Aprael S. Yaro

Peach juice as an anti‐corrosion inhibitor of mild steel

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 30‐60°C and concentration range of 5‐50 cm3/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 50°C, while at temperatures above 50°C 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 50°C in the 50 cm3/l inhibitor concentrat...

ADSORPTION MECHANISM OF BENZOTRIAZOLE FOR CORROSION INHIBITION OF COPPER-NICKEL ALLOY IN HYDROCHLORIC ACID

ABSTRACT 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 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. Keywords: adsorption isotherms, corrosion inhibition, copper-nickel alloy, benzotriazole, inhibitor efficiency INTRODUCTION Copper and its alloys are commonly employed as a material in heating and cooling systems due to their good thermal conductivity and mechanical properties. Hydrochloric acid pickling is extensively used for the removal of rust and scale on heat transfer in several industrial processes. However, these systems should be regularly cleaned from carbonates and oxides that diminish their heating transmission. Diluted hydrochloric acid is used to clean these surfaces; a corrosion inhibitor is added to avoid the action of this acid on copper. Corrosion inhibitor is a chemical substance when it is added with little concentration to environment effectively checks, decreases or prevents the reaction of metal with environment

Modeling of corrosion inhibition of copper-nickel alloy in hydrochloric acid by benzotriazole

The corrosion inhibition of copper-nickel alloy by benzotriazole (BTA) in 1.5 M HCl has been investigated by weight loss and polarization techniques at different temperatures. Maximum value of inhibitor efficiency was 99.8% at 35°C and 0.1 M inhibitor concentration, while the lower value was 86.3% at 65°C and 0.02 M inhibitor concentration. The activation energy values were higher in presence of BTA which indicate that in presence of inhibitor, corrosion reaction requires more energy to occur. Two mathematical models were used to represent the weight loss corrosion rate data with high correlation coefficients. Electrochemical polarization measurements showed that BTA is a mixed type inhibitor.

Protection of low carbon steel in phosphoric acid by potassium iodide

The corrosion of low carbon steel in 2.5 M phosphoric acid at temperature range of 30–60°C in presence and absence of potassium iodide as an inorganic inhibitor in the range of 0.02–0.05 M at static condition has been investigated. Weight loss and polarization techniques were employed in this investigation. The maximum value of inhibitor efficiency obtained was 99.95% at 50°C in presence of 0.05 M inhibitor concentration. The fraction of surface covered calculated from corrosion rates followed the Langmuir adsorption isotherm. Polarization experiments showed that for a given temperature, the curves were shifted towards the potential axis leading to lower the corrosion rates as the inhibitor concentration increased. Potassium iodide inhibits carbon steel corrosion in H3PO4 acid by affecting both anodic and cathodic partial reactions with the anodic reaction being more prevailing.

Polarisation resistance behaviour of corrosion inhibition of low carbon steel in H3PO4 acid

The non-linear region of polarisation curve near the corrosion potential can be discussed depending on data of over potential as a function of current densities. These data can be analysed by suggesting a mathematical model taking into account the effect of mass transfer on activation process. This model was used to evaluate the values of polarisation resistance Rp in presence and absence of potassium iodide (KI) as a corrosion inhibitor of low carbon steel in 2.5 M phosphoric acid at different temperatures. The values of polarisation resistance obtained by mathematical model compared with these obtained by Tafel parameters. The suggested s-model was very useful in evaluating the values of Rp. The maximum value of polarisation resistance was 5049.13 Ωcm² at 30°C in presence of 0.05 M KI, while the minimum value was 1.885 Ωcm² at 60°C in absence of KI. These results indicate that the polarisation resistance values increased with the increase of KI concentration, and decreased with the increase of temperature.

Study for prevention of steel corrosion by sacrificial anode cathodic protection

Corrosion of steel tube in sea water was controlled by cathodic protection. Sacrificial anode technique was used. In this technique, weight loss method was used to determine the rate of zinc consumption as a function of temperature, time, pH and solution velocity. Reaction kinetics studies showed that the rate of zinc consumption was first order. Activation parameters were obtained from Arrhenius equation and transition state equation. Two mathematical models were suggested to represent the consumption data. Statistical analysis proved that the second-order multi-terms model was better than the one-term model.

Mathematical model for cathodic protection in a steel-saline water system

Abstract The corrosion of steel tubes in sea water was controlled by cathodic protection. The impressed current technique was used. The rate of reaction was evaluated as a function of the temperature, pH and solution velocity. In this technique, the polarization method was used to determine the protection potential and current. The rate of zinc consumption, the protection potential, and the protection current are highly dependent on the variables of the study. The boundary element technique was suitable for modelling corrosion problems. The average percentage of error among the experimental and theoretical data was 1.27%.