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Wyświetlanie 1-22 z 22
Tytuł:
On the Nitinol properties improvement after electrochemical treatments
Autorzy:
Hryniewicz, Tadeusz
Rokicki, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/1178042.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Nitinol
SMA
electropolishing (EP)
fatigue resistance
inclusions
magnetoelectropolishing (MEP)
Opis:
Shape Memory Alloys (SMAs) are a group of intermetallic compounds, which can undergo deformation at one temperature, and then recover their original undeformed shape upon heating above their transformation temperature. Superelasticity occurs just above the alloy’s transformation temperature in a very narrow range. In this case no heating is necessary to cause the deformed shape to recover upon load relieve to its original undeformed shape. It has to be emphasized that nitinol exhibits enormous elasticity when compared with other medical metal alloys. In recent years, the use of nitinol (NiTi), almost equiatomic binary (50:50 ratio) intermetallic compound of nickel and titanium, has been steadily growing, particularly in medical and dental devices markets. However, broader and further application of nitinol has been slowed down by leaking nickel and unavoidable inclusions during producing in this compound. This work is to present some electrochemical treatment methods in view of reducing of both these phenomena. It appears that changing electrical conditions of electropolishing (EP) above the plateau region (EP+) may improve the quality of surface obtained on NiTi of over 60% in comparison with as-received (AR) nitinol part. What’s more, introducing a magnetic field into the electrolysis system results in numerous positive features of nitinol surface and increase of mechanical properties. Thus the magnetoelectropolishing (MEP) process appears to increase higher the fatigue resistance of the treated NiTi part. The experiments carried out on chirurgical needles show an unusual triple (and higher) growth in resistance to bending until fracture. Further increase in fatigue resistance is usually limited by different size inclusions appearing on the nitinol part surface under magnetoelectropolishing (MEP).
Źródło:
World Scientific News; 2018, 95; 52-63
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Highly improved Nitinol biomaterial devices by magnetoelectropolishing (MEP)
Autorzy:
Hryniewicz, Tadeusz
Rokicki, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/1166214.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Biocompatibility
Fatigue resistance
Nitinol biomaterial
Surface roughness
XPS
magnetoelectropolishing
Opis:
In recent years, the use of Nitinol as a metallic biomaterial being compound of nickel and titanium, has been steadily growing, particularly in medical and dental devices markets. However, further application of Nitinol has been slowed down due to leaching nickel and unavoidable inclusions appearing on the surface during manufacture of this intermetallic compound. Electropolishing of Nitinol biomaterial samples as-received (AR) was carried out under different conditions: (a) on the plateau level (EP), (b) above the plateau (EP+), and (c) in the magnetic field (MEP). This work is to present magnetoelectropolishing (MEP) as an electrochemical processing method able to significantly improve the Nitinol biomaterial properties. Following our previous SEM/EDS studies, and corrosion resistance improvement of Nitinol, in this work XPS and XRD study methods were used. First of all, as indicated by XPS study results concerning biocompatibility, it was proved that MEP leaves Nitinol surface enriched in oxygen and with nickel reduced to zero. Thus the titanium oxides, generally TiO2, are formed on Nitinol surface. It appears that by introducing a magnetic field into the electrolysis system, another effect relying on a considerable increase of Nitinol mechanical properties is obtained. The experiments carried out on surgical needles show an unusual multiple growth in resistance to bending until fracture. Further increase in fatigue resistance is usually limited by different size of inclusions which happen to appear on the Nitinol part surface. Moreover, in this work also a simple method is proposed to reject the Nitinol parts, with the inclusions detected on the biomaterial surface, before their application.
