Corrosion Protection of Monel Alloy Coated with Graphene Quantum Dots Starts with a Surge

There has been an active interest in protecting metals and alloys using graphene coating. The mechanism by which corrosion protection occurs has not been well understood as the couple involved are both good electron conductors. In this work, we demonstrate that Monel alloy coated with graphene quantum dots (GQD) changes the corrosion rate with a surge (increase) caused by the galvanic coupling of the two materials. This surge results in the protective layer formation on Monel to inhibit the corrosion. X-ray fluorescence spectrum of Monel (400) alloy showed the composition of it as Ni (67.05%) and Cu (29.42%). The Tafel experiments carried out in NaCl and Na2SO4 electrolytes showed an initial enhancement of the corrosion rate followed by a decrease upon successive polarizations. Monel coated with graphene oxide (an insulator) shows no initial enhancement of corrosion rate; the coated samples showed a lower corrosion rate in comparison to the uncoated samples. X-ray fluorescence, Fourier Transform spectroscopy (FTIR) and Raman imaging studies have been carried out for understanding this transformation. Distinct peaks due to Ni-O stretching and Ni-O-H bending vibration were observed in the FTIR spectrum

Effect of Nanostructure on the Thermal Oxidation of Atomized Iron

The effect of nanostructure on the thermal oxidation of atomized iron has been investigated. Above 500oC atomized iron is oxidized in the presence of air. However, when iron is compacted with multiwalled carbon nanotubes (MWCNT) this oxidation is shifted by more than 100oC. Iron is protected by the nanostructure environment A large number of compositions of atomic ratios of iron and MWCNT have been examined in this study to understand the effect in detail. The effect of nanostructure in the thermal oxidation of iron is interpreted as due to iron atom experiencing extensive overlap and confinement effect causing spin transfer. Based on the theoretical calculations reported in the literature this confinement effect of iron is suggested to produce a transformation from 3d64s2 to an effective configuration of 3d84s0 producing spintronics effect. (Refer to PDF file for exact formulas)

Evaluation of Natural Plant Powders with Potential Use in Antimicrobial Packaging Applications

This study investigates the antimicrobial effects of vanillin, turmeric and curcumin in the forms of Dimethyl Sulfoxide (DMSO) solution as well as polymer packaging. Five types of common pathogens and food spoilage bacteria were used in this study: Staphylococcus aureus and Listeria monocytogenes representing gram-positive bacteria; Shigella sonnei, Salmonella typhimurium as well as E.coli O157:H7 representing gram- negative bacteria. Turmeric is chosen as the antimicrobial agent to be incorporated into packaging materials. In order to study the antimicrobial effect as packaging application, two types of the polymer based turmeric products were produced. They are LDPE based turmeric pellets produced by a single screw extruder, and turmeric coated BOPP films. Finally, a comparison on antimicrobial effect was conducted. between two solvents regent alcohol and DMSO