In this work, iron chloride (FeCl3.6H2O), a single reagent, was used to create the phases of hematite (α-Fe2O3) and akaganeite (β-FeOOH) without the need of organic solvents using the microwave-assisted hydrothermal technique (HM). X-ray diffraction demonstrated the efficacy of the HM technique in the generation of crystalline phases of α-Fe2O3 at 180oC and β-FeOOH at 120oC. The development of pseudo-cunic and stick-like particles was a result of changes in experimental variables, which also had a substantial impact on the materials structural characteristics. The nitrogen (N2) adsorption/desorption isotherms of the samples containing akaganeite and hematite phase resembled those of mesoporous materials. Hematite has a surface area of 25.44 m2 g-1, while akaganeite has a surface area of 110.60 m2 g-1, according to the calculation. Thermodifferential and thermogravimetric techniques were used to assess thermal degradation. The use of microwave hydrothermal synthesis was promoted as being quick, easy, affordable, and safe for the environment. work FeCl3.6H2O, FeCl36H2O FeClHO FeCl3.6H2O , FeCl3 6H2O FeCl H O (FeCl3.6H2O) reagent αFe2O3 αFeO α Fe2O3 Fe (α-Fe2O3 βFeOOH β FeOOH (β-FeOOH microwaveassisted assisted HM. . (HM) Xray X ray α-Fe2O oC 120oC pseudocunic pseudo cunic sticklike stick like variables characteristics N2 N (N2 adsorptiondesorption adsorption desorption 2544 25 44 25.4 m g1, g1 g 1, 1 g-1 11060 110 60 110.6 calculation degradation quick easy affordable environment HO (FeCl3.6H2O αFe αFe2O FeO Fe2O (α-Fe2O (HM (N 254 2 4 25. g- 1106 11 6 110.

Low carbon steel was exposed at two sites in Mauritius, namely Port Louis and Belle Mare. The site at Port Louis is basically an industrial marine one whereas the one at Belle Mare is a purely marine site. Though the corrosion loss trend at both sites follow the power law, the corrosion loss at Port Louis was found to be higher than that at Belle Mare. This study has been performed to investigate the surface characteristics of the rust layers of the samples exposed at the two sites, through Raman spectroscopy and SEM, so as to get a better insight into the mechanism of the atmospheric corrosion process. For Port Louis, it was observed that there was not much change in the corrosion products in the rust layer over the 3 years period. The structure was less compact than that at Belle Mare with the presence of lepidocrocite and akaganeite as commonly observed corrosion products. The corrosion rate at Port Louis is, therefore, expected to follow the same trend over the long term. For Belle Mare, the corrosion products changed significantly after 3 years of exposure. Though lepidocrocite and akaganeite were observed on the surface after 0.2 years of exposure, magnetite was the most probable corrosion product in the more compact rust layer after 3 years of exposure. This compactness of the rust layer is expected to have reduced the corrosion rate as compared to that of Port Louis. Significant changes in the corrosion rate at Belle Mare are, therefore, expected over the medium and the long term.

Foi realizada uma investigação durante seis meses em sete atmosferas marinhas com velocidades de deposição de cloretos (salinidades) médias compreendidas entre 41 e 886 mg Cl-/m².dia. O presente trabalho considera a influência do avanço do aerosol marinho e a variação exponencial entre os valores da salinidade atmosférica e a distância à costa. Apresenta também a velocidade de corrosão do aço macio e os produtos e camadas de corrosão resultantes e a sua dependência da salinidade atmosférica local. A caracterização dos produtos de corrosão foi realizada por microscopia electronica de varrimento (MEV) e difracção de raios X (DRX). Para além da lepidocrocite e goetite (maiores teores), foram ainda encontradas akaganeite e magnetite (menores teores), principalmente na interface aço/ferrugem.

Research has been carried out for 6 months in seven pure marine atmospheres with average chloride deposition rates (salinities) of 41-886 mg Cl-/m².day. The paper considers the entrainment of marine aerosol inland and the exponential relationship between the atmospheric salinity values and the shore distance. The paper also considers mild steel corrosion rate and the resulting corrosion products and layers, and its dependence of atmospheric salinity of the site. Characterization of corrosion products was performed by SEM and XRD. In addition to lepidocrocite and goethite (major contents), high akaganeite and magnetite (minor contents) were found in the corrosion products, the latter ones found mainly at the steel/rust interface.

El refinamiento del espectro Mössbauer, i.e. la asignación del número correcto de componentes espectrales y su origen físico, ha sido por mucho tiempo un tema controversial en el caso de la akaganeita. La mayoría de las interpretaciones están basadas en la estructura tetragonal reportada anteriormente, y muy pocas en la recientemente reportada estructura monoclínica. Por otro lado, la estructura magnética se ha propuesto como colineal antiferromagnética, esperomágnetica ó asperomágnetica. En esta reseña revisamos críticamente algunos de los trabajos que se han hecho hasta la fecha y se esbozan futuros estudios experimentales y teóricos necesarios para conocer mejor la estructura magnética de la akaganeita.

The refinement of the Mössbauer spectra, i.e. the assignation of the correct number of spectral components and their physical origin, has been a long controversy in the case of akaganeite. Most interpretations are based upon the earlier reported tetragonal structure, and very few upon the recently reported monoclinic structure. On the other hand, the magnetic structure has been proposed to be collinear antiferromagnetic, speromagnetic or asperomagnetic. In this paper we critically revise some of the works that have been done to date and outline future experimental and theoretical studies required to gain a better understanding of the magnetic structure of akaganeite.