الفهرس 
Chapter I : IntroductionOnly 14 pages are availabe for public view
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Abstract
The corrosion is one of the problems that face the world a long time ago, and even now, where we cannot permanently prevent corrosion, but we can reduce the risk of metals and alloys, this work discusses c-steel ally corrosion in an acid environment and how to protect it. The basics of metal corrosion forms and methods of protection. Were also reviewed published research on C-steel alloy corrosion in acidic solutions and the ability of plant extracts on the corrosion resistance, also included the target of the thesis.Chemical composition of C-steel used in the study and also ways to prepare solutions of acid (hydrochloric acid) and description of measurement methods. Electrochemical that was used to measure the rate of corrosion, as well as the preparation of the electrodes, the cell and solutions. Methods testing process and methods of calculations. This method is used to find out the effect of temperature on the inhibition of corrosion alloy C- steel in a solution of hydrochloric acid at four different grades in the range 25 - 45° C, and found that the corrosion rate decreases with decrease temperature and efficiency of inhibition which shows that inhibition occurs for through chemical adsorption. extracts obey isotherm langumiur and drawing the relation between (C/θ) vs. C. The negative values of ΔG˚ads ensure the spontaneity of the adsorption process and the stability of the adsorbed layer on the C-steel surface. The results obtained from thermodynamic parameters give further support to that obtained before. A number of mathematical relationships for the adsorption isotherms have been suggested to fit the experiment data of the present work. SEM, FT – IR and AFM experiments were carried out in order to verify if the investigation of extract compounds are in fact adsorbed in the C-steel surface.