Method of phosphating metal surface with zinc phosphate
CA 2032541 C · Owner: Shirahata, Seiichiro · Inventors: Tokuyama, Akio; Sobata, Tamotsu; Shirahata, Seiichiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
To treat an iron-based, zinc-based, and an aluminum-based surfaces etc. with zinc phosphate using the same solution, a treating solution is adjusted in concentrations so as to contain a simple fluoride in a range of 200 ~ 500 mg/l upon converting into a HF concentration and to contain a fluoride complex in a range shown in the following formula;, and also, it is adjusted in an active fluorine concentration so as to be 15 ~ 130 µ A at a value indicated by a silicon electrode meter. Instead of such adjusting aluminum ions in the treating solution is precipitated in an outside of a treating bath to separate them from the treating solution and then, this treating solution may be returned into …
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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 December 18, 1990 and granted May 18, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 18, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 18, 2012.
- 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
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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.