scholarly journals STRUCTURE OF MULTI-ELEMENT COATINGS BEFORE AND AFTER EXPOSURE TO LASER RADIATION

2020 ◽  
Author(s):  
V. Yurov ◽  
S. Guchenko ◽  
K. Makhanov
Keyword(s):  
Laser Radiation ◽  
Friction Coefficient ◽  
Laser Beam ◽  
Laser Treatment ◽  
Dislocation Structure ◽  
Laser Action ◽  
Decisive Role ◽  
Argon Atmosphere ◽  
Initial Structure ◽  
Before And After

It is shown in this work that the effect of laser action on nanostructured coatings can be quite diverse. In this case, the decisive role is played by the initial structure of the coating, which sets the mechanism and direction of its transformation under external, including laser, influences. It is shown that for a CrMnSiCuFeAlTi coating in an argon atmosphere, the friction coefficient after laser treatment decreases, while the microhardness increases. We associate the first effect with a decrease in the roughness of the coating when it is melted by a laser beam. The second effect is due to the formation of the dislocation structure of the coating upon sharp heatingcooling.

scholarly journals Effect of laser treatment modes on metal surface marking color

2020 ◽  
pp. 37-40
Author(s):  
S. M. Gorbatyuk ◽  
I. G. Morozova ◽  
M. G. Naumova ◽  
N. A. Chichenev
Keyword(s):  
Surface Roughness ◽  
Laser Beam ◽  
Laser Treatment ◽  
Metal Surface ◽  
Color Space ◽  
Laser Action ◽  
Luminous Flux ◽  
Index Number ◽  
Diffraction Effect ◽  
Destructive Effect

The laser beam marking process is considered to be a subject to important scientific research. In this area, there are insufficiently studied problems and concepts requiring their experimental validation and determining the solutions. Upon laser action, the effect of metal surface coloration can be caused by different processes. The most probable is formation of thin oxidic films, although formation of the other compounds is not unlikely as well [1–2]. Under actual values of luminous flux density, however, scanning with laser beam results in occurrence of regular surface roughness. Therefore, the analysis of diffraction effect impact on the image color is also necessary [3–4]. The color images on the metal surface were assessed based on range of colors RAL “Reich Ausschluß für Lieferbedingungen”. In this system, the color space is divided to ranges with identification of each color by its unique index number. When doing research of the metal surface composite regular relief [5] obtained using laser marker, the depth of microroughnesses in differently colored samples was determined. The was performed using non-contact VICWU profilometer. Due to the method of measurement technological specificity, this equipment does not have destructive effect on the object under study. The roughness values (Rz and Ra) of the surfaces under study were measured based on acceptably small areas, thereat the base lines were selected in such way that to consider the surface waviness effect on the roughness values Rz and Ra [6]. The research results demonstrated that change of surface roughness values Ra and Rz by 1.5 times (owing to change of the surface laser treatment mode), changes the specimen metal surface coloration drastically.

Friction Coefficient of the Coating PG-CP4 Sprayed to 40H13 Steel by Plasma and Processed by Laser

2021 ◽  
Vol 410 ◽  
pp. 482-488
Author(s):  
Valentin V. Morozov ◽  
Vladimir G. Gusev ◽  
Aleksey V. Morozov
Keyword(s):  
Friction Coefficient ◽  
Laser Beam ◽  
Laser Treatment ◽  
Plasma Spraying ◽  
Laser Processing ◽  
Factor Model ◽  
Radiation Power ◽  
Laser Head ◽  
Laser Systems

This article deals with laser treatment of plasma spraying of PG-CP4 powder on steel 40H13. A multi-factor model is obtained that relates the friction coefficient of the coating to the radiation power W, the longitudinal feed of the laser beam Spr, and the distance L from the protective glass of the laser head to the sample’s surface. The model allows you to control the modes of laser processing, in order to reduce the friction coefficient of the coating. The greatest influence on the friction coefficient is exerted by the longitudinal feed Spr of the laser beam, followed by the radiation power W and the distance L. A multi-factor model of the friction coefficient of uncoated 40H13 steel treated under the same conditions as coated 40H13 steel is also established. Comparison of the two variants showed that of all the samples providing reliable adhesion of the coating to the substrate, the greatest reduction in the friction coefficient (by 30.2 %) was achieved at W = 5 kW, Spr = 25 mm/s and L = 85 mm. The results of the research are recommended for use in enterprises that implement the processes of plasma and laser processing of materials, as well as in design organizations that develop modern laser systems.

