الفهرس 
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Abstract
The thesis is about Prevention of corrosion by some plant extracts, Literature survey of low C-steel corrosion and aim of this study. The chemical composition of the investigated compounds, preparation of the investigated Hydrochloric acid solutions, the investigated plant extracts solutions and procedures used for the corrosion measurements such as chemical measurements, electrochemical techniques and surface analysis techniques. The effect of temperature on the corrosion inhibition of low C-steel in 1M HCl was determined over the temperature range 30-500C using weight loss measurements. The inhibition efficiency increases with increase in the concentration of these extracts .The rate of corrosion increases with increasing the temperature together with increase in inhibition efficiency increase for the plant extracts, indicating that the inhibition occurs through chemical adsorption for plant extracts on low C-steel surface. The effect of plant extracts on the cathodic and anodic polarization of low C-steel in 1M HCl was investigated. The results obtained from (EIS) show that the corrosion reactions in the absence and presence of inhibitors proceeds under charge transfer control. The weight loss, polarization, electrochemical impedance spectroscopy (EIS) and EFM measurements support the assumption that corrosion inhibition primarily takes place through adsorption of the inhibitors on the low carbon steel surface. Agreement among these different independent techniques indicates the validity of the obtained results.