Begell House Inc.
High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes
HTM
1093-3611
8
1
2004
DETECTION OF BACTERIAL DEPOSITS AND BIO AEROSOLS BY TIME-RESOLVED LASER-INDUCED BREAKDOWN SPECTROSCOPY (TRELIBS)
1-22
10.1615/HighTempMatProc.v8.i1.10
N.
Leone
Section détection physique, Centre d'Etudes du Bouchet, Delegation Generate pour l'Armement, BP 3, 91710 Vert le Petit, France
G.
D'Arthur
Section detection physique, Centre d'Etudes du Bouchet, Delegation Generate pour l'Armement, BP 3, 91710 Vert le Petit, France
P.
Adam
Section détection physique, Centre d’Etudes du Bouchet, Direction des Centres d'Expertise et d'Essais, Delegation Generate pour l’Armement, BP 3, 91710 Vert le Petit, France
Jacques
Amouroux
Laboratoire de Genie des Precedes Plasmas Universite P. et M. Curie, ENSCP 11 rue P. et M. Curie 75005 Paris France
Potentialities of Time-REsolved Laser-Induced Breakdown Spectroscopy technique (TRELIBS or LIBS method) are investigated in order to detect biological matter in bulk and aerosolized forms. Alert detection of biological weapons is the main purpose. With this aim in view, eight different species in bulk form have been primarily considered: six bacteria and two pollens under a pellet form. A cumulative intensity ratio is proposed as a quantitative criterion due to its linearity and reproducibility. TRELIBS exhibits a good ability to differentiate between all these species whatever the growing medium, the specie or the strain. Studies are also extended to the analysis of aerosolized models with generated dry particulate matter and micrometric droplets to simulate single bacterial elemental compositions and concentrations. The expected capabilities make TRELIBS a potential candidate to trigger alarms either on surfaces or in ambient air.
DUST PARTICLE FORMATION IN A LOW PRESSURE CH4-N2 RADIO-FREQUENCY (13.56 MHz) PLASMA.
23-30
10.1615/HighTempMatProc.v8.i1.20
lsabelle
Geraud-Grenier
LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, Rue G.Berger, BP 4043, 18028 BOURGES CEDEX, France
Veronique
Massereau-Guilbaud
LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, Rue G.Berger, BP 4043, 18028 BOURGES CEDEX, France
Andre
Plain
LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, Rue G.Berger, BP 4043, 18028 BOURGES CEDEX, France
Polymer-like hydrogenated amorphous carbon nitride (a-CNx:H) nanoparticles are observed in a CH4(50 %)/N2(50 %) rf plasma. SEM micrographs show that the dust particles are spherical with diameters in the range 0.2-1.1 μ;m for rf powers in the range 40-120 W. They are trapped in the plasma bulk volume. The absorption spectra of the a-CNx:H particles reveal the presence of C-H, C=N and C≡N bonds. The absorption peak intensities strongly depend on the incident rf power. The C≡N triple bonds increase with the rf power whereas the C-H bonds decrease.
USE OF GLIDARC REACTOR FOR DECOMPOSITION OF TOLUENE VAPOURS IN HOT EXHAUSTS
31-38
10.1615/HighTempMatProc.v8.i1.30
Zofia
Ferenc
Politechnika Saska, Katedra Technologii i Urzajdzen Zagospodarowania Odpadow, 44-100 GLIWICE, Poland
Janusz W.
Wandrasz
Politechnika Slqska, Katedra Technologii i Urzajizen Zagospodarowania Odpadow, 44-100 GLIWICE, Poland
Electric energy can be regarded as "clean" and well adapted to eliminate most of toxic vapors and gases while using specific electric discharges generated directly in polluted air or fumes. Such a discharge produces very active particles which catalyze oxidation reactions toxic or foul-smelling compounds. Low temperature plasma generated in a low temperature plasma generator can be employed to transform almost all of the gases and gaseous mixtures.
OPTIMIZATION OF LOW ENERGY LASER ION SOURCE WITH THE USE OF MAGNETIC AND ELECTRIC FIELDS
39-44
10.1615/HighTempMatProc.v8.i1.40
J.
Wolowski
Institute of Plasma Physics and Laser Microfusion, 23 Eery St (23), 00-908 Warsaw, Poland
J.