scholarly journals Scientific validation of three-dimensional stereophotogrammetry compared to the IGAIS clinical scale for assessing wrinkles and scars after laser treatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Barbara Helena Barcaro Machado ◽  
Ivy Dantas De Melo E. Silva ◽  
Walter Marou Pautrat ◽  
James Frame ◽  
Mohammad Najlah
Keyword(s):  
Laser Treatment ◽  
Three Dimensional ◽  
Skin Surface ◽  
Clinical Scale ◽  
3D Images ◽  
Laser Resurfacing ◽  
Before And After ◽  
Measuring Outcomes ◽  
Skin Scar ◽  
Scientific Validation

AbstractMeasuring outcomes from treatments to the skin is either reliant upon patient’s subjective feedback or scale-based peer assessments. Three-Dimensional stereophotogrammetry intend to accurately quantify skin microtopography before and after treatments. The objective of this study is comparing the accuracy of stereophotogrammetry with a scale-based peer evaluation in assessing topographical changes to skin surface following laser treatment. A 3D stereophotogrammetry system photographed skin surface of 48 patients with facial wrinkles or scars before and three months after laser resurfacing, followed immediately by topical application of vitamin C. The software measured changes in skin roughness, wrinkle depth and scar volume. Images were presented to three observers, each independently scoring cutaneous improvement according to Investigator Global Aesthetic Improvement Scale (IGAIS). As for the results, a trend reflecting skin/scar improvement was reported by 3D SPM measurements and raters. The percentage of topographical change given by the raters matched 3D SPM findings. Agreement was highest when observers analysed 3D images. However, observers overestimated skin improvement in a nontreatment control whilst 3D SPM was precise in detecting absence of intervention. This study confirmed a direct correlation between the IGAIS clinical scale and 3D SPM and confirmed the efficacy and accuracy of the latter when assessing cutaneous microtopography alterations as a response to laser treatment.

Cleaning with Laser Radiation on Istria Stone

1992 ◽  
Vol 267 ◽  
Author(s):  
Pagona Maravelaki ◽  
G. Biscontin ◽  
E. Zendri ◽  
R. Polloni ◽  
W. Cecchetti
Keyword(s):  
Laser Radiation ◽  
Laser Treatment ◽  
Chemical Processes ◽  
Original Material ◽  
Stone Surface ◽  
Stone Conservation ◽  
Physico Chemical

ABSTRACTCleaning treatments necessary for stone conservation consist of removing compounds that were superimposed on the original material by means of physico-chemical processes.,The purpose of this work is to identify the transformation of stone surface by the LASER treatment. Cleaning test on Istria stone with LASER radiation at different energies and in different regimes have been performed. The depletion of the original material has been evaluated by means of SEM microprobe analyses.

Local Laser Treatment of Tribological Plasma Sprayed Coatings

1998 ◽  
Author(s):  
T. Otmianowski ◽  
B. Antoszewski ◽  
W. Zorawski
Keyword(s):  
Laser Beam ◽  
Laser Treatment ◽  
Coating Layer ◽  
Tribological Test ◽  
Test Pieces ◽  
Steel Base ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Abstract In the article the results of set of experiments concerning the changes in microstructure of plasma sprayed Al2O3, Cr2O3 and W2C coatings of tribological test pieces obtained with use of locally applied laser beam treatment are given and discussed. The improvement of sprayed on coating layer adhesion to the steel base was ascertained and evaluated. The possibilities of the application of the described technology for development and production of slide elements of tribological joints are noticed.

Measurement of Ex Vivo Porcine Lens Shape During Simulated Accommodation, Before and After fs-Laser Treatment

2015 ◽  
Vol 56 (9) ◽  
pp. 5332 ◽  
Author(s):  
Jan Hahn ◽  
Michael Fromm ◽  
Fedaa AL Halabi ◽  
Silke Besdo ◽  
Holger Lubatschowski ◽  
...  
Keyword(s):  
Laser Treatment ◽  
Ex Vivo ◽  
Before And After ◽  
Fs Laser

scholarly journals The use of laser biostimulation in human and animal physiotherapy – a review

2017 ◽  
Vol 86 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Paulina Zielińska ◽  
Maria Soroko ◽  
Anna Zwyrzykowska ◽  
Zdzisław Kiełbowicz
Keyword(s):  
Veterinary Medicine ◽  
Laser Beam ◽  
Laser Treatment ◽  
Laser Therapy ◽  
Laser Light ◽  
Regenerative Processes ◽  
Physical Methods ◽  
Animal Organism ◽  
Positive Effect ◽  
Class Iv

