Abstract: The application relates to a process for producing a coating by thermal spraying, in particular by plasma spraying, in which a component, in particular a cylinder liner, is internally coated with an alloy, wherein a plasma nozzle, to which a plasma gas and a transporting gas are fed, rotates about a wire and is movable along a longitudinal axis of the bore, such that the bore is coated as seen from the inside all around and in the axial direction of the bore. What is proposed is a variable gas stream or a variable flow rate of the transporting gas and/or of the plasma gas, it being possible for the flow rate to be set over the axial length (x) of the bore to be coated.

Abstract: Method of thermally depositing metal at increased rates onto a target surface, comprising: establishing and operating a high velocity plasma transferred wire arc between a cathode and the free-end of a consumable wire electrode, the energy of such plasma and arc being sufficient to not only melt and atomize the free-end of the wire into metal particles, but also project the particles as a column onto the target surface at an enhanced deposition rate for continuous periods in excess of 50 hours; surrounding the plasma and arc with high velocity and high flow gas streams that converge beyond the intersection of the wire free-end with the plasma-arc to limit turbulence of the plasma-arc, avoid direct impingement with the wire and assist the projection of the particles to the target surface; and impinging a low velocity gas flow along the axis of the advancing wire to counteract any destabilizing fluid dynamic forces attempting to move melted particles back along the wire away from the wire free end.

Abstract: A method of staggering reversal of thermal spray inside a cylinder bore of an internal combustion engine. The method includes the steps of thermally spraying a surface of the cylinder bore by moving a thermal spray gun along a length of the surface. The method also includes the steps of reversing a direction of travel of the thermal spray gun inside the cylinder bore at different points along the length of the surface to provide a multi-layered coating on the surface.

Abstract: A plasma transferred wire arc thermal spray apparatus and method producing an extended-arc and supersonic plasma jet stream for applying a dense metallic coating on a substrate, such as a concave internal surface of a bore. The apparatus includes a plasma generating torch assembling having a cathode and an anode nozzle surrounding the cathode and a wire feeder which continuously feeds the tip of a wire feedstock opposite a constricted nozzle orifice and wherein the wire feedstock is maintained at the same positive electrical potential as the nozzle. Plasma gas is directed into the nozzle, preferably generating a vortex flow around the cathode and exiting the restricted nozzle orifice. The improved apparatus includes a pilot power supply and a high voltage or high frequency power supply which initiates the electric arc and the constricted plasma arc and a separate main power supply which extends the constricted plasma arc to the wire tip.

Abstract: A method of eliminating unevenness in pass-reversal thermal spraying of a substrate surface by: uniformly thermally spraying a substrate surface by moving a wire fed arc spray gun along the length of the substrate surface at constant spray parameters while using a first wire feed rate and a first current level for the gun's power supply; (b) when said spray gun approaches an end zone of the pass length requiring reversal of spray gun movement, reducing the wire feed rate and current by up to about 25% until the spray gun has completed such reversal and has exited from said end zone in the opposite direction; (c) while still continuing thermal spraying, restoring the wire feed rage and current to said first levels; and (d) repeating steps (b) and (c) as the spray gun approaches other or repeated end zones of the substrate length during repeated passes.

Abstract: A method of thermally spraying at least one adherent metallic coating onto an unroughened cleansed aluminum or aluminum alloy substrate to produce a coated substrate, comprising: wire-arc thermally spraying of melted metallic bonding droplets and fluxing particles onto the substrate using air propulsion to concurrently adherently deposit flux particles and bonding droplets, the spraying using air propulsion and a wire feedstock having a core and a sheath, the wire core being constituted of both metal powder readily metallurgically bondable to the substrate and a fluxing powder that readily deoxidizes the substrate, the wire sheath being constituted of pliable metal that is metallurgically compatible with the core metal powder, the fluxing powder having a halide salt chemistry effective to deoxidize the substrate upon contact of the melted fluxing powder therewith, said fluxing powder and bonding metal having a particle size that more uniformly promotes distribution throughout said spray.

Abstract: A method of fluxing a cast light-weight metal substrate for thermally adhering sprayed metallic coatings thereto, comprising: (a) preparing the substrate to be clean of grease and oil and to have a uniform and homogeneous surface energy; (b) electrostatically depositing a dry flux powder coating onto such prepared surface; and (c) thermally depositing melted metal onto and across the flux coated surface to further thermally activate the flux if not already activated, for stripping away any substrate oxides and to thermally metallurgically bond the deposited molten metal to the substrate.