Materials Letters 

About: Materials Letters is an academic journal. The journal publishes majorly in the area(s): Thin film & Microstructure. It has an ISSN identifier of 0167-577X. Over the lifetime, 31426 publication(s) have been published receiving 570466 citation(s). The journal is also known as: Materials Letters: X.

Glycine-nitrate combustion synthesis of oxide ceramic powders

Abstract: A new combustion synthesis method, the glycine-nitrate process, has been used to prepare oxide ceramic powders, including substituted chromite and manganite powders of high quality. A precursor was prepared by combining glycine with metal nitrates in their appropriate stoichiometric ratios in an aqueous solution. The precursor was heated to evaporate excess water, yielding a viscous liquid. Further heating to about 180°C caused the precursor liquid to autoignite. Combustion was rapid and self-sustaining, with flame temperatures ranging from 1100 to 1450°C. The chromite product was compositionally homogeneous with a specific surface area of 32 m2/g, while the manganite product was composed of two distinct phases with a 23 m2/g surface area after calcination. When compared to similar compositions made using the amorphous citrate process, glycine-nitrate-produced powders had greater compositional uniformity, lower residual carbon levels and smaller particle sizes.

Biological synthesis of silver nanoparticles using the fungus Aspergillus flavus

Abstract: The fungus, Aspergillus flavus when challenged with silver nitrate solution accumulated silver nanoparticles on the surface of its cell wall in 72 h. These nanoparticles dislodged by ultrasonication showed an absorption peak at 420 nm in UV–visible spectrum corresponding to the plasmon resonance of silver nanoparticles. The transmission electron micrographs of dislodged nanoparticles in aqueous solution showed the production of reasonably monodisperse silver nanoparticles (average particle size: 8.92 ± 1.61 nm) by the fungus. X-ray diffraction spectrum of the nanoparticles confirmed the formation of metallic silver. The Fourier transform infrared spectroscopy confirmed the presence of protein as the stabilizing agent surrounding the silver nanoparticles. These protein-stabilized silver nanoparticles produced a characteristic emission peak at 553 nm when excited at 420 nm in photoluminescence spectrum. The use of fungus for silver nanoparticles synthesis offers the benefits of eco-friendliness and amenability for large-scale production.

Natural products as corrosion inhibitor for metals in corrosive media — A review

Abstract: The use of inhibitors for the control of corrosion of metals and alloys which are in contact with aggressive environment is an accepted practice. Large numbers of organic compounds were studied and are being studied to investigate their corrosion inhibition potential. All these studies reveal that organic compounds especially those with N, S and O showed significant inhibition efficiency. But, unfortunately most of these compounds are not only expensive but also toxic to living beings. It is needless to point out the importance of cheap, safe inhibitors of corrosion. Plant extracts have become important as an environmentally acceptable, readily available and renewable source for wide range of inhibitors. They are the rich sources of ingredients which have very high inhibition efficiency. This article gives a vivid account of natural products which are used as corrosion inhibitors for various metal and alloys in aggressive media.

Effect of molecular weight on fibrous PVA produced by electrospinning

Abstract: The effects of polymer weight average molecular weight (MW) on the fiber structure of electrospun polyvinylalcohol (PVA) have been studied. PVA with a degree of hydrolysis of 98–99% and with molecular weights ranging from 9000 to 186,000 g/mol was dissolved in water. The concentration (C) of the polymer in the solution was varied depending on the molecular weight. The solution was electrospun at 30 kV and the sample obtained on the collector was examined by scanning electron microscopy. It was observed that for each molecular weight, a fibrous structure was stabilized above a minimum concentration, generally corresponding to [η]C>5. The average fiber diameter was between 250 nm and 2 μm. The fiber diameter increases with MW and concentration. At low MW and/or concentrations ([η]C 9).

A novel combustion process for the synthesis of fine particle α-alumina and related oxide materials

Abstract: Synthesis of fine particle α-alumina and related oxide materials such as MgAl2O4, CaAl2O4, Y3Al5O12 (YAG), Image , β′-alumina, LaAlO3 and ruby powder (Image ) has been achieved at low temperatures (500°C) by the combustion of corresponding metal nitrate-urea mixtures. Solid combustion products have been identified by their characteristic X-ray diffraction patterns. The fine particle nature of α-alumina and related oxide materials has been investigated using SEM, TEM, particle size analysis and surface area measurements.