Process for producing crystalline silicon nitride powder
CA 2000949 A1 · Owner: Union Carbide Corporation · Inventors: Shen, Wei-Ming
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract, A process for producing crystalline silicon nitride powder by a gas phase reaction of ammonia (NH3) and silane (SiH4) with a molar ratio of 7:1 or above at a temperature of 900°C or above and then heating the as-reacted amorphous powders at a temperature of 1350°C to 1800°C to convert the powders to a highly pure and submicron crystalline silicon nitride powder comprising at least a 90% .alpha.-Si3N4 phase. D-15936
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 18, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 18, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 18, 2011.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.