Plasma Nitriding Mechanisms of Low-Density Sintered Metal Products

2021 ◽  
Vol 76 (1) ◽  
pp. 58-63
Author(s):  
E. Roliński ◽  
M. Woods
Keyword(s):  
Formation Mechanism ◽  
Plasma Nitriding ◽  
Active Species ◽  
Low Density ◽  
Nitrogen Species ◽  
Powder Metal ◽  
Active Nitrogen ◽  
Sintered Metal ◽  
Metal Plasma ◽  
Metal Products

Abstract The mechanism of plasma nitriding include the formation of various active species generating nitrogen atoms reacting with the metal. Which species prevail in supplying nitrogen depends on nitriding conditions as well as the nature of the treated metal. Plasma nitriding of low-density powder metal (PM) products results in a formation of the layers whose thicknesses may depend on the gas pressure used for the process. Higher pressure can cause locally deeper penetration of the surface by active nitrogen species formed from ammonia compounds generated by the plasma. While a low processing pressure reduces this effect significantly. The formation mechanism of a locally thicker layer relies on the presence of open porosities in the surface as they can be penetrated by the ammonia species generated by the plasma. The same porosities cannot be penetrated by the ions of nitrogen formed at the same time since their mean free life is much shorter than that of ammonia species. ◼

Influence of Nitrogen Species on InN Grown by PAMBE

2005 ◽  
Vol 892 ◽  
Author(s):  
P. A. Anderson ◽  
R. J. Kinsey ◽  
C. E. Kendrick ◽  
I. Farrel ◽  
D. Carder ◽  
...  
Keyword(s):  
Emission Spectroscopy ◽  
Molecular Nitrogen ◽  
Optical Emission ◽  
Lattice Relaxation ◽  
Plasma Source ◽  
High Energy ◽  
Active Species ◽  
Nitrogen Species ◽  
Active Nitrogen ◽  
Molecular Flux

AbstractActive nitrogen species produced by an Oxford Applied Research HD-25 plasma source have been monitored by optical emission spectroscopy and quadrapole mass spectroscopy. Both techniques confirmed that at higher RF powers and lower flow rates the efficiency of atomic nitrogen production increased; emission spectroscopy confirmed that this was at the expense of active molecular nitrogen (N2*). InN films grown on (0001) sapphire/GaN with higher relative molecular content were found to have lower carrier concentrations than the corresponding films grown with higher atomic content. However, electrical properties of films grown on (111) YSZ showed insensitivity to the active nitrogen content. Etching experiments revealed that films grown on sapphire/GaN were nitrogen-polar, while films grown on YSZ were In-polar, suggesting that film polarity can greatly influence the effect active species have on growth. Lattice relaxation, as measured by reflection high-energy electron diffraction, revealed that the N-polar films grown under high relative molecular flux relaxed fully after ∼60 nm of growth, while the corresponding In-polar film relaxed fully within the first several nm of growth.

AMETEK 820 ALLOY

Alloy Digest ◽  
1999 ◽  
Vol 48 (3) ◽  
Keyword(s):  
Physical Properties ◽  
Production Process ◽  
Tensile Properties ◽  
Powder Metal ◽  
Nickel Chromium ◽  
Chromium Alloys ◽  
Metal Products ◽  
Specialty Metal

Abstract AMETEK 820 alloy is a powder metallurgically produced strip that is used in hardfacing weld wire. The production process, however, can produce other special strip compositions such as the nickel-chromium alloys used as resistance alloys. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on powder metal forms. Filing Code: Ni-549. Producer or source: AMETEK Specialty Metal Products.

