High temperature ceramic composites
US5137852A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1991 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Jan 11, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2938
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Thermodynamically stable ceramic composites are provided for use in high temperature oxidizing environments. The composites comprise high strength alumina fibers (Al.sub.2 O.sub.3) in a ceramic matrix. The ceramic matrix comprises material similar to the fibers to improve compatibility of the composite materials. A material selected from the .beta.-alumina and magnetoplumbite family of materials is used to provide a weakly bonded interface between the fibers and the ceramic matrix. .beta.-aluminas and magnetoplumbites have weak layers as an intrinsic characteristic of their crystal structure, which comprise spinel layers (basically Al.sub.2 O.sub.3) separated by very weakly bonded planes containing the .beta.-forming ions. The weak planes of these materials allow preferential debonding and sliding, and thus inhibit crack growth across the interface between the fibers and the ceramic matrix. The alumina fibers can be coated with .beta.-alumina by any of several methods such as heat treating the fibers in an atmosphere containing the desired .beta.-forming ions. Composite structures can be fabricated by placing the coated fibers in powdered matrix material and hot pressing. .beta.-al…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.