Showing 5 results for Saremi
Dehghanian C., Saremi M., Mohammadi Sabet M.,
Volume 2, Issue 1 (Oct 2005)
Abstract
The synergistic behavior of molybdate and phosphate ions in mitigating the corrosion of mild steel in simulated cooling water was evaluated performing potentiodynamic polarization and impedance spectroscopy tests. Phosphate and molybdate showed a synergistic effect on corrosion inhibition of steel in simulated cooling water. The observed reduction in anodic and cathodic current densities could be the consequence of incorporation of both phosphate and molybdate ions in forming a protective layer on the surface. The charge transfer resistance of the protective layer formed on steel surface was much greater in presence of both ions in solution than that when each inhibitor used alone.
Saremi M., Nouri Delavar A., Kazemi M.,
Volume 2, Issue 4 (Jul 2005)
Abstract
An investigation of the electrochemical noise generation during Stress Corrosion Cracking (SCC) of 70-30 Brass in Mattson's solution was conducted. The fluctuations of potential and current were monitored. The relationship between potential and current fluctuations has been evaluated in time domain and the obtained data has been analyzed in the frequency domain using Power Spectral Density (PSD). It is shown that 70-30 Brass has characteristic noise behavior during SCC that is step-by-step change in current and potential up to the final stage of fracture, and this may be used for SCC monitoring.
Saremi M., Motaghi Golshan B.,
Volume 3, Issue 3 (Jul 2006)
Abstract
A film of osteoconductive and biocompatible material on biomedical metallic implants can create bioactivity of the implant and shorten healing time. Hydroxyapatite, that is the most important mineral part of human bone, was coated on Ti6Al4V using cathodic electrode position process. Pulse electrode position technique was used and the effects of different parameters such as potential, duty cycle (on time/ (on time+ off time)), temperature and current density on the morphology of the deposits were examined. Nano size deposits were formed under controlled temperature and optimization of voltage and current density.
S. Ahmadi,, H. R. Shahverdi*, S. S. Saremi,
Volume 7, Issue 4 (Autumn 2010 2010)
Abstract
Abstract: In this research work, crystallization kinetics of Fe55Cr18Mo7B16C4 alloy was evaluated by X-ray diffraction, TEM observations and differential scanning calorimetric tests. In practice, crystallization and growth mechanisms were investigated using DSC tests in four different heating rates. Results showed that a two -step crystallization process occurred in the alloy in which - Fe phase was crystallized in the first step after annealing treatments. Activation energy for the first step of crystallization i.e. - Fe was measured to be 276 (kj/mol) according to Kissinger model. Further, avrami exponent calculated from DSC curves was 2 and a three -dimensional diffusion controlled mechanism with decreasing nucleation rate was observed in the alloy. It is also known from the TEM observations that crystalline á – Fe phase nucleated in the structure of the alloy in an average size of 10 nm and completely mottled morphology.
Z. Valefi, M. Saremi,
Volume 14, Issue 2 (June 2017)
Abstract
In this paper the effect of plasma spray parameters, atomizing gas and substrate preheat temperature on microstructure and phase composition of YSZ coatings produced by SPPS process have been investigated. The experimental results showed that increasing the power of plasma, using hydrogen as the precursor atomizing gas and increasing substrate preheat temperature decrease the amount of non-pyrolyzed precursor in the coatings. At low plasma power most of the deposited precursor is in non-pyrolyzed state, and consequently the applied coatings are defective. The increase in substrate temperature beyond 800oC either by preheating or heat transfer from plasma torch to the substrate, prevent the coating formation. In SPPS coating formation, up to a special spray distance the optical microscopy image of the coatings showed a snowy like appearance. XRD analysis showed that in this situation the amount of un-pyrolyzed precursor is low. Beyond this spray distance, spherical particles, are obtained and XRD analysis showed that most of the precursor is in un-pyrolyzed state.
