Synthesis and control of micro to noanscale porous structures of diamond like carbon films

2006 ◽  
Vol 954 ◽  
Author(s):  
Peter Feng ◽  
Ben Yang ◽  
H. X. Zhang ◽  
X. P. Wang ◽  
Noel Upia ◽  
...  
Keyword(s):  
Power Density ◽  
Laser Power ◽  
Carbon Films ◽  
Laser Power Density ◽  
Diamond Like Carbon ◽  
Excimer Laser Ablation ◽  
Target Yield ◽  
Krf Excimer Laser ◽  
And Control ◽  
The Relationship

ABSTRACTDiamond like carbon (DLC) films are synthesized on various substrates using a pulsed KrF excimer laser ablation deposition technique. Variations of laser power density, substrate temperature, angle and distance between the substrate and target yield different sizes of porous surfaces of DLC films. Microscope is used to examine the surfaces. Raman scattering is used to characterize the samples, and the typical G and D bands have been identified. Intensities and profiles of the G and D bands closely depend on laser power density. The relationship between the deposition rate and the power density is also studied.

scholarly journals Effect of the laser power density on the properties and structures of the diamond-like carbon films deposited by pulsed laser ablation of graphite

2005 ◽  
Vol 54 (9) ◽  
pp. 4294
Author(s):  
Peng Hong-Yan ◽  
Zhou Chuan-Sheng ◽  
Zhao Li-Xin ◽  
Jin Zeng-Sun ◽  
Zhang Bing ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Power Density ◽  
Laser Power ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Carbon Films ◽  
Laser Power Density ◽  
Diamond Like Carbon

Pulsed Laser Deposition of Diamond-Like Carbon Thin Films: Ablation Dynamics and Growth

1996 ◽  
Vol 438 ◽  
Author(s):  
Peidong Yang ◽  
Z. John Zhang ◽  
Jiangtao Hu ◽  
Charles M. Lieber
Keyword(s):  
Thin Films ◽  
Kinetic Energy ◽  
Pulsed Laser Deposition ◽  
Power Density ◽  
Laser Power ◽  
Large Fraction ◽  
Pulsed Laser ◽  
Laser Power Density ◽  
Laser Deposition ◽  
Diamond Like Carbon

AbstractThin films of diamond-like carbon have been grown by pulsed laser deposition using a Nd:YAG laser at 532 nm. Time-of-flight mass spectroscopy was used to investigate the effects of laser power density and background gas pressure on the plume characteristics including the species in the plume and the kinetic energy distribution of each species. We found that with increasing laser power density (1) the relative amount of C+ ions increases, (2) the kinetic energy distributions of C+ get broader and can be deconvoluted into fast and slow components, and (3) the kinetic energy of the fast component of C+ ions increases from several to 40 eV. The resistivity and the local carbon bonding in films grown under these same conditions were also characterized. It was found that there is direct correlation between the characteristics of fast part of C+ ions in the plume and the diamond-like properties of the thin films. Under optimal growth conditions diamond-like carbon films with a large fraction of sp3 bonding can be prepared, although the maximum fraction appears to saturate at 70%. The implications of these results are discussed.

Research on Pre-Loaded Composite Irradiated by Laser Beam

2011 ◽  
Vol 462-463 ◽  
pp. 872-877 ◽  
Author(s):  
Lian Chun Long ◽  
Zhong Ying Chen ◽  
Zhi Guang Yang
Keyword(s):  
Power Density ◽  
Laser Power ◽  
High Speed ◽  
Laser Power Density ◽  
Failure Behavior ◽  
Time To Failure ◽  
Experiment Data ◽  
Holding Device ◽  
The Relationship ◽  
Power Densities

This paper investigates failure behavior tests of T300/AG80 composite laminated specimens under tensile and compressive preload using a load holding device and laser irradiation from an Nd: YAG laser. By changing the magnitudes of the preload and the power densities of the laser, the effects of preload and laser power density on the time-to-failure of the specimens were observed. The response process of specimens was synchronized taken in using high-speed camera in experiment. The experimental results showed that tensile mechanical properties of T300/AG80 composite laminated specimens were obviously superior to ones in compression test. The relational expressions between the time-to-failure of specimens and pre-loads as well as with laser power densities were acquired through fitting experiment data. The time-to-failure reduced with the pre-load increasing, the relationship is approximating linear when the laser power density kept invariable. When the pre-load kept unchanged, the time-to-failure reduced as the laser power density increased. The relationship is approximating exponential. A basis for life prediction of structure mechanically loaded in either tension or compression during the irradiation by laser is provided by fitting expression.

