Patents by Inventor Diwakar Garg

Diwakar Garg has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5284526
    Abstract: An integrated two-step process for producing low-cost atmospheres suitable for annealing ferrous and non-ferrous metals and alloys, brazing metals, sealing glass to metals, and sintering metal and ceramic powders in continuous furnaces from non-cryogenically produced nitrogen containing up to 3% residual oxygen is disclosed. The residual oxygen present in non-cryogenically produced nitrogen is converted to moisture by mixing it hydrogen and passing the mixture through a reactor packed with a platinum group catalyst in the first step of the process. The reactor effluent stream containing a mixture of nitrogen, unreacted hydrogen, and moisture is mixed with a predetermined amount of a hydrocarbon gas and introduced into the heating zone of a continuous furnace in the second step of the process to 1) convert moisture to a mixture of carbon monoxide and hydrogen by reaction with the hydrocarbon gas via water gas shift reaction and 2) produce atmospheres in-situ suitable for heat treating.
    Type: Grant
    Filed: December 22, 1992
    Date of Patent: February 8, 1994
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Diwakar Garg, Brian B. Bonner, Donald P. Eichelberger
  • Patent number: 5277987
    Abstract: An extremely hard, fine grained tungsten carbide produced by thermochemical deposition is described. The tungsten carbide consists primarily of substantially pure tungsten carbide wherein the tungsten carbide consists of WC.sub.1-x, where x is 0 to about 0.4. The disclosed tungsten carbide is free of columnar grains and consists essentially of extremely fine, equiaxial crystals. Also disclosed is a method of producing the disclosed material.
    Type: Grant
    Filed: February 1, 1991
    Date of Patent: January 11, 1994
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Diwakar Garg, Paul N. Dyer, Robert E. Stevens, Christopher Ceccarelli
  • Patent number: 5262202
    Abstract: A method for heat treating a coated substrate is described wherein the outer coating on the substrate is comprised of a chemically vapor deposited mixture of tungsten and tungsten carbide. The coated substrate is heated to the deposition temperature or not substantially above the deposition temperature in a non-reactive atmosphere. The heat treating temperature is sufficient to confer a desired improvement in erosive and abrasive wear resistance in the outer coating but does not result in substantial degradation of the mechanical properties of the substrate or in formation of undesirable inter-metallic layers.
    Type: Grant
    Filed: June 20, 1989
    Date of Patent: November 16, 1993
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Diwakar Garg, Paul N. Dyer, Duane Dimos
  • Patent number: 5259893
    Abstract: A process for generating in-situ low-cost atmospheres suitable for annealing and heat treating ferrous and non-ferrous metals and alloys, brazing metals, sealing glass to metals, and sintering metal and ceramic powders in a continuous furnace from non-cryogenically produced nitrogen containing up to 5% residual oxygen is presented. The disclosed process involves mixing nitrogen gas containing residual oxygen with a predetermined amount of a hydrocarbon gas, feeding the gaseous mixture through a nonconventional device into the hot zone of a continuous heat treating furnace, converting residual oxygen to an acceptable form such as a mixture of moisture and carbon dioxide, a mixture of moisture, hydrogen, carbon monoxide, and carbon dioxide, or a mixture of carbon monoxide, moisture, and hydrogen, and using the resultant gaseous mixture for annealing and heat treating metals and alloys, brazing metals, sintering metal and ceramic powders, and sealing glass to metals.
    Type: Grant
    Filed: November 5, 1991
    Date of Patent: November 9, 1993
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Brian B. Bonner, Diwakar Garg, Donald P. Eichelberger
  • Patent number: 5254180
    Abstract: An improved process for producing high-moisture containing nitrogen-based atmospheres suitable for oxide and decarburize annealing of carbon steels from non-cryogenically generated nitrogen is presented. These nitrogen-based atmospheres are produced by 1) mixing non-cryogenically generated nitrogen containing less than 5.0 vol. % residual oxygen with a specified amount of hydrogen, 2) humidifying the gaseous feed mixture, 3) feeding the gaseous mixture into the heating zone of a furnace through a diffuser, and 4) converting in-situ the residual oxygen present in it to moisture. According to the present invention, the total amount of hydrogen required for producing suitable atmospheres can be minimized by simultaneously humidifying the feed gas and controlling the residual oxygen level in it. The key features of the present invention include a) humidifying the feed gas prior to introducing it into the heating zone of a furnace operated above about 600.degree. C.
