The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
M A Arenas - One of the best experts on this subject based on the ideXlab platform.
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corrosion behaviour of super hydrophobic electrodeposited nickel Cobalt Alloy film
Applied Surface Science, 2016Co-Authors: S Khorsand, K Raeissi, F Ashrafizadeh, M A Arenas, A CondeAbstract:Abstract Hierarchical super-hydrophobic Ni–Co film with enhanced corrosion resistance was fabricated on a copper substrate by one-step electrodeposition process. The contact angle and water repellence properties of the Ni–Co film were measured to determine its wettability. The Ni–Co film exhibited excellent super-hydrophobic properties with a static water contact angle of 158° and a sliding angle of ≤5°. The corrosion performance of the super-hydrophobic surface (SHS) was investigated by electrochemical potentiodynamic measurements and electrochemical impedance spectroscopy in NaCl solution (3.5 wt.%). Moreover, to study the long-term stability of the super-hydrophobic film, SHS samples were immersed into NaCl solution and their corrosion behaviour was investigated by the electrochemical impedance spectroscopy. Additionally, the changes of surface wettability were also monitored over the whole immersion time up to 11 days. Experimental results indicated that super-hydrophobic samples had much more corrosion resistance in comparison with freshly prepared samples or the bare substrate.
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super hydrophobic nickel Cobalt Alloy coating with micro nano flower like structure
Chemical Engineering Journal, 2015Co-Authors: S Khorsand, K Raeissi, F Ashrafizadeh, M A ArenasAbstract:Abstract A simple electrodeposition process was proposed to fabricate super-hydrophobic nickel–Cobalt Alloy coating without modification by low free energy materials. In this paper, the correlation between wettability and surface characteristics has been investigated. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), confocal profilometry and optical tension measurements were used to characterize the micro-structure and wettability properties of the coatings. The results showed that surface morphology, surface roughness and surface energy play critical roles for the wettability of the coatings. The surface of freshly prepared Ni–Co Alloy coatings was highly hydrophilic with a water contact angle of 0°. Meanwhile, after being exposed to air for two weeks, surface of the coatings fabricated by one and two electrodeposition steps became super-hydrophobic with water contact angles of 158° and 163°, respectively. This phenomenon was attributed to micro-nano flower-like structure of Ni–Co coating as well as adsorption of airborne hydrocarbon adsorbates on coating surface. The super-hydrophobic Ni–Co coatings possessed good chemical stability and long term durability. Moreover, the super-hydrophobic surfaces possessed self-cleaning properties.
S Khorsand - One of the best experts on this subject based on the ideXlab platform.
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corrosion behaviour of super hydrophobic electrodeposited nickel Cobalt Alloy film
Applied Surface Science, 2016Co-Authors: S Khorsand, K Raeissi, F Ashrafizadeh, M A Arenas, A CondeAbstract:Abstract Hierarchical super-hydrophobic Ni–Co film with enhanced corrosion resistance was fabricated on a copper substrate by one-step electrodeposition process. The contact angle and water repellence properties of the Ni–Co film were measured to determine its wettability. The Ni–Co film exhibited excellent super-hydrophobic properties with a static water contact angle of 158° and a sliding angle of ≤5°. The corrosion performance of the super-hydrophobic surface (SHS) was investigated by electrochemical potentiodynamic measurements and electrochemical impedance spectroscopy in NaCl solution (3.5 wt.%). Moreover, to study the long-term stability of the super-hydrophobic film, SHS samples were immersed into NaCl solution and their corrosion behaviour was investigated by the electrochemical impedance spectroscopy. Additionally, the changes of surface wettability were also monitored over the whole immersion time up to 11 days. Experimental results indicated that super-hydrophobic samples had much more corrosion resistance in comparison with freshly prepared samples or the bare substrate.
