Microstructure and Dielectric Properties in <TEX>$40Pb(Mg_{1/3}Nb_{2/3})O_3-30PbTiO_3-30Pb(Mg_{1/2}W_{1/2})O}3$</TEX> Ceramics with Excess <TEX>$91PbO-9WO_3$</TEX> Addition

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J. Korean Ceram. Soc. > Volume 34(3); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(3): 281.

$91PbO-9WO_3$가 과잉첨가된 $40Pb(Mg_{1/3}Nb_{2/3})O_3-30PbTiO_3-30Pb(Mg_{1/2}W_{1/2})O}3$계 세라믹스의 미세구조와 유전특성

길영배, 이응상

한양대학교 무기재료공학과

Microstructure and Dielectric Properties in $40Pb(Mg_{1/3}Nb_{2/3})O_3-30PbTiO_3-30Pb(Mg_{1/2}W_{1/2})O}3$ Ceramics with Excess $91PbO-9WO_3$ Addition

ABSTRACT

The effects of 0 to 6 mol% excess 91PbO-9WO3 addition on the microstructure and the dielectric pro-perties in 40Pb(Mg1/3Nb2/3)O3-30PbTiO3-30Pb(Mg1/2W1/2)O3 ternary system were investigated. Excess 91PbO-9WO3 addition enhanced densification at relatively lower temperature due to the formation of liquid phase. The dielectric constant of the specimen with standard composition was 16,400 and that of specimen with 1 mol% excess additive was the maximum of 18,500. And more than 2 mol% excess addition decreased dielec-tric constant. Specimens with 2~4 mol% 91PbO-9WO3 addition showed dual peak maxima in the tem-perature dependence of dielectric constant. In the specimens which have more than 5 mol% excess addition a new phase with W-rich composition was formed at grain boundary.

Key words: Dielectrics, Low sintering temperature, Excess $91PbO-9WO_3$ addition, Microstructure