Method for refining non-oxide ceramic powders
AssigneeNippon Kokan Kabushiki Kaisha
InventorsHiroaki Nishio, Michitaka Sato
Life of this patent
Estimating the term…
Abstract
A method for refining powders comprising the steps of: (a) adding polytetrafluoroethylene powders to non-oxide ceramic powders to form a mixture by mixing; and (b) heating the mixture in non-oxidizing atmosphere to convert oxides existing on the surface of the non-oxide ceramic powders into gaseous fluorides, and removing gaseous fluorides. The fluororesin is a polytetrafluoroethylene resin. The heating temperature in the non-oxidizing atmosphere is 500.degree. C. to 1300.degree. C.
Claims20
A method for refining non-oxide ceramic powders which comprises the steps of:
- admixing 1 to 10 wt. % of polytetrafluoroethylene resin powders with non-oxide ceramic powders having oxide on surfaces thereof to form a mixture;
- and
- heating the mixture to 500.degree. to 1300.degree. C. in a non-oxidizing atmosphere to convert said oxide on the surface of the non-oxide ceramic powders into gaseous fluorides, and removing the gaseous fluorides.
The method according to claim 3, wherein said polytetrafluoroethylene resin powders are admixed in an amount of 1 to 5 wt. %.
A method for refining non-oxide ceramic powders which comprises the steps of:
- admixing 0.5 to 10 wt. % of polytetrafluoroethylene resin powders with non-oxide ceramic powders having oxide on surfaces thereof to form a mixture;
- compacting said mixture into a green compact;
- and
- heating the green compact at 500.degree.-1300.degree. C. to to convert said oxide on the surface of the non-oxide ceramic powders to gaseous fluorides, and removing the gaseous fluorides.
Dependencies are inferred from the claim text.