Meghdad Yazdani, Abdollah Afshar, Namdar Mohammadi and Behrooz Paranj
This paper aims to investigate the corrosion behavior of AZ31 alloy as a prospective biomedical implant in two different simulated biological solutions and various immersion times.
Abstract
Purpose
This paper aims to investigate the corrosion behavior of AZ31 alloy as a prospective biomedical implant in two different simulated biological solutions and various immersion times.
Design/methodology/approach
Results of electrochemical experiments indicated that corrosion resistance of specimens immersed for 24 h was superior, suggesting that the surface layer is capable of protecting alloy.
Findings
Scanning electron micrographs revealed that this layer abounds with cracks, exhibiting optimum quality in 24 h immersion time, after which it begins to develop corrosion pits. Energy dispersive spectroscopy analysis suggested that the layer is mainly composed of magnesium hydroxide with precipitates of P and Ca containing species present on its surface, which is an indication of biocompatibility.
Originality/value
Finally, corrosion performance of Mg alloy was found to be slightly better in Lac-simulated biological solution (SBF) solution, which is more representative of actual physiological environment as compared to conventional SBF solutions.
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Keywords
Abdollah Afshar, Mohsen Shirazi, Masoud Rahman and Esmaeil Fakheri
The purpose of this paper is to evaluate the galvanic corrosion of nitinol orthodontic wires with six dental alloys in artificial saliva and consider the effect of initiated…
Abstract
Purpose
The purpose of this paper is to evaluate the galvanic corrosion of nitinol orthodontic wires with six dental alloys in artificial saliva and consider the effect of initiated localized corrosion and real surfaces of anode and cathode on galvanic current.
Design/methodology/approach
Linear polarization and cyclic polarization curves for each alloy in de‐aerated Duffo and Castillo's artificial saliva are obtained. Galvanic corrosion investigation is conducted by polarization curve intersection and mixed potential theory methods. In order to verify the initiation of localized corrosion, scanning electron microscopy is used.
Findings
Initiation of localized corrosion on the anode increases the galvanic current up to 45 times and therefore considering the effect of localized corrosion on galvanic corrosion is necessary. Placing stainless steel brackets or Aristaloy amalgam in direct contact to nitinol arch wire is not recommended.
Originality/value
In order not to underestimate the galvanic corrosion between two alloys, it is recommended to consider the effects of localized corrosion and anode/cathode surface area ratio. In this paper, an electrochemical method for estimating these factors is proposed.
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Juan Manuel Vázquez Martínez, David Piñero Vega, Jorge Salguero and Moises Batista
The evaluation of novel materials such as the acrylonitrile styrene acrylate (ASA) for tribological and mechanical conditions can provide a structural protection against the…
Abstract
Purpose
The evaluation of novel materials such as the acrylonitrile styrene acrylate (ASA) for tribological and mechanical conditions can provide a structural protection against the environmental and wear effects that results in the long-term integrity of the 3 D printed parts. Results of the experimental stage are intended to identify the influence of the printing conditions on the functional characteristics of ASA parts that results in variations of the friction coefficient, wear rate and tensile response. In addition, this study aims to highlight the relevance of printing parameters to avoid the use of chemical post-processing stages, increasing the performance and sustainability of the process.
Design/methodology/approach
In this research, an evaluation of the influence of printing parameters of layer thickness and temperature on the mechanical and tribological response have been carried out for ASA specimens manufactured by fused filament fabrication technology. For this purpose, a range of three different values of thickness of fused layer and three different printing temperatures were combined in the manufacturing process of tests samples. Mechanical behavior of the printed parts was evaluated by standard tensile tests, and friction forces were measured by pin-on-disk tribological tests against steel spheres.
Findings
Higher layer thickness of the printed parts shows lower resistance to tribological wear effects; in terms of friction coefficient and wear rate, this type of parts also presents lower tensile strength. It has been detected that mechanical and tribological behavior is highly related to the micro-geometrical characteristics of the printed surfaces, which can be controlled by the manufacturing parameters. Under this consideration, a reduction in the coefficient of friction near to 65% in the average value was obtained through the variation of the layer thickness of printed surfaces.
Originality/value
This research aims to fill a gap in the scientific literature about the use of specific additive manufacturing materials under dynamic contact. This paper is mainly focused on the influence of the manufacturing parameters on the tribological and mechanical behavior of a weather resistant polymer (ASA).