    Type: Grant
    Filed: December 22, 1992
    Date of Patent: October 19, 1993
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Brian B. Bonner, Diwakar Garg
  • Patent number: 5221369
    Abstract: A process for generating in-situ low-cost atmospheres suitable for annealing and heat treating ferrous and non-ferrous metals and alloys, brazing metals and ceramics, sealing glass to metals, and sintering metal and ceramic powders in a continuous furnace from non-cryogenically produced nitrogen containing up to 5% residual oxygen is presented. The disclosed process involves mixing nitrogen gas containing residual oxygen with a pre-determined amount of a reducing gas such as hydrogen, a hydrocarbon, or a mixture thereof, feeding the gaseous mixture through a non-conventional device into the hot zone of a continuous heat treating furnace, converting residual oxygen to an acceptable form such as moisture, a mixture of moisture and carbon dioxide, or a mixture of moisture, hydrogen, carbon monoxide and carbon dioxide, and using the resultant gaseous mixture for annealing and heat treating metals and alloys, brazing metals and ceramics, sintering metal and ceramic powders, and sealing glass to metals.
    Type: Grant
    Filed: July 8, 1991
    Date of Patent: June 22, 1993
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Donald J. Bowe, Brian B. Bonner, Diwakar Garg
  • Patent number: 5186973
    Abstract: A method for depositing a thick, adherent and coherent polycrystalline diamond (PCD) film onto a metallic substrate using a deposition rate of no greater than 0.4 .mu.m per hour. The resulting PCD Film has a smooth surface finish, enhanced crystal orientation in comparision to industrial grade diamond powder particularly in the (220) and (400) directions, and excellent electrical and thermal properties. The method enables one to deposit PCD films having a thickness of at least 12 microns for applications on flat as well as curved substrates having wide use in the electronics industry. Thick PCD films of this invention have been found to be ideal for dissipating heat from radio frequency (RF) and microwave (MW) devices.
    Type: Grant
    Filed: September 13, 1990
    Date of Patent: February 16, 1993
    Assignee: Diamonex, Incorporated
    Inventors: Diwakar Garg, Wilman Tsai, Fred M. Kimock, Robert L. Iampietro, Paul N. Dyer
  • Patent number: 5160544
    Abstract: An improved hot filament chemical vapor deposition (HFCVD) reactor is disclosed comprising a gas dispersion system, a filament network and an apertured support plate for the substrate. The apertures in the support plate provide for counteracting the natural pressure and temperature gradients which arise within the reactor so that a uniform deposit or material can be coated over the entire surface of multiple small pieces simultaneously. Specifically, the apertured support plate substantially reduces the extent of radial (stagnation point) gas flow adjacent to the substrate which significantly improves coating uniformity.
    Type: Grant
    Filed: September 6, 1990
    Date of Patent: November 3, 1992
    Assignee: Diamonex Incorporated
    Inventors: Diwakar Garg, Wilman Tsai, Robert L. Iampietro, Fred M. Kimock, C. Michael Kelly
  • Patent number: 5147687
    Abstract: A thick, adherent and coherent polycrystalline diamond (PCD) coated substrate product is disclosed which comprises either a metallic or ceramic substrate and a plurality of separately deposited PCD layers of substantially uniform microstructure and having high electrical resistivity. The method for depositing multi-layers of PCD film onto the substrate comprises chemically depositing at least two separate polycrystalline diamond layers onto the substrate deposition conditions which are substantially different between cycles. The method enables one to deposit PCD films having a thickness of at least 12 microns for applications on flat as well as curved substrates having wide use in the electronics industry. Thick PCT films of this invention have been found to be ideal for dissipating heat from radio frequency (RF) and microwave (MW) devices.
    Type: Grant
    Filed: May 22, 1991
    Date of Patent: September 15, 1992
    Assignee: Diamonex, Inc.
    Inventors: Diwakar Garg, Sui-Yuan Lynn, Robert L. Iampietro, Ernest L. Wrecsics, Paul N. Dyer
  • Patent number: 5146481
    Abstract: A substantially compressive stress-free, pin-holes free, and defects free continuous polycrystalline diamond membrane for an x-ray lithography mask is produced by placing a prepared substrate into a hot filament chemical vapor deposition reaction chamber, pre-heating the substrate to 400.degree. C.-650.degree. C. in the presence of an inert gas, heating the substrate to 650.degree. C.-700.degree. C. in the presence of hydrogen and carbon compounds, and chemically vapor depositing a polycrystalline diamond membrane onto the substrate.