Badziak
Institute of Plasma Physics and Laser Microfusion, 23 Eery St (23), 00-908 Warsaw, Poland
I.
Ivanova-Stanik
Institute of Plasma Physics and Laser Microfusion, 23 Eery St (23), 00-908 Warsaw, Poland
P.
Parys
Institute of Plasma Physics and Laser Micro fusion, 23 Eery St (23), 00-908 Warsaw, Poland
W.
Stepniewski
Institute of Plasma Physics and Laser Microfusion, 23 Eery St (23), 00-908 Warsaw, Poland
E.
Woryna
Institute of Plasma Physics and Laser Micro fusion, 23 Eery St (23), 00-908 Warsaw, Poland
The laser-produced plasma has been proposed to be an efficient source of ions for particle accelerators and ion implantation technology. The aim of the experiments performed at the IPPLM in Warsaw consisted of a study of the magnetic and electric fields effects on the laser-produced ions. A Nd:glass laser (1.06 μ;m, ≤ 2 J, 1 ns) was used for producing a low energy W ions and the Helmholtz coils was applied for generation of a magnetic field (0.2 - 1.2 T) in front of the target. A transverse electric field (about 250 V/cm) was used for the elimination of light contaminant ions from the ion beam or for the selection of a specific tungsten ion group. The ion diagnostics, i.e. ion collectors and an electrostatic ion-energy analyzer were based on the time-of-flight method. For measurements of angular dependencies of the ion stream parameters, a set of 5 small ion collectors was located at small angles (2.1° - 6.5°) on the both sides of the target normal. The measured angular distributions of ions show that the concentration of the ion stream close to the target normal increases with the increase of the magnetic field induction and laser energy. The simple Monte Carlo calculations taking into account experimental data confirm the effect of the concentration of the laser-produced ion stream as a result of the magnetic field action in our experimental conditions.
RECENT DEVELOPMENTS IN THERMAL SPRAYING FOR IMPROVED COATING CHARACTERISTICS AND NEW APPLICATIONS/ PROCESS CONTROLS AND SPRAY PROCESSES
45-93
10.1615/HighTempMatProc.v8.i1.50
Ghislain
Montavon
LERMPS laboratory, University of Technology of Belfortâ€Montbéliard
Thermal spraying has experienced very significant developments over the past five years, in terms of process controls and of developments of new processes. Controlling thermal spray processes requires firstly the capability to diagnose them. In-flight particle characteristics; i.e., their velocity and temperature, but also their diameter and their flux at a given location, constitute, with the accurate determination of the coating temperature during spraying, the most important parameters to record. Several systems, based on fast infrared pyrometry or on fluxmetry, were developed during these past few years. Controlling thermal spray processes requires secondly a robust strategy to correlate the diagnosed characteristics to the operating parameters. Very significant efforts were made as well to develop these strategies to reach, in a short to middle term, an on-line control of the processes. The efforts were also directed towards the development of new processes. Suspension plasma spraying (SPS), using d.c. or R.F. plasma spray torches, consists in injecting the powder particles into the plasma flow using a liquid as carrier media, instead of the classical carrier gas. This new approach offers unique possibilities to carry nano-sized particles to manufacture finely grained coatings. Very Low Pressure Plasma Spraying (VLPPS) is another way to manufacture thin and homogenous coatings with high deposition rate. Hybrid thermal spraying consists in coupling to a classical thermal spray gun a high power (i.e., a few MW.m−2) laser beam. Depending on the characteristics of the beam, several physical mechanisms can be induced. From surface ablation prior to particle spreading to surface heating and in situ complete or partial remelting, hybrid thermal spraying permits to modify locally the coating structures and hence their properties. Cold spraying differs from the other spray processes in the sense that the particles impact the surface to be covered in the solid state: the flattening results exclusively from the plastic deformation by dissipation of the kinetic energy. The system is based on the implementation of a De Laval nozzle through which a warm gas is released to produce a high velocity gas stream into which particles are injected. This process offers the unique possibility to process particles without melting them: oxidation does not take place and metastable materials can be considered as candidates to produce coatings.
UNDERSTANDING OF SUSPENSION PLASMA SPRAYING
95-117
10.1615/HighTempMatProc.v8.i1.60
V.
