Sometimes, we often compare people with machines. Of course, people can’t compare with machines. It’s not enough just in terms of lifespan, not to mention efficiency. The same is true for machines. Piston rings are the most important part of the engine of the machine.
Components, once there is a problem, it will be troublesome. The engine is the heart of the car, which everyone can understand. The role of the small part of the piston ring on the engine is also understood by everyone. Although the parts are small, but Great effect. So how to realize the anti-rust function of the piston ring? Let's have a look!
After the metal is subjected to the chemical and electrochemical action of the surrounding medium (such as moist air, water, sweat and dust, etc.), brown-yellow or brown-red stains appear on its surface, which is commonly known as rusting.
Steel contains ferrite, cementite, and pearlite, and the structure is uneven. Their electrolytic potentials in the electrolyte are different. When the water film exists, a potential difference is generated between each phase, which constitutes a micro-battery and causes rust. The cast iron structure of the piston ring contains pearlite and graphite, and also contains a small amount of ferrite and inclusions.
The graphite has a high electric plate potential to form the cathode, and the ferrite has a low electrode potential to form the anode. The potential difference between them is higher than that of iron in steel. The potential difference between the element body and the cementite is large, so it is easier to corrode than steel!