    Type: Grant
    Filed: June 25, 1991
    Date of Patent: September 8, 1992
    Inventors: Diwakar Garg, Vyril A. Monk, Carl F. Mueller
  • Patent number: 5126206
    Abstract: A coated substrate product is disclosed which comprises a substrate and a polycrystalline diamond layer having a smooth surface finish, enhanced crystal orientation in comparison to industrial grade diamond powder particularly in the (220) and (400) directions, and excellent electrical and thermal properties. Also disclosed is a method for fabricating such a coated substrate in which the polycrystalline diamond layer is chemically vapor deposited onto the substrate at substrate temperatures in the range of 650.degree. to 825.degree. C.
    Type: Grant
    Filed: September 6, 1990
    Date of Patent: June 30, 1992
    Assignee: Diamonex, Incorporated
    Inventors: Diwakar Garg, Wilman Tsai, Robert L. Iampietro, Fred M. Kimock, Paul N. Dyer
  • Patent number: 5124179
    Abstract: The method for depositing multilayers of PCD film onto the substrate comprises chemically depositing a polycrystalline diamond layers onto the substrate at deposition temperatures in the range of 650.degree. to 825.degree. C., interrupting the deposition process with a cool-down step and then depositing at least one other layer under the same deposition conditions. The method enables one to deposit PCD films having a thickness of at least 12 microns for applications on flat as well as curved substrates having wide use in the electronics industry. Thick PCD films of this invention have been found to be ideal for dissipating heat from radio frequency (RF) and microwave (MW) devices.
    Type: Grant
    Filed: September 13, 1990
    Date of Patent: June 23, 1992
    Assignee: Diamonex, Incorporated
    Inventors: Diwakar Garg, Sui-Yuan Lynn, Robert L. Iampietro, Ernest L. Wrecsics, Paul N. Dyer
  • Patent number: 5064728
    Abstract: A method is described for improving the erosion and abrasion wear resistance and hardness of the internal wear surfaces of structures such as nozzles, jets, ducts, chutes, powder handling tubes, valve housings, conveyors, drill bushings and the like. A substantially pure tungsten layer is chemical vapor deposited on the internal wear surface of the body of the structure followed by a chemical vapor deposited top coating comprising a mixture of tungsten and tungsten carbide. The tungsten carbide is selected from the group consisting of W.sub.2 C, W.sub.3 C, and mixtures thereof and is fine grained, non-columnar and has a substantially layered microstructure. Also described are structures formed by the method.
    Type: Grant
    Filed: October 19, 1990
    Date of Patent: November 12, 1991
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Swaminathan Sunder, Diwakar Garg, Paul N. Dyer
  • Patent number: 5052339
    Abstract: An improved capacitively coupled radio frequency-plasma enhanced chemical vapor deposition (PECVD) apparatus and process are disclosed for depositing a uniform coating of material on substrates. The apparatus includes a secondary electrode defining a reaction zone within an outer chamber and an RF electrode in concert with the secondary electrode for generating a plasma within the reaction zone. The electrode comprising a base and a finger extending through the reaction zone for distributing a plasma field uniformly throughout the reaction zone. The process comprises heating a substrate to a deposition temperature in the range of about 300.degree. to 650.degree. C. Reactant gases are introduced into the PECVD reactor and a coating of about 0.2 to about 20 .mu.m is deposited onto the heated substrate. This low temperature process is particularly adapted to coating three-dimensional objects of metals, metal alloys and mixtures of metals.
    Type: Grant
    Filed: October 16, 1990
    Date of Patent: October 1, 1991
    Assignee: Air Products and Chemicals, Inc.
    Inventors: George Vakerlis, Ward D. Halverson, Diwakar Garg, Paul N. Dyer
  • Patent number: 5024901
    Abstract: The method for producing the disclosed material comprises chemical vapor depositing on the substrate a substantially columnar, intermediate layer of tungsten and chemical vapor depositing on the intermediate layer a non-columnar, substantially lamellar outer layer of a mixture of tungsten and tungsten carbide. The tungsten carbide comprises W.sub.2 C, W.sub.3 C, or a mixture of both wherein the ratio of the thickness of the tungsten intermediate layer to the thickness of the outer layer is at least: (a) 0.35 in the case of tungsten plus W.sub.2 C in the outer layer, (b) 0.6 in the case of a mixture of tungsten and W.sub.3 C in the outer layer and (c) 0.35 in the case of mixtures of tungsten and W.sub.2 C and W.sub.3 C in the outer layer. The chemical vapor deposition steps are carried out at pressures within the range of 1 Torr to 1,000 Torr and temperatures within the range of about 300.degree. to about 650.degree. C.
