Granted Patent
Utility
US 5,772,740 · App. 08/872,303
Passivation method and composition for galvanized metal surfaces
Inventors:
Jiangbo Ouyang, William L. Harpel
Patented Case
View Patent ↗
Granted: Jun 30, 1998
Filed: Jun 10, 1997
Inventors
Jiangbo Ouyang
William L. Harpel
Assignee (at issue)
Betzdearborn, Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.