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super hydrophobic nickel Cobalt Alloy coating with micro nano flower like structure
Chemical Engineering Journal, 2015Co-Authors: S Khorsand, K Raeissi, F Ashrafizadeh, M A ArenasAbstract:Abstract A simple electrodeposition process was proposed to fabricate super-hydrophobic nickel–Cobalt Alloy coating without modification by low free energy materials. In this paper, the correlation between wettability and surface characteristics has been investigated. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), confocal profilometry and optical tension measurements were used to characterize the micro-structure and wettability properties of the coatings. The results showed that surface morphology, surface roughness and surface energy play critical roles for the wettability of the coatings. The surface of freshly prepared Ni–Co Alloy coatings was highly hydrophilic with a water contact angle of 0°. Meanwhile, after being exposed to air for two weeks, surface of the coatings fabricated by one and two electrodeposition steps became super-hydrophobic with water contact angles of 158° and 163°, respectively. This phenomenon was attributed to micro-nano flower-like structure of Ni–Co coating as well as adsorption of airborne hydrocarbon adsorbates on coating surface. The super-hydrophobic Ni–Co coatings possessed good chemical stability and long term durability. Moreover, the super-hydrophobic surfaces possessed self-cleaning properties.
Kazuhiro Hongo - One of the best experts on this subject based on the ideXlab platform.
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Mechanical evaluation of cerebral aneurysm clip scissoring phenomenon: comparison of titanium Alloy and Cobalt Alloy.
Journal of Materials Science: Materials in Medicine, 2017Co-Authors: Keiji Tsutsumi, Tetsuyoshi Horiuchi, Kazuhiro HongoAbstract:Cerebral aneurysm clip blades crossing during surgery is well known as scissoring. Scissoring might cause rupture of the aneurysm due to laceration of its neck. Although aneurysm clip scissoring is well known, there have been few reports describing the details of this phenomenon. Quasi-scissoring phenomenon was introduced mechanically by rotating the clip head attached to a silicone sheet. The anti-scissoring torque during the twist of the blades was measured by changing the depth and the opening width. The closing force was also evaluated. Sugita straight clips of titanium Alloy and Cobalt Alloy were used in the present study. In both materials, the anti-scissoring torque and the closing force were bigger 3 mm in thickness than 1 mm. The initial closing forces and the anti-scissoring torque values at each rotation angles were increased in proportion to depth. Closing forces of titanium Alloy clip were slightly higher than those of Cobalt Alloy clip. By contrast, anti-scissoring torque values of Cobalt Alloy clip were bigger than those of titanium Alloy clip in all conditions. In condition of 3 mm in thickness and 3 mm in depth, anti-scissoring torque vales of titanium Alloy clip decreased suddenly when an angle surpassed 70 degrees. Aneurysm clip scissoring phenomenon tends to occur when clipping the aneurysm neck only with blade tips. Based on the results of this experiment, titanium Alloy clip is more prone to scissoring than Cobalt Alloy clip under the condition that the wide blade separation distance and the shallow blade length.
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Mechanical evaluation of long titanium Alloy clip--comparison of Cobalt Alloy clip.
Neurologia Medico-chirurgica, 2013Co-Authors: Tetsuyoshi Horiuchi, Kazuhiro Hongo, Masato ShibuyaAbstract:Long titanium aneurysm clips have recently been released. In the present study, comparative study of long titanium and Cobalt Alloy clips was performed. Two kinds of Sugita long clips (straight clips of 25- and 35-mm blade length) made of titanium and Cobalt Alloys were tested by measuring the closing force, the anti-scissoring torque, and the maximum opening width. There were some differences between the two materials. In the 25-mm blade length clip, closing force and maximum opening width of titanium Alloy clip were greater than those of Cobalt Alloy clip. By contrast, the anti-scissoring torque of 35-mm blade length titanium clip was stronger than that of the Cobalt. The long titanium clips would have equivalent endurance to long Cobalt clip and are safe for clinical use.
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Revisit of aneurysm clip closing forces: comparison of titanium versus Cobalt Alloy clip
Neurosurgical Review, 2012Co-Authors: Tetsuyoshi Horiuchi, Nunung Nur Rahmah, Takao Yanagawa, Kazuhiro HongoAbstract:Although closing force of Cobalt Alloy clip is well studied, there is only little information of titanium Alloy clip available in the literature. In the present study, we examined and compared closing forces of various types and points of cerebral titanium and Cobalt aneurysm clips for cerebral aneurysms. Straight, temporary, bayonet, angled, and fenestrated titanium or Cobalt Alloy clips were tested by measuring the closing forces at various points along their blade length. Closing forces of all the tested clips linearly increased from tip to base of clip blades. Sugita Titanium II clips had bigger closing forces than Elgiloy clips in all type clips except for the temporary clips. The closing forces of Sugita Titanium II and Yasargil titanium clips were similar in straight permanent type clip although there were some differences in closing forces between other types of Sugita and Yasargil clips. Our data showed that the closing forces differed depending not only on manufacturers but also on materials and shapes.
