A. Azimi Dastgerdi, F. Ashrafizadeh, M. R. Toroghinejad, F. Shahriari , H. Zahraei,
Volume 30, Issue 2 (Dec 2011)
Abstract
In this paper, bare spot defects in hot-dip galvanized sheets were studied in terms of the microstructure and their influence on the corrosion and mechanical properties. Surface characteristics and microstructural features were examined by scanning electron microscopy equipped with energy dispersive spectroscopy microanalysis system. The results showed that the major cause of the bare spots was the lack of wetability of the sheet surface due to contamination, improper heat treatment or chemical composition. Corrosion resistance was evaluated by standard salt spray test. Mechanical properties were examined by tensile testing. The time to red rust was much shorter on the bare spots as compared to other regions, but it appeared that bare spot defects had no significant effect on the mechanical properties of the galvanized steel sheets.
S. Faraji, Gh. Dini, M. Zahraei,
Volume 37, Issue 1 (Journal of Advanced Materials-Spring 2018)
Abstract
Manganese ferrite nanoparticles (NPs) have different applications, especially in medical diagnosis and treatment as well as the biomolecule separation,. In this research, the effects of various parameters such as the pH of reaction solution and the hydrothermal process duration on the synthesis of spinel phase in NPs were evaluated. Crystal structure, chemical composition, morphology and size of synthesized particles were investigated by the X-ray diffraction (XRD) analysis and field-emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectroscopy (EDS). The XRD results showed that the process duration of 12 h and pH=11 were suitable for the formation of monophase manganese ferrite NPs. The FE-SEM investigations showed that the average size of the synthesized NPs was about 50 nm. Moreover, the EDS analysis showed the presence of about 20% of manganese in the NPs structure. Hydrothermally synthesized manganese ferrite NPs in this researchcould be, therefore, a good candidate for the biomedical application due to their small size and narrow size distribution.
