A device for microwave sintering large ceramic articles
Abstract
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 ceramicmore »
- Inventors:
- Issue Date:
- Research Org.:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- OSTI Identifier:
- 6742633
- Patent Number(s):
- 6077580
- Assignee:
- TIC; ERA-14-001257; EDB-88-185530
- Patent Classifications (CPCs):
-
B - PERFORMING OPERATIONS B29 - WORKING OF PLASTICS B29C - SHAPING OR JOINING OF PLASTICS
B - PERFORMING OPERATIONS B29 - WORKING OF PLASTICS B29L - INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- DOE Contract Number:
- AC05-84OR21400
- Resource Type:
- Patent
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 42 ENGINEERING; 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
Citation Formats
Kimrey, Jr, H D. A device for microwave sintering large ceramic articles. United States: N. p., 1987.
Web.
Kimrey, Jr, H D. A device for microwave sintering large ceramic articles. United States.
Kimrey, Jr, H D. Fri .
"A device for microwave sintering large ceramic articles". United States.
@article{osti_6742633,
title = {A device for microwave sintering large ceramic articles},
author = {Kimrey, Jr, H D},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1987},
month = {7}
}