FAILURE MECHANISMS IN CERAMIC DIELECTRICS
Abstract
With the objective of developing an empirical approach to factors influencing failure in ceramics of high dielectric constant (greater than 200), a number of perovskite (ABO3) dielectrics were prepared and studied. Small substitutions of Nb5 for the B4 ion (Ti4) and of Sc3 for the A2 ion (Pb2, Ba2, Sr2) were made. Nb5 and Sc3 thus act respectively as electron donor and acceptor. It was demonstrated that the zirconates, as a class, are far superior to the titanates with respect to long term degradation, which is probable best ascribed to electrolysis of oxygen. This can proceed more rapidly with the titanates, sunce Ti4 is much more readily reduced than is Zr4. In general, also, the zirconates have higher volume resistivities than the titanates, but there is no clear-cut difference in dielectric strength. Degradation in dielectrics with p-type conduction, which was found to be the usual case, is generally inhibited by donor doping.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1963
- Accession Number
- AD0414353
Entities
People
- Don A. Berlincourt