than 1460℃. It was also shown that a ball-milling technique strongly affected the density of sintered body and the resulting relative permittivity.
The Ceramic Society of Japanの論文
2002-02-01