Źródło:
World Scientific News; 2018, 106; 175-193
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modification of Nitinol Biomaterial for Medical Applications
Autorzy:
Hryniewicz, Tadeusz
Rokicki, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/1177981.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Nitinol biomaterial
electropolishing
fatigue resistance
magnetoelectropolishing (MEP)
modification methods
sterilization
Opis:
In the paper, a review of modification methods which have been applied to Nitinol intermetallic compound used as biomaterial for medical applications, is carried out. A variety of methods used for Nitinol improvement, beginning from its manufacture, covers mechanical treatment, heat treatment, chemical processing including water boiling, electropolishing, plasma ion implantation, coating to improve the corrosion resistance, minimize nickel leaching, improve osseointegration, and/or vascular compatibility, sterilization and disinfection. Nitinol alloying by addition of a third element to replace Ti or Ni has an enormous effect on phase transformation, corrosion resistance and biocompatibility of the newly created ternary Nitinol alloy. Unfortunately, the ternary nitinol alloys – apart from NiTiCu in actuators and NiTiCr in wires used as a pulling-pushing tool in minimally invasive spine operation – have not found a widespread industrial application yet. One of the most effective surface finishing operations used for metallic biomaterials, with a special attention directed to Nitinol, appears to be magnetoelectropolishing (MEP). A uniform magnetic field used in MEP process can be generated by permanent magnets or by electromagnets. MEP leads to refinement of surface chemical composition impossible to achieve by standard electropolishing. During MEP of alloys and intermetallic compounds, ferromagnetic elements, such as Fe (from stainless steels) or Ni, are primarily removed from the surface so that the passive film on Nitinol is totally composed of titanium oxide. One more unique feature of metal samples after MEP is their de-hydrogenation noticed both in stainless steels, niobium, titanium and Nitinol. In fact, the fatigue resistance of Nitinol after MEP referred to as-received, dependent on the refinement and displacement of inclusions, increases from three to seven times.
Źródło:
World Scientific News; 2018, 96; 35-58
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
XPS Analysis of nanolayers obtained on AISI 316L SS after Magnetoelectropolishing
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1192093.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
XPS Analysis
Magnetoelectropolishing (MEP)
AISI 316L SS
Nanolayers
Opis:
In the present paper, the passive layers' chemical compositions of AISI 316L austenitic stainless steel samples after three treatments, such as mechanical/abrasive polishing (MP), standard electropolishing (EP) and magnetoelectropolishing (MEP) are displayed. For the surface studies after each treatment, XPS analysis was performed. It has been noted that after MP treatment the Cr/Fe ratio in the passive layer is the lowest and equals to about 1, whereas after the MEP it is close to 3. Additionally, it has to be reported that the passive layers after MP consist mainly of Cr2O3 and Fe2O3, after a standard EP treatment – of CrOOH and FeOOH, and after MEP – of Cr(OH)3 and FeOOH compounds. Concerning the surface layer compositions, in the passive layer formed after MP the detected iron consisted partly of Fe0 (46.5 at %) and partly of iron compounds Fe2+ and Fe3+ (53.5 at %), whereas the detected chromium consisted of Cr0 (16.5 at %) and mostly of chromium compounds Cr3+ (80.8 at%), with a small amount of Cr6+ (2.7 at %). In case of the nanolayer after EP treatment, the detected iron consisted of Fe0 (39.5 at %) and iron compounds Fe2+ and Fe3+ (60.5 at %), whereas the detected chromium consisted in a small amount of Cr0 (6.6 at %), and mostly chromium compounds Cr3+ (83.8 at %) with some Cr6+ (9.6 at %). The XPS analysis of nanolayer formed on AISI 316L after MEP indicates that the detected iron consisted partly of Fe0 (27.1 at %) and mostly of iron compounds Fe2+ and Fe3+ (72.9 at %) whereas the detected chromium contained Cr0 (18 at %) and chromium compounds of Cr3+ (76 at %) and Cr6+ (6 at %).
