Fizikalno-kemijska svojstva pasivnog sloja na žicama vodilicama u endourologiji

The main criterion for austenitic steel X2CrNiMo 17-12-2 suitability for guide wire in endourology is its biotolerance. It is most of all connected with physical and chemical properties of wire surface, which should be adjusted to the characteristics of the environment of human urinary system tissues. Suitability of the proposed passive layer for purification of wire surface was determined to a great extent by its chemical composition. Therefore, this study included chemical composition tests by means of X-ray Photoelectron Spectroscopy (XPS), during which atomic concentration of elements in tested passive layers was identified and determined. Resistance to pitting corrosion was evaluated on the ground registered anodic polarisation curves by means of potentiodynamic method.Glavni kriterij za primjenu austenitnog Cr-Ni-Mo čelika za žice vodilice u endourologiji je biotolerancija. Ovaj zahtjev ovisi o fizikalnim i kemijskim svojstvima površine žice, koja moraju biti prilagođena uvjetima koji vladaju u ljudskom urinarnom sustavu. Pogodnost predloženog pasivnog sloja za žicu vodilicu, prvenstveno ovisi o njegovom kemijskom sastavu. Stoga, istraživanje u ovom radu obuhvaća određivanje kemijskog sastava pasivnog sloja žice metodom fotoelektronske rendgentske spektroskopije (XPS). Otpornost na jamičastu koroziju određena je korištenjem potenciodinamičke polarizacije, snimanjem anodnih polarizacijskih krivulja

Komparativno istraživanje korozije žice korištene pri urološkoj obradi uz sterilizaciju

The purpose of the tests was to determine whether and how sterilization process of samples made of AISI 316L stainless steel with different strain impacts their corrosion resistance. Tests were made on steel samples that had been electrochemically polished in order to assure proper surface roughness. In order to evaluate the influence of sterilization on physical and chemical properties of steel surface, tests of corrosion resistance were made by means of potentiodynamical method. The tests were made in alternative solution simulating human urine. Recorded anodic polarization curves created the ground for determination of typical parameters describing pitting corrosion resistance, that enabled to evaluate steel wire corrosion behavior under sterilization conditions.Svrha je ispitivanja bila da se ustanovi postoji li, i kakav je utjecaj sterilizacije na korozijsku otpornost žičanih uzoraka od nehrđajućeg čelika AISI 316L, oblikovanih plastičnom deformacijom različitog intenziteta. Ispitivanja su obavljena na uzorcima koji su elektrokemijski polirani kako bi se osigurala tražena niska hrapavost površine. U cilju procjene utjecaja sterilizacije na fizikalna i kemijska svojstva čelične površine, ispitivana je korozijska otpornost potenciodinamičkom metodom. Pritom je za simulaciju ljudske mokraće primijenjena zamjenska otopina. Snimljene krivulje anode polarizacije poslužile su za određivanje tipičnih parametara koji definiraju otpornost čelika prema jamičastoj koroziji, što je omogućilo procjenu korozijskog ponašanja čeličnih žica nakon sterilizacije

Influence of purge, time of waiting and TiCl4 dosing time in a low-pressure atomic layer deposition (ALD) reactor on properties of TiO2 layer

The aim of the study was to evaluate the influence of the ALD process parameters on mechanical properties and corrosion resistance of TiO2 layer. The TiO2 layer was deposited on stainless steel surfaces at constant temperature T = 200 °C and number of cycles nc = 500 (g ≈ 25 nm). The applied methodology consisted of potentiodynamic and impedance studies, as well as adhesion test. The obtained results were the basis for selection of surface treatment method for stainless steel implants for contact with blood. Appropriate parameters of surface treatment realized by means of the ALD method is of significant importance. It will contribute to the development of technological conditions of specified deposition parameters of TiO2 layers on steel implants

Physiochemical properties of TiO2 nanoparticle thin films deposited on stainless steel

