CaTiO3-based ceramics: Microstructural development and dielectric properties

Ceramics based on CaTiO3-NdAlO3 solid solutions were synthesized in order t o study their dielectric microwave properties. Microstructural analysis was performed with scanning electron microscopy (SEM) and transmission electro n microscopy (TEM) using different analytical methods such as energy-disper sive X-ray spectroscopy (EDXS). It was observed that the heating conditions during sintering and subsequent cooling strongly affect the microstructura l development of the CaTiO3-NdAlO3-based ceramics. Various types and concen trations of structural defects were identified, for example, dislocations, twins and/or antiphase boundaries. All such defects resulted in a degradati on of the dielectric microwave properties, in particular the quality factor Q. The dielectric properties of CaTiO3-NdAlO3-based ceramics can be improv ed by an appropriate thermal treatment. Some of the microwave dielectric pr operties can also be improved by using iso- or alio-valent dopants.