Źródło:
World Scientific News; 2016, 37; 232-248
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plasma Electrolytic Oxidation as a modern method to form porous coatings enriched in phosphorus and copper on biomaterials
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1190116.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Plasma Electrolytic Oxidation (PEO)
Niobium
Ti6Al4V
TNZ
Porous coatings
Opis:
In the paper, the porous coatings obtained on niobium and two titanium alloys (Ti6Al4V, and TNZ) after Plasma Electrolytic Oxidation (PEO), known also as Micro Arc Oxidation, were studied. The samples were treated at the voltage of 450 V for 3 minutes in the electrolyte consisting of 300 g and 600 g of copper nitrate Cu(NO3)2 in 1 litre of concentrated phosphoric acid H3PO4, consecutively. SEM and EDS studies were performed on the samples. Based on the obtained results it may be concluded that enriched in copper porous coatings on all studied materials were created in the electrolyte within copper nitrate amounting for 600 g. The proposed by the Authors factor to evaluate the obtained coatings, i.e. copper-to-phosphorus ratio, which for the studied materials amounted to 0.21, clearly indicates that the performed electrochemical PEO treatment for surface modification especially of bioimplants may be advised.
Źródło:
World Scientific News; 2016, 35; 44-61
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Fields for Electropolishing Improvement: Materials and Systems
Autorzy:
Hryniewicz, Tadeusz
Rokosz, Krzysztof
Rokicki, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/411721.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Magnetic field
Magnetoelectropolishing MEP
Materials
Electrochemical systems
Opis:
The paper aims to present the main objectives for using magnetic fields to improve process of electropolishing (EP), firstly by focusing on materials and electrochemical systems. The general introduction has been concerned on the sample surface treated under pseudopassivity conditions, in the process generally known as magnetoelectropolishing (MEP). Long-term up-to-date experiments have shown profound changes observed on metals and alloys. The advantageous effects gained by applying MEP to metals and alloys cover: improvement of corrosion resistance, bio- and haemocompatibility, roughness by modification of their surfaces. The improvements are also referred to the mechanical properties of metals and alloys treated by MEP namely: removal of hydrogen, fatigue resistance enhancement, etc. Further developments and the effects of magnetic fields on electropolishing of metals and alloys are to be presented in the next publications.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 4; 98-108
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative corrosion studies of 2205 duplex steel after electropolishing and passivation in Ringer’s solution
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Solecki, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1178066.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
electropolishing
passivation
pitting corrosion
potentiodynamic corrosion measurements
stainless steel duplex 2205
Opis:
In present work, the results of corrosion analysis of pitting and general corrosion of austenitic duplex 2205 (EN 1.4462) stainless steel in Ringer's solution, are presented. The corrosion rate was studied using potentiodynamic polarisation method by means of the ATLAS 98 potentiostat with POL 98 software. For these measurements the platinum EPT-101 and calomel reference EK-101P electrodes were used. For each run, the electrolytic cell made of glass was used, containing up to 500 ml of the electrolyte. The specimens used for the studies were obtained from a cold-rolled sheet of steel in three forms: as received (without any pretreatment), after abrasive polishing, and after electrochemical polishing. Some of them were passivated for 15 and 30 minutes, respectively, in 20% HNO3 by volume. The study results show clearly that the samples of duplex 2205 stainless steels after electropolishing and passivation for 15 minutes in 20% HNO3 by volume revealed the highest corrosion resistance.
Źródło:
World Scientific News; 2018, 95; 167-181
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion studies of austenitic and duplex stainless steels in the environment of ferment of biogas plants
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Kara, Marta
Powiązania:
https://bibliotekanauki.pl/articles/1179602.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
AISI 304L
AISI 316Ti
austenitic SS
biogas plant
corrosion
duplex SS 2205
Opis:
In the present paper, the study of pitting and general corrosion of stainless steels used in agriculture, specifically for the agricultural biogas plant constructions, is presented. The austenitic stainless steels AISI 304L, AISI 316Ti, and duplex steel 2205, were investigated. For the evaluation of corrosion resistance, the potentiodynamic studies were performed. General corrosion was determined in the Tafel region of potentiodynamic curve, while pitting corrosion was examined on the basis of the pitting corrosion initiation potential. Based on the studies carried out, it can be stated that the alloyed cold-rolled austenitic stainless steel AISI 304L placed in the environment of the biogas plant ferment has the lowest resistance to pitting and general corrosion of all studied steels. The cold-rolled duplex stainless steel 2205 placed in the same corrosive environment revealed the highest resistance to these types of corrosion. It should be also noted that the pitting and general corrosion resistances of tested alloy austenitic stainless steel AISI 316Ti are higher than those ones of AISI 304L, and less than those ones of duplex steel 2205. In conclusion, as could be expected, the best material for the biogas plant construction is duplex stainless 2205 because it shows the highest resistance to both types of corrosion studied. This steel can be advised as a material for construction of fermentation tanks and heating installations for mixture ferment.
