Incorporation of nanofillers into the organic coatings might enhance their barrier performance, by decreasing the porosity and zigzagging the diffusion path for deleterious species. Thus, the coatings containing nanofillers are expected to have significant barrier properties for corrosion protection and reduce the trend for the coating to blister or delaminate. On the other hand, high hardness could be obtained for metallic coatings by producing the hard nanocrystalline phases within a metallic matrix. This article presents a review on recent development of nanocomposite coatings, providing an overview of nanocomposite coatings in various aspects dealing with the classification, preparative method, the nanocomposite coating properties, and characterization methods. It covers potential applications in areas such as the anticorrosion, antiwear, superhydrophobic area, self-cleaning, antifouling/antibacterial area, and electronics. Finally, conclusion and future trends will be also reported.
This work emphasizes the use of the silver decorative method to enhance the antibacterial activity of TiO2 and ZnO nanoparticles. These silver-decorated nanoparticles (hybrid nanoparticles) were synthesized using sodium borohydride as a reducing agent, with the weight ratio of Ag precursors/oxide nanoparticles = 1:30. The morphology and optical properties of these hybrid nanoparticles were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, and UV-Vis spectroscopy. The agar-well diffusion method was used to evaluate their antibacterial activity against both Staphylococcus aureus and Escherichia coli bacteria, with or without light irradiation. The TEM images indicated clearly that silver nanoparticles (AgNPs, 5–10 nm) were well deposited on the surface of nano-TiO2 particles (30–60 nm). In addition to this, bigger AgNPs (<20 nm) were dispersed on the surface of nano-ZnO particles (30–50 nm). XRD patterns confirmed the presence of AgNPs in both Ag-decorated TiO2 and Ag-decorated ZnO nanoparticles. UV-Vis spectra confirmed that the hybridization of Ag and oxide nanoparticles led to a shift in the absorption edge of oxide nanoparticles to the lower energy region (visible region). The antibacterial tests indicated that both oxide pure nanoparticles did not exhibit inhibitory effects against bacteria, with or without light irradiation. However, the presence of AgNPs in their hybrids, even at low content (<40 mg/mL), leads to a good antibacterial activity, and higher inhibition zones under light irradiation as compared to those in dark were observed.
Article Corrosion of Deicers to Metals in Transportation Infrastructure: Introduction and Recent Developments was published on April 1, 2009 in the journal Corrosion Reviews (volume 27, issue 1-2).
Brackets are the load-bearing components in a satellite. The current age of satellites comprises specific brackets that set out as a link between the bodies of the satellite, reflector parts, and feeder facilities mounted at its upper end. Brackets are used to carry loads of the satellite body frame, supporting elements, batteries, and electronic goods. The article explicates the various brackets used in satellites and aircrafts. The strength of the bracket is of utmost importance since it is an important load supporting member in several assemblies of aircraft and satellites. In addition to the mechanical strength, the weight of the bracket is a major concern as it adds to the total weight of the aircraft and satellite. Thus, weight savings of brackets can be of paramount importance and Additive Manufacturing (AM) is found as an overall solution to achieve the same. Hence, in addition to various brackets used in satellites, the article presents an exhaustive review of the processing of various advanced functional materials using various AM techniques to make high strength-to-weight ratio satellite brackets. The use of DFAM by various satellite manufacturers globally for optimizing the structure of the brackets resulting in a significant weight saving of the brackets is also presented in the article.
1 November 2004 in Journal of Electroanalytical Chemistry