The effect of adding calcium on the microstructural evolution and properties of the Ti-Ca-O system has been investigated. Calcium-doped titanium (Ti-Ca) thin films were prepared by dual electron beam deposition with the assistance of an oxygen ion beam. The films were characterized by glow discharge optical emission spectroscopy (GD-OES), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), to determine the elemental composition, chemical bonds and crystallinity. Oxygen ion assistance produces non-completely oxidized Ti-Ca films. The addition of calcium led to increased formation and stabilization of titanium oxides in the titanium matrix under conditions of oxygen deficiency. Replacement of Ti by Ca in TiO and TiO2 was observed, rather than the formation of a CaO and TiCaO mixture. Compound formation, crystallite growth and lattice expansion with rising Ca concentration induced an increase in mechanical properties (hardness and reduced elastic modulus) and surface roughness. High Ca concentration (5 at%) led to a significant reduction in mechanical properties, and above 1 at% led to a significant reduction in adhesion strength. The Ti-Ca films showed hydrophobic behaviour. The water contact angle followed the increasing trend of Ca concentration and surface roughness. There is a discussion of the changes in the studied properties.

The impact of four pre-treatment techniques on the surface morphology and chemistry, residual stress, mechanical properties, corrosion resistance in a physiological saline solution and cell colonization of commercially pure titanium is examined in detail. Mechanical polishing, electrochemical etching, chemical etching in Kroll's reagent, and ion sputter etching with argon ions were applied. Surface morphologies reflect the nature of surface layer removal. Significant roughening of the surface and a characteristic microtopology become apparent as a result of the sensitivity of chemical and ion sputter etching to the grain orientation. The hardness in the near surface region was controlled by the amount of residual stress. Etching of the stressed surface layer led to a reduction in residual stress and surface hardness. A compact passivation layer composed of TiO, TiO2 and Ti2O3 native oxides imparted high corrosion resistance to the surface after mechanical polishing, chemical and electrochemical etching. The ion sputter etched surface showed substantially reduced corrosion resistance, where the corrosion process was controlled by electron transfer. The specific topology affected the adhesion of the cell to the surface rather than the cell area coverage. The cell area coverage increased with the corrosion stability of the surface.

The effect of an elevated temperature during nitrogen ion implantation on the microstructure and on the surface hardness of Ti6Al4V titanium alloy was examined. The implantation process was carried out at fluences of 1 . 10(17), 2.7 . 10(17) and 6 . 10(17) cm(-2) and at ion energy 90 keV. The implanted samples were annealed at 500 degrees C during the implantation process. X-ray diffraction analysis was performed to obtain a phase characterization and a phase quantification in the implanted sample surface. The surface hardness was investigated by nanoindentation testing, and the nitrogen depth distribution was measured by Rutherford Backscattering Spectroscopy. Elevated temperature led to increased formation of a TiN compound. It was found that a mixture of TiN and an alpha-Ti(+N) solid solution had a predominant amount of TiN for samples with fluence of 2.7 . 10(17) cm(-2) or higher. Elevated temperature during ion implantation caused an increase in surface hardening more towards the depth of the substrate in comparison with room temperature implantation. The hardness showed a remarkably significant increase at a fluence of 1 . 10(17) and 2.7 . 10(17) cm(-2) compared to samples implanted at the same fluences and at room temperature. There is a discussion of such mechanisms that explain the observed hardening more towards the depth of the substrate, and the increase in hardness. (C) 2014 Elsevier B.V. All rights reserved.

The ion beam assisted deposition (IBAD) method was chosen for preparing a carbon thin film with a mixing area on a substrate of Ti6Al4V titanium alloy. Nitrogen ions with energy 90 keV were used. These form a broad ion beam mixing area at the interface between the carbon film and the substrate. We investigated the chemical composition by the glow discharge optical emission spectroscopy (GD-OES) method and the phases by the X-ray diffraction (XRD) method. The measured concentration profiles indicate the mixing of the carbon film into the substrate, which may have an effect on increasing the adhesion of the deposited film. The nanohardness and the coefficient of friction were measured. We found that the modified samples had a markedly lower coefficient of friction even after damage to the carbon film, and they also had higher nanohardness than the unmodified samples. The increased nanohardness is attributed to the newly created phases that arose with ion implantation of nitrogen ions.

