为获得高介电常数低介电损耗的钛酸锶钡陶瓷,采用固相反应法制备了Y3+掺杂BST60,BST65,BST70陶瓷.用X射线衍射(XRD)、扫描电子显微镜(SEM)和阻抗分析仪,对陶瓷的微观结构和介电性能进行了测量.研究发现,Y3+的掺入并未改变陶瓷母体结构,Y3+在BST中形成了连续固溶体.最佳烧结温度处,随Ba/Sr比增大,晶粒尺寸增加;同一Ba/Sr比下,掺杂Y3+能促进晶粒生长,由开始的平均1 μm增大为3μm～4 μm,尺寸连续分布,致密度提高.适量Y3+掺杂有利于提高材料介电常数,降低介电损耗.当烧结温度为1450℃,Y3+掺杂量为0.3％(摩尔分数)时,BST70陶瓷相对密度为95.7％,介电常数最大为27891;此时BST65介电常数为17811,损耗最小为0.00869,频率稳定性最好.
In order to obtain barium strontium titanate with high dielectric constant and low dielectric loss,y3 +-doped BSTx (x =60,65,70) ceramics were synthesized by the conventional solid state route.The microstructure and dielectric properties of the ceramics were measured by using X-ray diffraction (XRD),scanning electron microscope (SEM) and impedance analyzer.It is found that all samples exhibit a typical perovskite structure by the doping of Y3 + and Y3 + in the BST forms a continuous solid solution.With the Ba/Sr ratio increasing,the grain size and the density will increase at optimum sintering temperature.Y3 + doping can promote grain growth,ranging from an average of 1 um to 3 ～4 um at the same Ba/Sr ratio.Adding proper Y3 + is helpful to enhance the dielectric constant and reduce the dielectric loss.When Y3 +-doped amount is 0.3％ (mole fraction),the relative density of BST70 ceramics is 95.7％ with the highest dielectric constant (27891) at the sintering temperature of 1450 ℃;BST65 ceramics have the lowest dielectric loss (0.00869),dielectric constant is 17811 at the same time,and its frequency stability is the best.
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