    Type: Grant
    Filed: May 3, 1989
    Date of Patent: June 18, 1991
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Diwakar Garg, Paul N. Dyer, Leslie E. Schaffer, Ernest L. Wrecsics, Duane Dimos, Carl F. Mueller
  • Patent number: 5009966
    Abstract: The invention discloses a coated substrate product comprised of a titanium of titanium alloy substrate, at least one thin interlayer composed of a non-reactive noble metal and a hard outer coating selected from the group comprised of a ceramic, a hard metal, a hard metal compound and a diamond-like carbon, wherein at least the non-reactive noble metal interlayer which is immediately adjacent to the titanium or titanium alloy substrate is deposited onto the substrate by means of an electroless plating procedure, and the hard outer coating is deposited onto the non-reactive interlayer(s) by means of known chemical and physical vapor deposition techniques. The invention also discloses a method for making these coated substrate products.
    Type: Grant
    Filed: September 19, 1989
    Date of Patent: April 23, 1991
    Inventors: Diwakar Garg, Carl F. Mueller, Leslie E. Schaffer, Paul N. Dyer
  • Patent number: 5006371
    Abstract: An improved highly erosive and abrasive wear resistant multi-layered coating system on a substrate which provides protection against impact of large particles is disclosed comprising a plurality of composite layers. In each of the composite layers, the first layer closest to the substrate comprises tungsten of sufficient thickness to confer substantial erosion and abrasion wear resistance characteristics to the coating system and a second layer deposited on the first layer comprises a mixture of tungsten and tungsten carbide and the tungsten carbide comprises W.sub.2 C, W.sub.3 C, or a mixture of both. Because the resulting coating system has enhanced high cycle fatigue strength over the substrate, the coating system is especially useful on such structures as turbine blades and similar articles of manufacture where such chemical vapor depositing the first and second layers at a temperature in the range of about 300.degree. to about 550.degree. C.
    Type: Grant
    Filed: March 8, 1990
    Date of Patent: April 9, 1991
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Diwakar Garg, Ernest L. Wrecsics, Leslie E. Schaffer, Carl F. Mueller, Paul N. Dyer, Keith R. Fabregas
  • Patent number: 4990372
    Abstract: A method is described for improving the erosion and abrasion wear resistance and hardness of the internal wear surfaces of structures such as nozzles, jets, ducts, chutes, powder handling tubes, valve housings, conveyors, drill bushings and the like. A substantially pure tungsten layer is chemical vapor deposited on the internal wear surface of the body of the structure followed by a chemical vapor deposited top coating comprising a mixture of tungsten and tungsten carbide. The tungsten carbide is selected from the group consisting of W.sub.2 C, W.sub.3 C, and mixtures thereof and is fine grained, non-columnar and has a substantially layered microstructure. Also described are structures formed by the method.
    Type: Grant
    Filed: July 31, 1989
    Date of Patent: February 5, 1991
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Swaminathan Sunder, Diwakar Garg, Paul N. Dyer
  • Patent number: 4945640
    Abstract: A method is described for improving the erosion and abrasion resistance of a sharp edged metal structure. A base layer of a noble metal is formed on the surface of the body of the structure followed by a chemical vapor deposited outer coating comprising a mixture of tungsten and tungsten carbide. The tungsten carbide is selected from the group consisting of W.sub.2 C, W.sub.3 C, and mixtures thereof and is fine grained, non-columnar and having a substantially layered microstructure. Also described is a sharp edged metal structure formed by the method.
    Type: Grant
    Filed: March 7, 1989
    Date of Patent: August 7, 1990
    Inventors: Diwakar Garg, Carl F. Meuller, Ernest L. Wrecsics, Paul N. Dyer, Mark A. Pellman
  • Patent number: 4927713
    Abstract: An improved highly erosive and abrasive wear resistant multi-layered coating system on a substrate which provides protection against impact of large particles is disclosed comprising a plurality of composite layers. In each of the composite layers, the first layer closest to the substrate comprises tungsten of sufficient thickness to confer substantial erosion and abrasion wear resistance characteristics to the coating system and a second layer deposited on the first layer comprises a mixture of tungsten and tungsten carbide and the tungsten carbide comprises W.sub.2 C, W.sub.3 C, or a mixture of both. Because the resulting coating system has enhanced high cycle fatigue strength over the substrate, the coating system is especially useful on such structures as turbine blades and similar articles of manufacture where such high stress cycles occur during normal operation. Also dislcosed is the method for preparing such improved composite coating systems.
    Type: Grant
    Filed: August 2, 1989
    Date of Patent: May 22, 1990
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Diwakar Garg, Ernest L. Wrecsics, Leslie E. Schaffer, Carl F. Mueller, Paul N. Dyer, Keith R. Fabregas