Solid state thermal conversion of polycrystalline alumina to sapphire
US5451553A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1993 |
| Grant date | Sep 19, 1995 |
| Priority date | — |
| Expiry date | Sep 24, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B29/20
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A solid state process for the bulk conversion of a dense polycrystalline ceramic body to a single crystal body has been accomplished by heating the polycrystalline material to a temperature above one-half of the melting temperature of the material but below the melting point of the material. As the process is a solid state process, no melting of the ceramic body is necessary to convert it to a single crystal. The process has been used to convert a dense polycrystalline alumina body (PCA) containing less than 100 wppm of magnesia to sapphire (single crystal alumina) by heating the PCA to temperatures above 1100.degree. C. but below 2050.degree. C., the melting point of alumina.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.