Źródło:
World Scientific News; 2017, 74; 194-208
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Corrosion Behavior of Austenitic AISI 304L and 316Ti Stainless Steels in the Animal Slurry
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Uran, Michał
Powiązania:
https://bibliotekanauki.pl/articles/1192037.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Animal slurry
AISI 304L and 316Ti SS
Pitting corrosion
Comparison
Opis:
The aim of this study was to compare the pitting corrosion resistance of two austenitic stainless steels, AISI 304L and AISI 316Ti, which are often used for agricultural machinery building. For the corrosion experiments, animal slurry from a pig farm was used. The results obtained from electrochemical corrosion experiments were proceeded by significance tests in Statistica software. The average value of the pitting corrosion potential of AISI 304L stainless steel in the animal slurry is equal 1044.3±146.6 mVSCE whereas the average potential for AISI 316Ti SS equals 1058.4 ±28.3m mVSCE. Corrosion potential of AISI 304L SS is equal 549±80.5 mVSCE, while for AISI 316Ti SS it equals 425.9±80.5 mVSCE. The range of pitting corrosion potentials of AISI 304L SS (364 mVSCE) was over four times higher than that for AISI 316Ti SS (84 mVSCE); the minimum values of pitting corrosion potential for AISI 304L SS (779 mVSCE) was lower than that obtained for AISI 316Ti SS (1012 mVSCE). On the basis of the results it may be concluded that AISI 304L stainless steel is less resistant in case of pitting corrosion resistance than AISI 316Ti SS. For this reason, austenitic AISI 316Ti stainless steel should be used for the transportation or storage of animal slurry.
Źródło:
World Scientific News; 2016, 50; 174-185
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The studies of corrosion resistance of AISI 316Ti SS in Ringer’s solution after electropolishing and passivation in nitric acid
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Solecki, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1177846.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
AISI 316Ti/EN 1.4571
austenitic stainless steel
electropolishing
passivation
pitting corrosion
potentiodynamic corrosion measurements
Opis:
In present work, the continuation of general and pitting corrosion analysis of austenitic AISI 316Ti (EN 1.4571) stainless steel in Ringer's solution, is presented. The corrosion was studied by using the ATLAS 98 potentiostat with platinum EPT-101 and calomel reference EK-101P electrodes. The three types of specimens, i.e. as received (without any pretreatment), after abrasive mechanical polishing (MP), and after electrochemical polishing (EP), were used. The best pitting corrosion resistance was recorded for electropolished and passivated (in 20% vol. HNO3 for 30 minutes) surface, i.e. the pitting potential was equal to 761 mVSCE (855.4 ± 58.5 mVSCE), while the worst one was recorded for mechanically ground samples and the pitting corrosion potential was equal to 270 mVSCE (378.8 ± 60.3 mVSCE).
