# Dust aluminium atracted to magnet

• Looser74
In summary, the dust problem on nickel coatings is caused by the attraction of small aluminum particles. The particles are not being attracted by the static electricity from the magnet, but by the magnetic property of the nickel.

#### Looser74

Hi

Sorry I'm not good in physics at all.

I have the following dust problem becoming attached to Nickel coatings.
from what i know Nickel can become magnetic
but aluminium should not be attracted to magnets.

I did an experiment to confirm if the nickel coat is acting as magnet
in which i used a regular clean magnet and aluminium foil and a very sharp knife.

Cut small pieces of aluminium foil (less that hair thickness) without touching them
I clean the magnet with alcohol and let it dry.
the i passed the magnet near the aluminium particles or touch them.
if aluminium foil particles are small enough you can pick them with the magnet.

the smaller particles are attached faster and
you can even see the pull of the magnet when its getting near.

I tryed also to pick the same particles with the knife, and they just don't get attached to the knife.

DOES ANY ONE HAS AN EXPLANATION WHY ALUMINIUM PARTICLES GET ATTACHED TO THE MAGNET?

Looser74, Welcome to Physics Forums! You can become a competent observer of nature by using the scientific method. You already seem to have a good handle on the method. You may want Google it and learn it thouroghly...it always serves the observer and experimenter well.

As for your experiment: we know aluminum is non-magnetic, so why were those little aluminum particles attracted? You have misinterpred the results of your experiment. It is not magnetic attraction you are seeing. Answer: Unlike static electrical charges attract. So one object, say the aluminum, has a small positive static charge and the magnet has a negative static charge. You could probably get the same results using your rubber comb. Try experimenting with other materials. Google static electricity. Wikipedia and Google are your friends.

In fact only one of them would have to have a small net charge which would polarize the other object and still cause attraction.

Bobbywhy said:
Looser74, Welcome to Physics Forums! You can become a competent observer of nature by using the scientific method. You already seem to have a good handle on the method. You may want Google it and learn it thouroghly...it always serves the observer and experimenter well.

As for your experiment: we know aluminum is non-magnetic, so why were those little aluminum particles attracted? You have misinterpred the results of your experiment. It is not magnetic attraction you are seeing. Answer: Unlike static electrical charges attract. So one object, say the aluminum, has a small positive static charge and the magnet has a negative static charge. You could probably get the same results using your rubber comb. Try experimenting with other materials. Google static electricity. Wikipedia and Google are your friends.

If this was electric static wouldn't the aluminium foil be released as soon as it touches the magnet?
to attrack objects by electric static they need to have oposite charge, once they touch both materials are conductive, and should neutralize the charge, but they stay attached
even if waved strongly.
until i remove with my hand or other object to pull the aluminium away, they stay attached.
the attraction is not that strong but strong enough for the aluminium particle not to be released by gravity.

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static electricity...one they touch they should neutralize? Not so fast.

Growing up in México, I remember having parties where the girls/women would come in, inflate balloons, rub them against their hair and place them along the top of the walls of the room...such balloons would stay there for the duration of the party or even longer.

gsal said:
static electricity...one they touch they should neutralize? Not so fast.

Growing up in México, I remember having parties where the girls/women would come in, inflate balloons, rub them against their hair and place them along the top of the walls of the room...such balloons would stay there for the duration of the party or even longer.

Well, balloons are not conductive, actually not even dissipative, charge doesn't go anywhere in balloons, unless you increase the air moisture.

wait, who has a point here, you or me?

I mean, if balloons are not conductive...how did the charge got in there in the first place? I had a balloon in my hand, push it against the wall and it does not stick...rub it against my hair, push it against the wall and it sticks.

By the way, you said
If this was electric static wouldn't the aluminium foil be released as soon as it touches the magnet?
to attrack objects by electric static they need to have oposite charge, once they touch both materials are conductive, and should neutralize the charge
are you sure that your magnet is conductive? I think this is one big assumption on your part...I think most popular magnets are made out of some non-conductive ceramic material.

gsal said:
wait, who has a point here, you or me?

I mean, if balloons are not conductive...how did the charge got in there in the first place?

He is correct about the conductivity and his point is valid. It is NOT necessary for objects to be conductive in order to get a STATIC charge. Is your hair conductive? Rub a balloon against it and see what happens.

It is not true that aluminium is non-magnetic. It is not ferromagnetic but is quite strongly paramagnetic. This could be sufficient to explain sticking to a magnet.

DrDu said:
It is not true that aluminium is non-magnetic. It is not ferromagnetic but is quite strongly paramagnetic. This could be sufficient to explain sticking to a magnet.

Paramagnetic materials generate currents when a magnet moves near it, but would this be enough for the aluminium to hold to the magnet if its small enough?

I just cut a strip of foil, 3 cm by 15 cm, and used a rare Earth magnet to see if there was any attraction. There was. I think there might be a percent or so of iron in the aluminum, perhaps to make it a little more rigid.

Front Office said:
I just cut a strip of foil, 3 cm by 15 cm, and used a rare Earth magnet to see if there was any attraction. There was. I think there might be a percent or so of iron in the aluminum, perhaps to make it a little more rigid.

