Forming of magnesium alloy microtubes in the fabrication of biodegradable stents

Magnesium alloys have, in recent years, been recognized as highly promising biodegradable materials, especially for vascular stent applications. Forming of magnesium alloys into high-precision thin-wall tubes has however presented a technological barrier in the fabrication of vascular stents, because of the poor workability of magnesium at room...

Characterization of porous TiO2 surfaces formed on 316L stainless steel by plasma electrolytic oxidation for stent applications

In this study, a porous oxide layer was formed on the surface of 316L stainless steel (SS) by combining Ti magnetron sputtering and plasma electrolytic oxidation (PEO) with the aim to produce a polymer-free drug carrier for drug eluting stent (DES) applications. The oxidation was performed galvanostatically in Na3PO4 electrolyte. The surface...

Effect of the size distribution of nanoscale dispersed particles on the Zener drag pressure

In this article, a new relationship for the calculation of the Zener drag pressure is described in which the effect of the size distribution of nanoscale dispersed particles is taken into account, in addition to particle radius and volume fraction, which have been incorporated in the existing relationships. Microstructural observations indicated...

Magnesium-based composites with improved in vitro surface biocompatibility

In this study, bioactive glass (BG, 45S5) particles were added to a biodegradable magnesium alloy(ZK30) through a semi-solid high-pressure casting process in order to improve the surface biocompatibility of the biomaterial and potentially its bioactivity. The observation of the as-cast microstructures of ZK30-BG composites indicated homogeneous...

In vitro degradation behavior and cytocompatibility of Mg–Zn–Zr alloys

Zinc and zirconium were selected as the alloying elements in biodegradable magnesium alloys, considering their strengthening effect and good biocompatibility. The degradation rate, hydrogen evolution, ion release, surface layer and in vitro cytotoxicity of two Mg–Zn–Zr alloys, i.e. ZK30 and ZK60, and a WE-type alloy (Mg–Y–RE–Zr) were...

Correlation between Electrical Resistivity, Particle Dissolution, Precipitation of Dispersoids, and Recrystallization Behavior of AA7020 Aluminum Alloy

This research concerns the effect of homogenization treatment on the electrical resistivity of AA7020 aluminum alloy variants with different Zr and Cr contents. Small changes in the Zr and Cr contents of the as-cast alloy increase the electrical resistivity significantly. After employing various homogenization treatments, the electrical...

Release of PLGA–encapsulated dexamethasone from microsphere loaded porous surfaces

The aim of the present study was to investigate the morphology and function of a drug eluting metallic porous surface produced by the immobilization of poly lactide-co-glycolide microspheres bearing dexamethasone onto plasma electrolytically oxidized Ti–6Al–7Nb medical alloy. Spheres of 20 µm diameter were produced by an oilin-water emulsion...

Characteristics of the Friction Between Aluminium and Steel at Elevated Temperatures During Ball-on-Disc Tests

Appropriate specification of the frictional boundary condition for the finite-element (FE) simulation of metal-forming processes is of great importance to the trustworthiness of the results. The research reported in this communication aimed at understanding the interfacial contact between aluminium and steel at elevated temperatures and...

Size effect of PLGA spheres on drug loading efficiency and release profiles

Drug delivery systems (DDS) based on poly (lactide-co-glycolide) (PLGA) microspheres and nanospheres have been separately studied in previous works as a means of delivering bioactive compounds over an extended period of time. In the present study, two DDS having different sizes of the PLGA spheres were compared in morphology, drug (dexamethasone...

Evolution of Grain Boundary Phases during the Homogenization of AA7020 Aluminum Alloy

The presence of large constitutive particles formed during solidification decreases the strength and hot workability of aluminum alloys especially when they are located in the grain boundary (GB) regions. Therefore, the evolution of these phases is a major issue in the homogenization process of these alloys. There is a lack of information on the...

Strain-dependent constitutive analysis of three wrought Mg–Al–Zn alloys

The commonly used hyperbolic sine constitutive equation for metal forming at elevated temperatures, with no strain incorporated, is in principle applicable only to deformation in the steady state. However, the actual deformation processes applied to magnesium alloys are mostly in the non-steady state. In the present research, the results of hot...

Enrichment of anodic MgO layers with Ag nanoparticles for biomedical applications

The growing fight against infections caused by bacteria poses new challenges for development of materials and medical devices with antimicrobial properties. Silver is a well known antimicrobial agent and has recently started to be used in nanoparticulate form, with the advantage of a high specific surface area and a continuous release of enough...

Self-healing layer on non-ferrous metals using polyoxometalates

The invention relates to a method for applying a multifunctional layer on a substrate. Accordingly said layer is applied by means of a process by using an aqueous solution that comprises a POM and/or a crack-healing agent, which POM and/or a crack healing agent is/are incorporated in said layer during said process to obtain a self-healing layer.

Method for reactively joining materials

Method for reactively joining materials in solid form, such as intermetallic compounds and technical ceramics, wherein: a) a mixed powder is provided in solid form between the materials to be joined; b) at least the powder mixture is locally heated, causing exothermic reactions to take place, whereby the heat is released at the contact surfaces...

Method of preparing an Al-Ti-B grain refiner for aluminium-comprising products, and a method of casting aluminium products

The invention relates to a method of preparing an Al-Ti-B grain refiner for cast aluminium-comprising products. According to the invention the preparation is realized by mixing powders selected from the group comprising aluminium, titanium, boron, and alloys and intermetallic compounds thereof, compressing, heating in an inert environment until...

Method of manufacturing molded articles from metallic or ceramic powdered particles and binder system suitable for use therein

The invention relates to a method of manufacturing molded articles by mixing metallic or ceramic powder particles homogeneously with a binder system, whereafter the mixture is shaped in fluid condition by injection molding, the molding obtained is treated with an aqueous liquid in order to wash out a part of the binder system, and the molding...