How does rust work?
Rust is created when iron molecules combine with oxygen in the presence of water. The result is a red flaky oxide that deteriorates easily, exposing more material to further corrosion. Iron and standard carbon steels are highly susceptible to this type of corrosion.
Stainless steel has the ability to form a protective surface that prevents such corrosion. How does this happen? The chromium in stainless steel reacts with oxygen, like iron. The difference is that only a very fine layer of chromium will oxidize. This layer is often only a few molecules in thickness. This barrier is highly durable and non-reactive. It also adheres to the rest of the stainless steel and won’t break off or react further with other materials. It will also replenish if damaged or removed. Once oxidized, also called passivized, stainless steel typically rusts at a rate of less than 0.002″ in a given year.
Corrosion Resistance of 304 vs 316
As the amount of chromium and molybdenum (among other elements) varies, so do the corrosion resistance. Today we’ll be focusing on 304 vs 316, which are the two most popular grades. There are a lot of other different alloys in stainless, but we’ll talk about those another time. One big difference between 304 and 316 is the presence of molybdenum in the latter’s makeup, which gives it the extra corrosion resistance that befits the name “marine grade stainless”.
Corrosion is a natural part of exposure to the wind, water and environment. Pure elements such as iron inherently react with the surrounding environment. This is especially true when alkaline or salt water is present. Because of this, very few elements can be found naturally in their pure form. They naturally mix with other elements or change due to exposure. These sort of mixtures – alloys – have synergistic properties that retain the special characteristics from each of the elements.
When kept in best condition, stainless steel offers clean and bright surfaces ideal for many building and landscape designs.
304 Stainless Steel Diagonal backsplash