Synthesis and Mössbauer characterization of Cu and Cr doped magnetites

Abstract

A detailed Móssbauer investigation of magnetites prepared under different hydrothermal conditions and doped with Cu and Cr is presented. The samples were characterized by means of room temperature Móssbauer spectrometry, infrared spectroscopy, and X-ray diffraction. Móssbauer results show that the hydrothermal method produces highy stoichiometric and relativelly well-crystallized magnetites. The results suggest that the best samples are obtained when the alkaline solution is added quickly to the ferrous solution. It was also found that mixing the solutions under constant ultrasonic stirring produce magnetites with slightly better crystallinity and stoichiometry than the samples produced under magnetic or nitrogen bubbling stirring. The effect of the Cu and Cr on the hyperfine parameters is also presented and discussed.

Influence of Surface Treatment on Magnetic Properties of Fe3O4 Nanoparticles Synthesized by Electrochemical Method

“…In order to determine the degree of oxidation through the Mössbauer spectra results, first it is necessary to consider the ratio of subspectral areas of sites A and B at room temperature ( R = Area (A)/Area (B)). Second, the relationship proposed by Barrero . This can determine the oxidation parameter x = (2 R – 1.06)/(5.3 + 6 R ), which is also shown in Table .…”

In-Situ Detection of Early Corrosion of Ferritic Cr-Mo Steel in Aqueous Solutions of different Anions using Laser Raman Spectroscopy

“…This transport depends on the grain size, crystal structure, chemical stability, and porosity of the rust. Further, it is known that alloying elements like chromium and manganese play an important role in the formation of corrosion products [69][70][71] as they can hinder nucleation and growth of magnetite 69 and promote stable goethite formation 70 and refinement of rust grains 71 that reduces corrosion. Thus, this study demonstrates the better corrosion resistance of the modified 9Cr-1Mo steel with 9% Cr through faster goethite formation as compared to CS.…”

Effects of Alloying Elements (Cr, Mn) on Corrosion Properties of the High‐Strength Steel in 3.5% NaCl Solution

“…As an alloying element, manganese not only impedes the formation of magnetite [31,32] but also encourages the formation of refined goethite. Chromium hinders magnetite's nucleation [33] and growth [34], while it promotes the nucleation [33] and growth [35] of goethite and refinement of grain [36]. Both manganese and chromium improve corrosion resistance of steel; however, chromium has a greater effect than manganese [36].…”