Influence of chromium on the corrosion behaviour of stainless steels in sulphuric acid containing halide ions

The passivation of iron in aqueous media has been investigated over a number of years [1-4.] Bartlett and Stephenson [5] and Froment et al. [6] pointed out that, the anodic deposition of FeSO[4] on iron in sulphuric acid solutions. Krstulonic et al. [7] reported the anodic passivation of Armco iron I in a wide range of sulphuric acid concentration

Electrochemical behaviour of stainless steel in acidic water-ethylene glycol mixture

The corrosion behavior of stainless steel type 304 in acidic solutions of water-ethylene glycol mixtures have been studied by both potentiostatic polarization and weight loss methods at 25. The active passive transition depends strongly on the acid concentration and water content of the medium. The results are interpreted in terms of the dependence of corrosion rate of the metal on the properties of the medium such as viscosity, dielectric constant, solvation and Hammett acidity function

Corrosion and galvanic corrosion of steels in distilled, tap and sea water

Galvanic interaction of 3 G-steels with titanium has been studied in distilled, tap and sea water using current and weights loss measurements for 7 days. The results showed that Ti was a very corrosive resistant material in these solutions and this behavior was not affected by coupling with the different steels. Potentiostatic method was also used to study the effect of chloride on the corrosion behavior of the above steels in the 3 solutions at different temperatures

effect of molybdenum on the corrosion behaviour of stainless steel in acid solution containing halide ions

The corrosion rate of different types of stainless steels in sulphuric acid [1-7N] with and without different additions of 1-, BR-has been measured using potentiostatic and gasometric methods. The results indicated that halide ions adsorbed on the metal surface inhibit the dissolution reaction. The inhibition capacity is more for 1- than Br- than Cl-ions. The addition of Molybdenum to 17 cr. ferritic st. steel significantly decrease the critical current density [Icr] and increase the stability of the passive film

Medium effect on the corrosion behaviour of stainless steel in acidic water-organic solvent mixtures I, st.st. /430 in acidic water-methanol and water-ethanol mixtures

Electrochemical behavior of stainless steel type 430 in acidic solutions of methanol, ethanol and in their binary mixtures with water [covering the whole range from 0 to 100% alcohol] at 25C have been studied. Potentiostatic polarization and weight loss methods were used. The corrosion rate of the metal was influenced by the physicochemical properties of the media such as, viscosity, state of solvation, molar volume contraction, proton availability and dielectric constant. It was demonstrated by the potentiostatic study that the active-passive transition depends strongly on the concentration of the acid, and the water content of the media

Physico-chemical studies of alcohol-water binary systems at different temperatures

Density and viscosity measurements carried out in aqueous binary mixtures of n-propanol, and iso-propanol at different temperatures. The volume contraction either [Delta] or [Delta V] for these systems revealed occurrence of a minimum at X [alc approximately 0.31 indicates the probability of the existence of [1 alcohol: 2 water] molecular complex. Calculation of the deviation of the molar viscosity [Delta neta [M12]] for both mixtures at different compositions gives negative values with a minimum at the same mole fraction of alcohol which supports the existence of the suggested molecular complex. The Eyring's equation for the temperature dependence of viscosity is used to predict enthalpy [Delta H degree] and entropy [Delta S degree] of activation for the flow process. The conclusion is that the behaviour of each alcohol when mixed with water is dependent mainly on its structure

use of Hammett acidity function for the characterization of the corrosion behavior of stainless steel in aqueous and mixed methanol-water media containing acid

The electrochemical behavior of stainless steel [304 and 316] has been investigated in aqueous solutions of hydrochloric acid and in acidic mixed methanol-water solvents. The comparison of the results obtained in different concentrations would be questionable if the main physicochemical properties of the solutions were not vigorously defined. In the case of acidity which is one of the most important parameters for comparison of the corrosion mechanism, the use of the Hammett acidity function, Ho, is more suitable than scale in the organic mixed solvents. This study pointed out that Hammett acidity function, may be a correct measurement of the acid strength of the proton, is the main factor governing the corrosion phenomenon

Effect of some organic additives on the pitting corrosion of stainless steel in sulphuric acid solutions containing Cl-Ions

The effect of some organic additive on pitting corrosion of stainless steel type 304 in H2SO4 solution containing CI-ions has been studied. From the results, the effect of the additives are classified into three groups, the first group comprises the compounds which inhibit both the active dissolution and pitting corrosion of the steel. The second group is characterized by retarding the active dissolution of the stainless steel, but catalyzing the pitting attack. The third group enhance both the dissolution and the pitting potentials