Study of formation mechanism of double metal plasma jets in a low-current pulsed vacuum arc discharge

2021 ◽  
Vol 33 (3) ◽  
pp. 037103
Author(s):  
Jia Tian ◽  
Wenzheng Liu ◽  
Wenjun Zhang ◽  
Xitao Jiang
Keyword(s):  
Formation Mechanism ◽  
Arc Discharge ◽  
Plasma Jets ◽  
Vacuum Arc ◽  
Metal Plasma

Three-dimensional mesoporous graphene-like carbons derived from a biomolecule exhibiting high-performance oxygen reduction activity

2019 ◽  
Vol 3 (10) ◽  
pp. 2809-2818 ◽  
Author(s):  
Baobing Huang ◽  
Yuchuan Liu ◽  
Qiaohua Wei ◽  
Zailai Xie
Keyword(s):  
Oxygen Reduction ◽  
High Performance ◽  
Three Dimensional ◽  
Mesoporous Structure ◽  
Nitrogen Species ◽  
Active Nitrogen ◽  
Reduction Activity ◽  
Defect Sites ◽  
Orr Activity ◽  
Cost Efficient

We develop a simple, cost-efficient and sustainable strategy for construction of a novel graphene-like 3D nanocarbon with developed mesoporous structure, abundant defect sites and active nitrogen species for high-performance ORR activity.

Growth of AlN and TiN Structures by Plasma-Enhanced Pulsed Laser Deposition

2000 ◽  
Vol 648 ◽  
Author(s):  
Edward Poindexter ◽  
Yan Xin ◽  
Steven M. Durbin
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Plasma Source ◽  
Thin Film Deposition ◽  
Growth Conditions ◽  
High Energy ◽  
Film Deposition ◽  
Rf Plasma ◽  
Nitrogen Species ◽  
Active Nitrogen

AbstractNitride materials are of interest for a wide variety of applications, including wear-resistant coatings, insulating layers, high-temperature semiconductor devices, and short-wavelength emitters and detectors. TiN and AlN appear to be particularly amenable to crystalline thin film deposition, with stoichiometric material easily obtained even without the use of active nitrogen species. This paper describes the growth of crystalline AlN and TiN thin films on silicon and sapphire substrates using a KrF excimer laser (λ = 248 nm) to ablate elemental metallic targets, and an inductively-coupled RF plasma source to supply active nitrogen species. Growth was monitored in-situ using reflection high-energy electron diffraction (RHEED), and films were characterised using fourier-transform infrared spectroscopy (FTIR) and electron microscopy techniques. Optimised growth conditions led to single-crystal growth of TiN on both substrates, but only polycrystalline AlN was formed directly. Use of a TiN buffer layer on (0001) sapphire led to the successful growth of a single-crystal AlN layer as confirmed by RHEED and high-resolution transmission electron microscopy (HRTEM).

scholarly journals Influence of Active Nitrogen Species on the Nitridation Rate of Sapphire

1998 ◽  
Vol 537 ◽  
Author(s):  
A.J. Ptak ◽  
K.S. Ziemer ◽  
M.R. Millecchia ◽  
C.D. Stinespring ◽  
T.H. Myers
Keyword(s):  
Molecular Nitrogen ◽  
Active Species ◽  
Operating Conditions ◽  
Rf Plasma ◽  
Atomic Nitrogen ◽  
Active Nitrogen ◽  
Plasma Sources ◽  
Electrostatic Deflector ◽  
Low Energy Ions ◽  
Operating Regimes

AbstractThe operating regimes of two rf-plasma sources, an Oxford CARS-25 and an EPI Unibulb, have been extensively characterized. By changing the exit aperture configuration and using an electrostatic deflector, the Oxford source could produce either primarily atomic nitrogen, atomic nitrogen mixed with low energy ions, or a large flux of higher energy ions (>65eV) as the active species in a background of neutral molecular nitrogen. The EPI source produced a significant flux of metastable molecular nitrogen as the active species with a smaller atomic nitrogen component. Nitridation of sapphire using each source under the various operating conditions indicate that the reactivity was different for each type of active nitrogen. Boron contamination originating from the pyrolytic boron nitride plasma cell liner was observed.

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