The purpose of this study was to evaluate the usefulness of TiO2 layer to improve hemocompatibility of 316LVM stainless steel. The TiO2 layers studied in this work were deposited from TiCl4 and H2O in a low-pressure Atomic Layer Deposition (ALD) reactor taking into account number of cycles and process temperature. As a part of the research electrochemical studies of the layer after 28 days exposure to artificial plasma were carried out. In particular, potentiostatic, potentiodynamic and impedance studies were conducted. The obtained results were the basis for selection of surface treatment method dedicated to blood-contacting stainless steel implants

Influence of purge, time of waiting and TiCl4 dosing time in a low-pressure atomic layer deposition (ALD) reactor on properties of TiO2 layer

The aim of the study was to evaluate the influence of the ALD process parameters on mechanical properties and corrosion resistance of TiO2 layer. The TiO2 layer was deposited on stainless steel surfaces at constant temperature T = 200 °C and number of cycles nc = 500 (g ≈ 25 nm). The applied methodology consisted of potentiodynamic and impedance studies, as well as adhesion test. The obtained results were the basis for selection of surface treatment method for stainless steel implants for contact with blood. Appropriate parameters of surface treatment realized by means of the ALD method is of significant importance. It will contribute to the development of technological conditions of specified deposition parameters of TiO2 layers on steel implants

Electrochemical behavior of guidewires made of X10CrNi 18-8 STEEL

The purpose of this study was to evaluate corrosion resistance of wires with differentiated of surface preparation and with differentiated work hardening, used in low-invasive cardiology in sterile environment. The study is devoted to voltamperometric and impedance tests, which were used to determine typical features describing corrosion resistance. Measurement system PGSTAT 302n together with a set of measurement electrodes were used for the tests. The tests were carried out in artificial blood plasma at the temperature of T = 37 °C. Obtained results were used as the ground for selecting the way of preparation of the surface of X10CrNi 18-8 steel in order to improve its biotolerance in blood environment

Self-referenced characterization of space-time couplings in near single-cycle laser pulses

We report on the characterization of space-time couplings in high energy sub-2-cycle 770nm laser pulses using a self-referencing single-shot method. Using spatially-encoded arrangement filter-based spectral phase interferometry for direct electric field reconstruction (SEA-F-SPIDER) we characterize few-cycle pulses with a wave-front rotation of 2.8x?10^11 rev/sec (1.38 mrad per half-cycle) and pulses with pulse front tilts ranging from to -0.33 fs/um to -3.03 fs/um.Comment: 6 pages, 6 figure

Corrosion resistance tests of magnesium alloy WE43 after extrusion

The purpose of the study was to evaluate resistance to electrochemical corrosion of magnesium alloy WE43 after plastic working. Potentiodynamic and immersion corrosion tests were performed in solutions with concentration of 0,01 – 2 M NaCl. The tests of microstructure of magnesium alloy after its exposure in NaCl solutions were performed with application of scanning microscope. The results of measurements of alloy surface topography were given, which were obtained by means of optical profile measurement gauge. The results of carried out tests prove explicitly that corrosion properties of extruded magnesium alloy WE43 deteriorate with the increase of molar concentration of NaCl solution. It was proved that irrespective of the concentration of the solution, WE43 alloy features pitting corrosion. It indicates the necessity to apply protective layers on the parts made of the tested alloy

Electrochemical characterisation of X10CrNi 18-8 steel in artificial plasma

Quality of applied guide wires conditions the course of treatment and its success to a great extent. In order to simulate conditions that can be found in blood vascular system samples were exposed to artificial blood plasma (T = 37 } 1 oC) for the time of 8 h. In order to obtain information regarding physical and chemical properties of modified surface of wire made of X10CrNi 18-8 steel, electrochemical impedance spectroscopy (EIS) test and tests of chemical composition of the surface layer X-ray photoelectron spectroscopy (XPS) were made. On the ground of performed EIS and XPS tests, favourable impact of steam sterilisation process on corrosion resistance of X10CrNi 18-8 steel was observed only for the case when chemical passivation was applied prior to sterilisation