That might be true, Iron would make magnetic, i wonder how much content of Iron the Aluminium foil has?.

how did you make the test?
You need to have both magnet and aluminium foil still.
otherwise you will generate eddy currents,
that will make the aluminium foil temporarily magnetic and make it follow the magnet
and it will look like the magnet is pulling it, but doesn't stick to the magnet.
its just the eddy currents.

DrDu said:
It is not true that aluminium is non-magnetic. It is not ferromagnetic but is quite strongly paramagnetic. This could be sufficient to explain sticking to a magnet.
Almost certainly that is the explanation. Liquid oxygen, too, is paramagnetic, and is attracted to a magnet. http://www.youtube.com/watch?v=yJs5ENtilIo"

Though, we haven't discounted the possibility that attraction is due a magnetic impurity in the Al metal. OP should cut foil into a pencil-length strip, and repeatedly stroke with his magnet to attempt to magnetise the metal strip. If foil is too weak to support itself, float it on a plate of water and determine whether one end is repelled, and the other attracted, by the approach of the magnet. This won't necessarily prove iron is present.

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Looser74 said:
how did you make the test?
You need to have both magnet and aluminium foil still.
otherwise you will generate eddy currents,
that will make the aluminium foil temporarily magnetic and make it follow the magnet
and it will look like the magnet is pulling it, but doesn't stick to the magnet.
its just the eddy currents.
I cut a strip of aluminum foil about an inch and a quarter wide by about 6 inches long. I dangled the long end down, in front of a rare Earth magnet on the refrigerator door. The foil deflected slightly when it got near the magnet, finally getting pulled to the magnet. The foil deflected even more when I pulled it away from the magnet.

The magnet was "still" insofar as it was on the door of the refrigerator. As for the strip of foil, I moved the bottom of the strip slowly toward the magnet till it began to deflect toward the magnet. The deflection was unambiguos.

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Looser74 said:
Hi

Sorry I'm not good in physics at all.

I have the following dust problem becoming attached to Nickel coatings.
from what i know Nickel can become magnetic
but aluminium should not be attracted to magnets.

I did an experiment to confirm if the nickel coat is acting as magnet
in which i used a regular clean magnet and aluminium foil and a very sharp knife.

Cut small pieces of aluminium foil (less that hair thickness) without touching them
I clean the magnet with alcohol and let it dry.
the i passed the magnet near the aluminium particles or touch them.
if aluminium foil particles are small enough you can pick them with the magnet.

the smaller particles are attached faster and
you can even see the pull of the magnet when its getting near.

I tryed also to pick the same particles with the knife, and they just don't get attached to the knife.

DOES ANY ONE HAS AN EXPLANATION WHY ALUMINIUM PARTICLES GET ATTACHED TO THE MAGNET?
It might be small amount of magnetic material on the aluminium, or static charge ofcourse. Btw., have you tried to approach a strong neodym magnet close to tapping water? If you poor water carefully, in a narrow flow, the water will deflect away from the magnet. How cool is that? :-))

Vidar

Low-Q said:
Btw., have you tried to approach a strong neodym magnet close to tapping water? If you poor water carefully, in a narrow flow, the water will deflect away from the magnet. How cool is that?
Vidar,

I just tried that. Amazing. It pushed the stream of water away.

I saw, on the KJMagnetics site, a magnet depressing the surface of still water. The deflection was made evident by looking at a slant angle of a reflected pattern on the water.

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One more point: The force between two dipoles goes diminishes like 1/r⁶. Especially the corners of a magnet were the field is very inhomogeneous may correspond to a strong dipole of very small radius. So the attraction on a small particle in which a dipole moment is induced can be very large despite the relative small value of the permeability.

## 1. What causes dust aluminum to be attracted to a magnet?

Dust aluminum is attracted to a magnet because it contains a high amount of iron, which is a magnetic material. When the dust particles come into contact with a magnet, the iron within them aligns with the magnetic field, causing them to be attracted to the magnet.

## 2. Can all types of aluminum dust be attracted to a magnet?

No, only certain types of aluminum dust will be attracted to a magnet. This is because not all aluminum dust contains a high amount of iron. Other factors such as the size and shape of the dust particles, as well as the strength of the magnetic field, can also affect whether or not the dust will be attracted to the magnet.

## 3. Is dust aluminum attracted to a magnet the same as other magnetic materials?

No, dust aluminum being attracted to a magnet is different from other magnetic materials such as iron, nickel, and cobalt. While these materials are naturally magnetic, aluminum is not. The magnetic properties of dust aluminum are due to the presence of iron in the dust particles, not the aluminum itself.

## 4. Why is dust aluminum attracted to a magnet but not other non-magnetic materials?

Dust aluminum is attracted to a magnet because it contains a high amount of iron, which is a magnetic material. Other non-magnetic materials do not contain iron, so they do not have the ability to be attracted to a magnet.

## 5. Can dust aluminum be demagnetized?

Yes, dust aluminum can be demagnetized. This can be achieved by subjecting the dust particles to a strong magnetic field in the opposite direction of the original magnetization. This will cause the iron within the particles to lose their alignment and no longer be attracted to a magnet.