scholarly journals On the Interaction of a Microwave Excited Oxygen Plasma with a Jet of Precursor Material for Deposition Applications

2019 ◽  
Vol 6 (3) ◽  
pp. 243-246 ◽  
Author(s):  
R. Methling ◽  
F. Hempel ◽  
M. Baeva ◽  
T. Trautvetter ◽  
H. Baierl ◽  
...  
Keyword(s):  
High Speed ◽  
Oxygen Plasma ◽  
Quartz Substrate ◽  
Substrate Surface ◽  
Optical Emission ◽  
Plasma Source ◽  
High Speed Imaging ◽  
Precursor Material ◽  
Jet Behavior ◽  
Excited Oxygen

<p>A plasma source based on a microwave discharge at atmospheric pressure is used to produce an oxygen plasma torch. An admixture of liquid precursor material is evaporated and injected into the torch through a nozzle, causing oxidization and deposition of doped silica at a nearby quartz substrate. The temperature generated inside the plasma source and in the plume, in the region of treatment, and at the substrate surface are key parameters, which are needed for process description and optimization of plasma-chemical reactions.</p><p>Optical emission spectroscopy, high-speed imaging, and thermography were applied to observe and to characterize the jet behavior and composition. The experimental results are compared with self-consistent modeling.</p>

Experimental Investigation Into the Spatter Particle Behaviour of Maraging Steel During Selective Laser Melting

2020 ◽  
Author(s):  
Tatsuaki Furumoto ◽  
Kyota Egashira ◽  
Kazushi Oishi ◽  
Satoshi Abe ◽  
Yohei Hashimoto ◽  
...  
Keyword(s):  
Metal Powder ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
High Speed ◽  
Substrate Surface ◽  
Laser Melting ◽  
High Speed Imaging ◽  
Melt Pool ◽  
Particle Behaviour

Abstract The quality of built parts by selective laser melting (SLM) relies on the comprehension of the phenomena that takes place during the melting and solidification of the metal powder. The scattering of spatter particle as liquid metal during SLM process affects the layer consolidation of powder bed in addition to the surface quality of built part. The present study is focused on the spatter particle behaviour of maraging steel during SLM to achieve a thorough understanding of the phenomena that occur during the melting and fusing of the metal powder. The spatter particles are tracked using high speed imaging, and the effects of the process parameters on the spatter particle behaviour are investigated. The spatter particles ejected from the melt pool are also physically and chemically evaluated. The results showed that the spatter particles were classified as being spherical or satellite types, according to their scattered volumes; some spatter particles were larger than the particles in the initial metal powder. Most spatter particles were ejected from the droplet formed around the melt pool and from the melted powder in front of the melt pool; the number of spatter particles ejected from the melt pool was relatively low. The surface roughness affected the generation locations and tracks of the spatter particles, and the substrate surface wettability was the principal factor affecting the spatter particle behaviour.

Roles of Hydrogen Atmospheres in Growth of Ultrananocrystalline Diamond by Pulsed Laser Deposition

2010 ◽  
Vol 638-642 ◽  
pp. 1685-1690
Author(s):  
Kenji Hanada ◽  
Takashi Nishiyama ◽  
Tsuyoshi Yoshitake ◽  
Kunihito Nagayama
Keyword(s):  
Pulsed Laser Deposition ◽  
High Speed ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Optical Emission ◽  
Hydrogen Atmosphere ◽  
Laser Deposition ◽  
Growth Time ◽  
Iccd Camera ◽  
Ultrananocrystalline Diamond

The growth of ultrananocrystalline diamond (UNCD) by pulsed laser deposition necessitates hydrogen atmospheres during the deposition. Optical emission spectroscopy was used to study the roles of the hydrogen atmosphere on the UNCD growth. Time-resolved images of a plume that expanded from a laser-irradiation spot toward a substrate were taken using a high-speed ICCD camera equipped with narrow-bandpass filters. While the plume disappeared at the longest within 1 s in vacuum, the emission from C+ lasted above the substrate surface for approximately 7 microseconds at a hydrogen pressure of 53.3 Pa. Since emission lifetimes of species are approximately 10 nanoseconds, this implies that C+ ions collided actively for such a long time. The hydrogen atmosphere has a role of forming a high number density of C+ ions. In addition, we believe that atomic hydrogen that might be generated by the collisions with carbon species contributes to the UNCD crystallite formation by their terminating the dangling bonds of carbon clusters as theoretically predicted in previous reports.

