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Wyświetlanie 1-8 z 8
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:
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:
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:
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:
Diagnosing helicopter propulsion units with the FAM-C method
Autorzy:
Gębura, Andrzej
Zieja, Mariusz
Masiewicz, Mariusz
Kowalczyk, Henryk
Cieślik, Andrzej
Rokicki, Edward
Tokarski, Tomasz
Florczak, Jarosław
Kwiatkowski, Tadeusz
Handzel, Kacper
Kołcon, Andrzej
Poradowski, Michał
Michałowski, Piotr
Sibilski, Krzysztof
Setlak, Lucjan
Powiązania:
https://bibliotekanauki.pl/books/33500685.pdf
Data publikacji:
2024-07-01
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Opis:
The monograph addresses the issue of diagnosing propulsion units of helicopters operated in the Polish Air Force from the perspective of diagnostic measurements via the innovative FAM-C and FDM-A methods. It contains seven chapters.
Dostawca treści:
Biblioteka Nauki
Książka
    Wyświetlanie 1-8 z 8

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