Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : ferrite

Synthesis and Studying Dielectric Properties of Mixed Nanoferrites

Zainab I. Dhary; Mohammed S. Hamza; Fadhil A. Chyad

Engineering and Technology Journal, 2015, Volume 33, Issue 1, Pages 154-164

Based on a low temperature route (sol-gel autocombustion) a nano-ferrite CoFe2O4and Li0.5Fe2.5O4 and different percentages of cobalt-ferrite are synthesized. The crystalline structure by XRD and dielectric properties with TEM micrographs are presented. The XRD (crystallite size and lattice parameter) are determined which affected by cobalt content. TEM micrographs show a nano-particles in the range of (8-20) nm which correlate with crystallite size. Dielectric properties (dielectric constant, loss tangent and dielectric loss factor) are decreased with frequency and cobalt content.

The Influence of Microstructure on the Corrosion Rate of Carbon Steels

Sami I. Al-rubaiey; Eman A. Anoon; Mahdi M. Hanoon

Engineering and Technology Journal, 2013, Volume 31, Issue 10, Pages 1825-1836

This paper presents the influence of carbon steel microstructure on the corrosion rates. Four types of microstructures have obtained by quenching and tempering and iso-thermal annealing. These microstructures are:
banded ferrite/pearlite microstructure, fine ferrite/pearlite microstructure, coarse ferrite/pearlite microstructure and tempered martensite microstructure.
General corrosion and localized corrosion (penetration rates) were determined via mass loss and optical microscopy. The different microstructures of steels investigated in this paper revealed corrosion rate variations of 0.8– 3.2 mm y-1 and 3.3–6.4 - mm y-1 for the general and localized forms, respectively. The corrosion stability of the various microstructures may arise from variations of phases within the steel. A banded ferrite/pearlite microstructures have worse general corrosion properties, while tempered martensite worse microstructures have localized pitting corrosion properties. Coarse ferrite/pearlite microstructures have better localized pitting corrosion resistances compared to others investigated microstructures This paper has demonstrated that, microstructure is an important consideration when selecting carbon steel for an industrial corrosion resistance application.