The Experts below are selected from a list of 8406 Experts worldwide ranked by ideXlab platform

Per Nylen - One of the best experts on this subject based on the ideXlab platform.

Guruprasad Sundararajan - One of the best experts on this subject based on the ideXlab platform.

  • The influence of process parameters and heat treatment on the properties of cold Sprayed silver coatings
    Surface and Coatings Technology, 2011
    Co-Authors: Naveen Manhar Chavan, P. Sudharshan Phani, D. Srinivasa Rao, M. Ramakrishna, Guruprasad Sundararajan
    Abstract:

    Cold Spray coating Technology is a promising low temperature variant of Thermal Spray Technology which can deposit pure, dense and thick coatings at a rapid rate. Unlike the other Thermal Spray coating techniques, cold Spray is especially suitable for depositing coatings with high electrical and Thermal conductivity as the integrity of the feedstock is maintained during the coating process. In the present study, the effect of process parameters and heat treatment on the properties of silver coatings has been investigated. An attempt has been made to correlate the powder particle velocity with the properties and microstructure of the coating. The effect of heat treatment temperature and atmosphere on the properties of the coatings, especially electrical conductivity, has been studied in detail in conjunction with a thorough analysis of the evolution of microstructure of the coatings. © 2011 Elsevier B.V.

A. Edrisy - One of the best experts on this subject based on the ideXlab platform.

  • The Effect of Deposition Rate on Microstructural Evolution in WC-Co-Cr Coatings Deposited by High-Velocity Oxy-Fuel Thermal Spray Process
    Journal of Materials Engineering and Performance, 2019
    Co-Authors: K. Farokhzadeh, R. M. Fillion, A. Edrisy
    Abstract:

    Tungsten carbide-reinforced cermet composites are widely used as wear- and erosion-resistant coatings due to their combination of hardness, strength, toughness and Thermal properties. In this study, WC-Co-Cr coatings were deposited using high-velocity oxy-fuel Thermal Spray Technology under different kinematic Spray parameters. The microstructure of coatings was investigated using scanning electron microscopy and transmission electron microscopy techniques, and elemental/phase analysis was completed using x-ray diffraction, electron energy loss spectroscopy and x-ray energy-dispersive spectroscopy. The findings indicated the presence of W_2C and W_6Co_6C in addition to WC and chromium oxide (Cr_2O_3) in a nanocrystalline cobalt-rich matrix. The newly developed phases (W_2C and W_6Co_6C) were formed as a result of decarburization/oxidation of tungsten carbide (WC). They were found as individual particles (0.2-0.4 µm) embedded in the metallic binder phase as well as surrounding existing WC particles. Nonetheless, increasing the coating deposition rate, i.e., reduction of coating build-up per pass, increased the coating hardness from 1516 ± 124 to 1713 ± 106 HV_0.3 and led to a higher degree of phase transformation reactions in the coating.

Keith O Legg - One of the best experts on this subject based on the ideXlab platform.

  • replacement of chromium electroplating on helicopter dynamic components using hvof Thermal Spray Technology
    2009
    Co-Authors: B. D. Sartwell, Keith O Legg, Robert Kestler, Aaron T Nardi, Greg Haataja, Robert Guillemette, Robert Vingenzo Luchenta, Robert B Mason, Anne Kaltenhauser, Phil Betz
    Abstract:

    Abstract : Electrolytic hard chrome (EHC) plating is a technique that has been in commercial production for over 50 years. It is a critical process that is used both for applying hard coatings to a variety of aircraft components in manufacturing operations and for general rebuild of worn or corroded components that have been removed from aircraft during overhaul. Chromium plating baths contain chromic acid, in which the chromium is in the hexavalent state, with hexavalent chromium (hex-Cr) being a known carcinogen. During operation, chrome plating tanks emit a hex-Cr mist into the air, which must be ducted away and removed by scrubbers. Wastes generated from plating operations must be disposed of as hazardous waste, and plating operations must abide by U.S. Environmental Protection Agency (EPA) emissions standards and the Occupational Health and Safety Administration (OSHA) permissible exposure limit (PEL). In February 2006, OSHA reduced the PEL for worker exposure to Cr(6+) from 52 micrograms/m(3) of Cr(6+) to 5 micrograms/m(3). However, at the time of writing this PEL is still in litigation, and the PEL may be further reduced in the next few years. A Navy/industry task group has concluded that the cost of compliance for all Navy operations that utilize hex-Cr (i.e., not just plating) would be in excess of $10 million if the PEL were reduced to less than 5 micrograms/m(3).

