(福州大学 材料科学与工程学院，福州 350108)
摘 要: 针对CaCu3Ti4O12 (CCTO)陶瓷的巨介电性起源存在较大争议的情况，以少量MnO2取代CCTO中CuO或TiO2、采用固相反应法烧结制备名义成分为CaCu3−xMnxTi4O12 (x=0~0.3)和CaCu3Ti4−yMnyO12 (y=0~0.1)的陶瓷。通过微结构和电性能的演变讨论CCTO陶瓷的巨介电响应机理。结果表明：加入少量MnO2后，所有陶瓷均为体心立方(BCC)类钙钛矿结构的CCTO单相；但是，CCTO陶瓷显微结构从异常长大的晶粒转变成均匀的细小晶粒；同时，CCTO陶瓷的电阻率从107Ω·cm显著提高到109 Ω·cm；介电常数从104显著下降到102；介电损耗从10−1急剧降低到10−3；CCTO陶瓷的巨介电响应是由半导体化的晶界/亚晶界和相对绝缘的晶粒/亚晶粒组成的内部阻挡层电容器(IBLC)所致。在较低温度下(＜1 100 ℃)烧结获得高介电常数、低损耗和温度稳定的CCTO基陶瓷，找到一种降低CCTO陶瓷介电损耗的有效方法。
关键字: CaCu3Ti4O12陶瓷；巨介电常数；内部阻挡层电容器(IBLC)；低介电损耗
（College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, China）
Abstract:According to the debate on the origin of the giant permittivity of CaCu3Ti4O12 (CCTO) ceramics, a small amount of MnO2 substitution for CuO or TiO2 was adopted to prepare the ceramics with nominal composition of CaCu3−xMnxTi4O12 (x=0−0.3) or CaCu3Ti4−yMnyO12 (y=0−0.1) by solid-state reaction method. The mechanism of giant dielectric response in CCTO ceramics was discussed in view of microstructure evolution and variation of electric properties. The results show that CCTO ceramics with a small amount of MnO2 substitution exhibit BCC perovskite single phase, but the abnormal growth grain gradually disappears and grains become obviously uniform and fine. Meantime, resistivity significantly increases from 107 to 109 Ω·cm, dielectric constant is abruptly suppressed from 104 to 102, and dielectric loss is greatly reduced from 10−1 to 10−3. An internal barrier layer capacitor (IBLC) is associated with relative insulating grains/subgrains and semiconducting grain boundaries/subgrain boundaries. CCTO ceramics with high dielectric constant, low dielectric loss and good temperature stability are achieved at lower sintering temperature (<1 100 ℃). An effective method is found to decrease the dielectric loss of CCTO ceramics.
Key words: CaCu3Ti4O12 ceramics; giant dielectric constant; internal barrier layer capacitor (IBLC); low dielectric loss
