Corrosion is a fundamental process playing an important role in economics and safety, particularly for metals and alloys. It can cause disastrous damage to metal and alloy structures causing economic consequences in terms of repair, replacement, product losses, safety, and environmental pollution. Due to these harmful effects, corrosion is an undesirable phenomenon that ought to be prevented. There are several ways of preventing corrosion and the rates at which it can propagate with a view of improving the lifetime of metallic and alloy materials.<br /> In spite of much advancement in the field of corrosion science and technology, the phenomenon of corrosion (mainly of Fe, Al, Cu, Zn, Mg and their alloys) remains a major concern to industries around the world. Though the serious consequences of corrosion can be controlled to a great extent by selection of highly corrosion resistant materials, the cost factor associated with the same favors the use of cheap metallic materials along with efficient corrosion prevention methods in many industrial applications. In this aspect, the exploration of natural products of plant origin as inexpensive eco-friendly corrosion inhibitors is an essential field of study. In addition to being environmentally friendly, ecologically acceptable, plant products are cheap, readily available and renewable sources of materials. The extracts from their leaves, barks, seeds, fruits and roots comprise of mixtures of organic compounds containing nitrogen, sulphur, and oxygen atoms and some have been reported to function as effective inhibitor of metal corrosion in different aggressive environments. Corrosion inhibitors have ample significance as individual inhibitors or as a component in chemical formulations. They have wide commercial applications such as in cooling waters, oil and gas fields, paints pigments, lubricants etc.<br />Aluminum and its alloys have excellent durability and corrosion resistance, but, like most materials, their behavior can be influenced by the way in which they are used. Aluminum is commercially important metal and its alloys are widely used in many industries such as reaction vessels, pipes, machinery and chemical batteries because of their advantages. Aluminum is a well-known sacrificial anode if coupled with more passive metal as it is most reliable and cost effective anode. Aluminum sacrificial anode has been used in major project all over the world. It is used in offshore application including structures, platforms, pipelines, jetties and power plants. Aluminum anode is also used for ship-hull and ballast tank protection. Aluminum is an active metal and its resistance to corrosion depends on the formation of the protective oxide film.<br />There are several methods to protect the aluminum and its alloys from corrosion such as coatings (metallic, inorganic, conversion and organic coatings), control of environment (operating variable i.e. pH, dissolved oxygen, temperature and etc.) and corrosion inhibitors (organic and inorganic additives).<br /> <br /> أعداد: م. د مروان عباس مظلوم<br />