I’m having a hard time wrapping my head around classifying metals. So far, I’ve seen two divisions:
1. Pure metals and Alloys
2. Ferrous and Non-ferrous
But I haven’t exactly seen a source that takes both classification divisions into account. Sources keep saying ferrous metals contain iron, so is iron the only pure metal that’s ferrous? Is iron even a ferrous metal? What about the other magnetic metals like nickel and cobalt?
In: Chemistry
Ferrous is literally iron, hence why it is Fe on the periodic table, so a ‘ferrous metal’ is noting whether it contains iron, not whether or not it’s magnetic.
As for your other question, a pure metal is a metal composed of a single element, while an alloy has a blend of two or more elements. This can be advantageous because the alloy can have properties between the metals used or notably different–for example, bronze is an alloy of mostly copper with primarily tin as an additive, which makes it stronger and less prone to wearing down.
Are you thinking of ferrous as shorthand for “magnetic?”
Because while that’s useful for most applications, ferrous metals aren’t the only magnetic ones. Nickel and cobalt, which you mention, can also be magnetic. Heck, rare earth elements like neodymium makes the most powerful magnets.
“Ferrous” means “iron-containing”. Like…that’s the literal definition of what the word means.
So yes, iron is the only pure metal that’s ferrous, by definition. Any other pure metal contains 0% iron, so is non-ferrous.
[Magnetic vs. Non-Magnetic Metals](https://www.meadmetals.com/blog/types-of-magnetic-metals-list)
The three elemental metals that are naturally ferromagnetic are iron, cobalt, and nickel. Compounds and alloys can also be magnetic if they contain iron, cobalt, or nickel, such as steel and stainless steel. Non-magnetic metals include aluminum, copper, lead, tin, titanium, zinc, and alloys such as brass and bronze.
Ferrous literally means ‘iron bearing’ (roughly). Its latin name is Ferrum, which is the reason the chemical symbol is Fe.
Nothing is ferrous unless it’s iron or has iron in it.
You might be referring to magnetic, which is not the same thing (though they are sometimes used interchangeably). Magnetism is not limited to iron, but it’s the most strongly interacting common magnetic material.
The latin term for iron is ferrum that’s why it is Fe on the periodic table. Ferrous is derived from the word meaning iron and just means iron containing. Classifying something as ferrous or non-ferrous is just making a distinction if it contains iron or not because iron is a common metal that has certain properties that we need to be aware of in chemistry and physics.
The two classifications are used for different reasons which is why you don’t see them used together. You’re mainly only concerned whether alloys are ferrous or not. If you are dealing with pure metals than you deal with the metal itself.
Iron in many other languages start with “fer” or some derivative. In french it is literally “fer”
Ferrous means “contains iron.” So yeah, if it’s ferrous and pure it can only be iron.
If you’re asking about “ferromagnetic,” which means that a material reacts to magnets like iron does (attracted to a magnet, can amplify a magnetic field, can turn into a permanent magnet), then there are other metals that have this property including cobalt and nickel.
Just to add to the numerous other comments on magnetism.
The rabbit hole goes deeper.
Ferrous, as described, means that the material is or contains iron.
Ferromagnetic means the material is attracted to magnets. It’s named after iron, but include nickel and cobalt.
Here’s where the rabbit hole begins.
When we say something is ‘magnetic’ we commonly mean ‘ferromagnetic’.
But there are two other related phenomena.
Diamagnetic materials are weakly repelled by magnetic fields. Not attracted. Copper is diamagnetic. But you’d hardly ever notice without extremely strong magnetic fields.
And then the weird one. Paramagnetic. These materials don’t get attracted to magnets or repelled by magnets but resist *changes* in magnetic fields. Aluminum is an example.
So here’s an example of an experiment you can do.
Take three tubes or pipes. A copper pipe, a steel pipe, and an aluminum tube. You can find all of these at your local hardware store.
Hold the pipe vertically and drop a rare earth magnet into the top of each tube.
The magnet falls straight through the copper pipe, sticks to the top of the steel pipe, and the cool one you wanna show your kids – floats slowly down the aluminum tube to the bottom. So slow you can drop it with one hand, and easily reach down and catch it with the same hand.
Then put the pipes back on the shelf. You didn’t think you needed to buy them and bring them home, did you?
Pure metals is made of 1 element, alloys are made of more than 1 element.
Ferrous materials are based on iron, non-ferrous materials are not based on iron.
1. Non-ferrous pure metal: any metal on the periodic table except iron.
2. Ferrous pure metal: iron. This “category” doesn’t make sense because there’s only 1 thing in it. Just say “iron” if you want iron.
3. Non-ferrous alloy: any alloy which is not primarily iron.
4. Ferrous alloy: any alloy which is primarily iron or has enough iron to behave like steel.
The reason for the ferrous vs non-ferrous alloy dichotomy is that steel is one of the most common and most important materials. It also tends to behave differently than other alloys because they have different metallurgical mechanisms.
>What about the other magnetic metals like nickel and cobalt?
You may be confusing “ferrous” with “ferromagnetic.” Technically all materials are magnetic, but only some are magnetic enough to easily detect. These are said to be “magnetic similar to iron,” hence the name ferromagnetic.
>Is iron the ONLY ferrous pure metal, while every other ferrous metal is an alloy?
Yes.
Iron’s short form “Fe” is from its Latin name “ferrum”. “Ferrous metal” is pretty literally “metal containing iron”.
>Is iron the only pure metal that is ferrous?
Yes. Trivially. See above.
>Is iron even a ferrous metal?
Yes. Trivially. See above.
>What about other metals like nickel and cobalt?
If they’re pure, then no. If they’re an alloy containing iron, then yes.
If they don’t explicitly contain iron but instead just trace amounts, then we probably wouldn’t consider them ferrous metals. Where precisely that line gets drawn gets a little hazy.
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