Effects of Rust
Most recent answer: 9/4/2020
Rusting has a number of effects on metal objects. It makes them look orange and rough. It makes them weaker, by replacing the strong iron or steel with flaky powder. Some oxides on some metals such as aluminum form just a thin layer on top which slows down further corrosion, but rust can slowly eat away at even the biggest piece of iron. If a piece of irons strength is important for safety, such as a bridge support or a cars brake caliper, it is a good idea to inspect it for rust damage every now and then.
Rust also can cause metal parts that are supposed to slide over one another to become stuck. Just ask someone who has tried to get a rusty nut unstuck from a rusty bolt.
Rust can make holes in sheet metal. Rusty car mufflers sometimes develop holes in them, and the sheet steel making the outer bodies of cars will often rust through, making holes.
Rust is a lot less magnetic than iron. An iron magnet will probably still work almost as well when it has a thin coating of rust on it, but if it has rusted so badly that most of the metal is gone, then it will not work very well as a magnet.
Rust is an insulator, meaning that it doesnt conduct electricity easily, unlike iron, which is a metallic conductor. So if some electrical connection is made with iron, its likely to go bad when the iron surface rusts.
Tom J. (and mike)
(published on 10/22/2007)
Follow-Up #1: What are the environmental impacts of rust?
(published on 12/13/2010)
Follow-Up #2: iron rust and other metals
- Anonymous (age 18)
Nice question. Many metals oxidize when exposed to the atmosphere, but iron has particular problems with rust. Aluminum, for example, forms a thin very tough sapphire-like oxide coat. It slows down the diffusion of oxygen to the metal, so it's self-limiting. It's very protective for most purposes, but it's electrically insulating, which is why there are big problems with aluminum wiring. Most other oxide layers aren't so tough, but I don't know of any others that are as loose and flaky as rust.
(published on 09/04/2020)