scholarly journals Spheroidization of Nickel Powder and Coating with Carbon Layer through Laser Heating

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1641 ◽  
Author(s):  
Shuang Li ◽  
Yu-Ling Shao ◽  
Lan Cui ◽  
Sergei Kulinich ◽  
Xi-Wen Du
Keyword(s):  
Laser Heating ◽  
Nickel Powder ◽  
Carbon Layer ◽  
Liquid Droplets ◽  
Pure Ethanol ◽  
Precipitation Mechanism ◽  
Excess Carbon ◽  
Lower Solubility ◽  
Long Pulse ◽  
Laser Heated

We developed a simple and efficient process, laser heating of nickel powder in ethanol, to produce carbon-encapsulated nickel microspheres. Long-pulse-width laser heated nickel powder suspended in pure ethanol into liquid droplets. In turn, the latter droplets became sphere-like, pyrolyzed surrounding ethanol and dissolved the produced carbon atoms. Because of their lower solubility in solid nickel, excess carbon atoms were then expelled from the metal core after solidification, thus forming graphite-like shells on the laser-modified Ni spheres. Hence, after pyrolysis the transformation of carbon was found to follow the dissolution-precipitation mechanism. The produced carbon-encapsulated nickel microspheres exhibited higher oxidation resistance compared with the initial nickel powder, while keeping their magnetic properties essentially unchanged.

Boubaker Polynomials Expansion Scheme Solution to the Heat Transfer Equation Inside Laser Heated Biological Tissues

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
M. A. Aweda ◽  
M. Agida ◽  
M. Dada ◽  
O. B. Awojoyogbe ◽  
K. Isah ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Analytical Solution ◽  
Numerical Simulations ◽  
Laser Heating ◽  
Transfer Equation ◽  
Biological Tissues ◽  
Heat Transfer Equation ◽  
Boubaker Polynomials ◽  
Laser Heated ◽  
Expansion Scheme

In this study, an analytical solution to the heat transfer equation in biological tissues during laser heating is presented. The results were compared to recently published numerical simulations.

Preparation and Properties of SiC Fiber with a Stable Excess Carbon Layer on the Surface

2009 ◽  
Vol 24 (6) ◽  
pp. 1209-1213 ◽  
Author(s):  
De-Yin WANG ◽  
Xian-He MAO ◽  
Yong-Cai SONG ◽  
Ying-De WANG
Keyword(s):  
Carbon Layer ◽  
Excess Carbon ◽  
Sic Fiber

Dynamics of CO2 laser heated solenoids

1982 ◽  
Vol 60 (9) ◽  
pp. 1247-1256 ◽  
Author(s):  
D. C. D. McKen ◽  
W. Tighe ◽  
R. Fedosejevs ◽  
A. A. Offenberger
Keyword(s):  
Laser Energy ◽  
Plasma Temperature ◽  
Wave Model ◽  
Hydrogen Gas ◽  
Pressure Balance ◽  
Scaling Models ◽  
Simple Scaling ◽  
Gas Breakdown ◽  
Long Pulse ◽  
Laser Heated

Experimental results are reported for long pulse CO2 laser production and heating of magnetically confined plasma columns. The plasma column is produced by an ionizing and heating wave propagation along the axis of a linear magnetic solenoid when laser radiation is focused into hydrogen gas contained inside the solenoid. The axial behavior is found to be reasonably well described by a "bleaching" wave model which predicts column length as a function of time. Radial behavior, following a transient ionization and expansion phase, is determined by a balance of ion thermal conduction and inverse bremsstrahlung laser heating. A finite ionization time is observed at the gas breakdown front. Energy balance measurements indicate that most of the incident laser energy is effectively coupled to ionization and heating of the plasma. Temperature measurements show good agreement with predictions of simple scaling models from which pressure balance gives a density value in agreement with experiment.

scholarly journals A portable on-axis laser-heating system for near-90° X-ray spectroscopy: application to ferropericlase and iron silicide

2020 ◽  
Vol 27 (2) ◽  
pp. 414-424 ◽  
Author(s):  
Georg Spiekermann ◽  
Ilya Kupenko ◽  
Sylvain Petitgirard ◽  
Manuel Harder ◽  
Alexander Nyrow ◽  
...  
Keyword(s):  
Laser Heating ◽  
Iron Silicide ◽  
Heating System ◽  
Laser Source ◽  
Nuclear Inelastic Scattering ◽  
X Rays ◽  
X Ray ◽  
Signal Collection ◽  
Diamond Anvil ◽  
Laser Heated

A portable IR fiber laser-heating system, optimized for X-ray emission spectroscopy (XES) and nuclear inelastic scattering (NIS) spectroscopy with signal collection through the radial opening of diamond anvil cells near 90°with respect to the incident X-ray beam, is presented. The system offers double-sided on-axis heating by a single laser source and zero attenuation of incoming X-rays other than by the high-pressure environment. A description of the system, which has been tested for pressures above 100 GPa and temperatures up to 3000 K, is given. The XES spectra of laser-heated Mg0.67Fe0.33O demonstrate the potential to map the iron spin state in the pressure–temperature range of the Earth's lower mantle, and the NIS spectra of laser-heated FeSi give access to the sound velocity of this candidate of a phase inside the Earth's core. This portable system represents one of the few bridges across the gap between laser heating and high-resolution X-ray spectroscopies with signal collection near 90°.