Źródło:
World Scientific News; 2018, 98; 46-60
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Corrosion Study of Austenitic AISI 304L and 316Ti Stainless Steels in the Ammonium nitrate/Urea Solution (AUS)
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Trzeszczkowski, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/1182940.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ammonium nitrate/urea solution (aus)
cold-rolled 304l and 316ti ss
comparison
pitting corrosion
Opis:
The aim of the study was to determine the corrosion behavior of two austenitic stainless steels, AISI 304L and AISI 316Ti, after cold rolling (AR) and mechanical polishing/grinding (MP), in a 32% aqueous solution of AUS (RSM®) Ammonium Nitrate/Urea Solution, used as fertilizer, and compared with the corrosion resistance results obtained in 3% aqueous solution of sodium chloride (NaCl). The studies have shown that cold rolled austenitic stainless steels (AISI 304L and AISI 316Ti) in the 32% aqueous solution of AUS have more than two times higher pitting corrosion resistance than that obtained in 3% aqueous solution of sodium chloride (NaCl). Surface scratch of the cold rolled austenitic AISI 304L stainless steel and submersion of the samples in 3% aqueous solution of sodium chloride resulted in decreasing of its pitting corrosion resistance of more than three times; on the other hand, the pitting corrosion resistance of AISI 316Ti in the same solution decreased of two times. It was found that for both stainless steels (AISI 304L and AISI 316Ti) after mechanical grinding, as simulated by the surface scratch, and submersion of the samples in 32% aqueous solution of AUS, the pitting corrosion resistance was not worsened, because of the passivation properties of AUS solution. The study results have shown that in the natural environments containing aqueous solutions of sodium chloride (NaCl), the use of austenitic stainless steel containing chromium, nickel, molybdenum and titanium (AISI 316Ti) is advised. In other environments without chlorides, such as the AUS fertilizer, the use of austenitic AISI 304L stainless steel may be considered as adequate.
Źródło:
World Scientific News; 2016, 49, 2; 249-271
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and characterisation of porous, calcium enriched coatings formed on Titanium via Plasma Electrolytic Oxidation
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Powiązania:
https://bibliotekanauki.pl/articles/1179160.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
85% orthophosphoric acid H3PO4
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
calcium nitrate tetrahydrate Ca(NO3)2∙4H2O
Opis:
The SEM and EDS study results of porous and calcium enriched coatings obtained via Plasma Electrolytic Oxidation (Micro Arc Oxidation) on the Commercial Purity Titanium Grade 2 samples, at three potentials 450 VDC, 550 VDC, 650 VDC in electrolytes containing 500 g Ca(NO3)2∙4H2O in 1000 mL H3PO4, are presented in the paper. In the same electrolyte three Titanium samples, one after other, were treated, with the PEO processing time equaling 3 minutes after each immersion. Based on SEM and EDS results, it was possible to state that all obtained coatings are porous and their calcium-to-phosphorus (Ca/P) ratio decreases with decreasing PEO voltage. In addition, it was found out that electrolyte aging results in decreasing Ca/P ratio, too.
Źródło:
World Scientific News; 2017, 83; 29-44
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SEM and EDS studies of porous coatings enriched in calcium and zinc obtained by PEO with ramp voltage
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Powiązania:
https://bibliotekanauki.pl/articles/1178366.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
calcium nitrate Ca(NO3)2∙4H2O
linear polarization
ramp voltage
zinc nitrate Zn(NO3)2∙6H2O
Opis:
In this work, the SEM and EDS results of porous and enriched in calcium or zinc coatings, which were obtained during 3-minute treatments using Plasma Electrolytic Oxidation (Micro Arc Oxidation) processes on CP Titanium Grade 2 at ramp potentials (linear polarization) from 0 up to 650 VDC in electrolytes containing 500 g Ca(NO3)2∙4H2O and/or 500 g Zn(NO3)2∙6H2O in 1 L H3PO4, are presented. It was found that obtained coatings have pores with different shapes and diameters. The Ca/P and Zn/P ratios by atomic concentration are the same and equal to 0.2, what may suggest hydroxyapatite-like structure (M,Ti)x(PO4)y, where M = {Ca, Zn}.