Mechanical and tribological properties of the thin carbon film with tungsten interlayer were investigated. The carbon film (130 nm) and the tungsten interlayer (20 nm) were prepared by ion beam assisted deposition (IBAD) method. Both layers were electron beam evaporated and were simultaneously irradiated by the beam of argon (Ar) or nitrogen (N) ions with energy of 700 eV. Mechanical properties of the thin carbon film with tungsten interlayer were investigated by the nanoindentation method. Concerning tribological properties the coefficient of friction was investigated by means of pin on disc tribometer. Phase composition was investigated by X-ray diffraction method (XRD), and bonding characterization of carbon thin film was characterized by Raman spectroscopy.

The effect of gamma irradiation and subsequent thermal treatment on the wear resistance and friction behavior of ultrahigh molecular weight polyethylene (UHMWPE) has been studied. Irradiation of the polymer was performed using a 60Co γ-emitter at laboratory temperature. Radiation dose 50 kGy was applied. Some irradiated samples were thermally treated at 150˚C for period of 30 min. and then slowly cooled to room temperature. A linear reciprocating tribometer was used to investigate the wear behavior of UHMWPE against Co-Cr-Mo alloy. The tests have been performed in unlubrication conditions. An important increase in wear resistance of the modified UHMWPE in comparison with the original material was proved. Besides wear rate the selected mechanical characteristics (friction coefficient, Young’s modulus, yield strength, fracture strength, and hardness) of original and modified samples of UHMWPE have been determined.

Nanoindentation technique is being widely used for measuring intrinsic mechanical properties of hard thin coating. However, what are the limits of the nanoindentation methods if we have to follow 1/10 rule according to EN ISO 14577-1:2002. How we can analyse very thin coatings about 100 nm thicknesses if we have to follow that rule? We are limited by the size of tip radius, system sensibility, quality of sample surfaces etc. Our paper will be focused on these limits of nanoindentation technique.

We present a method to produce superhydrophobic surfaces in thermoplastic polymer substrates. The method involves the creation of a nickel stamp using a customized laser interference lithography technique and electroplating processes. This stamp is used to emboss sub-micrometer periodic structures into the thermoplastic. The modified surface is coated with a hydrophobic plasma-polymerized hexafluoropropene layer. Surfaces with different periodicity and relief depth were created. On the surface with the highest aspect ratio, advancing water contact angles of 167° were measured with a water contact angle hysteresis of below 5°.

Multifunctional wear and corrosion resistant decorative nanostructured carbon-base coatings were prepared by PACVD (Plasma Assisted Chemical Vapour Deposition) method on steel substrates. As the multifunctional coating the carbon-base, particularly DLC (Diamond-Like Carbon) nanolayer, was chosen. For the deposition of adherent DLC coating on steel substrate a very thin Si-O-C interlayer was applied in some cases. Deposition of DLC coating and Si-O-C interlayer was performed using dc plasma without additional heating and with the HMDSO (hexamethyldisiloxane) and methane as precursors. During coating growth with increasing of thickness of DLC nanolayer the colour of nanolayer is changed. Whole spectrum of attractive colours is obtained, what is possible to use to decorative purposes. Effect of film thickness on colour is following: The reference specimen (bare stainless steel) has a bright metallic sheen. In the order of increasing thickness, the DLC films produced by PACVD have colours as follows: dark violet at ~75 nm; medium blue at ~130 nm; golden light at ~170 nm; deep rose pink at ~240 nm; golden brown at ~320 nm; and soot black at ~1200 nm. Decorative coatings must be adherent and hard for good wear resistance. Adhesion was tested by scratchtester and microhardness was determined by nanoindentation. The microhardness data were thickness-dependent, influenced by substrate. The highest measured value was 23 GPa. Tribology of the coatings was assessed by wet friction tests.

Resumen en: Carbon based thin films have been prepared by PECVD method. Silicon and steel substrates were used for thin films preparation. Deposition was carried out...

Crystal structure and microwave dielectric properties of M(Nb x Ta