Product Failure Mechanism Analysis - Chemical Corrosion

       Among the reasons for product failure, in addition to wear, the other most important reason is corrosion. There are various types of corrosion, but all corrosion can be divided into two categories, chemical corrosion and electrochemical corrosion. Today we are going to talk about chemical corrosion first, and chemical corrosion is relatively simple.



Chemical corrosion refers to the direct chemical effect of metal and external media, causing surface damage. It differs from electrochemical corrosion in that no current is generated.



Chemical corrosion process: At the beginning, a very thin oxide film is formed on the metal surface, and then gradually develops into a thicker oxide film. To protect, but the formed film must be intact to prevent the continued oxidation of the metal.



Metal and air contact to form oxide film is a kind of chemical corrosion. When the metal surface is in contact with the oil, the surface of the parts is strongly corroded because the oil contains organic acids or acidic substances; the fuel and lubricating oil contain sulfur components. It has a great influence on bearing alloys and also has a strong corrosive effect on steel. The corrosion of the metal surface has greatly changed the properties of the metal material, and even seriously damaged it. For example, the organic acid corrodes the lead of the copper-lead alloy bearing, which increases the load stress and friction coefficient of the bearing, accelerates the wear, and often causes the alloy to fall off.