Barium oxide-rare earth oxide-titanium dioxide based ceramics exhibiting isotropy
US5620638A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 12, 1994 |
| Grant date | Apr 15, 1997 |
| Priority date | — |
| Expiry date | May 12, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/468
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Ceramics resulting from the oxide system barium oxide-rare earth oxide-titanium oxide have been found to exhibit an isotropy with respect to electrical properties such as the temperature coefficient of frequency at the first resonant frequency, dielectric constant, and, to some extent, the loss factor, Q. Such anisotropy effects reproducibility in fabricating ceramic articles for use in the microwave region and in the performance of these articles. Isotropic ceramics from the same ternary oxide system can be made by compacting non-nucleated powders followed by the usual sintering of the green compact. Anisotropic bulk ceramic workpieces can be machined to reproducibiy afford ceramic articles with the appropriate value of the electrical property in question by measuring the components of the electrical property along the three principal axes of the workpiece, and then determining the angles between the principal axes necessary to give a resultant having the preselected value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.