异相陶瓷界面对多层陶瓷电容器介电特性的影响

Effects of Interfaces of Different Ceramic Phases on Dielectric Properties of MLCCs

借助于电子显微镜和介温谱仪，研究了热稳定型复相多层陶瓷电容器中存在的异质、异相陶瓷界面的互扩散对其介电特性的影响。结果表明，异质界面之间存在明显的扩散层。其中不同铁电陶瓷之间过渡层的形成虽有助于改善电容器的容温特性，提高界面的粘接强度，但这也在一定程度上破坏了原先的结构设计，改变了元件的电容值。另外，由于不同铁电陶瓷相的烧结特性的不匹配易导致出现界面裂纹和空洞等共烧缺陷，从而提高了元件的介电损耗，相对疏松的界面易出现在涂覆端电极时镀液的渗入，降低了可靠性。

By means of scanning electron microscope and the impedance analyzer, the effects of interfaces among different ceramic phases on dielatric properties of composite MLCCs were investigated. The experimental results indicate that evident diffusion layers exist at the interfaces of different phases. On one hand, the formation of interfaces between dielectric ceramics with different Curie temperatures seem helpful to improve the permittivity-temperature characteristic of MLCCs and the adhesion intensity of interfaces, but it will destroy the original design of structure and then change the capacitance of parts. One the other hand, the cofiring defects, such as cracks, holes and so on, tend to appear because of the sintering mismatch between different ceramics, which will raise the dielectric loss. Relatively loosen niterfaces easily cause the paste leakage when electroplating the end electrode, degrading the reliability of MLCCs.