Method for removing oxide contamination from silicon carbide powders

Patent · Wed Aug 01 00:00:00 EDT 1984

OSTI ID:5786688

Brynestad, J; Bamberger, C E

The described invention is directed to a method for removing oxide contamination in the form of oxygen-containing compounds such as SiO/sub 2/ and B/sub 2/O/sub 3/ from a charge of finely divided silicon carbide. The silicon carbide charge is contacted with a stream of hydrogen fluoride mixed with an inert gas carrier such as argon at a temperature in the range of about 200/sup 0/ to 650/sup 0/C. The oxides in the charge react with the heated hydrogen fluoride to form volatile gaseous fluorides such as SiF/sub 4/ and BF/sub 3/ which pass through the charge along with unreacted hydrogen fluoride and the carrier gas. Any residual gaseous reaction products and hydrogen fluoride remaining in the charge are removed by contacting the charge with the stream of inert gas which also cools the powder to room temperature. The removal of the oxygen contamination by practicing the present method provides silicon carbide powders with desirable pressing and sintering characteristics. 1 tab.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: AC05-84OR21400
• Assignee: Dept. of Energy
• Application Number: ON: DE85011648
• OSTI ID: 5786688
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
BORON OXIDES
REMOVAL
SILICA
SILICON CARBIDES
PURIFICATION
CHEMICAL REACTIONS
HIGH TEMPERATURE
HYDROFLUORIC ACID
PRESSING
REFRACTORIES
SINTERED MATERIALS
BORON COMPOUNDS
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
FABRICATION
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MATERIALS
MATERIALS WORKING
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SILICON OXIDES
400201* - Chemical & Physicochemical Properties
360201 - Ceramics
Cermets
& Refractories- Preparation & Fabrication