Fine-grained ceramics and method for making the same
US4891341A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1987 |
| Grant date | Jan 2, 1990 |
| Priority date | — |
| Expiry date | Dec 28, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/651
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
High surface area, submicron ceramic powders are synthesized by reducing an oxide in the presence of another metal (i.e., Mg, Al, Ca, and the like) and a source of carbon, nitrogen or boron to form a new oxide and a carbide, nitride (or carbonitride). or boride. The oxide phase can be leached out to leave submicron carbides, nitrides or borides. Alternatively milling of reacted powders allows intimate mixtures of uniform, fine grained ceramic powders to be prepared inexpensively. These multiple-phase composite powders can be formed into a body and densified using conventional techniques to form dense, fine-grained ceramic bodies. Alternatively, containment of unreacted powders and subsequent heating results in multiple-phase dense ceramics with unique microstures. Transformation toughening of composites is possible by adding zirconia or hafnia either before or after the powder synthesis step.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.