A. Biliński

Effect of calcium-ion implantation on the corrosion resistance and biocompatibility of titanium

This work presents data on the structure and corrosion resistance of titanium after calcium-ion implantation with a dose of 10(17) Ca+/cm2. The ion energy was 25 keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by XPS and SIMS. The corrosion resistance was examined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 degrees C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells (HDBC) in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both calcium-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by TEM results, the surface layer formed during calcium-ion implantation was amorphous. The results of electrochemical examinations indicate that calcium-ion implantation increases the corrosion resistance, but only under stationary conditions; during anodic polarization the calcium-ion-implanted samples undergo pitting corrosion. The breakdown potential is high (2.7-3 V).

Effect of phosphorus-ion implantation on the corrosion resistance and biocompatibility of titanium

This work presents data on the structure and corrosion resistance of titanium after phosphorus-ion implantation with a dose of 10(17)P/cm2. The ion energy was 25keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The corrosion resistance was examined by electrochemical methods in a simulated body fluid at a temperature of 37 C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both phosphorus-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by transmission electron microscope results, the surface layer formed during phosphorus-ion implantation was amorphous. The results of electrochemical examinations indicate that phosphorus-ion implantation increases the corrosion resistance after short-term as well as long-term exposures.

XANES investigations of Pd-doped polyaniline

Polyaniline doped with palladium (PANI-Pd) demonstrated a particular catalytic activity and selectivity in reaction of the hydrogenation of the triple C-C bond. Pd K-edge X-ray absorption near edge structure (XANES) studies were performed for PANI-Pd and several palladium compounds like PdCl 2 , (NH 4 ) 2 PdCl 4 , Pd(NH 3 ) 4 Cl 2 , (NH 4 ) 2 PdCl 6 , K 2 PdCl 4 , [(C 3 H 5 )PdCl] 2 , PdCl 2 (CH 3 CN) 2 and PdO. The measurements were carried out in transmission mode at the station Xl in HASYLAB. Chemical shifts of Pd K edge for PANI-Pd and other palladium compounds were evaluated. The experimental XANES spectra were compared with the theoretical XANES spectrum calculated for PdCl 2 by applying the FEFF8 program. It was found that the Pd K edge XANES spectrum for PANI-Pd was similar to that for ammonium tetrachloropalladate (NH 4 ) 2 PdCl 4 . Our results indicated that in the PANI-Pd catalyst the tetrachloropalladate ion [PdCl 4 ] -2 is coordinated to the amine part of the polymer chain and is responsible for specific catalytic properties.

Effect of the heating temperature on the corrosion resistance of alkali-treated titanium.

The paper presents the results of examinations of the corrosion resistance of titanium after its being subjected to the surface modification by the alkali- and heat-treatments. The material examined was commercially pure titanium (grade 2). The samples were soaked in an aqueous 10M NaOH solution at 60 degrees C for 24 h and subsequently heated at 500, 600, or 700 degrees C for 1 h. The chemical composition of the surface layers was determined by X-ray photoelectron spectroscopy and secondary ion mass spectroscopy. The phases present in the layers were identified by XRD. The corrosion resistance was evaluated by electrochemical methods (Sterns method, potentiodynamic method, and impedance spectroscopy) at a temperature of 37 degrees C after short- and long-time exposures. The 13 h exposure was aimed to allow the corrosion potential to stabilize. The aim of the long-term exposures was to examine how the corrosion resistance of the modified samples changes during the exposure. Under the conditions prevailing during the experiments, the highest corrosion resistance was achieved with the samples heated at a temperature of 700 degrees C.

Sublimation TiN Coating of RF Power Components

Titanium evaporation in a reactive atmosphere of ammonia has been chosen to deposit thin (up to 10 nm) protective surface layers containing titanium nitride and titanium oxinitrides which suppress secondary electron emission. The coating procedure, applied by the author in DESY (Hamburg) for TESLA couplers anti-multipactor protection, has been recently implemented in The Andrzej Soltan Institute for Nuclear Studies (IPJ) where a new coating device is used, equipped with a special titanium sublimation setup in a 100 1 vacuum chamber. Several arrays of cylindrical and coaxial RF coupler windows have been coated so far after optimizing the processing parameters.A check of the obtained surface layers ability to attenuate secondary electron emission has been performed; measurements of the secondary electron yield from TiN layers deposited on alumina samples were done in IPJ on as-delivered coated samples, then after vacuum bake-out and finally after additional electron bombardment of their surfaces. Also chemi...

EUV-induced surface modification of polymers

Radiation coming from a laser-plasma EUV source based on a gas puff target was used for surface modification of selected polymers. The source was equipped with a proper collector allowing for effective focusing of radiation of Kr plasmas within the wavelength range of 9 – 70 nm. Irradiation was performed with 10 Hz repetition rate and different time duration varying from 1s to 2 min. Different kinds of surface morphologies depending on a polymer and EUV intensity were obtained. Significant changes of the chemical structures after irradiation were revealed.