Physico-Mechanical Properties of the Cr-C and Mo-C Coatings

2013 ◽  
Vol 750-752 ◽  
pp. 1959-1962
Author(s):  
Е.A. Stepanova ◽  
I.L. Pobol ◽  
J. Rajczyk
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Arc Discharge ◽  
Plasma Source ◽  
Pulse Repetition ◽  
Vacuum Arc ◽  
The Coefficient Of Friction ◽  
The Individual

The investigation of physico-mechanical properties of metal-carbon (Cr-C and Mo-C) coatings obtained using pulsed vacuum arc deposition has been carried out. Changing the arc discharge pulse repetition rate of the individual plasma sources equipped with metal and graphite cathodes allows significant varying of the composition, surface roughness and friction coefficient of the coatings. When reducing the pulse repetition rate in metal plasma source from 10 Hz to 5 Hz while retaining that constant in carbon source, the metal content in the coating can be decreased from 30 at.% to 2 at. % with increasing the surface roughness by a factor of 3.5. The tribological investigations of Cr-C and Mo-C coatings under the dry friction conditions showed the uniform adhesive wear of the coating upper layers. The coefficient of friction measured against steel counterbody was in the range of 0.08 to 0.1. However, in this case Mo-C coatings were more wear-resistant than Cr-C coatings.

scholarly journals The Influence of the Processing Parameters on the Laser-Ablation of Stainless Steel and Brass during the Engraving by Nanosecond Fiber Laser

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 232
Author(s):  
Luka Hribar ◽  
Peter Gregorčič ◽  
Matej Senegačnik ◽  
Matija Jezeršek
Keyword(s):  
Surface Roughness ◽  
Fiber Laser ◽  
Pulse Duration ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Removal Rate ◽  
Average Power ◽  
Laser Pulses ◽  
Processing Parameters ◽  
Pulse Repetition

In this paper, we investigate the influence of the following parameters: pulse duration, pulse repetition rate, line-to-line and pulse-to-pulse overlaps, and scanning strategy on the ablation of AISI 316L steel and CuZn37 brass with a nanosecond, 1064-nm, Yb fiber laser. The results show that the material removal rate (MRR) increases monotonically with pulse duration up to the characteristic repetition rate (f0) where pulse energy and average power are maximal. The maximum MRR is reached at a repetition rate that is equal or slightly higher as f0. The exact value depends on the correlation between the fluence of the laser pulses and the pulse repetition rate, as well as on the material properties of the sample. The results show that shielding of the laser beam by plasma and ejected material plays an important role in reducing the MRR. The surface roughness is mainly influenced by the line-to-line and the pulse-to-pulse overlaps, where larger overlap leads to lower roughness. Process optimization indicates that while operating with laser processing parameters resulting in the highest MRR, the best ratio between the MRR and surface roughness appears at ~50% overlap of the laser pulses, regardless of the material being processed.

Laser Surface Polishing of Ti6Al4V Titanium Alloy in Air, Nitrogen and Argon Environments

2021 ◽  
Vol 897 ◽  
pp. 15-20
Author(s):  
Pakin Jaritngam ◽  
Viboon Tangwarodomnukun ◽  
Chaiya Dumkum
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
High Repetition Rate ◽  
Laser Surface ◽  
Pulse Repetition ◽  
Polished Surface ◽  
Surface Polishing ◽  
Scan Speed

This paper presents the laser surface polishing of titanium alloy (Ti6Al4V) by using a nanosecond pulse laser. Air, nitrogen and argon were employed as a shielding gas in this study, where the areal roughness (Sa) of laser-polished surface was measured and compared. The results showed that argon was the suitable assist gas for improving the metal surface without causing the oxidation. The effect of laser pulse repetition rate and scan speed on the surface roughness was also investigated in this study. The use of high repetition rate together with slow scan speed was able to reduce the surface roughness of titanium alloy. The roughness was found to be reduced by 47% when the pulse repetition rate of 500 kHz and scan speed of 50 mm/s were applied.

scholarly journals Parameter Optimization of Laser Direct-Write Patterning on Indium Tin Oxide/Polycarbonate Thin Films Using Multi-Performance Characteristics Analysis

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5808
Author(s):  
Yi-Cheng Chen ◽  
Yi-Kai Hsiung ◽  
Chih-Yuan Chang ◽  
Shih-Fu Ou
Keyword(s):  
Surface Roughness ◽  
Line Width ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Pulse Repetition ◽  
Direct Write ◽  
Optimal Parameters ◽  
Laser Direct Write

Indium tin oxide (ITO) thin films on polycarbonate (PC) substrates were patterned using the laser direct-write (LDW) technique to form an isolation line. The effect of the LDW parameters (power, pulse repetition rate, and defocusing distance) on the isolation line width, depth and roughness of the PC within the line was investigated. Additionally, the Taguchi method of experimental design was applied to determine the optimal parameters of LDW. Results showed that increasing the power led to an increase in the isolation line width and decrease in the surface roughness of the PC within the line. The increase in the pulse repetition rate and defocusing distance caused a decrease in the isolation line width. The optimal parameters were found to be A2B3C3, consisting of power of 5 W, pulse repetition rate of 100 kHz, and defocusing distance of +3 mm. Under these parameters, we obtained an isolation line width of 48.4 μm, and a surface roughness of Ra 38 nm of the PC within the isolation line. We confirmed that the ITO films separated by the isolation lines attained electrical isolation.

scholarly journals Two Approaches to the Laser-Induced Formation of Au/Ag Bimetallic Nanoparticles in Supercritical Carbon Dioxide

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1553
Author(s):  
Alexey Rybaltovsky ◽  
Evgeniy Epifanov ◽  
Dmitriy Khmelenin ◽  
Andrey Shubny ◽  
Yuriy Zavorotny ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Ag Nanoparticles ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Bimetallic Nanoparticles ◽  
Side Wall ◽  
Pulse Repetition ◽  
Gold Core ◽  
Supercritical Carbon

Two approaches are proposed for the synthesis of bimetallic Au/Ag nanoparticles, using the pulsed laser ablation of a target consisting of gold and silver plates in a medium of supercritical carbon dioxide. The differences between the two approaches related to the field of “green chemistry” are in the use of different geometric configurations and different laser sources when carrying out the experiments. In the first configuration, the Ag and Au targets are placed side-by-side vertically on the side wall of a high-pressure reactor and the ablation of the target plates occurs alternately with a stationary “wide” horizontal beam with a laser pulse repetition rate of 50 Hz. In the second configuration, the targets are placed horizontally at the bottom of a reactor and the ablation of their parts is carried out by scanning from above with a vertical “narrow” laser beam with a pulse repetition rate of 60 kHz. The possibility of obtaining Ag/Au alloy nanoparticles is demonstrated using the first configuration, while the possibility of obtaining “core–shell” bimetallic Au/Ag nanoparticles with a gold core and a silver shell is demonstrated using the second configuration. A simple model is proposed to explain the obtained results.

Development of high-power KrF lasers with a pulse repetition rate up to 5 kHz

2000 ◽  
Vol 30 (9) ◽  
pp. 783-786 ◽  
Author(s):  
V M Borisov ◽  
A Yu Vinokhodov ◽  
V A Vodchits ◽  
A V El'tsov ◽  
A S Ivanov
Keyword(s):  
High Power ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Pulse Repetition
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