摘要
基于SwartzandShrout的二次合成法,采用改进的两步法,部分原料预合成,一次烧结合成具有完全钙钛矿结构的75Pb(Zn1/3Nb2/3)O310PbTiO315BaTiO3固溶体陶瓷。首先按75∶10∶15一次性称量PbO(并且PbO过量5mol%),然后与ZnNb2O6在660℃预反应1h。粉碎后再加入TiO2和BaCO3,充分混合后,在1060～1140℃保温2h烧结成陶瓷试样。XRD结果表明660℃预合成的中间相中没有钙钛矿相,不同于传统的预合成和烧结,改进的两步法工艺在烧结阶段陶瓷的成瓷和致密化同时进行,完成了中间相向钙钛矿相的完全转变。与二次合成法相比,本方法简化了工艺,降低了预合成温度,拓宽了烧结温度,所获得的陶瓷试样介电性能优良。对陶瓷试样进行相同条件的退火,在1100℃烧结的陶瓷试样,介电常数ε获得95%的增幅;在1140℃烧结的陶瓷试样介电常数ε则获得16%的降幅。
Based on the columbite route proposed by Swartz and Shrout, pure perovskite 75Pb(Zn1/3Nb2/3)O3- 10PbTiO3-15BaTiO3 solid-solution ceramics was synthesized by the modified two-step method. The ZnNb2O6 and PbO (additional 5 mol%) were ball-milled and then pre-reacted at 660°C for 1 h. This pre-reacted mixture was wet mixed with the corresponding amounts of TiO2 and BaCO3 powders, and ball milled and dried again. Then the samples were sintered in a double sealed Al2O3 crucible at 1060-1140°C for 2 h. Although there was not any perovskite phase in the precursor powder analyzed by XRD, the ceramic specimens fired at 1060-1140°C for 2 h were 100% perovskite phase. The low pre-reacting temperature prevents PbO evaporation during the processing. Comparing with the columbite route, the processing was simplified and the pre-reacted temperature was decreased, the sintering temperature was broadened, the dielectric properties of sintered samples were improved in the modified method. Dielectric constant Ε, by the same thermal annealing, has a huge increase of up to 95% for the ceramics samples sintered at 1100°C and a sharp decrease of up to 16% for the ceramics samples sintered at 1140°C, respectively.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2005年第5期671-674,共4页
Journal of Functional Materials
基金
国家自然科学基金资助项目(50272052)
关键词
铁电陶瓷
介电性能
改进两步法
热处理
PZN-PT-BT
烧结温度
Annealing
Ball milling
Dielectric properties
Scanning electron microscopy
Sintering
Solid solutions
Synthesis (chemical)
X ray diffraction analysis
