Research/Patents/US 5891815
US 5891815Tier 3 — General Defense

SILICA, BORON NITRIDE, ALUMINUM NITRIDE, ALUMINA COMPOSITE, ARTICLE AND METHOD OF MAKING SAME

Assignee

General Electric

Filed as: GENERAL ELECTRIC COMPANY, A CORP. OF NY

Filed

Dec 21, 1988

Granted

Apr 6, 1999

Location

OAKS PA US

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 DEG C. and at a pressure of about 3775 p.s.i. for about 1 hour.

Source: Google Patents

35 USC §181 Secrecy Order

Imposed

Feb 28, 1990

Rescinded

Apr 29, 1998

Duration

8 years, 2 months

Inventor

  • 1GERALD C. DODDS

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Back to patent indexSource: USPTO 35 USC §181 secrecy order records