Abstract
$Pb(NO_3)_2$, $Mg(NO_3)_2$ and $NbCl_5$ were used as starting materials and made into solutions. For $Pb(Mg_{1/3}Nb_{2/3})O_3$ composition, each solution measured was mixed and heated to $70^{\circ}C$ to resolved $PbCl_2$ precipitated at lower temperature coprecipitates were formed by adding oxine and ammonia gas under pH ranging 8 to 10, and the prepared coprecipitates were filtered and washed by distilled water. The $Pb(Mg_{1/3}Nb_{2/3})O_3$ powders were synthesized by calcination of coprecipitates at the temperature range of $700^{\circ}C$ to $1000^{\circ}C$, for 5hr. The average particle size of the synthesized powders showing spherical shape was $0.3{{\mu}m}$. The powders were formed to make pellets under pressure of $2000Kg/cm^2$, and the formed pellets were sintered at the temperature range of 1100 to $1200^{\circ}C$, for 5hr. The speciman sintered at $1200^{\circ}C$ showed theoretical density of 97.4%, dielectric constatnt of 17000 at 1kHz, and dielectric loss of 0.02% at 1kHz
출발물질로 $Pb(NO_3)_2$, $Mg(NO_3)_2$, $NbCl_5$를 선정하여 이들을 수용액상으로 $Pb(Mg_{1/3}Nb_{2/3})O_3$조성에 맞도록 각 수용액을 정확히 취하여 $Pb(Mg_{1/3}Nb_{2/3})O_3$ 1M용액이 되도록 조제하였다. 이 혼합용액은 상온에서 $PbCl_2$를 형성하므로 $70^{\circ}C$로 가열하여 $PbCl_2$를 용해시킨 후, 침전제 oxine을 가하여 pH 8~10에서 공침물을 얻었다. 이 침전물을 여과, 건조의 공정을 거처 $700{\sim}1000^{\circ}C$로 5시간 하소하여 $Pb(Mg_{1/3}Nb_{2/3})O_3$을 합성하였으며 합성된 분말은 평균입경이 $0.3{{\mu}m}$ 정도이고 모양은 구형이었다. 그리고 합성된 분말을 $2000Kg/cm^2$의 압력으로 성형하고, $1100{\sim}1200^{\circ}C$로 소성하여 이론밀도의 97.4%인 소결체를 얻었고 이때의 유전율은 1kHz에서 17000이고 유전손실은 상온에서 0.02%이었다.
(Dept. of Chem. Eng., College of Eng., Dan Kook Univ.)