SiC Growth by Solvent-Laser Heated Floating Zone

2012 ◽  
Vol 717-720 ◽  
pp. 49-52 ◽  
Author(s):  
Andrew A. Woodworth ◽  
Philip G. Neudeck ◽  
Ali Sayir ◽  
David J. Spry ◽  
Andrew J. Trunek ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Laser Heating ◽  
Source Material ◽  
Floating Zone ◽  
X Ray ◽  
Single Crystal Sic ◽  
Growth Method ◽  
Laser Heated ◽  
Growth Methods

In an effort to grow single crystal SiC fibers for seed crystals the following two growth methods have been coupled in this work: traveling solvent and laser heated floating zone to create the solvent-laser heated floating zone (Solvent-LHFZ) crystal growth method. This paper discusses the results of these initial experiments, which includes, source material, laser heating, and analysis of the first ever SiC crystals (confirmed by synchrotron white beam x-ray topography)

Two-dimensional hydrodynamic simulations of a laser heated gas target plasma

1979 ◽  
Vol 57 (4) ◽  
pp. 514-521 ◽  
Author(s):  
R. D. Milroy ◽  
C. E. Capjack ◽  
J. N. McMullin ◽  
C. R. James
Keyword(s):  
Computer Simulation ◽  
Shock Front ◽  
Laser Heating ◽  
Characteristic Scale ◽  
Two Dimensional ◽  
Heated Region ◽  
Hydrodynamic Simulations ◽  
Gas Target ◽  
Target Plasma ◽  
Laser Heated

The CO2 laser heating and the resulting hydrodynamic expansion of a gas target plasma is examined by means of a two-dimensional computer simulation. These plasmas are found to exhibit characteristic scale lengths of the order of 1 mm. Electron temperatures vary up to about 200 eV whereas ion temperatures vary up to about 50 eV. Electron density is found to vary all the way from above critical in a shock front to well below critical in the laser heated region behind the shock.

Containerless Study of Metal Evaporation by Laser Induced Fluorescence

1986 ◽  
Vol 87 ◽  
Author(s):  
Robert A. Sghiffman ◽  
Paul C. Nordine
Keyword(s):  
Laser Heating ◽  
Electronic States ◽  
Laser Induced Fluorescence ◽  
Temperature Data ◽  
Radiative Heating ◽  
Atomic Vapors ◽  
Metal Evaporation ◽  
Tungsten Filaments ◽  
Laser Heated ◽  
Electromagnetically Levitated

AbstractLaser induced fluorescence (LIF) detection of atomic vapors was used to study evaporation from electromagnetically levitated and CW CO2 laser heated molydenum spheres and resistively heated tungsten filaments. Electromagnetic (EM) levitation in combination with laser heating of tungsten, zirconium, and aluminum specimens was also investigated. LIF intensity vs temperature data were obtained for molybdenum ( 7S3 ) atoms and six electronic states of atomic tungsten, at temperatures up to the melting point of each metal. The detected fraction of the emitted radiation was reduced by self-absorption effects at the higher experimental temperatures.Vaporization enthalpies derived from data for which less than half the LIF intensity was self-absorbed were ΔHo0 = -636 ± 24 kJ/g-mol for Mo and 831 ± 32 kJ/g-mol for W. Space-based applications of EM levitation in combination with radiative heating are discussed.

Raman Study of Kinetics of Graphitization of Carbon Blacks

2000 ◽  
Vol 73 (2) ◽  
pp. 284-292 ◽  
Author(s):  
T. Waldek Zerda ◽  
Tyler Gruber
Keyword(s):  
Laser Heating ◽  
Continuous Wave ◽  
Fast Rate ◽  
Pulsed Laser ◽  
Reaction Rates ◽  
Carbon Blacks ◽  
Raman Study ◽  
Laser Heated ◽  
Pulsed Laser Heating ◽  
Kinetics Of

Abstract Raman spectra of laser heated carbon blacks provide information on the dynamics of the graphitization process. Continuous wave and pulsed-laser heating is used. It is shown that two ordering mechanisms of distinctly different reaction rates are present during the heat treatment. The dominating mechanism, during the initial stages of graphitization, is characterized by a very fast rate. The rate during the later stages of the process, after the initial first couple of seconds, is orders of magnitude slower.

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