What are the factors affecting corrosion of stainless steel applications in seawater environments?

Neutral seawater has more dissolved oxygen. Except for magnesium and other alloys, the corrosion of most marine structural materials in seawater is due to the cathodic process controlled by oxygen depolarization. All conditions that are conducive to oxygen supply, such as waves, splashing, accelerated flow rates, etc., will promote the cathodic depolarization reaction of oxygen, thereby increasing the corrosion of stainless steel materials.
Because the conductivity of seawater is relatively large, the resistive resistance to seawater corrosion is very small. Therefore, the activity of micro-batteries and macro-batteries generated on the surface of stainless steel application materials in seawater corrosion is very high. Different stainless steels in seawater are very prone to galvanic corrosion when in contact. Even if the two metal materials are tens of meters or even further apart, as long as there is a potential difference and there is an electrical connection, galvanic corrosion is very easy to occur.
Since the content of chloride ions in seawater is very high, it is difficult for most metal materials, such as iron, ordinary steel, cast iron, zinc, cadmium, etc., to establish a passive state in seawater. During seawater corrosion, the polarizability of the anode is very small, so the corrosion rate is quite high. This type is very prone to small hole corrosion in seawater, and the corroded holes will be deeper.
Oxygen content, the wave action of seawater and the photosynthesis of marine plants can increase the oxygen content. As the oxygen content of seawater increases, the corrosion rate will increase accordingly. The corrosion rate of carbon steel in seawater increases with the increase of flow rate, but remains basically unchanged after it increases to a certain value. The passivation metal is different. Under a certain flow rate, the passivation of high-chromium stainless steel application products will be promoted to improve the corrosion resistance of the material. When the flow rate is too high, the degree of corrosion of stainless steel application materials will increase rapidly. In addition, there is a temperature, which is the same as fresh water. The higher the temperature, the faster the corrosion rate. The influence of biological factors is very complex. Some organisms will produce a protective coating, but most organisms will accelerate the corrosion of stainless steel application products.