用传统的烧结法,经850-950℃预烧和1050-1090℃烧结,制备了CaCu3Ti4O12 巨介电常数陶瓷,通过X射线衍射(XRD)、扫描电镜(SEM)分别对体系进行了结晶性能和形 貌测试,用阻抗分析仪对试样在50-300K温区范围内介电性能进行了测试.研究结果表明, CaCu3Ti4O12结晶完整性、晶界及缺陷对其巨介电常数的大小、出现低介电常数向高介电常数 转变时对应温度的高低有直接的影响.在950℃预烧和1090℃下烧结的样品要比880℃预烧 和1050℃下烧结样品出现极化子松弛时对应的温度下降约70K,介电常数相对提高约300％, 在较大的温区范围具有高的介电常数.材料的结晶越完整,由低到高介电常数的转变速度越快.
CaCu3Ti4O12 ceramics with giant dielectric constant were prepared by the traditional ceramic method, in which the oxide powders were mixed and pre-sintered at 850～950℃, and then
sintered at 1050～1090℃, respectively. XRD, SEM and LCR were used to measure the phase structure, the morphology and dielectric properties of the ceramics. The results show that the dielectric
constant and the temperature at which the low dielectric constant typically transforms to special high are seriously controlled by the perfection and the defects of grain boundaries of the crystalline. The
relaxation temperature of the dipole in the sample pre-sintered at 950℃ and sintered at 1090℃ is 70K lower than that of the dipole in the sample pre-sintered at 880℃ and sintered at 1050℃,
and the dielectric constant is 300% enhanced, and simultaneously remains giant in a relative wide temperature range. The better the crystallinity of the ceramic, the faster the transation of the dielectric
constant from low to high.
参考文献
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