초록 ▼

Thin coatings of normally solid materials are applied to target substrates using an inductively coupled plasma. Particles of the coating material are vaporized by plasma heating, and pass through an orifice to a first vacuum zone in which the particles are accelerated to a velocity greater than Mach

Thin coatings of normally solid materials are applied to target substrates using an inductively coupled plasma. Particles of the coating material are vaporized by plasma heating, and pass through an orifice to a first vacuum zone in which the particles are accelerated to a velocity greater than Mach 1. The shock wave generated in the first vacuum zone is intercepted by the tip of a skimmer cone that provides a second orifice. The particles pass through the second orifice into a second zone maintained at a higher vacuum and impinge on the target to form the coating. Ultrapure coatings can be formed.

대표청구항 ▼

The process for applying a coating of a normally solid material to a target substrate, comprising: (a) within a zone at essentially atmospheric pressure generating an inductively coupled toroidal plasma from a monatomic gas, said generated plasma being in the form of an annulus with a plasma-free ce

The process for applying a coating of a normally solid material to a target substrate, comprising: (a) within a zone at essentially atmospheric pressure generating an inductively coupled toroidal plasma from a monatomic gas, said generated plasma being in the form of an annulus with a plasma-free central portion; (b) passing a carrier stream of said monatomic gas through the central portion of said plasma annulus; (c) introducing a finely-divided, particulate solid coating material into said carrier gas upstream of said plasma annulus, the particles of said material having an average size of less than 50 microns; (d) vaporizing the particles of said coating material by inductively coupled plasma heating as said stream passes through said plasma annulus; (e) downstream of said annulus directing said stream containing said vaporized coating material through a first orifice which separates said atmospheric pressure zone from a first-vacuum zone, said orifice being of circular shape and having a diameter of from 0.125 to 2.5 millimeters, said first vacuum zone having a pressure maintained therein below 20 Torr, the diameter of said first orifice and the vacuum in said first zone being related so that said stream accelerates on passing through said first orifice to a velocity greater than Mach 1 within said first zone generating a shock wave along a front downstream of said first orifice, said shock wave providing a Mach disk at a predetermined distance from said first orifice and the vacuum being applied to said first-vacuum zone on the downstream side of said Mach disk; (f) providing a second circular orifice having a diameter greater than the diameter of said first orifice in stream flow alignment therewith, said second orifice being provided in the tip of conical skimmer means extending downstream from said first orifice and separating said first vacuum zone from a second vacuum zone within said skimmer means which is maintained at a pressure below 10-4 Torr, said second orifice being located in relation to said first orifice so that said Mach disk is pierced by said skimmer means adjacent its orifice-providing tip; (g) passing at least a portion of the coating material-containing stream through said second orifice; and (h) supporting a target substrate within said second zone in alignment with said second orifice so that said stream portion impinges thereon, the coating material in the carrier stream being cooled below its melting temperature as it passes through said first and second vacuum zones and depositing in solid form on the target substrate.