Laser biostimulation involves applying a laser beam to the tissue to facilitate healing and regenerative processes. Laser therapy is one of the most important physical methods used in human physiotherapy. In veterinary medicine, laser therapy is a new and so far poorly examined method. The results of studies conducted so far are very promising, yet the positive effect of laser light, especially that of class IV, has yet to be confirmed. This article presents an overview of the available literature on the effect of laser treatment on the human and animal organism.

scholarly journals Temperature Calibration Measurements based on Laser-Induced Phosphorescence Technique for Combustion Applications

2015 ◽  
Vol 10 (1) ◽  
Keyword(s):  
Laser Radiation ◽  
Laser Beam ◽  
Intensity Ratio ◽  
Laser Power ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Temperature Calibration ◽  
Phosphor Powder ◽  
Calibration Methods

Phosphor powder and phosphor-binder mixtures are successfully employed for temperature calibration measurements by using laser-induced phosphorescence (LIP) technique with an emphasis on higher precisions and accuracies than other non-intrusive methods. The phosphorescence intensities are used to perform these calibrations in three different strategies. The influence of laser power regular changes on particles heating and the calibration analyses is also carried out. A pulsed laser at 355 nm was used for exciting specimens of the phosphor powder as well as the phosphor-binder mixtures. The laser beam was directed onto the specimens and varied in three laser power levels (LPLs). The samples were kept in an oven with temperatures ranging from room temperature up to 1800 °C. The three strategies which are expressed in terms of non-dimensional intensity versus wavelength (NDI-W), normalised intensity (NI) and intensity ratio (IR) were used for the calibration assessments. A modified IR was compared with two different IRs. A precision of around ± (0.50-1.41)% was attained for different calibration methods. This research confirmed that these calibrations are possible using three different strategies, given high precisions and accuracies. The laser power alternations influenced the NI and do affect neither the NDI-W nor the IR curves. The laser radiation does not play any role for heating the particles of the studied powder.

scholarly journals Influence of parameters of impulse laser impact on the formation of the gradient of the structure of porous titanium powder

2018 ◽  
pp. 88-94
Author(s):  
D. V. Minko
Keyword(s):  
Laser Radiation ◽  
Titanium Powder ◽  
Structural Characteristics ◽  
Selective Laser Sintering ◽  
Light Flux ◽  
Laser Action ◽  
Pulsed Laser ◽  
Powder Materials ◽  
Solid Core ◽  
Powder Particles

The possibility of selective laser sintering of graded porous and compactly porous structures by surface fusion of powder particles is demonstrated while maintaining a solid core, which leads to the formation of interparticle contacts in the presence of a liquid phase. The interaction of the light flux of the laser pulse with the surface of the powder particles under multiple reflection is considered. It is shown that the effect of single pulses of laser radiation leads to the formation of sintered structural elements of a powder material having a diameter approximately equal to the diameter of the focal spot. Technological regimes of pulsed laser action are established at which steady contact formation of titanium powder particles of the fractional compositions under study occurs. The possibility of obtaining powder materials with a gradient structure by controlling the parameters of pulsed laser action is experimentally demonstrated. It was found that accurate dosing of thermal energy and the number of pulses of laser radiation makes it possible to minimize shrinkage of powder layers in the absence of particle conglomeration, to control the structural characteristics and properties of products, to preserve the microstructure and phase composition of the initial materials.

Friction and Wear Response of a Hard-Anodized AA6082

2021 ◽  
Vol 1016 ◽  
pp. 1235-1239
Author(s):  
Eleonora Santecchia ◽  
Marcello Cabibbo ◽  
Abdel Magid S. Hamouda ◽  
Farayi Musharavati ◽  
Anton Popelka ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Scientific Community ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Anodized Aluminum ◽  
Tribological Tests ◽  
Hard Anodizing ◽  
Before And After ◽  
Wear Response

The properties of anodized aluminum, and wear resistance in particular, are of high interest for the scientific community. In this study, discs of AA6082 were subjected to a peculiar hard anodizing process leading to anodized samples having different thicknesses. In order to investigate the wear mechanism of samples, unidirectional tribological tests were performed against alumina balls (corundum) under different loading conditions. Surface and microstructure of all the samples were characterized before and after the tribological tests, using different characterization techniques. The tribological tests showed remarkable differences in the friction coefficient and wear behavior of the anodized AA6082 samples, related to the microstructure modifications and to the specific applied sliding conditions.

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