【作者】 胡国辛； 高峰； 曹宵； 刘亮亮； 田长生；

【Author】 HU Guo-xin,GAO Feng,CAO Xiao,LIU Liang-liang,TIAN Chang-sheng (College of Material Science,Northwestern Polytechnical University,Xi’an 710072,China)

【机构】 西北工业大学材料学院；

【摘要】 以Ba_0.6Sr_0.4TiO₃为基体材料,采用传统电子陶瓷制备工艺,研究复合掺杂低介电常数氧化物Al₂O₃和MgO对BSTO材料显微组织结构和介电性能的影响规律。结果表明,BSTO/MgO/Al₂O₃（BMA）陶瓷可在1350～1450℃烧结成瓷,主晶相为BSTO和MgAl₂O₄;Al³⁺比Mg²⁺更易于进入Ba_0.6Sr_0.4TiO₃的晶格中置换Ti⁴⁺,当Al₂O₃含量超过25.0%（质量分数）,Al₂O₃会与BaAl₂O₄反应生成新相BaAl₁₂O₁₉;适量的Al₂O₃-MgO复合掺杂可降低BSTO陶瓷的介电常数,同时保持较高的介电可调性;随Al₂O₃添加量的增加,BMA陶瓷材料的介温谱线出现了明显的频率色散现象,当Al₂O₃添加量>25%（质量分数）时,陶瓷材料的介温谱线出现了双峰,介电峰被压低、宽化;当Al₂O₃添加量为20%（质量分数）时,材料在1kV/mm下的可调性达到33.9%。更多还原

【Abstract】 The Ba_0.6Sr_0.4TiO₃（BSTO） ceramics were prepared by traditional electrical ceramic methods.Effects of co-doping low dielectric constant oxides A1₂O₃ and MgO on microstructures and dielectric properties of Ba_0.6 Sr_0.4TiO₃ ceramics were investigated.The results show that BSTO/MgO/Al₂O₃（BMA） ceramics can be sintered at 1350-1450℃.The main crystal phases are Ba_0.6Sr_0.4TiO₃ and MgAl₂O₄.A1³⁺ is easier to enter Ba_0.6Sr_0.4 TiO₃ lattice in the replacement of Ti⁴⁺ than Mg²⁺.When A1₂O₃ content exceeds 25wt%,A1₂O₃ will react with BaAl₂O₄ to generate a new phase BaAl₁₂O₁₉.Proper amount of Al₂O₃-MgO can reduce the dielectric constant of BSTO ceramics which also can ensure the higher tunability.There is obvious frequency dispersion characteristic in BMA ceramics with the increase of A1₂O₃.When A1₂O₃ content exceeds 25wt%,two dielectric peaks are observed in the temperature spectrums of ceramics,which decrease and broaden.When A1₂O₃ content is 20wt%, the tunability amounts to 33.9%under a bias field of 1.0kV/mm dc.更多还原