Yi Wang - One of the best experts on this subject based on the ideXlab platform.
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Study on Present Situation and New Trends of the Electrodeposition of Nickel-Cobalt Alloy
Advanced Materials Research, 2012Co-Authors: Ming-ming Yu, Hong You Li, Yi WangAbstract:Nickel-Cobalt Alloys have broad application prospect for their excellent properties (i.e. high microhardness, strength, abrasion, corrosion resistance and magnetic properties.etc). Present situation and new trends on mechanism of the anomalous codeposition and technology of electrodepostion of nickel-Cobalt were studied. Effects of electrolysis parameters (e.g. concentration of co2+in the electrolyte, cathodic current density, pH value, temperature.etc) on the Alloy composition, morphology and mechanical properties were analyzed. The formation of the monovalent intermediate (hydroxides or colloid) may cause the Cobalt preferential deposition or the faster charge-transfer of Co2+ reduction compared to that of Ni2+ reduction is the main factor that causes the anomalous codeposition behavior of the nickel-Cobalt Alloy.
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quantitative evaluation of susceptibility and shielding effects of nitinol platinum Cobalt Alloy and stainless steel stents
Magnetic Resonance in Medicine, 2003Co-Authors: Yi Wang, Thuy N Truong, Cecil Chernchyi Yen, Deniz Bilecen, Richard Watts, David W Trost, Martin R PrinceAbstract:The purpose of this study is to quantitatively estimate the shielding and susceptibility effects of commonly used metallic stents on MR signal. Two experiments were performed using a 3D gradient echo sequence with short TE to image a stent phantom: 1) short TR and high flip angle (contrast enhanced MRA parameters), and 2) long TR (TR ≫ T1) and low flip angle. The factor characterizing susceptibility effects was estimated from the signal phase of the first experiment, and then the factor characterizing the shielding effects was derived from the second experiment. Susceptibility induced signal loss was negligible (<1%) for nonstainless-steel (nitinol, platinum, and Cobalt-Alloy) stents and totally destructive (100%) for the stainless steel stent. Signal loss due to RF shielding was 31–62% for nitinol stents, 14–50% for platinum stents, 50–77% for the Cobalt-Alloy stents (undetermined for the stainless steel stent), varied with stent orientation, diameter, and wall geometry. In summary, stents made of nitinol, platinum, and Cobalt-Alloy have negligible susceptibility effects but stents made of stainless steel may have complete dephasing. All stents have substantial shielding effects, which vary with composition, geometry, and orientation. Large platinum stents may have the smallest artifacts and are the best suited for postinterventional MR imaging. Magn Reson Med 49:972–976, 2003. © 2003 Wiley-Liss, Inc.
A Conde - One of the best experts on this subject based on the ideXlab platform.
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corrosion behaviour of super hydrophobic electrodeposited nickel Cobalt Alloy film
Applied Surface Science, 2016Co-Authors: S Khorsand, K Raeissi, F Ashrafizadeh, M A Arenas, A CondeAbstract:Abstract Hierarchical super-hydrophobic Ni–Co film with enhanced corrosion resistance was fabricated on a copper substrate by one-step electrodeposition process. The contact angle and water repellence properties of the Ni–Co film were measured to determine its wettability. The Ni–Co film exhibited excellent super-hydrophobic properties with a static water contact angle of 158° and a sliding angle of ≤5°. The corrosion performance of the super-hydrophobic surface (SHS) was investigated by electrochemical potentiodynamic measurements and electrochemical impedance spectroscopy in NaCl solution (3.5 wt.%). Moreover, to study the long-term stability of the super-hydrophobic film, SHS samples were immersed into NaCl solution and their corrosion behaviour was investigated by the electrochemical impedance spectroscopy. Additionally, the changes of surface wettability were also monitored over the whole immersion time up to 11 days. Experimental results indicated that super-hydrophobic samples had much more corrosion resistance in comparison with freshly prepared samples or the bare substrate.