Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: Rusty metal and magnetism

Learn more physics!

Most recent answer: 09/15/2011
Q:
I am working on a science project on whether or not there is a difference in how magnets attract metal that is and is not rusty or corroded. Do you know anything about that?

Also, what metals are magnetic?

Thank you.
why people cheat marriage affairs how many people cheat
the best android phone mealmixer.com phone tracking apps
internet drug coupons site prescription coupon
types of abortions read what happens when you get an abortion
cvs discount card cvs coupon online prescription drugs discount cards
married cheaters site dating for married men
buy sildenafil 100mg viagra without a doctor prescription viagra 100 mg
buy sildenafil 100mg viagra without a doctor prescription viagra 100 mg
finasteride lasix 40mg cialis 80mg
ventolin 2mg bistromc.org deltasone 40mg
free viagra samples coupon open viagra 2016 coupon
coupons prescriptions blog.brunothalmann.com manufacturer coupons for prescription drugs
coupon for viagra viagra trial coupon viagra discount coupons online
coupon for viagra open viagra discount coupons online
can i take escitalopram in the morning can i take escitalopram in the morning can i take escitalopram in the morning
can i take minocycline with birth control can i take minocycline with birth control can i take minocycline with birth control
diabetes affect sexuality diabetes sexuality treatment
acheter viagra pas http://acheterviagraenfrance.com/pas acheter viagra pas
where buy viagra online http://viagraforsaleuk1.com online viagra buy
augmentin générique arbot.cz augmentin sirop
naprosyn roche rileytech.net naprosyn nedir
arcoxia 30 go arcoxia wiki
proscar vs propecia for hair loss proscar proscar pris
seroquel 25 mg click seroquel debljanje
amlodipine 5 mg amlodipine bijwerkingen amlodipine accord
lasix injetavel lasix para emagrecer lasix

- Nathaniel (age 9)
San Diego, CA US
A:
Hi Nathaniel,

That sounds like a very good project to work on! Just be careful with the kinds of metals you investigate. Do not investigate lead, because it is poisonous. It also only has very weak magnetic properties anyway. Ask your teacher about the safety of other metals.

Rust and corrosion strongly affect the magnetic properties of metals. Ferromagnetic metals like iron in which interactions between the electrons of neighboring atoms tend to make their little bits of magnetism point in the same direction, forming magnetic domains. In a magnetic field, these domains line up with the field making a strong magnet. Other common ferromagnetic metals are nickel, and cobalt. Some of the strongest magnets are made with . In some materials, the domains can get stuck so the material stays magnetized even when the field is removed, leaving a permanent magnet, but that usually involves introducing some non-magnetic components.

Rusting and corrosion introduce atoms of other elements (typically oxygen), making new chemical forms with different interactions between neighboring atoms electrons. Usually these end up either non-ferromagnetic or less ferromagnetic than the pure magnetic metal.

There are several different oxides of iron, with different fractions of oxygen. They are Fe0, Fe2O3, and Fe3O4. Rust consists mostly of Fe2O3, with additional water molecules attached. There are several forms of Fe2O3, and a common mineral composed of Fe2O3 is called hematite, which is a shiny-blackish mineral. Hematite is not ferromagnetic, but it does still respond to a magnetic field and will be attracted to the poles of a permanent magnet. Hematite itself has the interesting property of being nearly antiferromagnetic, in which the spinning electrons producing magnetic fields in neighboring atom groups like to align opposite to one another, canceling their fields out. This isnt perfect in hematite, with a small tip, or "canting" of the spins so that they dont cancel exactly, hence the attraction to the poles of a permanent magnet. I suspect that the addition of water molecules in ordinary orangey-yellow rust does not help the material become more magnetic than its hematite cousin, but its hard to be less magnetic than an antiferromagnet. Why dont you try an experiment? FeO is also not ferromagnetic, but it is pulled about twice as much as Fe2O3 towards the poles of a magnet. Magnetite, Fe3O4, is ferromagnetic, and is about 1/4 as strong as pure iron. One warning is that rust may be a collection of the different oxides quite possibly other contaminants. In particular, there may be bits of unrusted iron left in a sample of rust, and these would be attracted very strongly to a magnet.

Some substances change the signs of their response entirely when they corrode. For instance, aluminum is very weakly attracted to the poles of magnets, while aluminum oxide is very weakly repelled by the poles of magnets. The scientific words for these interactions is:

Materials attracted by magnets: Paramagnetic

Materials repelled by magnets: Diamagnetic

Materials which spontaneously form magnetized domains: Ferromagnetic

Materials in which neighboring spins like to align opposite to each other: Antiferromagnetic

Only ferromagnets are useful for making permanent magnets. Paramagnetic and diamagnetic forces tend to be very weak, except for the diamagnetism of superconductors, which is strong enough to levitate them.


