US 12,224,165 B2
Magnetic-field-assisted plasma coating system
Thomas Schuelke, Pinckney, MI (US); Michael Becker, East Lansing, MI (US); Lars Haubold, East Lansing, MI (US); and Qi Hua Fan, Okemos, MI (US)
Assigned to Board of Trustees of Michigan State University, East Lansing, MI (US); and Fraunhofer USA, East Lansing, MI (US)
Filed by Board of Trustees of Michigan State University, East Lansing, MI (US); and Franhofer USA, East Lansing, MI (US)
Filed on Feb. 24, 2023, as Appl. No. 18/113,703.
Application 18/113,703 is a division of application No. 16/620,341, filed on Dec. 6, 2019, abandoned.
Prior Publication US 2023/0203641 A1, Jun. 29, 2023
Int. Cl. C23C 14/06 (2006.01); C23C 14/04 (2006.01); C23C 14/32 (2006.01); C23C 14/35 (2006.01); F02F 1/00 (2006.01); H01J 37/34 (2006.01)
CPC H01J 37/3405 (2013.01) [C23C 14/046 (2013.01); C23C 14/0605 (2013.01); C23C 14/325 (2013.01); C23C 14/35 (2013.01); F02F 1/00 (2013.01); F02F 2200/00 (2013.01)] 30 Claims
OG exemplary drawing
 
1. A method for coating a workpiece, the method comprising:
(a) inserting an elongated cathode inside an elongated internal bore of the workpiece;
(b) sealing at least one open end of the bore, such that the workpiece itself defines a portion of a vacuum chamber;
(c) creating a vacuum in the vacuum chamber between the workpiece and the cathode;
(d) emitting a process gas into the vacuum chamber;
(e) generating an arc in a plasma between the cathode and the workpiece, the workpiece acting as an anode;
(f) ionizing the gas in the vacuum chamber while depositing an ionic ta-C plasma arc deposition coating on the internal bore of the workpiece within a magnetic field;
(g) longitudinally spacing apart at least two electromagnets and locating the electromagnets within a hollow interior of the cathode;
(h) a programmable controller and an electrical circuit being connected to the electromagnets;
(i) moving the magnetic field within the vacuum chamber to assist in linearly and rotationally moving the arc relative to the workpiece, the arc spanning between the cathode and the internal bore of the workpiece;
(j) sequentially energizing and de-energizing the at least two electromagnets to sequentially energize and de-energize the electromagnetic field in corresponding locations;
(k) causing the arc and coating ions to linearly follow the magnetic field locations without movement of the cathode, the electromagnets or the workpiece during the depositing;
(l) a complete coating cycle from when vacuum pressure is started to when vacuum pressure ends, is no greater than five minutes; and
(m) exposing an exterior of the workpiece to ambient air during the coating cycle.