Silica, boron nitride, aluminum nitride, alumina composite, article and method of making same
US5891815A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1988 |
| Grant date | Apr 6, 1999 |
| Priority date | — |
| Expiry date | Dec 21, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q1/42
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Multiphase ceramic composites containing 47% to 52% by weight aluminum nitride, 23% to 27% by weight silica, 3% to 7% alumina and the balance boron nitride wherein the boron nitride is one phase in the composition and the reaction products of aluminum nitride, silica and alumina are the other phase in the composite. The boron nitride phase is uniformly distributed in the form of discrete particles throughout the reaction products of aluminum nitride, silica and alumina. A window transparent to electromagnetic radiation in a predetermined frequency spectrum is made by forming a homogeneous, finely-divided mixture of the foregoing composite and compacting the homogeneous, finely-divided mixture at an elevated temperature and pressure for a sufficient time to form reaction products of the aluminum nitride, silica and alumina. In preferred embodiments, the homogeneous, finely-divided mixture of aluminum nitride, silica, boron nitride and alumina is densified at a temperature of 1760.degree. C. and at a pressure of about 3775 p.s.i. for about 1 hour.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.