Surface topography analysis of water vapor plasma irradiation induced effects in Ті films

In the present work, the changes of surface topography driven by interaction of ions extracted from low-pressure water vapor plasma are studied. Titanium 0.5-1 um thickness films were deposited on silicon wafer substrates using magnetron sputtering technique and immersed in water vapor plasma at pressure 1-10 Pa. The samples were located on the cathode of magnetron and affected by high-flux, low-energy ions extracted by 250-300V bias negative voltage. The used Ti and W cathodes were water cooled. It is shown that the surface roughness of irradiated films changes in dependence of irradiation fluence and intensity. The experimental results are explained on the basis of the analysis of the selective erosion of oxide phases synthesized in the near-surface region. Three sputtering modes are distinguished: (i) metallic, (ii) oxide and (iii) composite: metallic with clusters of oxide. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2084

SURFACE TOPOGRAPHY ANALYSIS OF WATER VAPOR PLASMA IRRADIATION INDUCED EFFECTS IN Ti FILMS

ABSTRACT In the present work, the changes of surface topography driven by interaction of ions extracted from low-pressure water vapor plasma are studied. Titanium 0.5-1 m thickness films were deposited on silicon wafer substrates using magnetron sputtering technique and immersed in water vapor plasma at pressure 1-10 Pa. The samples were located on the cathode of magnetron and affected by high-flux, low-energy ions extracted by 250-300V bias negative voltage. The used Ti and W cathodes were water cooled. It is shown that the surface roughness of irradiated films changes in dependence of irradiation fluence and intensity. The experimental results are explained on the basis of the analysis of the selective erosion of oxide phases synthesized in the near-surface region. Three sputtering modes are distinguished: (i) metallic, (ii) oxide and (iii) composite: metallic with clusters of oxide

Combined XRD and XPS analysis of ex-situ and in-situ plasma hydrogenated magnetron sputtered Mg films

Contrary to traditional methods including top layer catalyst deposition and ex-situ hydrogenation in current study Mg-H films were synthesized using magnetron sputtering in Ar+ atmosphere and their in-situ hydrogenation in magnetron induced hydrogen plasma. XRD analysis of hydrogenated Mg-H films revealed changes of preferred crystallographic orientation. After 1-3 h of in-situ plasma hydrogenation XRD does not indicate presence of any crystalline MgH2 phase but it is observed after 5 h. The appearance of significant amount of crystalline MgH2 phase after prolonged time of in-situ hydrogenation presupposed that samples without clear expression of MgH2 crystal phase might still have hydrogen rich amorphous Mg phase which is not observable by XRD. The analysis of predicted hydrogen containing phase was performed using combination of conventional SEM; AFM, Q-Q XRD, GI-XRD and XPS analysis techniques. The obtained data of hydrogen containing phase distribution at the surface of the samples and its distribution depth profiles are presented together with considerations related to the efficiency of the proposed in-situ hydrogenation approach and combined analysis methods. (C) 2015 Elsevier B.V. All rights reserved

Electrochemical studies and phase-structural characterization of a high-capacity La-doped AB(2) Laves type alloy and its hydride

This work was focused on studies of structural and electrochemical properties of the La-doped AB2-type Zr/Ti-based metal hydride anode alloys. The Ti0.2Zr0.8La0-0.05Ni1.2Mn0.7V0.12Fe0.12 alloys were characterized using SEM, EDS and XRD, which concluded that the major C15 Laves type AB2 compound co-exists with a minor La-Ni intermetallic. NPD study indicated that vanadium together with Ti and Zr partially fills the A site, while the rest of V together with Ni, Mn and Fe statistically fills the B site. NPD showed that in a trihydride (Ti,Zr,V)(Ni,Mn,Fe,V)2D2.9 D atoms occupy A2B2 tetrahedra. The alloys were characterized during high-rate discharge and on cycling. La addition resulted in a significant improvement of the activation performance caused by a catalytic influence of LaNi hydride. The highest content of La greatly accelerated the activation, but it also caused an obvious decrease in discharge capacity and cycling stability. The alloy with an optimized La addition (x = 0.03) demonstrated a maximum discharge capacity of 420 mAh g−1 and the discharge capacity maintained at 79% at 0.71 C, while the capacity retention after 500 cycles was also high, 63%. Based on the EIS results, we conclude that the decay of the alloy electrode is related to the irreversible capacity loss and its pulverization

Failure analysis by indentation test of electrodeposited nanocrystalline CO-W and Fe-W thin films

The aim of this paper is to study the failure of the electrodeposited Co-W and Fe-W alloys onto copper and steel substrates by the indentation technique, examine plastic strain distributions around indentations and evaluate behaviour of the system "coating-substrate". The alloys of Co-W and Fe-W obtained electrodeposited from citrate-ammonia baths are nanocrystalline. The values of grain size were evaluated based on the XRD spectrum and show values 30-37 Å. An experimental investigation into the Vickers indentation hardness and associated plastic deformation in electrochemically performed coatings was conducted. The methodology applied for this study allows obtaining the qualitative data to describe the behaviour of the system "coating-substrate", when both are deforming plastically. Implications of this study in understanding the mechanical behaviour of coatings and their derivatives are discussed.status: publishe

Structural and Phase Transformations in Water-Vapour-Plasma-Treated Hydrophilic TiO 2

We have investigated structural and phase transformations in water-vapor-plasma-treated 200–300 nm thick Ti films, maintained at room temperature, by injecting water vapor into radio frequency (RF) plasma at different processing powers. Scanning electron microscopy (SEM) combined with optical microscopy and surface nanotopography analysis were used to view tracks of adsorbed water layers and to detect bulges or blisters appeared on the surface of treated samples. Rough surfaces with different size of holes (5–20 μm) through the entire film thickness have been observed. X-ray diffraction results show that the oxidation rate of Ti film drastically increases in the presence of an adsorbed water on the hydrophilic layer. It is assumed that the defining factor which controls oxidation kinetics is the hydroxyl radicals formation

Cracking behavior of electrodeposited nanocrystalline tungsten-cobalt and tungsten-iron coatings

The use of micrometer thick coatings in tribosystems now is of increasing interest in the area of mechanical engineering to reduce friction and wear. This work was initiated to analyse critically the deformation of electrodeposited Co-W and Fe-W coatings resulting from indentation tests, and to identify the microscopic features of the surfaces of such electrodeposited layers. On other hand, the present work focuses on an improved understanding of the plastic deformation field of the indentation made in thin layer deposited on a substrate, especially the mechanisms formation of the pile-ups around the indenter.status: publishe