Method and apparatus for the preparation of transparent alumina ceramics by microwave sintering
US6812441B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 2003 |
| Grant date | Nov 2, 2004 |
| Priority date | — |
| Expiry date | Feb 3, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B2206/046
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An apparatus (10) for the development of transparent alumina ceramics using microwave energy at the frequency between 0.915 and 2.45 GHz inclusive in hydrogen atmosphere at ambient pressure comprises an enclosed, insulated chamber (14) to retain a workpiece (12) for the application of microwave energy. The chamber comprises a TE103 single mode or a multimode microwave cavity into which is mounted a quartz tube (18). An insulation material (20), transparent to microwave energy, is positioned within the quartz tube. A port (28) for the introduction of hydrogen penetrates the cavity so that the microwave sintering of the workpiece is performed in an ultra-pure hydrogen atmosphere. The workpiece is preferably mounted on a refractory ceramic such as alumina tube for the microwave sintering process. A method, preferably using the apparatus, develops transparent alumina ceramics and single crystal sapphire.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.