Spectroscopic Study of Radiofrequency Oxygen Plasma Stripping of Negative Photoresists. II. Visible Spectrum

1977 ◽  
Vol 31 (2) ◽  
pp. 134-137 ◽  
Author(s):  
J. E. Griffiths ◽  
E. O. Degenkolb
Keyword(s):  
Spectroscopic Study ◽  
Oxygen Pressure ◽  
Flow Rate ◽  
Oxygen Plasma ◽  
Visible Spectrum ◽  
Optical Emission ◽  
Active Species ◽  
Semiconductor Surface ◽  
Electronically Excited ◽  
Excited Oxygen

The rf O2 plasma-induced stripping of negative photoresists from semiconductor surfaces has been detected and monitored using the optical emission from electronically excited CO product molecules at 483.5 and 519.8 nm. The active species producing the stripping has been identified as electronically excited oxygen atoms. The end point of the stripping process is easily identified as is the final cleanup of the semiconductor surface. The dependence of the stripping time as a function of flow rate and oxygen pressure has also been determined.

In Situ Plasma Characterization of Laser-Ablated BaxSr1-xTiO3

1997 ◽  
Vol 502 ◽  
Author(s):  
D. T. Venizelos ◽  
S. Sengupta ◽  
R. C. Sausa
Keyword(s):  
Electron Density ◽  
Emission Spectroscopy ◽  
High Speed ◽  
Substrate Surface ◽  
Leading Edge ◽  
Wave Theory ◽  
Oxide Material ◽  
Stark Broadening ◽  
High Speed Imaging ◽  
Time Resolved

ABSTRACTHigh speed imaging and emission spectroscopy are used to characterize the plumes generated from the ablation of bulk barium strontium titanium oxide material in vacuum and 30–60 mTorr of O2 using a pulsed 248-nm laser with fluences ranging from 5–8 J/cm2. High speed imaging reveals that in vacuum the leading edge of the plume expands normal to the substrate surface with a velocity of 19.7 km/sec. The ratio of distance traveled to the plume's radius is ˜ 2 at the early stages of the expansion and 3.2 at the later stages near the substrate. Similar observations are observed when the plume expands in 30 mTorr of O2 for times less than 2.0 μsec. However, at times greater than 2.0 μsec the plume's expansion is retarded due to collisional momentum transfer and reactions with the background gas. This effect is more pronounced when the plume expands in 60 mTorr of O2. Blast wave theory is used to model these results. Time-resolved emission spectroscopy of Ba(I) lines in the 735–770 nm region reveals that the plume' electron temperatures, Te, in a vacuum expansion range from 18000±2000 K at 0.1 μsec to 15000±1500 K at 2.0 /μsec. In contrast, in 30 mTorr of O2 the values of Te range from 17000±2000 K at 0.1 μsec to 4000±500 K at 8.0 μsec. At 0.1 μsec the plume's electron density is estimated as 1.7±0.4 × 1017 cm−3 in both vacuum and 30 mTorr of O2. We also determine the Stark broadening of the Ba(I) line at 746 nm to be 0.5±0.1 Åat an electron temperature of 1 eV and an electron density of 1017 cm−3.

Experimental Measurement of In-Plane Rolling Nonpneumatic Tire Vibrations Using High-Speed Imaging

2019 ◽  
Vol 47 (3) ◽  
pp. 196-210
Author(s):  
Meghashyam Panyam ◽  
Beshah Ayalew ◽  
Timothy Rhyne ◽  
Steve Cron ◽  
John Adcox
Keyword(s):  
High Speed ◽  
Image Correlation ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
High Speed Imaging ◽  
Correlation Algorithm ◽  
Mode Decomposition ◽  
Series Of Experiments ◽  
Plane Deformations ◽  
Dominant Frequencies

ABSTRACT This article presents a novel experimental technique for measuring in-plane deformations and vibration modes of a rotating nonpneumatic tire subjected to obstacle impacts. The tire was mounted on a modified quarter-car test rig, which was built around one of the drums of a 500-horse power chassis dynamometer at Clemson University's International Center for Automotive Research. A series of experiments were conducted using a high-speed camera to capture the event of the rotating tire coming into contact with a cleat attached to the surface of the drum. The resulting video was processed using a two-dimensional digital image correlation algorithm to obtain in-plane radial and tangential deformation fields of the tire. The dynamic mode decomposition algorithm was implemented on the deformation fields to extract the dominant frequencies that were excited in the tire upon contact with the cleat. It was observed that the deformations and the modal frequencies estimated using this method were within a reasonable range of expected values. In general, the results indicate that the method used in this study can be a useful tool in measuring in-plane deformations of rolling tires without the need for additional sensors and wiring.

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