US 4921819
HAFNIA MODIFIED ALUMINA FIBERS
Assignee
E.I. DU PONT DE NEMOURS AND COMPANY, A CORP. OF DE
Filed
Sep 24, 1987
Granted
May 1, 1990
Location
HOCKESSIN DE US
Abstract
Alumina fibers which incorporate hafnia and optionally zirconia plus a fourth oxide exhibit surprising grain refinement on sintering, and thereafter excellent retention of strength after exposure to high temperatures.
Source: Google Patents
35 USC §181 Secrecy Order
Imposed
Mar 9, 1988
Rescinded
Apr 13, 1989
Duration
1 year, 1 month
Inventor
- 1SESHADRI RAMACHANDRAN
Record Details
- Patent number
- US 4921819
- Application
- 00710076
- Aerospace match
- No
- Dataset source
- 35 USC §181 SO records
Browse by Assignee
E.I. DU PONT DE NEMOURS AND COMPANY, A CORP. OF DEBack to patent indexSource: USPTO 35 USC §181 secrecy order records