Failure Behavior Tests of Preloaded T300/AG80 Composites Irradiated by Laser Beam

2012 ◽  
Vol 562-564 ◽  
pp. 171-174
Author(s):  
Li Ting Liu ◽  
Lian Chun Long ◽  
Zhong Ying Chen
Keyword(s):  
Laser Irradiation ◽  
Power Density ◽  
Laser Power ◽  
Composite Plate ◽  
High Speed ◽  
Failure Time ◽  
Experimental Testing ◽  
Laser Power Density ◽  
Failure Behavior ◽  
The Relationship

This paper predicts the effect of main parameters to the failure behavior of T300/AG80 composite plate under preload and laser irradiation by experimental testing and data fitting. The load holding device was used to give certain preload to composite plate specimens, and an Nd: YAG laser was used to give laser radiation simultaneously for testing the failure time of the specimens. By varying the magnitudes of preload and the laser power densities, the effect of preload and laser power density on the failure time is obtained. The reaction process was recorded with a high-speed camera. The experimental data were fitted to obtain the expression of the materials failure time with preload and laser power density. When the preload kept constant, the relationship between the failure time and laser power density was exponential function. When the laser power density kept constant, the relationship between the failure time and pre-tensile-loads was approximating linear, and pre-compress-load was quadratic. Fitting the empirical formula provides a reference to predict life for the composite structure applied both preload and the action of the laser irradiation.

Hard Amorphous Carbon Films Deposited by ArF Pulse Laser Ablation of Graphite at Room Temperature

1992 ◽  
Vol 270 ◽  
Author(s):  
Fulin Xiong ◽  
R. P. H. Chang
Keyword(s):  
Laser Ablation ◽  
Power Density ◽  
Amorphous Carbon ◽  
Laser Power ◽  
Room Temperature ◽  
High Vacuum ◽  
Carbon Films ◽  
Laser Wavelength ◽  
Laser Power Density ◽  
Amorphous Carbon Films

ABSTRACTHard amorphous carbon films have been deposited by ArF pulsed laser ablation of graphite at room temperature, with the laser power density of 5x108 W/cm2. The films prepared in the high vacuum environment possess remarkable diamond-like properties with a hardness up to 38 GPa and an optical energy band gap of 2.4 eV. The properties of the films doped with nitrogen vary with the nitrogen content, but improve interface adhesion, resulting in the extension of the film thickness limit to a greater range. The results suggest that the properties of the laser ablation deposited diamond-like carbon films depend not only on the laser power density, but also strongly on the laser wavelength or photon energy.

scholarly journals Influence of Saturation Phenomena on Laser-Excited Atomic Fluorescence Flame Spectrometry

1973 ◽  
Vol 28 (2) ◽  
pp. 273-279
Author(s):  
J. Kühl ◽  
S. Neumann ◽  
M. Kriese
Keyword(s):  
Power Density ◽  
Laser Power ◽  
Atomic Emission ◽  
Equation Model ◽  
Laser Power Density ◽  
Atomic Level ◽  
Dye Laser ◽  
Atomic Fluorescence ◽  
Emission Flame ◽  
Flame Spectrometry

Using a simple rate equation model, the laser power density Ic necessary to reach 50% of the saturation limited population of the excited atomic level under typical flame conditions is calculated. For Na atoms aspirated into the flame a saturating power density for irradiation with a narrow dye laser line (bandwidth 0.033 Å) of Ic ~ 0.4 kW/cm2 was determined. With the aid of a dye laser with an appropriate laser power density, analytical curves for Na were measured yielding a detection limit of 0.2 ng/ml. This sensitivity is comparable with the best results obtained by atomic emission flame spectrometry.

Experimental Study on Testing Ni-Containing Stainless Steel Protective Coatings by Pulsed Laser Scratching

2010 ◽  
Vol 43 ◽  
pp. 651-656
Author(s):  
Ai Xin Feng ◽  
Yu Peng Cao ◽  
Chuan Chao Xu ◽  
Huai Yang Sun ◽  
Gui Fen Ni ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Power Density ◽  
Laser Power ◽  
Protective Coatings ◽  
Three Dimensional ◽  
Pulsed Laser ◽  
Laser Power Density ◽  
The Matrix ◽  
The Impact

In the experiment, we use pulsed laser to conduct discrete scratching on Ni-containing stainless steel protective coatings to test residual stress situation after the matrix is scratched; then to analyze the the impact of the impact stress wave on coating - substrate bonding strength according to the test results, finally to infer the laser power density range within which it occurs coating failure. The study shows that: after laser discrete scratching, the residual stress of the center of the laser-loaded point on matrix surface gradually reduces when the pulsed laser power density increases. The matrix produces a corresponding residual compressive stress under the laser power density reaches a certain value. The actual failure threshold values are 12.006 GW/cm2, 11.829GW/cm2 and 12.193GW/cm2 measured by the three-dimensional topography instrument testing the discrete scratch point of three groups of samples and verified by using a microscope

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