热压烧结SiC/CCTO陶瓷电容器的工艺和性能

Processing and Properties of SiC/CCTO Ceramic Capacitors by Hot-Pressing Sintering

首先采用固相法合成CaCu3Ti4O12(CCTO)粉体,与SiC粉体均匀混合后,采用真空热压制备了SiC/CCTO复合陶瓷电容器。采用DSC-TG技术分析了SiC/CCTO复合粉体的热行为,采用XRD、SEM等手段对样品进行表征,研究了SiC/CCTO复合陶瓷电容器的介电性能,并对其介电机理进行了探讨。结果发现,在950℃和30MPa的热压条件下制备出的SiC/CCTO复合陶瓷电容器具有最高的介电常数εr≈3×10(81kHz),分析认为其介电机理属于阻挡层机制,载流子在SiC与CCTO界面处聚积,形成空间电荷极化。

SiC particles were mixed with CCTO powders which were prepared firstly via conventional solid-state reaction. SiC/CCTO composite ceramic capacitors were prepared by hot pressing sintering. The DSC-TG technique was used to detect the thermal behaviors of SiC/CCTO composite powders. XRD and SEM techniques were used to characterize the samples. The effects of sintering processes on dielectric response of SiC/CCTO composites were investigated. It was found that the highest dielectric constant of sample via hot pressing process at 950 ℃ under 30 MPa was about 3.0× 10^8 （at 1 kHz）. The mechanism accords with the internal barrier layer capactior model. The charge carriers can be piled up at the interface between SiC and CCTO grains, resulting in polarization.