Centrifuges are generally made of stainless steel metal, so there may be more or less corrosion phenomena. The corrosion forms of metals are mainly divided into two categories: uniform corrosion and localized corrosion. The former is easy to detect due to its apparent phenomena and is clearly stated in most manual data. Therefore, it will not be described in detail here, only the latter will be discussed. Localized corrosion only occurs locally and is an extremely serious and harmful form of damage, such as pitting corrosion, crevice corrosion, intergranular corrosion, stress corrosion, wear corrosion, etc. Localized corrosion is commonly present in centrifuges, and its formation mechanism should be analyzed and measures should be taken to overcome it.
1. Cavitation corrosion is a highly corrosive phenomenon that mainly exists in metals that are prone to passivation, such as stainless steel. Due to possible surface defects and the presence of active ions in the solution that can damage the passivation film, the passivation film is locally damaged, forming galvanic pairs and causing pitting corrosion. After the formation of pitting corrosion, the dynamic process of the electric couple inside the hole will be accelerated by centrifugal force, ensuring the continuity of pitting corrosion until perforation, which is different from the static pitting phenomenon.
2. Intergranular corrosion can cause parts to lose strength and ductility, leading to brittle fracture. It is a hazardous damage that develops inward from the surface along the grain boundary without any signs of corrosion on the outer surface.
3. Wear and corrosion refers to the simultaneous wear and corrosion damage to the surface of a component.
4. Stress corrosion is damage caused by certain tensile stress in a corrosive environment. It has the following characteristics: residual tensile stress, external tensile stress, corrosive infiltration environment, and local defects. The above four types of corrosion have extremely serious effects on the separation of TK and machinery, and may lead to serious consequences.
So the centrifuge must be regularly inspected to prevent material corrosion of the centrifuge.