Rat
PCTS -CNRS UMR 6638, University of Limoges, 123 av. A. Thomas, 87060 Limoges cedex, France
C.
Delbos
Laboratoire Sciences des Precedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS-Universite de Limoges, conventionne avec le CEA n° M08
C.
Bonhomme
Laboratoire Sciences des Precedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS-Universite de Limoges, conventionne avec le CEA n° M08
J.
Fazilleau
Laboratoire Sciences des Precedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS-Universite de Limoges, conventionne avec le CEA n° M08
J. F.
Coudert
Laboratoire Sciences des Procédés Céramiques et Traitements de Surface, UMR-CNRS 6638, Université de Limoges, 87060 Limoges Cedex, France
Pierre
Fauchais
Laboratoire Sciences des Procedes Ceramiques et de Traitements de Surface UMR CNRS 6638 University of Limoges 123 avenue Albert Thomas, 87060 LIMOGES - France
The aim of this paper is to present the recent advances regarding the Suspension Plasma Spraying process (SPS). The latter is devoted to synthesize finely structured coatings which are of great interest for the electrolytes (of low thickness, 20-30 μ;m) of Solid Oxide Fuel Cells (SOFC). Powders of Yttria (13.5wt%) Stabilised Zirconia (YSZ) are dispersed in ethanol to produce a stable suspension. The latter is injected by using a mechanical injection into a plasma jet generated by a DC plasma torch. Four centimetre square coatings are built with a deposition efficiency ranging between 50 and 60 % and a deposition rate up to 15 μ;m.h−1.m−2.
The injection pressure of suspensions is optimized by using a pulsed infra-red illumination of the atomization processes of suspensions which is observed with a fast shutter camera.
The influences of the preheating and roughness of the substrates, the plasma gas composition and the particle size distribution on the flattening degree of collected splats are investigated. Moreover, the effect of these experimental parameters on the coating microstructures is then studied. It is shown that substrates have to be polished and preheated to enable the most favorable flattening of splats. Moreover, the particle size distribution of powder in suspension has to be narrow with a size adapted to the spraying conditions, for example, centered on about l μ;m for a plasma enthalpy of 17.5 MJ.kg−1. The results about splats are confirmed when analyzing coating microstructures which present micro-sized porosity.
PLASMA PROCESSING OF CARBON NANOMATERIALS
119-138
10.1615/HighTempMatProc.v8.i1.70
L.
Fulcheri
Centre D'Energetique, Ecole Des Mines De Paris; Rue Claude Daunesse, B. P. 207, F-06904 Sophia Antipolis Cedex
T. M.
Gruenberger
Ecole des Mines de Paris, B.P. 207, P-06904 Sophia Antipolis, France
J. Gonzales
Aguilar
Center for Energy and Processes, Ecole des Mines de Paris, Rue Claude Daunesse B.P.. 207, F-06904 Sophia-Antipolis Cedex, France ; Dpto. De Fisica Aplicada, Universidad de Cantabria, Av. Los Castros s/n, 39005 Santander, SPAIN
Frederic
Fabry
C. N. R. S., Institut de Science et de Genie des Materiaux et Procedes B. P. 5, Odeillo, F-66125 Font-Romeu Cedex
E.
Grivei
Timcal Belgium S.A., 534, av, Louise, B-1050 Brussels, Belgium
N.
Probst
Timcal Belgium S.A., 534, av, Louise, B-1050 Brussels, Belgium
Gilles
Flamant
CNRS PROMES UPR 8521, Tecnosud, Rambla de la Thermodynamique, 66100 Perpignan, France
H.
Okuno
University of Louvain, Unit of Physico-Chemistry and Physics of Materials, LLN, Belgium
J.-C.
Charlier
University of Louvain, Unit of Physico-Chemistry and Physics of Materials, LLN, Belgium
Thermal plasma processes show certain advantages over conventional gas phase synthesis process for the production of carbon nanomaterials. Due to the extreme temperature conditions and the unique flexibility, very different structures can be produced at high selectivity. An overview is given of the three principal families of nanostructures, carbon blacks, fullerenes and nanotubes, produced so far by the original three-phase AC plasma technology presented. Various examples of individual structural types are used to illustrate and explain the multitude of different particle formation processes adjustable in plasma systems. Numerical simulation of arc region, kinetics and fluid dynamics appears as a central tool for the control of the three main process parameters: temperature profile, particle residence time and species concentrations.
