No abstract

The effect of phenylthiourea as a corrosion inhibitor for low carbon steel at different hydrochloric acid concentrations, different temperatures and fixed speed of electrode rotation, were addressed in this work. Polarization technique was used to evaluate the corrosion rates parameters. The corrosion rate of low carbon steel increases with temperature and follows Arrhenius equation in all acid concentrations in presence and absence of the inhibitor. Detailed thermodynamic parameters of activation (∆H act and ∆S act) for the corrosion reaction were obtained using nonlinear estimation method, while adsorption parameters (∆G ads , ∆H ads and ∆S ads) were obtained using graphical method. Maximum inhibitor efficiency was (96.44%) obtained at 1 M HCl at 333 K and 1 g/L inhibitor concentration.

Problem statement:The effect of different temperatures and acid concentrations on the corrosion of low carbon steel in hydrochloric acid were addressed in this study. Approach: The effect of temperature was explained by application of Arrhenius equation and transition state theory, while the acid concentration effect was explained using reaction kinetic equations. The combined effect of temperature and acid concentration then modeled using a nonlinear regression method. Results: A detail of thermodynamic parameters of activation (E, ∆H * and ∆S * ) and kinetic studies for the corrosion reaction were obtained. Nonlinear corrosion rates as a function of temperature and acid concentration equation were estimated with a good prediction corrosion rates values. Conclusion: The values of activation energy E and enthalpy of activation ∆H* decrease with increase in acid concentration indicating the increasing in reaction rate. Entropy of activation ∆S * tend to lower values with increasing in acid concentration which indicated that the activated complex was more orderly relative to the initial state. The corrosion reaction was approximately firs order reaction. The observed corrosion rate values from the experimental data were in a good agreement with that predicated by the mathematical equation.

The inhibition of copper corrosion by Benzotriazole (BTA) in 5% HCl has been investigated by weight loss technique at different temperatures. Langmuir adsorption isotherm, Freundlich Adsorption Isotherm and Kinetic-Thermodynamic Model were used to describe the adsorption process depending on values of surface converge. Maximum value of surface converge was 0.998 for BTA at 35 o C and 15 g/l inhibitor concentration, while the lower value was 0.868 at 55 o C and 1 g/l inhibitor concentration. The films formed on the copper-nickel alloy surface of BTA appeared to obey the Langmuir Adsorption Isotherm more than Freundlich adsorption isotherm. In the other hand, results showed that the Kinetic-Thermodynamic Model was unsuitable to fit the experimental data of the BTA of the present study.

Purpose -The aim of this paper is to investigate peach juice as a cheap, raw, green and non-toxic anti-corrosion material for mild steel corrosion in hydrochloric acid at different temperatures. Design/methodology/approach -The corrosion inhibition of mild steel in 1 M HCl solution in the presence of peach juice at temperature range of 30-608C and concentration range of 5-50 cm 3 /l was studied using weight loss and polarization techniques. The inhibition effect, adsorption characteristics, mathematical and electrochemical modeling of peach juice were addressed. Findings -Results show that inhibition efficiency rose with the increase of inhibitor concentration and temperature up to 508C, while at temperatures above 508C the values of efficiency decreased. The inhibitor adsorbed physically on metal surface and followed the Langmuir adsorption isotherm. Monolayer formed spontaneously on the metal surface. Maximum inhibition efficiency obtained was about 91 percent at 508C in the 50 cm 3 /l inhibitor concentration. Originality/value -This work is an attempt to find a new, safe to environment, non-toxic corrosion inhibitor. Peach juice is a readily available material in Iraq and Middle East markets.

No abstract

No abstract

No abstract