Biomedical Implants: Corrosion and its Prevention Recent Patents on Corrosion Science, 2010, Volume 2 43 oxide films present on metallic materials play a very important role, not only for corrosion resistance but also for tissue compatibility. This chapter presents important aspects of corrosion in industrial infrastructure, its causes, impacts, control, protection and prevention methods. 2. Materials in industry Metallic materials play a key role in the development of a country and its sustained growth in the context of the global economy. Corrosion prevention by design improvements, anodic and cathodic protection, metallic, non- metallic and inorganic coatings, mechanical and chemical methods and various corrosion inhibitors TEXTBOOKS: l. Raj Narayan, [dn Introduction to Metallic Corrosion and its Prevention 1st Edition, Oxford and 1983 2. The factors like pH, oxygen content, chemical makeup of water, dissimilar metals, temperature, velocity and pressure in pipeline are important in corrosion of piping systems. Coating, galvanizing, tinning, electroplating, anodizing are few common methods for corrosion prevention. 11.2 Corrosion prevention compounds. Corrosion prevention compounds (CPCs) are materials that can prevent new corrosion sites from forming and, more importantly, suppress corrosion that has already initiated. CPCs are applied as a post-production treatment to provide cost-effective, temporary corrosion protection and to control existing corrosion. to crevice corrosion is another protective measure. Fig1: Mechanism of active and passive corrosion and its corresponding Anodic and Cathodic reactions in crevice corrosion[3] 5.Conclusion This paper review theory and mechanisms of crevice corrosion as well as its prevention methods. It is good to know that the mechanism for the crevice corrosion pipe may contain water and CO2 which will contribute to corrosion in the pipe. If VCIs are present in the vapour phase they will also condense and provide a protective film. The volatility of the inhibitor is dependent on the vapour pressure of the compound. For the prevention of CO2 corrosion on steel, amines are used as the VCI. The vapour This layer of aluminium oxide protects it from further corrosion. Factors Affecting Corrosion 1. Exposure of the metals to air containing gases like CO 2, SO 2, SO 3 etc. 2. Exposure of metals to moisture especially salt water (which increases the rate of corrosion). 3. Presence of impurities like salt (eg. NaCl). 4. DEFINITION OF CORROSION Corrosion is the deterioration of a substance or its properties as a result of an undesirable reaction with the environment. It is irreversible and degenerative and related to the Second Law Thermodynamics - NACE International "Energy spontaneously tends to flow only from being concentrated in one place to becoming Corrosion and its prevention. Corrosion- The process of decay of a metal from its surface due to unwanted chemical (or) electro chemical interactions with its environment is called corrosion.1. Ex:- Formation of reddish brown layer of rust (Hydrated ferric oxide) on the surface of iron (Fe2O3H2O). 2. Ex:-Formation of green layer of basic carbonates on the surface of copper (CucO3 + Cu (OH)2 Corrosion prevention refers to the measures that are put in place to prevent the occurrence of corrosion. Prevention measures are designed to protect materials, substrates and metallic structures from the deteriorati