Proposta de melhoria de protecção da estrutura metálica do Jetty contra corrosão - Kenmare

Abstract

Marine corrosion is commonly related to the external penetration of chloride ions, according to Araujo and Panossian (2010). Chlorides, through water, marine atmosphere or melting salts, penetrate the material through the process of diffusion, impregnation or capillary absorption of water containing chloride content. Chloride ions are responsible for accelerating electrical conductivity, acting as a catalyst for the corrosion process and corrosion products, causing loss of resistance in structures (CAVALCANTI; CAVALCANTI, 2010). Sulfate ions act through the crystallization process of sulfate salts, occurring when the concentration of salts becomes very high, due to the evaporation of water (PONTES, 2019). It is important to highlight the importance of the characteristics of the materials involved in the structure, physical-chemical and microbiological characteristics of the water, dissolved gases, speed and temperature of the fluid for correct assessment of the corrosion process. The pH of seawater acts as a propellant for the corrosion process, as the water becomes an excellent electrolyte, commonly forming crevice and galvanic corrosion. According to Pannoni (2007), in a much more aggressive environment, localized corrosion can develop and cause corrosion inside the crack, just as two metals when exposed to an electrically conductive solution, such as sea water, can develop galvanic corrosion. And the entire marine atmosphere is a driver of uniform corrosion under materials. In general, preventive strategies are functional through the development of a durability monitoring system, the use of paint coating and abrasive blasting must be analyzed according to the structure and the type of material that constitutes it, emphasizing the need to carry out corrosion speed tests and components that are present in the environment acting as corrosion catalysts.