Papers by Author: Amir Eliezer

Abstract: Micro-arc oxidization of AM50 magnesium alloys was studied. The influence of micro-arc oxidization process was investigated; phase structure were analyzed using X-ray diffraction (XRD). Open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion resistance of ceramic coatings formed on magnesium alloys under stress conditions. XRD analyses indicate that the ceramic coatings fabricated on the surface of magnesium alloys by micro-arc oxidization are composed of spinel phase MgAl2O4 The corrosion resistance of ceramic coatings is improved compared with magnesium alloy substrate.

Abstract: This research has focused on understanding the correlation between the raw material, processes, microstructure and corrosion behavior of AM50 containing SiC particles magnesium sheet. The magnesium sheets were produced from cast ingot AM50 containing different amount of SiC particles. The magnesium sheets were exposed to 3.5 % NaCl solution with Mg(OH)2 , pH=10.5 in room temperature. The influence of SiC particles on the micro-galvanic corrosion was studies by Scanning Kelvin Probe Force Microscopy.

Abstract: High rates of degradation in corrosive media represent the Achilles heel of Mg alloys, which hinders their applications in various areas, particularly in prosthetics. We present an investigation of the degradation behavior of magnesium alloy AZ91D and AM50 in different solutions that simulates bodily fluids. The degradation rate is shown to be significantly reduced by different Al contents in the alloy. Furthermore, the corrosive solutions containing protein influenced on the oxidation behavior of the studied alloys

Abstract: New interest in magnesium alloys as temporary biomaterials was reborn in the recent years. Especially metals based on physiological trace elements seem to be promising as an alternative to current biodegradable implant materials in cardiovascular and musculoskeletal applications. First clinical reports can be dated back before 1900. Magnesium alloys were used by surgeons of different clinical background in cardiovascular, neural, skin, general and musculoskeletal surgery. All patients have benefited from the treatment with magnesium alloys, although rapid corrosion caused sometimes painless subcutaneous gas cavities. These reports encouraged researchers to study and invent new magnesium alloys which aim to provide more uniform and slow corrosion rates. The most challenging part was to analyze the corrosion of implanted magnesium alloys in-vivo, since the magnesium alloys interlock with the surrounding tissue during corrosion. Therefore, the implanted samples could not be retrieved without damaging the fragile implant-tissue interface. Synchrotron-radiation based microtomography (SRµCT) was introduced as a solution to this challenge. SRµCT enables to measure non-destructively the in-vivo corrosion rates of magnesium alloys as well as their corrosion morphology. Based on these data, it was concluded that suitable magnesium implants should provide small grains, which are distributed very homogenously and should be produced with highest purity. The future of biodegradable magnesium alloys might be directed towards implant areas where high ductility, maximal tensile strength as well as high compression strength is needed and the properties of current biodegradable implant-materials are exceeded by the properties of magnesium alloys.