Abstract: A cathode arc source comprises: a cathode target; a first magnetic field source located above the target; a second magnetic field source located below the target; and a third magnetic field source located between the first and second magnetic field sources and having an opposite polarity to the first magnetic field source; wherein the resultant magnetic field from the first, second and third magnetic field sources has zero field strength in a direction substantially normal to the target at a position above the target. The invention also provides methods of striking a cathode target and methods of depositing coatings which can be carried out using the cathode arc source described herein.

Abstract: A filter (104a, 104b, 108) for a cathode arc source comprises: a filter duct having at least one bend (104a, 104b), and a first magnetic field source for steering plasma through the filter duct for removal of macroparticles from the plasma; wherein the apparatus comprises a second magnetic field source (108) which is rotatably mounted surrounding a portion of the filter duct. Cathode arc sources (102) and cathode arc deposition apparatuses (106) comprise the filters described herein, and methods of filtering macroparticles from a beam of plasma emitted from a cathode arc source use the filters.

Abstract: A method of coating a piston ring comprises: providing at least first and second piston rings in a coating chamber; spacing the piston rings apart, so that the first piston ring is spaced from and not in contact with the second piston ring, and applying a ta-C coating to the piston rings, whereby the spacing between the adjacent piston rings enables simultaneous coating of upper, outer and lower piston ring surfaces of the first and second piston rings during rotation of rings in a plane co-planar with the coating beam. Piston rings are obtained comprising a substantially hydrogen free ta-C coating of 0.1 to 8 microns on at least their lower surface.

Abstract: A filter (104a, 104b, 108) for a cathode arc source comprises: a filter duct having at least one bend (104a, 104b), and a first magnetic field source for steering plasma through the filter duct for removal of macroparticles from the plasma; wherein the apparatus comprises a second magnetic field source (108) which is rotatably mounted surrounding a portion of the filter duct. Cathode arc sources (102) and cathode arc deposition apparatuses (106) comprise the filters described herein, and methods of filtering macroparticles from a beam of plasma emitted from a cathode arc source use the filters.

Abstract: A cathode arc source comprises: a cathode target; a first magnetic field source located above the target; a second magnetic field source located below the target; and a third magnetic field source located between the first and second magnetic field sources and having an opposite polarity to the first magnetic field source; wherein the resultant magnetic field from the first, second and third magnetic field sources has zero field strength in a direction substantially normal to the target at a position above the target. The invention also provides methods of striking a cathode target and methods of depositing coatings which can be carried out using the cathode arc source described herein.

Abstract: A method of continuously depositing a coating on a substrate comprises (a) depositing a first layer of ta-C on a substrate via a CVA process, said first layer having a first hardness and a first thickness of 100 mm or greater; (b) adjusting the parameters of the CVA process and depositing a second layer of ta-C on a substrate via a CVA process, said second layer having a second hardness and a second thickness of 10 mm or less, and (c) repeating the above steps to provide a coating comprising at least 5 such first layers and at least 4 such second layers, wherein the first thickness is greater than the second thickness and the first hardness is greater than the second hardness.