A simple, easy, and rapid process of fabricating superhydrophobic surfaces on magnesium alloy AZ31 by a one-step immersion at room temperature was developed. The myristic acid-modified micro-/nanostructured surfaces showed static water contact angles over 150° and water contact angle hysteresis below 10°, thus illustrating superhydrophobic property. The shortest treatment time for obtaining the superhydrophobic surfaces was 30 s. In addition, we demonstrated for the first time that crystalline solid myristic acid could be formed on a Mg alloy using a suitable molar ratio of Ce ions and myristic acid. The contact angle hysteresis was lowered with an increase in the immersion time. Potentiodynamic polarization curve measurements revealed that the corrosion resistance of AZ31 treated by the immersion process improved considerably by the formation of superhydrophobic surfaces. The chemical durability of the superhydrophobic surfaces fabricated on AZ31 was also examined. The static water contact angle values for the superhydrophobic surfaces after immersion in aqueous solutions at pHs 4, 7, and 10 for 12 h were estimated to be 90 ± 2°, 119 ± 2°, and 138 ± 2°, respectively, demonstrating that their chemical durability in a basic solution was high.

Al alloys offer excellent physical and mechanical properties, such as a low density, high specific strength, and good ductility. However, their low corrosion resistance has restricted their application in corrosive environments. There is a need, therefore, for a novel coating technology that is capable of improving the corrosion resistance of Al alloys. In the present study, we examined a steam-based method of forming a corrosion-resistant film on Al alloys. Al-Mg-Si alloy was used as the substrate. The cleaned substrates were set in an autoclave with ultrapure water as the steam source and processed using different temperatures and holding times, resulting in the formation of anticorrosive films on the alloy. FE-SEM images of the film surfaces showed that plate-like nanocrystals were densely formed over the entire surface. XRD patterns indicated that the film was composed mainly of AlOOH crystals. The potentiodynamic polarization curves revealed that the corrosion current density of the film-coated substrates significantly decreased, and that the pitting corrosion was completely suppressed, indicating that the corrosion resistance of the Al-Mg-Si alloy was improved by the film formed by means of steam coating.

Corrosion-resistant films were fabricated on AlZnMg alloy by steam coating using an acidic aqueous solution of Zn(NO 3) 2 at different concentrations. X-ray diffraction patterns and Fourier transform-infrared spectrometer spectra demonstrated that nitrate-type ZnAl layered double hydroxide (LDH) and ZnO films were formed on the AlZnMg surface by steam coating at temperatures of 373, 433, and 473 K, using Zn(NO 3) 2 aqueous solution at 1000 mM. At 513 K, £-AlO(OH) films were formed on the AlZnMg surface by steam coating using 1 to 100 mM Zn(NO 3) 2 aqueous solution. The corrosion resistance of the films was investigated by potentiodynamic polarization curve measurements, which revealed that the £-AlO(OH) films prepared by steam coating at 513 K using 1 mM of Zn(NO 3) 2 aqueous solution was the most effective treatment for suppression of pitting corrosion and anodic current density.

Superhydrophobic film was prepared on magnesium alloy AZ31B by one-step immersion process for 30 min. The solution for immersion process was composed of an aqueous solution containing Ce(NO 3 ) 3 and ethanol containing myristic acid. The water contact angle of the prepared film was more than 150 degree and found to be superhydrophobic. The film was composed mainly of crystalline myristic acid. The corrosion behavior of the superhydrophobic film in 5 mass% NaCl aqueous solution were investigated by polarization curve. The corrosion resistance was considerably improved by preparing the superhydrophobic film. In addition, the corrosion process of the superhydrophobic AZ31B was also investigated using XRD, SEM, and water contact angle measurement.

Hyperthermia is a promising cancer therapy due to its minimally-invasive procedure, and the cancer therapeutic efficacy can be improved by magnetic hyperthermia combined with pharamacotherapy. Iron oxide (IO) nanoparticle is a popular medium for hyperthermia treatment, and hydroxyapatite (HA) has been widely used for bone filling and augmentation. IO nanoparticle embedded on hydroxyapatite (HAIO) was synthesized through co-precipitation method, and chitosan or poly (N-isopropylacrylamide) (PNIPAAM) were coated on the HAIO with calcium alginate to form the spheres (Chitosan coated HAIO and PNIPAAM coated HAIO). HAIO, Chitosan coated HAIO and PNIPAAM coated HAIO were used as carriers of 5-fluorouracil (5-FU), one of the drugs for cancer chemical therapy, and the 5-FU release behavior in PBS solution was investigate at ambient and elevated temperatures. The amount of the released 5-FU from the HAIO, Chitosan coated HAIO and PNIPAAM coated HAIO are almost the same at ambient temperature. But at elevated temperature, that from Chitosan coated HAIO was reduced while that from the PNIPAAM coated HAIO was increased.