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In nature, metal is a common material, widely used in industry, construcción, manufacturing and other fields. Sin embargo, metal materials often encounter corrosion problems in the process of use, and local corrosion is one of the common and dangerous corrosion forms. Local corrosion does not occur uniformly throughout the metal surface like ordinary corrosion, but occurs in local areas, but the harm may be greater. This article will discuss the principle, influencing factors, detection methods and prevention measures of local corrosion in depth, so as to help readers better understand and deal with this invisible killer.
Local corrosion, also known as pitting, pitting, or seam corrosion, is a form of metal corrosion characterized by the formation of local corrosion spots or pits on the metal surface. Compared with ordinary corrosion, the rate of local corrosion is faster, but the harm range is smaller, but it poses a serious threat to the strength and safety of metal components. Local corrosion occurs because the local area of the metal surface is eroded by the corrosive medium, forming a small anode and cathode region, resulting in a local electrochemical reaction. In these tiny anode regions, the metal surface loses electrons and dissolves into ionic forms, while in the cathode region a reduction reaction occurs. This local electrochemical reaction leads to the formation of local corrosion on the metal surface.
Método de detección
By observing with the naked eye whether there are abnormal spots, pits and other forms on the metal surface, determine whether local corrosion occurs. The corrosion products on metal surface were analyzed by chemical analysis method to determine the type and degree of corrosion. The potential and current density of metal surface are measured by electrochemical test method to determine whether local corrosion occurs. The use of non-destructive testing technology, such as ultrasonic testing, X-ray testing, etc., to detect whether there is local corrosion inside the metal.
Prevention and control measures
First of all, the selection of metal materials with good corrosion resistance can reduce the risk of local corrosion. The metal surface is treated with anti-corrosion coating to reduce the corrosion of the metal surface by corrosive media. Using cathodic protection technology, the metal surface becomes a cathode to slow down the occurrence of local corrosion. Optimize the production process, reduce the risk of local corrosion, and improve the corrosion resistance of metal materials.
As a special form of metal corrosion, local corrosion has fast corrosion rate and serious harm. Through in-depth understanding of its principle, influencing factors, detection methods and prevention and control measures, we can better prevent and respond to local corrosion problems and protect the integrity and safety of metal materials. In the future engineering and scientific research, we should further strengthen the study of local corrosion mechanism, explore more effective prevention and control methods, and provide reliable guarantee for the application and development of metal materials.
