Evaluation of Bioabsorbable Mg–Mn Alloy with Anodic Oxidation Treatment

Magnesium alloys as biodegradable materials have been examined that may replace bone screws and plates in recent studies. But the velocity control of magnesium alloy is very difficult. Until now, the magnesium alloys degrade very fast, thus it couldn’t maintain the function in clinical field. Thus the purpose of this study is to evaluate the degradability of anodized magnesium alloy for control the velocity. For this experiment, a Mg–xMn (x = 0, 0.5, 1 wt%) binary alloy was cast in argon gas (99.99%) atmosphere. The specimens of the surface treatment group were anodized for 15 minutes at a voltage of 120 V at room temperature using calcium gluconate, sodium hexametaphosphate, and sodium hydroxide electrolyte. For the mechanical test, SEM, roughness test, hardness test were examined. The degradation test was conducted to measure the hydrogen gas formation volume. For biologic test, cell viability were tested. After anodic oxidation treatment, the surface showed the crater formation, the size of craters were about 200~300 nm. Among nonanodized group, the Mg–0.5Mn showed the highest Vickers hardness and cell viability. However for biodegradability test, Mg–1Mn showed the lowest the hydrogen gas formation. For anodic oxidation treatment, anodic oxidation treatment makes rougher surface, higher hardness, good cell response and lower degradation rate. Overall, anodized Mg–1Mn showed the possibility for clinical application in bone screw and bone plate.

Surface Observation of Plasma Electrolytic Oxidation-Treated Ti–6Al–4V Alloy After 2-Step Nano-Mesh Formation

The purpose of this study was to investigate the surface observation of PEO-treated Ti–6Al–4V alloy after 2-step nano-mesh formation was investigated by FE-SEM, EDS, and XRD. Anodic oxidation treatment was performed on the electrolyte containing 0.8 wt.% Na/F and 1M H3PO4 to form a nanotube structure on the Ti–6Al–4V alloy. After removing the nanotube layer, PEO-treatment was performed on the electrolyte containing Mg and Zn ions. After forming the nanotubes, the nanomesh surface was obtained by removing the layer, and the surface roughness increased with cycle number of nanotube formation. Also, as the number of nanotubes increased, the anatase peak increased.

The Effect of Potential on Surface Characteristic and Corrosion Resistance of Commercial Pure Titanium Processed by Anodic Oxidation Treatment

Anodic oxidation treatment of commercial pure titanium was carried out at the voltage of 30, 50 V in 0.5 M H2SO4 solution so as to obtain the effects of the anodic potential on the surface characteristic and corrosion resistance of passive film. The morphology and corrosion resistance of the treated samples were investigated using scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization curves and electrode impedance spectroscopy (EIS). The results show that increasing anodic potential can significantly enhance the corrosion resistance of commercial pure titanium.

Preparation and Anodizing of SiCp/Al Composites with Relatively High Fraction of SiCp

By properly proportioned SiC particles with different sizes and using squeeze infiltration process, SiCp/Al composites with high volume fraction of SiC content (Vp = 60.0%, 61.2%, 63.5%, 67.4%, and 68.0%) were achieved for optical application. The flexural strength of the prepared SiCp/Al composites was higher than 483 MPa and the elastic modulus was increased from 174.2 to 206.2 GPa. With an increase in SiC volume fraction, the flexural strength and Poisson’s ratio decreased with the increase in elastic modulus. After the anodic oxidation treatment, an oxidation film with porous structure was prepared on the surface of the composite and the oxidation film was uniformly distributed. The anodic oxide growth rate of composite decreased with SiC content increased and linearly increased with anodizing time.

Anodic Oxidation of Carbon Fiber Surfaces: Influence of Static and Dynamic Process Conditions

We investigate the effects of static and dynamic anodic oxidation treatment on the surface chemical composition and functionality of carbon fibers. During static treatment, the electrolytic surface oxidation process is performed on a spatially fixed carbon fiber bundle, while in the dynamic process a moving, continuous carbon fiber tow is oxidized. In both treatment modes electrolytic current density and treatment time were varied. Surface chemical composition and functionality of the resulting carbon fibers were analyzed by x-ray photoelectron spectroscopy. A good agreement between the chemical composition and the functionality of fibers from static and dynamic anodic oxidation treatment is found. This suggests that results from static fiber treatment in a variable, easy to handle laboratory setup can be applied to dynamic anodic oxidation process conditions on a large scale.

Corrosion Resistance and Blood Compatibility of AZ31B Mg Alloy with Anodic Oxidation/TiO2 Composite Film

The anodic oxidation/TiO2 composite film was prepared on the surface of AZ31B Mg alloy by DC magnetron sputtering. The corrosion resistance and blood compatibility of the film were systematically studied by electrochemical, dynamic clotting time and platelet adhesion test. The results shows that the corrosion current of AZ31B Mg alloy was 6.409×10-8A/cm2 after anodic oxidation treatment, which has decreased 4 orders of magnitude compared to the untreated samples and the corrosion resistance is improved greatly. The clotting time of anodic oxidation/TiO2 film is about 53 min, which has increased 1.3 times compared to anodic oxidation film (40min). Platelets adhesion to anodic oxidation/TiO2 film are less than the one adhesion to anodic oxidation film, and there are no pseudopodia and aggregation, which indicate that the blood compatibility of anodic oxidation/TiO2 film is better than anodic oxidation film.

Investigation of the Preparation of Anodized Nanoporous Alumina Array

This study produced a regularly arranged membrane, called anodic aluminum oxide (referred AAO), by mean of anodic oxidation treatment. The structure of AAO can be molecular self-assembly and its pore size is consistent. Also, the manufacturing process cost is low. These properties make the AAO be a nanotemplate material. This study further created a high quality of nanostructured film by electrochemical mould with the design of electrolyzer. In addition, a uniform nanothin film was grown on the aluminum surface in the stable control of current and temperature according to the conditions of different anode treatment. This film can form a nanopore array which the diameter can be controlled the size ranging from 15 nm to 400 nm. As results, the study can produce nanoporous template for various aperture by mean of anodic oxidation.