Źródło:
World Scientific News; 2017, 77, 2; 242-255
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the biological response of austenitic stainless steels after electrochemical -EP and MEP- polishing
Autorzy:
Hryniewicz, Tadeusz
Lewicka-Rataj, Katarzyna
Rokosz, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/1179275.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
austenitic stainless steels
bacteria Escherichia coli
electrochemical polishing
electropolishing EP
magnetoelectropolishing MEP
statistical approach
water contamination
Opis:
The austenitic cold-rolled AISI 316L stainless steel was used for the studies. Corrosion resistance measurements were performed on the samples after three types of treatments: abrasive finishing (MP), standard electropolishing (EP), and magnetoelectropolishing (MEP). They were carried out in Ringer's solution at a room temperature, indicating a considerable difference in the breaking potential Epit values, dependent on surface treatment. Two groups of samples, those after EP and MEP, were submerged in broth culture wild strain of Escherichia coli from contaminated river water. Images of the steel samples submerged for 2 and 4 hours are displayed in the paper. A statistical approach has been performed. In each case the number of bacteria deposited on the MEP steel samples was higher in comparison with that one noticed on EP samples, increasing much faster with time on the MEP ones.
Źródło:
World Scientific News; 2017, 80; 284-296
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The alternative, novel technology for improvement of surface finish of SRF niobium cavities
Autorzy:
Rokicki, Ryszard
Hryniewicz, Tadeusz
Konarski, Piotr
Rokosz, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/1179599.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
SRF niobium cavities
electrochemical polishing
hydrogen content
surface roughness
Opis:
Pure niobium is used for making superconducting radio frequency (SRF) cavities. These cavities need to have a good surface finish to achieve maximum performance. The high smoothness, lack of subsurface hydrogen content and sulfur contamination removal of SRF niobium cavities are the three most important factors to achieving a high accelerating gradient. For finishing niobium surface, electropolishing (EP) in hydrofluoric/sulfuric acid electrolyte is commonly used as a final process. Unfortunately this process had been considered to cause hydrogen absorption that could result in hydrogen Q-disease in niobium SRF cavities. This is why a new electrolyte was compounded to substitute the one presently used. Moreover, the additional imposition of a magnetic field during the electropolishing process (magnetoelectropolishing MEP) not only increases hydrogen removal, but also results in reduction of surface roughness when compared to the roughness achieved by the electropolishing process alone (Rz much over 300 nm). This effect of sharp decrease in hydrogen content was found previously in our experiments with titanium and stainless steels after MEP processing. Our present studies, with the electrolyte consisting of a mixture of 70% methanesulfonic acid with 49% hydrofluoric acid by volume in 3:1 ratio, resulted in intensifying and speeding-up the electrochemical processes of dissolution and polishing niobium surface. It was found that the imposition of a magnetic field of ≈ 100 mT upon the EP process is able to reduce niobium surface roughness of up to 50% (Rz below 200 nm) compared to the roughness achieved by conventional electropolishing.
Źródło:
World Scientific News; 2017, 74; 152-163
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SEM and EDS analysis of enriched in phosphorus and copper coatings fabricated by AC-PEO treatment
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Dudek, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/1178082.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
copper nitrate Cu(NO3)2∙3H2O
Opis:
In the present paper, SEM and EDS studies of coatings obtained on CP Titanium Grade 2 under sinusoidal alternating voltage (AC) with frequency 50 Hz in Plasma Electrolytic Oxidation (PEO) process at voltages of 200 Vpp, 250 Vpp and 300 Vpp during 3-minute treatments, are displayed. Based on SEM micrographs it may be stated that the porous surfaces, which are needed for biomedical and catalysis application, are obtained only for samples fabricated at 200 Vpp. It was found out that thickest and most morphologically developed surfaces were obtained at 200 Vpp, too. The surfaces obtained at 250 Vpp and 300 Vpp are cracked and had low concentration of copper, i.e. 0.9 at% and 1.1 at%, respectively, while that one obtained at 200 Vpp was porous and had 8.6 at% copper.
