制備及電性能
(江蘇科技大學 數(shù)理學院，鎮(zhèn)江 212003)
摘 要: 采用有機凝膠法結(jié)合固相燒結(jié)技術(shù)制備Sm1-xSrxAl1-yFeyO3-δ (SSAF, x = 0.10~0.20, y = 0.10~0.70)系列新型混合導電陶瓷。利用TG—DTA、XRD、FTIR、Archimedes法和直流四線法分別對凝膠前驅(qū)體的熱分解及相轉(zhuǎn)化過程、燒結(jié)體的相結(jié)構(gòu)、相對密度和電導率進行表征，研究燒結(jié)溫度及Sr和Fe摻雜量對樣品的結(jié)構(gòu)、電性能及輸運機制的影響。結(jié)果表明：凝膠前驅(qū)體在900 ℃焙燒5 h可以形成結(jié)晶良好的四方鈣鈦礦相納米粉體；隨著燒結(jié)溫度的升高，Sm0.9Sr0.1Al0.5Fe0.5O3−δ(SSAF9155)陶瓷的電導率和相對密度都先增大后減小，1 450 ℃燒結(jié)5 h制得的SSAF9155陶瓷具有最高的電導率和相對密度；SSAF陶瓷的電導率主要取決于p型電導，且隨Sr和Fe摻雜量的增加而增大，在中低溫段電導率隨著溫度的升高而增大，遵從Arrhenius關(guān)系，導電行為符合p型小極化子跳躍導電機制；樣品的表觀活化能隨著Fe摻雜量的增加而減小，隨著Sr摻雜量的增加而增大。
關(guān)鍵字: 導電陶瓷；Sr；Fe；摻雜；SmAlO3；有機凝膠法；電性能
new mixed conducting ceramics Sm1-xSrxAl1-yFeyO3-δ
（School of Mathematics and Physics, Jiangsu University of Science and Technology, Zhenjiang 212003, China）
Abstract:A series of new perovskite-type mixed conducting ceramics Sm1-xSrxAl1-yFeyO3-δ (SSAF) were prepared by the organic gel method combined with solid state sintering technique. The thermal decomposition and phase inversion processes of the gel precursors and phase structure of the sinters were analyzed by means of TG—DTA, XRD and FTIR. The relative density of the ceramics was measured by Archimedes method, and the electrical conductivity of the samples in air was studied by the direct current four-wire method. The effects of sintering temperature and concentrations of Sr and Fe on the structures, electrical properties and transport mechanism of the samples were investigated. The results show that the well-crystallized nanopowders with tetragonal perovskite structure can be obtained by calcining the gel precursors at 900 ℃ for 5 h. With increasing the sintering temperature, both the electrical conductivity and relative density of SSAF9155 ceramics become large initially and then decrease, and the sample sintered at 1 450 ℃ for 5 h has the highest relative density and electrical conductivity. The electrical conductivities of SSAF ceramics are dominated by p-type electronic conduction and increase with increasing Sr and Fe doping content. Besides, the electrical conductivities of these samples increase with increasing temperature in medium-low temperature region and obey the Arrhenius relationship, indicating that the mechanism of electronic transport is the hopping of p-type small polaron. The apparent activation energies for SSAF ceramics decrease with increasing Fe doping content, but increase with increasing Sr doping content.
Key words: conducting ceramics; Sr; Fe; doping; SmAlO3; organic gel method; electrical property
