Dielectric ceramic composition
US4824813A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1987 |
| Grant date | Apr 25, 1989 |
| Priority date | — |
| Expiry date | Dec 17, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/495
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A dielectric ceramic composition consisting essentially of a BaO-TiO.sub.2 -WO.sub.3 ternary system wherein molar percentages of BaO, TiO.sub.2 and WO.sub.3 are within the range enclosed by a line joining the points of A(21.5, 78.5, 0), B(40.0, 30.0, 30.0), C(37.0, 30.0, 33.0), D(20.0, 75.0, 5.0), E(21.5, 75.0, 3.5) and A of a composition diagram shown in the attached FIGURE, the range excluding molar percentages of BaO, TiO.sub.2 and WO.sub.3 laying on a line joining said points A, E and D. In the dielectric ceramic composition, up to 10 mole % of TiO.sub.2 may be replaced by tetravalent metal oxide and, further, MnO is contained in amounts of 3 mole % or less with respect to 100 mole % of the sum of BaO, TiO.sub.2 and WO.sub.3. Since the dielectric ceramic composition has a beneficial combination of dielectric properties, particularly a high Q, properly small dielectric constant and sufficiently small temperature coefficient of resonant frequency, .tau..sub.f, and .tau..sub.f, can be adjusted to a desired value in the vicinity of 0 ppm/.degree.C., it is especially greatly useful at the microwave range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.