Granted Patent
Utility
US 4,552,852 · App. 06/625,095
Alumina ceramic comprising a siliceous binder and at least one of zirconia and hafnia
Inventor:
William R. Manning
Patented Case
View Patent ↗
Granted: Nov 12, 1985
Filed: Jun 27, 1984
Inventor
William R. Manning
Assignee (at issue)
Champion Spark Plug Company
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.