The United States of America As Represented by the Administrator of the

James S Sovey

Bruce A Banks

Michael J Mirtich

Michael J Mirtich, Jr

Edwin G Wintucky

Ralph Forman

Arthur N Curren

Robert F Roman

Robert C Bill

Vincent K Rawlin

Albert J Weigand

Paul F Penko

Charalampus Marinos

Ralph J Zavesky

A polymeric substrate 10 is coated with a metal oxide film 22 to provide oxidation protection in low earth orbital environments. The film contains about four volume percent polymer to provide flexibility.

Oxidation protection coatings for polymers

An electrothermal thruster utilizes a generally cylindrical heat exchanger chamber. A textured, high emissivity heater element radiatively transfers heat to the inner wall of this chamber that is ion beam morphologically controlled for high absorptivity. This, in turn, raises the temperature of a porous heat exchanger material in an annular chamber surrounding the cylindrical chamber. Propellant gas flows through the annular chamber and is heated by the heat exchanger material.

Heat exchanger for electrothermal devices

A polymeric substrate 10 is coated with a metal oxide film 22 to provide oxidation protection in low earth orbital environments. The film contains about 4 volume percent polymer to provide flexibility. A coil of polymer material 30, 42 moves through an ion beam 14 as it is fed between reels. The ion beam first cleans the polymer material surface and then sputters the film material from a target 24 onto this surface.

Apparatus for producing oxidation protection coatings for polymers

A diamondlike carbon film is deposited in the surface of a substrate by exposing the surface to an argon ion beam containing a hydrocarbon. The current density in the ion beam is low during initial deposition of the film. Subsequent to this initial low current condition, the ion beam is increased to full power. At the same time a second argon ion beam is directed toward the surface of the substrate. The second ion beam has an energy level much greater than that of the ion beam containing the hydrocarbon. This addition of energy to the system increases mobility of the condensing atoms and serves to remove lesser bound atoms.

Deposition of diamondlike carbon films

An improved ion thruster (10) for low specific impulse operation in the 1500 sec to 6000 sec range has a multicusp boundary field (48) provided by high strength magnets (30-38) on an iron anode shell (14) which lengthens the paths of electrons from a hollow cathode assembly (20). A downstream anode pole piece in the form of an iron ring (40) supports a ring of magnets (44) to provide a more uniform beam profile. A cylindrical cathode magnet (46) can be moved selectively in an axial direction along a feed tube (22) to produce the desired magnetic field at the cathode tip (24).

Ring-cusp ion thruster with shell anode

A specially textured surface of pyrolytic graphite exhibits extremely low yields of secondary electrons and reduced numbers of reflected primary electrons after impingement of high energy primary electrons. Electrode plates of this material are used in multistage depressed collectors. An ion flux having an energy between 500 eV and 1000 eV and a current density between 1.0 mA/cm.sup.2 and 6.0 mA/cm.sup.2 produces surface roughening or texturing which is in the form of needles or spires. Such textured surfaces are especially useful as anode collector plates in high efficiency electron tube devices.

Ion sputter textured graphite electrode plates

A specially textured surface of pyrolytic graphite exhibits extremely low yields of secondary electrons and reduced numbers of reflected primary electrons after impingement of high energy primary electrons. An ion flux having an energy between 500 eV and 1000 eV and a current density between 1.0 mA/cm.sup.2 and 6.0 mA/cm.sup.2 produces surface roughening or texturing which is in the form of needles or spines. Such textured surfaces are especially useful as anode collector plates in high efficiency electron tube devices.

Ion sputter textured graphite

This invention is concerned with providing improved surface texturing for adhesive bonding, metal bonding, substrate plating, decal substrate preparation, and biomedical implant applications. The invention is particularly concerned with epoxy bonding to polymers that typically exhibit low adhesion and bonding metals to a desired thickness to a polymer substrate. The surface 12 to be bonded is first dusted in a controlled fashion to produce a disbursed layer of fine mesh particles 14 which serve as masks. The surface texture is produced by impinging gas ions on the masked surface. The textured surface takes the form of pillars or cones. The bonding material, such as a liquid epoxy, flows between the pillars which results in a bond having increased strength. For bonding metals a thin film of metal is vapor or sputter deposited onto the textured surface. Electroplating or electroless plating is then used to increase the metal thickness to the desired amount.

Surface texturing of fluoropolymers

This invention is directed to an improved thermal barrier system by improving the adherence between a ceramic thermal barrier coating and a metal bond coating. First a primer film is deposited on the bond coat by ion sputtering a ceramic film thereon. A ceramic thermal barrier coating is then plasma-sprayed onto this primer film. This improves the integrity and strength of the interface between the plasma-sprayed ceramic layer and metallic bond coat which insures stronger adherence between the metal and the ceramic.

Thermal barrier coating system having improved adhesion

This invention is concerned with fabricating textured surfaces on polymers without altering their surface chemistries. A surface of a fluorocarbon polymer 10 is exposed to a beam 12 of ions from a source 14 to texture it. The polymer 18 which is to be surface-roughened is then cast over the textured surface 20 of the fluorocarbon polymer. After curing, the cast polymer is peeled off the textured fluorocarbon polymer, and the peeled off surface 22 has a negative replica of the textured surface 20. The microscopic surface texture provides large surface areas for adhesive bonding. In cardiovascular prosthesis applications the surfaces are relied on for the development of a thin adherent well nourished thrombus.

Texturing polymer surfaces by transfer casting

A source of hydrogen ions is disclosed and includes a chamber having at one end a cathode which provides electrons and through which hydrogen gas flows into the chamber. Screen and accelerator grids are provided at the other end of the chamber. A baffle plate is disposed between the cathode and the grids and a cylindrical baffle is disposed coaxially with the cathode at the one end of the chamber. The cylindrical baffle is of greater diameter than the baffle plate to provide discharge impedance and also to protect the cathode from ion flux. An anode electrode draws the electrons away from the cathode. The hollow cathode includes a tubular insert of tungsten impregnated with a low work function material to provide ample electrons. A heater is provided around the hollow cathode to initiate electron emission from the low work function material.

Hydrogen hollow cathode ion source

An electron bombardment argon ion source is used to treat polyimide and fluorinated ethylene propylene polymers to form textured surfaces thereon. This improves the optical and electrical properties so that these polymers can be used in industrial and space applications.

Growing community of inventors

Strongsville, OH, United States of America

James S Sovey