Nanoparticle Generation From Nitinol Target Using Pulsed Laser Ablation

Abstract

Nanostructure formation on bulk metals (copper, gold, and silver) by picosecond (FWHM = 10 ps) Nd:YAG laser irradiation was studied aiming at the production of low-reflectivity surfaces. The experiments were performed at two distinct wavelengths (λ = 355 and 1064 nm) using 20 kHz repetition frequency. The fluence was varied in the 1-11 J/cm 2 range, while the samples were shot by an average pulse number from 0 to 50 depending on the scanning speed of the applied galvanometric scanner. The reflectivity of the treated surfaces was recorded with a visible near-infrared microspectrometer in the 450-800 nm range. Morphological investigations of the irradiated metal surfaces were performed with scanning electron microscope, which showed that mainly two types of nanostructures can be responsible for the reflectivity decrease depending on the type of the illuminated metal. Finite element modeling was performed to simulate the laser absorption-induced heating of the illuminated samples, which helps in the understanding of the structure formation process. It was found that two main processes take place in the production of micro-and nanostructures on the surface; the ejection and falling back of molten metal droplets, and the back scattering and aggregation of nanoparticles.

In-Situ Plasma Monitoring during the Pulsed Laser Deposition of Ni60Ti40 Thin Films

“…The thin layers of shape memory alloys need only a small amount of thermic capacity to heat or cool, which is why the answer time is substantially reduced and the working speed increases considerably. The effective power capacity on a volume corresponding to a layer obtained from an alloy with shape memory exceeds the one of the classic mechanisms proposed for micro-activation [8][9][10]. The transformation process of a bulk alloy with shape memory in thin film is accompanied by numerous important changes at the level of the mechanical, physical, chemical, electric, and optical properties such as the load resistance, elastic module, hardness, and attenuation capacity, regaining the initial form, electric resistivity, thermic conductivity, thermic expansion coefficient, surface rugosity, vapors permeability, and the dielectric constant, etc.…”

Pulsed Laser in Liquids Made Nanomaterials for Catalysis

“…Nickel-core−TiO 2 -shell nanoparticles were synthesized by 8 or 18 ns pulsed laser ablation of nitinol wire in water or ethanol, respectively, by Hopp et al 404 Two different lasers were used, a KrF laser at 248 nm and a Nd:YAG laser at 1064 nm. Depending on the laser wavelength, particle sizes ranged from 5 to 1000 nm, with an average of 200 nm (Figure 56).…”

Influence of laser parameters in generating the NiTi nanoparticles with a rotating target using underwater solid state Nd: YAG laser ablation

“…The oxide peaks was observed might be due the possible chance to ablate the nanoparticle in air contact as the flow rate of the liquid was not in continuous stream. The interaction of the alloy with the oxygen content results in the formation of titanium oxide [2]. …”

“…Nanoparticles are 100 times smaller in diameter than human hair and have attracted great attention due to the number of application possibilities based on the wide range of available physical, chemical, mechanical, electrical and even biological properties [1][2][3][4][5][6][7]. The properties of metal nanoparticles strongly depend on their shape and size distribution.…”

“…So number of researches have been done to control these parameters through various synthesis methods such as milling, grinding, thermal gas-phase decomposition process, electrochemical etching and chemical methods like sol-gel process. But all of these processes have drawbacks related to the purity and variety of accessible materials [1,2,7]. Under water pulsed laser ablation is an alternative method to address the deficits of the conventional methods as the nanoparticles can be generated from almost any solid material [7,8].…”