ON THE TRANSPORT PHENOMENA IN HIGHLY IONIZED PULSED PLASMA DURING FeCuNbSiB THIN FILM DEPOSITION PROCESS

The transport of sputtered particles in a magnetron discharge is of considerable interest for optimizing the deposition technique with respect to both deposition rate and control of the thin film properties. The High Power Impulse Magnetron Sputtering (HiPIMS) is a relatively new sputtering-based ionized physical vapor deposition technique with high density and high ionization degree of sputtered atoms which offers favorable conditions for better control and high-quality growing of thin films. Operating the HiPIMS in short pulse mode allows increasing the deposition rate due to the reduced gas rarefaction effect and reducing the ion back-attraction of the ionized sputtered material. Results concerning the spatial and temporal evolution of both the sputtered atoms density and plasma potential, the temporal evolution of the ion current intensity recorded by an electrostatic probe placed close to the substrate and the total positive electrical charge collected by the target and the probe during Fe 73.5 Cu 1 Nb 3 Si 15.5 B 7 thin film deposition process are presented. Most of the depositions and investigations have been made for a constant pulse voltage value of -1 kV, short pulse durations (4-20 µs), 10 mTorr working gas pressure and 30 W average power

Ti-Zr-Si-Nb nanocrystalline alloys and metallic glasses: Assessment on the structure, thermal stability, corrosion and mechanical properties

The development of novel Ti-based amorphous or \u3b2-phase nanostructured metallic materials could have significant benefits for implant applications, due to improved corrosion and mechanical characteristics (lower Young's modulus, better wear performance, improved fracture toughness) in comparison to the standardized \u3b1+\u3b2 titanium alloys. Moreover, the devitrification phenomenon, occurring during heating, could contribute to lower input power during additive manufacturing technologies. Ti-based alloy ribbons were obtained by melt-spinning, considering the ultra-fast cooling rates this method can provide. The titanium alloys contain in various proportions Zr, Nb, and Si (Ti60Zr10Si15Nb15, Ti64Zr10Si15Nb11, Ti56Zr10Si15Nb19) in various proportions. These elements were chosen due to their reported biological safety, as in the case of Zr and Nb, and the metallic glass-forming ability and biocompatibility of Si. The morphology and chemical composition were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy, while the structural features (crystallinity, phase attribution after devitrification (after heat treatment)) were assessed by X-ray diffraction. Some of the mechanical properties (hardness, Young's modulus) were assessed by instrumented indentation. The thermal stability and crystallization temperatures were measured by differential thermal analysis. High-intensity exothermal peaks were observed during heating of melt-spun ribbons. The corrosion behavior was assessed by electrocorrosion tests. The results show the potential of these alloys to be used as materials for biomedical applications

Plasma-wall interaction studies within the EUROfusion consortium: Progress on plasma-facing components development and qualification

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma-material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO.European Commission; Consortium for Ocean Leadership 633053; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Photocatalytical and corrosion behavior of sputtered zirconium oxynitride thin films doped with titanium

ZrTiON coatings were deposited by reactive magnetron sputtering process of a single Zr target, while Ti was added by placing Ti ribbons on the erosion track of the Zr sputtering target. The variation of parameters such as the number of Ti ribbons, the applied sputtering current, and the reactive gas flow led to obtaining different sample configurations. The coatings were analyzed in terms of chemistry (chemical composition and chemical states) by X-ray Photoelectron Spectroscopy, morphology by Atomic Force Microscopy, surface energy, photodegradation tests, electrochemical studies, and accelerated corrosion tests. It was found that the coatings show features of oxides, nitrides, and oxynitrides, depending on the deposition conditions applied. The photodegradation efficiency regarding methylene blue solutions under visible light varies between 58% and 96%, depending on the type of illuminant and the sample characteristics, while the lowest corrosion rate was exhibited by the reference samples deposited without the addition of Ti. The samples doped with Ti and deposited with 1.5 A sputtering current exhibited a more efficient photodegradation effect, compared to the reference ZrON sample. The accelerated corrosion tests showed that the coatings deposited with an applied current of 2 A behaved significantly better than the ones deposited with 1.5 A sputtering current after 8 h of exposure to the water vapor and sulfur dioxide gas atmosphere.This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS - UEFISCDI, project number PN-IIIP1–1.1-TE-2019–1209, within PNCDI III. Part of the work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020

Metastable Al\u2013Si\u2013Ni alloys for additive manufacturing: Structural stability and energy release during heating

Rapid solidification with high cooling rates of metal alloys determines both the improvement of mechanical properties, due to the finishing of the structure, as well as obtaining metastable structures in the form of supersaturated or amorphous/nano solid solutions, which could potentially confer the material outstanding properties. It is of particular interest to use the energies released during the heating stage for these materials, due to the potentially lower input energy required to melt/fuse these materials. This phenomenon could add to the development and diversification of additive manufacturing technologies. The paper presents results concerning the structural development and phase transformation of metastable structures from Al\u2013Si\u2013Ni-based alloys, obtained by melt spinning and atomization techniques. It was observed that the structural transformations occurring during the heating process, starting from metastable structures, generate significant amounts of energy. This is of practical importance in the use of metallic powders in additive manufacturing technology, due to potentially reduced energy input

The effect of vacuum and air annealing in the physical characteristics and photocatalytic efficiency of In2S3:Ag thin films produced by spray pyrolysis

Indium sulfide thin films, doped with silver, were synthesized by spray pyrolysis technique. These samples were subsequently annealed in air and in vacuum, at the temperature of 400 ◦C, for 2 h. This work reports the effect of the thermal treatments on the structure, morphology and optical characteristics of the films, but also the study of the photodegradation efficiency of methylene blue solution. The as-produced films are polycrystalline, exhibiting the tetragonal β-phase structure of In2S3. The annealing treatments cause an increase of 27% and 74% of the crystallite size, and of the roughness of the films (20% and 56%), for the vacuum and air annealed samples, respectively, but provoke a significant decrease of the optical transmittance. The optical band gap decreases from 2.71 eV in the as-produced film, to 2.45 eV and 2.39 eV in the vacuum and air-annealed films, respectively. The photodegradation efficiency of the methylene blue solution increases from 83.0% for the as-produced film to around 95.4%, regardless the type of annealing.Grant of the Romanian Ministry of Education and Research, CNCS - UEFISCDI, project number PN–III–P1-1.1-TE-2019-1209, within PNCDI II