Transcript
So how does this work?
Think of aluminum like the coolest kid at the high school party- the one that everyone flocks to. Noo bitterness here.
You know how it goes. You’re talking to someone, you think you’ve bonded, but then suddenly STEVE walks in a swhooosh- away they go!
In this example, you are a silver fork. Or maybe a steel knife. You had just bonded with a nice bit of oxygen or sulfur that happened by, and your budding love showed as some surface discoloration (e.g. tarnish). Because love can be messy.
But metals have what’s called an Order of Reactivity– like a popularity ranking, but of how likely they are to react with stuff. And because aluminum is above iron and silver, as soon as it shows up all the oxygen and sulfur at the party leave who they’re with and flock to it. And presto. Steve dulls and you get all shiny and sad.
(Oh, and the detergent sort of helps the transfer happen.)
Additional Notes
- Ordinary carbon steel surfaces form ferric oxide when exposed to oxygen.
- Ferric oxide does not form a continuous layer, so it eventually spalls off, leaving raw steel exposed and prone to a destructive rusting cycle.
- Cascade uses NaCO3. Dawn is sodium organosulfate salts
- Baking soda= NaHCO₃
- Stainless Steel = Iron + Chromium
Causes of stainless steel corrosion
Chromium can protect stainless steel if the localized concentration is 12% or higher. Anything reducing the localized chromium concentration below the 12% threshold will cause staining or rust. Common causes of stainless steel corrosion include chlorides, hydrochloric acids, sulfuric acids, iron or carbon steel contact, and high temperatures.
Iron and carbon steel particles
Stainless steel corrosion can also be triggered by contact with iron or carbon steel particles. Trace particles from iron or carbon steel will rust stainless steel surfaces. If left unattended, rust spots may compromise the chromium oxide surface and evolve into localized corrosion such as pitting. Contamination occurs when stainless steel is subject to sparks or particles from nearby welding, cutting, drilling, or grinding of carbon steel.