A device for microwave sintering large ceramic articles
A microwave sintering system is provided for uniform sintering of large and/or irregular shapes ceramic articles at microwave frequencies of at least 28 GHz in the hundreds of kilowatts power range in an untuned cavity. A 28 GHz, 200 kw gyrotron with variable power output is used as the microwave source connected to an untuned microwave cavity formed of an electrically conductive housing. The part to be sintered is placed in the cavity and supported on a removable high temperature table in a central location within the cavity. The part is surrounded by a microwave transparent bulk insulating material to reduce thermal heat loss at the part surfaces and maintain more uniform temperature. The cavity may be operated at a high vacuum to aid in preventing arcing. The system allows controlled increased heating rates of greater than 200/degree/C/min to provide rapid heating of a ceramic part to a selected sintering temperature where it is maintained by regulating the microwave power applied to the part. As a result of rapid heating, the extent on non-isothermal processes such as segregation of impurities to the grain boundaries are minimized and exaggerated grain growth is reduced, thereby strengthening the mechanical properties of the ceramic part being sintered. 1 fig.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- AC05-84OR21400
- Assignee:
- TIC; ERA-14-001257; EDB-88-185530
- Patent Number(s):
- PATENTS-US-A6077580
- OSTI ID:
- 6742633
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Method and device for microwave sintering large ceramic articles
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Related Subjects
36 MATERIALS SCIENCE
MICROWAVE EQUIPMENT
DESIGN
SINTERING
CERAMICS
INVENTIONS
MICROWAVE HEATING
SINTERED MATERIALS
ELECTRONIC EQUIPMENT
EQUIPMENT
FABRICATION
HEATING
MATERIALS
420200* - Engineering- Facilities
Equipment
& Techniques
360601 - Other Materials- Preparation & Manufacture