Process for producing magnetic metal powder and coating for magnetic recording medium
CA 2039899 A1 · Owner: Kojima, Katsuo · Inventors: Aoki, Yoshio; Kadono, Yasuo; Nakamura, Hiroyuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A magnetic metal powder, having a large specific surface are, a high coersive force, a high dispersibility and an excellent corrosion resistance is, produced by converting an aciculate goethite having a silicon and/or aluminum compound layer formed thereon or an aciculate goethite modified with a metal other than iron into magnetite forming, thereon a nonferrous transition metal compound layer, further forming thereon a silicon or aluminum compound layer, and reducing the coated magnetite to prepare a magnetic metal powder mainly composed of iron and having on the surface thereof a layer containing a nonferrous transition metal element characterized in that the formation of the silicon …
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 April 5, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 5, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 5, 2013.
- 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.