Recently we received some inquiries like “Even though it was made of stainless steel, it soon got rusted” from our customers.
Stainless steel is a very rust-resistant alloy of iron.
Indeed, compared to iron, it is quite hard to rust, but it doesn’t mean it doesn’t rust at all.
Why is stainless steel so resistant to rust?
When exposed to air, it will form a self-healing barrier!
When exposed to air, it will form a self-healing barrier!In stainless steel, chromium bonds with oxygen in the air (=oxidation) before iron, which causes rust, and forms a very thin passive film (protective coating) of a few nanometers.
The passive film is resistant to chemical change and it is so strong that can prevent iron from oxidation(=rust).
Passive coating can be damaged and torn, but it can self-heal in a moment, so it does not leave room for iron to rust.