李涛
,
薛运才
,
陈镇平
,
苏玉玲
,
刘文涛
功能材料与器件学报
doi:10.3969/j.issn.1007-4252.2009.06.003
以稀土氧化物Eu_2O_3为添加剂,采用固相反应法制备了不同掺杂比例(质量比:x=0,0.2%,0.5%,1%)的CCTO陶瓷样品,利用SEM、XRD、4294A型高精密阻抗分析仪等测试手段对样品的微观结构、介电性能和交流电阻率进行了测试分析.掺杂之后样品的晶格结构并未发生改变,但是样品内部相对晶相含量和晶粒平均尺寸减小,同时掺杂阻碍了样品内部晶界处富铜相的生成;纯CCTO的XRD图谱中分别出现了CuO、TiO_2和CaCO_3杂相,掺杂样品的图谱中并未出现上述杂相;样品的介电性能与相同组分材料内部的相对晶相含量,晶粒平均尺寸和晶界处富铜相有很大关系.Eu_2O_3掺杂提高了样品介电性能的频率和温度稳定性.当掺杂量为0.2%和0.5%时,样品的介电性能得到较好改善效果.样品在低频40Hz和高频3.5MHz的交流电阻率测量结果很好的验证了Eu_2O_3掺杂导致的微结构变化对样品介电性能的影响.
关键词:
介电常数
,
频率(热)稳定性
,
富铜相
,
阻挡层电容
Z.El-Gohary
,
M.El-Nahass
,
H.Soliman
,
Y.L.El-Kady
材料科学技术（英）
The different optical dispersion parameters of SrLaAlO4 single crystals have been studied by the transmission and reflection measurements at normal incidence for the three orientations 001, 100 and 101 in the spectral range 400nm-2500nm.The optical absorption data revealed the existance of allowed indirect and direct transition. The refractive index has abnormal behaviour in the spectral region 400-900nm, but has a normal one in the higher wavelength region. The optical dispersion parameters, the single oscillator energy Eo and the dispersion energy Ed were determined and indicated the ionic structure of the material. The high-frequency dielectric constant, the lattice dielectric constant and the electronic polarizability were determined by the free carriers and the lattice vibration modes. The real dielectric constant ε1 the dielectric loss tangent (tanδ), the volume (VELF) and the surface energy loss function (SELF) have also been discussed.
关键词:
Optical parameters
,
null
,
null
唐培毅
,
李洪深
,
裴雨辰
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2015.04.017
为了获得更低介电常数及介电损耗的材料,采用单官能团氰酸酯改性氰酸酯树脂,研究了单官能团单体对聚合物分子网络结构形成过程、反应过程的流变行为及固化产物性能的影响.研究结果表明,单官能团单体在固化反应初期参与反应比例较小,反应后期才逐步参与反应进入分子网络并促进反应程度的提高,改性树脂体系介电常数为2.8～2.9 (7～18 GHz),介电损耗也有一定下降.
关键词:
单官能团单体
,
氰酸酯
,
介电性能