  • validation of hvof Thermal Spray coatings as a replacement for hard chrome plating on hydraulic pneumatic actuators
    2007
    Co-Authors: B. D. Sartwell, Jerry Zimmerman, Jeff Gribble, Keith O Legg
    Abstract:

    Abstract : Electrolytic hard chrome (EHC) plating is a technique that has been in commercial production for over 50 years. It is a critical process that is used both for applying hard coatings to a variety of aircraft components in manufacturing operations and for general re-build of worn or corroded components that have been removed from aircraft during overhaul. Chromium plating baths contain chromic acid, in which the chromium is in the hexavalent state, with hexavalent chromium (hex-Cr or Cr6+) being a known carcinogen. During operation, chrome plating tanks emit a hex-Cr mist into the air, which must be ducted away and removed by scrubbers. Wastes generated from plating operations must be disposed of as hazardous waste and plating operations must abide by U.S. Environmental Protection Agency (EPA) emissions standards and Occupational Safety and Health Administration (OSHA) permissible exposure limits (PEL). High-velocity oxygen-fuel (HVOF) Thermal Spray Technology can be used to deposit both metal alloy coatings and ceramic/metals (cermets) such as tungsten carbide/cobalt (WC/Co) that are dense and highly adherent to the base material. Previous research, development and validation efforts had established HVOF Thermal Spray coatings as the leading candidates for replacement of hard chrome. This led to industry acceptance of HVOF WC/CoCr and WC/Co in place of hard chrome for landing gear, to the point that landing gear on most new aircraft designs are now specified with HVOF. In addition, in overhaul operations these coatings can be built up to thicknesses needed for dimensional restoration, as is currently done with EHC. HVOF systems are commercially available and installed in several depots, and there are numerous commercial vendors supplying the OEM community. Although HVOF coatings are now coming into wide use for landing gear, their qualification as an acceptable replacement for EHC plating on actuators has not been adequately demonstrated.

  • Validation of HVOF Thermal Spray Coatings as a Replacement for Hard Chrome Plating on Hydraulic/Pneumatic Actuators
    2007
    Co-Authors: B. D. Sartwell, Jerry Zimmerman, Jeff Gribble, Keith O Legg
    Abstract:

    Abstract : Electrolytic hard chrome (EHC) plating is a technique that has been in commercial production for over 50 years. It is a critical process that is used both for applying hard coatings to a variety of aircraft components in manufacturing operations and for general re-build of worn or corroded components that have been removed from aircraft during overhaul. Chromium plating baths contain chromic acid, in which the chromium is in the hexavalent state, with hexavalent chromium (hex-Cr or Cr6+) being a known carcinogen. During operation, chrome plating tanks emit a hex-Cr mist into the air, which must be ducted away and removed by scrubbers. Wastes generated from plating operations must be disposed of as hazardous waste and plating operations must abide by U.S. Environmental Protection Agency (EPA) emissions standards and Occupational Safety and Health Administration (OSHA) permissible exposure limits (PEL). High-velocity oxygen-fuel (HVOF) Thermal Spray Technology can be used to deposit both metal alloy coatings and ceramic/metals (cermets) such as tungsten carbide/cobalt (WC/Co) that are dense and highly adherent to the base material. Previous research, development and validation efforts had established HVOF Thermal Spray coatings as the leading candidates for replacement of hard chrome. This led to industry acceptance of HVOF WC/CoCr and WC/Co in place of hard chrome for landing gear, to the point that landing gear on most new aircraft designs are now specified with HVOF. In addition, in overhaul operations these coatings can be built up to thicknesses needed for dimensional restoration, as is currently done with EHC. HVOF systems are commercially available and installed in several depots, and there are numerous commercial vendors supplying the OEM community. Although HVOF coatings are now coming into wide use for landing gear, their qualification as an acceptable replacement for EHC plating on actuators has not been adequately demonstrated.

Naveen Manhar Chavan - One of the best experts on this subject based on the ideXlab platform.

  • The influence of process parameters and heat treatment on the properties of cold Sprayed silver coatings
    Surface and Coatings Technology, 2011
    Co-Authors: Naveen Manhar Chavan, P. Sudharshan Phani, D. Srinivasa Rao, M. Ramakrishna, Guruprasad Sundararajan
    Abstract:

    Cold Spray coating Technology is a promising low temperature variant of Thermal Spray Technology which can deposit pure, dense and thick coatings at a rapid rate. Unlike the other Thermal Spray coating techniques, cold Spray is especially suitable for depositing coatings with high electrical and Thermal conductivity as the integrity of the feedstock is maintained during the coating process. In the present study, the effect of process parameters and heat treatment on the properties of silver coatings has been investigated. An attempt has been made to correlate the powder particle velocity with the properties and microstructure of the coating. The effect of heat treatment temperature and atmosphere on the properties of the coatings, especially electrical conductivity, has been studied in detail in conjunction with a thorough analysis of the evolution of microstructure of the coatings. © 2011 Elsevier B.V.