A .A.Khedr
,
I.Z.Selim
,
K.M.El-Sobki and O.S.Shehata(Physical Chemistry Dept.
,
National Research Centre
,
Dokki
,
Cairo
,
Egypt)
材料科学技术（英文）
Electrochemical behaviour of stainless steel type 430 in acidic solutions of methanol, ethanol and in their binary mixtures with water (from 0 to 100% alcohol) at 25℃ has been studied. using potentiostatic poIarization technique and weight loss method. It was found that the corrosion rate of the metal was affected by the physico-chemical properties of the media such as, viscosity, state of solvation, molar volume contraction, proton availability and dielectric constant, it was demonstrated from the potentiostatic study that the active passive transition strongly depended on the concentration of the acid, and on the water content of the media.
关键词:
V.K.Gouda
,
I.Z.Selim
,
A.A.Khedr
,
A.M.Fathi
材料科学技术（英文）
Pitting corrosion behavior of Monel-400 alloy in 3.5 wt pct NaCl sodium chloride solution has been investigated using the cyclic potentiodynamic anodic polarization technique. The effects of chloride ion concentration, pH values and different temperatures on the pitting parameters were determined. The morphology of the pits produced after anodic polarization treatments were inspected by scanning electron microscope (SEM). The results indicated that, the increase in chloride ion concentration shifts Epit and Eprot of the alloy toward negative values and the pitting potential is much more dependent on pH value in the basic region. The breakdown of passivity with increasing temperature may be due to kinetic changes of passivating films and dissolution rate of the alloy in its passive state.
关键词:
Z.A.El-Hadi
,
N.S.Tantawi
,
I.Z.Selim
材料科学技术（英文）
Electrochemical and corrosion behaviour of reinforced steel embedded in cement pastes incorporating different amounts of silica fume as a partial replacement of cement has been studied in chloride and sulphate solutions by using different electrochemical techniques. The results indicate that, while steel passivity degree is low in the control samples upon soaking in the corrosive media, it has been high in samples incorporating silica fume and increased with increasing silica fume content. The improvement effect of silica fume may be attributed to the pore solution structure of the cement paste, which limits the mobility of aggressive ions near the surface of the steel. The mechanism of steel corrosion due to chloride and sulphate attack and passivation effect of silica fume are discussed.
关键词:
Corrosion
,
null
,
null
,
null
,
null
