Search results for "nd:yag"
showing 10 items of 32 documents
Large-sized pleomorphic adenoma of the cheek treated with Nd:Yag laser: Report of a case and review of the literature
2020
Pleomorphic adenoma (PA) mostly involves parotid glands, while extra-parotid localizations are relatively uncommon. Particularly, PAs of the cheek minor salivary glands with a size larger than 4 cm are exceedingly rare, with only few cases reported. Surgical treatment of PA usually consists in radical excision. However, despite a presumptive radicality, recurrences, sometimes followed by malignant transformation, may occur. Here we report a case of a large-sized (6 cm) PA of the cheek minor salivary glands in a 70 year-old female patient, successfully treated through a conservative approach, based on the use of Nd:YAG Laser (λ=1064 nm). No recurrences were observed after a 2-year follow-up.…
Luminescence properties of neodymium-doped yttrium aluminium garnet obtained by the co-precipitation method combined with the mechanical process.
2005
Nanopowders of yttrium aluminium garnet Y3Al5O12 (YAG) doped with neodymium ions were obtained by the co-precipitation method from the reaction of aluminium and yttrium nitrate and neodymium oxide with ammonia. After washing and drying the hydroxide precursors were calcined at 500, 700, 800 and 900 °C for 1 hour and at 1000 °C for 3 hours. This product was treated by ball milling in a zirconia vial for 0.5, 1.5 and 10 h in order to achieve smaller nanoparticles. The structure, microstructure, morphology and optical properties were investigated by means of diffractometric, microscopic and spectroscopic techniques. The course of the amorphous-to-crystalline transformation was complete after c…
Study of magnesium and aluminum alloys absorption coefficient during Nd:YAG laser interaction
2007
International audience; In laser processes, the absorption factor of laser Nd:YAG by metals plays a very important role. In order to model laser welding, we need to know its evolution during the process. The theoretical calculation does not enable the prediction of the absorption factor in the case of a keyhole mode. It is difficult to predict the effect of plasma and recoil pressure on the shape of the keyhole. In this paper, an integrating sphere is used to determine the absorption factor during the laser process, which is carried out on two types of magnesium alloys (WE43 and RZ5) and an aluminum alloy. We obtain the evolution in time of the absorption factor according to different steps…
Growth of titanium oxynitride layers by short pulsed Nd:YAG laser treatment of Ti plates: Influence of the cumulated laser fluence.
2009
International audience; Titanium oxynitride layerswere formed by surface laser treatment of Ti plates in air using a Nd:YAG laser source of short pulse duration about 5 ns. The cumulated laser fluence was varied in the 100–1200 J cm2 range and its influence on the composition and the structure of the formed layers was studied by different characterization techniques providing physico-chemical and structural information. It was shown that the laser treatment induces the insertion of light elements as O, N and C in the formed layer with the amount increasing with the laser fluence. The in-depth composition of the layers and the co-existence of different phases were also studied. The way in wh…
Physical-mechanical effects of Nd:YAG laser on the surface of sound dental enamel.
1993
Human dental enamel samples were irradiated using a 5 kHz Q-Switched Nd:YAG laser. An increase in Knoop microhardness and modification of the membrane permselectivity were detached. These results and the changes observed by SEM, can be connected with the fusion of the enamel surface.
Effect of the dopant selection (Er, Eu, Nd or Ce) and its quantity on the formation of yttrium aluminum garnet nanopowders
2008
Abstract Hydroxide precursors, synthesized using the co-precipitation method, were calcined for 1 h at the temperatures of 900, 1000 and 1100 °C, respectively, and heated directly to 1500 °C to produce various Y 3 Al 5 O 12 (YAG) nanopowders with different doping quantities of erbium, europium, neodymium and cerium. All samples were investigated using thermo-gravimetry (TG) and differential thermal analysis (DTA), field emission gun-scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). TG and DTA experiments were performed from room temperature up to 1500 °C; the weight loss curves combined with the presence of exo- and endo-thermal even…
Hardening of Steel Perforated Tape by Nd:YAG Laser
2016
One of the directions of application of the perforated metal material is their use as cutting elements in the production of processing tools. In this case it is necessary to carry out hardening of cutting surfaces to increase their hardness. One of the methods of hardening metals could be laser treatment. Therefore, the present work is a study of the effect of Nd:YAG laser radiation on the microstructure and hardness of fragments formed from steel perforated tape. Different laser scan speeds (doses) were used in the experiments. The results have shown that the increase the microhardness of 30-40% after the laser treatment of steel perforated tape in the surface layer in a depth range up to …
Evidence for a Double Doping Regime in Nd:YAG nanopowders
2009
Nanopowders of Yttrium Aluminium Garnet doped with neodymium (Nd:YAG) were investigated by X-Ray Absorption Fine Structure (XAFS) at the Nd LIII-edge in the 1.3 - 20.8 % doping range. XANES spectra appear similar in the full range of the Nd concentration. However, a significant decrease in the white line intensity of XANES is revealed as the quantity of Nd doping ions increases. Plotting the white line intensity as a function of Nd doping ions reveals two linear trends with two different slopes, identifying a threshold value where the neodymium concentration reaches 5 at.% This experimental finding provides support for the existence of a double doping regime in Nd:YAG nanopowders.
The formation of intermetallics in dissimilar Ti6Al4V/copper/AISI 316 L electron beam and Nd:YAG laser joints
2011
Abstract The welds of titanium alloys with steels suffer from the brittleness of resulting intermetallic compounds. In present study, we report the feasibility of Ti6Al4V to stainless steel AISI 316L welding through pure copper interlayer carried out by electron beam and pulsed Nd:YAG laser. The nature and the localization of intermetallic phases in these welds have been studied by SEM, EDS, XRD and microhardness measurements. The simplified scenario of weld formation has been proposed in order to understand the mechanism of weld formation and to explain the way local phase content determines the mechanical properties. It can be concluded that the insertion of 500 μm pure copper interlayer …
Synthesis of Nd:YAG nanopowder using the citrate method with microwave irradiation
2010
Abstract Nd:YAG nanopowders were prepared using the Pechini process with microwave irradiation ( MWs ). A reference sample was also prepared using conventional heating. XRD pattern analysis showed that nanopowder obtained by means of conventional heating and calcination for 1 h at 900 °C has a structure made up of the garnet phase together with the hexagonal phase that disappeared after two additional hours of thermal treatment. The MWs powder calcined for 1 h consists of the single garnet phase. SAXS data analysis indicated that nanoparticles are characterized by a sharp interface. TEM investigation showed crystalline particles with remarkable agglomeration in both samples, although a more…