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Industrial Applications
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
A micro-accelerator of particles generates a highly energetic ion beam penetrating and modifying the surface of materials to enhance their properties without any coating. The penetration depth might reach up to 10 microns and the treatment effects are still measurable until 1mm. Depending on the nature of the implanted ions and the process parameters, you may obtain nano hammering effect, doping effect, surface amorphization, re-alloying, nano-structuring effect and even chemical modification if reactive gases are used. The part temperature never exceeds 80 °C: a cold metallurgy. The technology might be combined with other low-pressure technologies like PVD and PECVD processes to obtain even more breakthrough properties and performances: surface preparation for hard coatings, cobalt depletion, enhanced adhesion, etc.
Nickel Metal and Alloys
Published in Jurij J. Hostýnek, Howard I. Maibach, Nickel and the Skin, 2019
G. Norman Flint, C. Peter Cutler
Iron-base alloys containing more than about 10.5% chromium are termed stainless steels and derive their good resistance to corrosion from the presence of a surface film of chromium oxide (Cr2O3). There is a wide range of stainless-steel compositions (grades) and a correspondingly wide variation in resistance to corrosion. Alloying elements considered beneficial to resistance to corrosion are chromium, nickel, molybdenum, and nitrogen, while those detrimental to corrosion performance are sulphur, phosphorus, and carbon if present as carbide. Copper is beneficial in acid environments but is thought to be detrimental to resistance to chlorides. Compositions of some commonly used stainless steels in increasing order of resistance to corrosion are given in Table 9.3.
Basics of magnesium biodegradation
Published in Yoshinobu Onuma, Patrick W.J.C. Serruys, Bioresorbable Scaffolds, 2017
Michael Haude, Daniel Lootz, Hubertus Degen, Matthias Epple
Magnesium hydroxide serves as a corrosion protective layer in water, but when the chloride concentration rises, magnesium hydroxide starts to convert into highly soluble magnesium chloride, promoting pitting corrosion. Magnesium and its alloys are highly susceptible to microgalvanic corrosion because impurities like iron, copper, and nickel are known to form efficient cathodic centers for galvanic corrosion, increasing the corrosion rate to more than 50 times that of pure magnesium [3,21–23,28]. The accompanying hydrogen evolution can form gas cavities which are of potential concern for orthopedic implants in tissues with a low diffusion coefficient of hydrogen [1,21,28]. Although necessary to modify physical properties of the implants, most alloying elements are, like impurities, susceptible to microgalvanic corrosion [24,28].
Applications of trimetallic nanomaterials as Non-Enzymatic glucose sensors
Published in Drug Development and Industrial Pharmacy, 2023
Israr U. Hassan, Gowhar A. Naikoo, Fareeha Arshad, Fatima Ba Omar, Alaa A. A. Aljabali, Vijay Mishra, Yachana Mishra, Mohamed EL-Tanani, Nitin B. Charbe, Sai Raghuveer Chava, Ángel Serrano-Aroca, Murtaza M. Tambuwala
Au-based nanomaterials are also great alternatives to Pt or its derivatives. Not only is Au highly stable, but it is also nontoxic and demonstrates excellent resistance to poisoning during oxidation reactions [31,32]. Furthermore, studies suggest that Au displays catalyst-like activity during oxidation reactions involving small organic molecules [55]. Therefore, several attempts have been made at developing Au-based nanomaterials that display enhanced catalytic performance and can be used in developing FGGS [56–58]. Also, as discussed previously, alloying of metals reduces production expenses and helps develop tunable nanocomposites that can be modified per the reaction requirement [59]. In addition, such alloys also enhance the overall surface adsorption or desorption during the chemical reaction, thereby increasing the catalytic performance of the nanocomposite during the reaction [60]. Furthermore, the development of nanosized composites allows researchers to control the size and structure of the material developed, allowing for an easy modification of their surface properties [61]. This, thus, also helps control the catalytic activity of the nanocomposites synthesized.
Design approaches and challenges for biodegradable bone implants: a review
Published in Expert Review of Medical Devices, 2021
The routine implant removal appears to be not the most preferred option due to higher health-care costs and significant difference in viewpoints among the orthopedic surgeons across the globe over its efficacy and side effects [5–7]. To avoid such problems, a definite need was felt to develop a temporary or degradable type of implant [8]. An implant made up of a bioinert/biocompatible material with high mechanical strength and good biodegradable properties in PE was likely to serve the purpose. A number of metals, ceramics, and polymers have been investigated for this purpose. Metals or metal alloys, which provide a combination of good biodegradation properties, biological properties, and adequate mechanical properties, have been found to be suitable [9,10]. One such material is magnesium (Mg), which, when mixed with some alloying elements, may play a crucial role as it fulfills almost all requirements for manufacturing a quality biodegradable implant for orthopedic applications [11]. The search for improved implant design is still on, though. For a specific type of bone, its fracture and age groups, multi-scale design will have to be categorized to suit different patient groups and even individual patients [12].
Mechanical properties and performances of contemporary drug-eluting stent: focus on the metallic backbone
Published in Expert Review of Medical Devices, 2019
Ply Chichareon, Yuki Katagiri, Taku Asano, Kuniaki Takahashi, Norihiro Kogame, Rodrigo Modolo, Erhan Tenekecioglu, Chun-Chin Chang, Mariusz Tomaniak, Neville Kukreja, Joanna J. Wykrzykowska, Jan J. Piek, Patrick W. Serruys, Yoshinobu Onuma
The advantage of magnesium as a material for stents is its biocompatibility to human tissue [48]. Magnesium has antithrombotic effect due to its electronegativity which is attractive as a material for coronary scaffold [49]. Magnesium usually serves as an alloying agent. The strength and physical features of magnesium alloy are modified by various elements such as aluminum, calcium, manganese or rare earth elements added to pure magnesium. The WE43-type alloy of Magnesium was initially used as medical devices. The tensile strength of WE43-type alloys is suitable and better than polymeric biodegradable materials. However, the ductility and elastic modulus are lower than durable metallic materials (Table 1). In addition, magnesium has relatively low corrosion resistance and the biodegradation time can be faster than the optimum treatment time [50,51]. Adding elements such as Zinc and Manganese or purification of the alloy may improve corrosion resistance of WE43-type alloy [52]. The Magnesium alloy used in current vascular scaffold provides high-temperature stability, deformation resistance, 12-month degradation process and light weight [52]. The low thrombogenicity of magnesium scaffold has been demonstrated in an ex-vivo animal arteriovenous shunt model [53]. Although magnesium scaffolds have shown promising results in clinical studies [54], using bioresorbable scaffolds (BRS) outside of clinical studies are not currently recommended [55].