U.S. nickels contain rather little nickel -- they are about 75% copper, and only 25% nickel. This alloy seems to be not very magnetic. Older pure nickel nickels stick to magnets. Pennies are 97.5% zinc with a thin coating of copper on the outside.

Some steels (steel is mostly made of iron) are more magnetic than others. Try comparing stainless steel with other kinds of steel you might find around the house.

Two suggestions of things that can affect your experiments:

1) Rust and corrosion usually only occur in a very thin layer of the material near the surface. The rest of the material will be just as magnetic as it ever was, just minus the rusty layer. You may not notice any effect of the rust if most of the material is intact.

2) The shape and orientation of the metal object is very important in determining how strongly it will be attracted to a magnet. Be sure that the shapes of your uncorroded and corroded objects are the same when you compare their magnetic attraction or you could have other effects confusing the results.

Good luck!

Tom J. and Mike W.
why people cheat marriage affairs how many people cheat
types of abortions site what happens when you get an abortion
prescription drugs discount cards link coupons for viagra printable
manufacturer coupons for prescription drugs online viagra coupons coupon prescription
can i take minocycline with birth control read can i take minocycline with birth control
viagra bestellen online viagra pillen kruidvat pillen kopen
where buy viagra online http://viagraforsaleuk1.com online viagra buy
lilly cialis coupon coupons for prescriptions coupons prescriptions
arcoxia 30 arcoxia 90 arcoxia wiki
fusidinezuur kopen blog.jp-sa.org fusidic acid
cefdinir red stool ski-club-auringen.de cefdinir nedir
renovacija stanovanja blog.myexpensesonline.co.uk renova g
lasix injetavel lasix lasix
cialis coupon card coupon prescription cialis coupon

(published on 10/22/2007)

Follow-Up #1: Non-magnetic rust spots

Q:
The body of my car has orange rust spots on it. My magnetic screwdriver is attracted to the car , but not to the rusty spots. why does this happend?
hillcrest abortion clinic abortive live abortion video
abortion pill clinics abortion pill prices for abortions
free prescription cards nwwebdesigns.net walgreens prints coupon codes
diprolene site furosemide 40mg
levaquin pill internetsellout.com furosemide pill
levitra pill go tadalafil pill
discount prescriptions coupons mba-institutes.com internet drug coupons
can i take minocycline with birth control can i take minocycline with birth control can i take minocycline with birth control
cialis dosage and go cialis dose for copd pts
acheter viagra pas acheter viagra pas acheter viagra pas
viagra bestellen online viagra online shop pillen kopen
cialis coupon card eblogin.com cialis coupons from manufacturer
cialis coupon card open cialis coupons from manufacturer
claritinekombo warpedfish.co.uk claritine za psa
champix alkohol go champix
buscopan hund buscopan wirkung buscopan dragees
buscopan hund go buscopan dragees
allods online go allo allo
motilium enceinte site motilium et grossesse
prescriptions coupons emergent-ventures.com drug prescription card

- Anna Beth Sherrod (age 13)
Flint,TX U.S.A
A:
Rust (a collection of some iron oxides: ) is virtually non-magnetic, unlike plain iron or most types of steel.  If the sheet metal on your car has really rusted through, there will be almost no magnetic force between it and the magnetized screwdriver. It sounds like those spots should be patched, since that's not just a thin surface layer of rust.

Mike W.
why people cheat infidelity signs how many people cheat
why people cheat catch a cheat how many people cheat
internet drug coupons open prescription coupon
married woman looking to cheat married men that cheat most women cheat
married cheaters redsoctober.com dating for married men
priligy 30mg bistromc.org cialis 40mg
imitrex 50mg site flagyl 200mg
online discount pharmacy viagra coupons and discounts coupon for prescription
prescription drugs discount cards link coupons for viagra printable
coupons prescriptions prescription savings cards manufacturer coupons for prescription drugs
manufacturer coupons for prescription drugs viagra 2016 coupon coupon prescription
cialis dosage and cialis dose for copd pts
where buy viagra online viagra for sale uk online viagra buy
cialis coupons from lilly coupon for free cialis coupons for prescriptions
cialis manufacturer coupon cialis discounts coupons prescription drug coupons
cialis coupon lilly click transfer prescription coupon
cialis coupon card read cialis coupons from manufacturer
claritinekombo warpedfish.co.uk claritine za psa
naproxennatrium zygonie.com naproxen migraine
naproxennatrium zygonie.com naproxen migraine
voltaren ára go voltaren
champix alkohol mdwguide.com champix
niacine movidafm.net niacin v hrani
flibanserin online click flibanserin buy
cialis open cialis walgreen coupon
voltaren retard voltaren pomada voltaren spray
allods online go allo allo

(published on 09/15/2011)

Follow-up on this answer.