TRANSPORT OF DUST IN LOW-PRESSURE RF DISCHARGES
139-148
10.1615/HighTempMatProc.v8.i1.80
W. J.
Goedheer
FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein, The Netherlands
M. R.
Akdim
FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein, The Netherlands
V.
Land
FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein, The Netherlands
The behaviour of dust particles in a discharge is the result of the concerted action of the charging process and forces like gravity, the ion and neutral drag force, and the thermophoretic force. When the amount of dust is large, the plasma parameters differ from those of a dust free discharge and self-consistent modelling of the plasma-dust coupling is needed. We have developed such a model and successfully applied it to dusty argon radio-frequency discharges under micro-gravity conditions.
Since the ion drag force plays a major role, the reactor geometry and the ion density profile are important. Therefore, the geometry and the shape of the powered parts (like rings) of the electrodes are tools that can be used to modify the shape of the dust cloud and of the dust free central part, the void, that is usually observed in microgravity experiments. Here, we will show applications of the model to asymmetric reactors, and reactors in which concentric ring electrodes are used to power the discharge. This shows a way to obtain larger crystalline regions.
ACTIVE AND PASSIVE SPECTROSCOPY ON EUV-PRODUCING DISCHARGE PLASMAS
149-160
10.1615/HighTempMatProc.v8.i1.90
E.R.
Kieft
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
Joost J. A. M.
van der Mullen
Department of Applied Physics, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
G. M. W.
Kroesen
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
V.
Banine
ASML Netherlands B.V, De Run 6501, 5504 DR Veldhoven, The Netherlands
K.N.
Koshelev
ISAN, Troitsk, Moscow Region, 142092 Russia
Short-lived discharge plasmas are currently investigated as candidate sources of extreme ultraviolet (EUV) radiation for application in semiconductor lithography. They are operated in elements such as xenon and (more recently) tin, because of their favorable emission at 13.5 nm. A common property of these plasmas is the current-induced 'pinch' effect, that causes the plasma to collapse to an elongated, needle-like shape on the discharge axis. The typical plasma lifetime is in the tens to hundreds of ns.
Various spectroscopic techniques can be applied for characterization of these plasmas. These include time-resolved EUV spectrometry and Stark broadening measurements at visible light wavelengths. Collective Thomson scattering of laser light can provide direct time and space resolved measurements of electron temperatures and densities.
Specific experimental difficulties and the ranges of applicability of the different methods for measurements on pinch plasmas are discussed. Results of these measurements on a hollow cathode discharge in xenon and a vacuum-arc discharge in tin vapor are presented.
OXIDATION AND CATALYCITY OF THERMAL PROTECTION MATERIALS AT HIGH TEMPERATURE
161-171
10.1615/HighTempMatProc.v8.i1.100
M.
Balat-Pichelin
Laboratoire "Precedes, Materiaux et Energie Solaire", PROMES-CNRS, rue du four solaire, BP 5,66125 Font-Romeu Odeillo, France
When a space vehicle enters in planetary atmospheres like Earth (air) and/or Mars (CO2), oxidation and catalycity coupled phenomena occur on the thermal protective materials of the nose cap and wing leading edges conducting to an important excess of heating and possible damage of the materials. At the PROMES-CNRS laboratory (formerly IMP-CNRS), in the research field "Interaction high solar fluxes-matter", oxidation under plasma conditions, and particularly the active-passive transition in the oxidation of silicon-based ceramics and the catalytic recombination of atomic oxygen under the same conditions are studied. The most important conditions for the ground simulation (high temperature, non-equilibrium plasma flow) have been realized in the MESOX set-up which associates a solar radiation concentrator and a microwave generator. In this paper, are presented some results about the transition between the active and passive oxidation regimes and the recombination of atomic oxygen and/or carbon monoxide at the surface of sintered silicon carbide at high temperatures and in a total pressure range of 102-104 Pa. The comparison is made between the two atmospheres: air (Earth entry) and CO2 (Mars entry) for the oxidation transition domain and for the atoms recombination.