The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 12, 1999
Filed:
Oct. 12, 1995
Ronghua R Wei, Calabasas, CA (US);
Jesse N Matossian, Canoga Park, CA (US);
Peter Mikula, Sterling Heights, MI (US);
Deborah Clark, Saline, MI (US);
Hughes Electronics Corporation, El Segundo, CA (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A plasma heating apparatus for heating a workpiece includes a chamber of sufficient size to receive a workpiece therein and a source of a reduced gas pressure within the chamber of from about 0.01 to about 100 millitorr. The plasma heating apparatus further includes a plasma source of an enveloping plasma. Optionally, a workpiece voltage may be applied between the workpiece and the wall of the chamber, and a source of a reactive gas can be provided to backfill the chamber, and radiant heaters can be provided to independently heat portions of the workpiece. In operation, the plasma source produces a plasma that surrounds and heats the workpiece. The plasma and the heating of the workpiece are tailored to achieve controllably uniform or nonuniform heat treatment and/or surface treatment of the workpiece. The apparatus can be used to heat treat the workpiece in vacuum, or a reactive gas such as a gaseous source of nitrogen, carbon, or boron can be backfilled into the chamber to alter the surface chemistry of the workpiece.