Źródło:
World Scientific News; 2018, 95; 246-259
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development and SEM/EDS characterisation of porous coatings enriched in magnesium and copper obtained on titanium by PEO with ramp voltage
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Dudek, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/1179226.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
calcium nitrate Mg(NO3)2∙6H2O
linear polarization
ramp voltage
zinc nitrate Ca(NO3)2∙3H2O
Opis:
In the present paper, the SEM and EDS results of porous and enriched in calcium and/or zinc coatings, which were obtained during 3-minute treatments by Plasma Electrolytic Oxidation/ Micro Arc Oxidation processes on CP Titanium Grade 2 at ramp potentials (liner polarization) from 0 up to 650 VDC in electrolytes containing 500 g Mg(NO3)2∙6H2O and/or 500 g Cu(NO3)2∙3H2O in 1 L H3PO4, are reported. It was found that the obtained coatings, dependent on the PEO process conditions, have pores with different shapes and diameters. The Mg/P and Cu/P ratios by atomic concentration are the same and equal to 0.09±0.01 (by wt %) | 0.11±0.01 (by at%) and/or 0.40±0.08 (by wt %) | 0.19±0.04 (by at%), respectively. That may testify the hydroxyapatite-like structures of Mg-Ti-PO43– and/or Cu-Ti-PO43– have been identified to occur.
Źródło:
World Scientific News; 2017, 80; 29-42
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porous PEO coatings on titanium, obtained under DC regime, enriched in magnesium, calcium, zinc, and copper
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Dudek, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/1156239.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
plasma electrolytic oxidation (peo)
micro arc oxidation (mao)
cp titanium grade 2
calcium nitrate ca(no3)2•4h2o
magnesium nitrate mg(no3)2∙6h2o
zinc nitrate zn(no3)2∙6h2o
copper nitrate cu(no3)2∙3h2o
Opis:
In the present paper, the analysis of SEM and EDS results of porous and enriched in calcium, magnesium, zinc, copper and phosphorus coatings, obtained during 3-minute treatments performed by Plasma Electrolytic Oxidation (PEO)/Micro Arc Oxidation (MAO) processes on CP Titanium Grade 2, is presented. The PEO process was carried out at DC potentials of 500 VDC, 575 VDC, and 650 VDC in electrolytes containing 125 g Ca(NO3)2•4H2O, and 125 g Mg(NO3)2∙6H2O, and 125 g Zn(NO3)2∙6H2O, and 125 g Cu(NO3)2∙3H2O in 1 L H3PO4. It was found that obtained coatings have pores with different shapes and diameters and/or size/dimentions. The Ca/P, Mg/P, Zn/P, Cu/P, and M/P ratios (M=Ca+Mg+Zn+Cu) were equal to 0.074, 0.046, 0.056, 0.042, and 0.218, respectively. The highest value of each of these ratios was recorded for 650 VDC. It may be concluded that the obtained PEO coatings structures most likely are similar to hydroxyapatite-like structures, in which the Ca2+ may be replaced with Zn2+, Mg2+, Cu2+.
Źródło:
World Scientific News; 2018, 94, 2; 99-114
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SEM and EDS studies of selected porous coatings obtained on titanium by Plasma Electrolytic Oxidation
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Dudek, Łukasz
Malorny, Winfried
Powiązania:
https://bibliotekanauki.pl/articles/1178480.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
calcium nitrate Ca(NO3)2∙4H2O
copper nitrate Cu(NO3)2∙3H2O
magnesium nitrate Mg(NO3)2∙6H2O
Opis:
In present work, SEM and EDS results of porous and enriched in calcium, copper, magnesium and phosphorus coatings, which were obtained during 3-minute treatments of Plasma Electrolytic Oxidation PEO (Micro Arc Oxidation MAO) processes on CP Titanium Grade 2 at two potentials, i.e. 500 VDC and 650 VDC, are presented. It was found that the voltage of that process influences the chemical composition of coatings shapes obtained on titanium in electrolytes containing calcium, copper and magnesium nitrates. The pores shapes of PEO coatings formed on titanium in electrolytes containing calcium, copper and magnesium nitrates are presented, too. In addition, it was also noted that with using of higher voltage (here 650 VDC) of PEO treatments, the higher Ca/P, Cu/P and Mg/P ratios were found than those after treatments at 500 VDC.
Źródło:
World Scientific News; 2017, 70, 2; 71-85
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
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