Difference between revisions of "Magnet"

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'''Magnets''' are a commonly-encountered form of material that can be useful to the amateur chemist.
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| Name = Neodymium-iron-boron magnet
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| IUPACName = N/A
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| OtherNames = Neodymium magnet, neo-magnet
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| Section1 = {{Chembox Identifiers
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| 3DMet =
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| Section2 = {{Chembox Properties
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| Appearance = Lavander solid
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| Density =
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| Formula = Nd<sub>2</sub>(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>
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| MolarMass = 1081.15 g/mol
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| Odor = Odorless
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| Solubility = Insoluble
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| SolubleOther = Insoluble in organic solvents
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| ExternalMSDS = [https://www.docdroid.net/98D4aIW/neodymiumiii-oxalate-hydrate-sa.pdf.html Sigma-Aldrich] (hydrate)
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| MainHazards = Irritant
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'''Neodymium oxalate''' or '''neodymium(III) oxalate''' is the chemical compound with the formula '''Nd<sub>2</sub>(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>'''. At standard temperature and pressure, it is a lavender-colored solid. It is most commonly encountered in the process of purifying neodymium from [[magnets]].
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(WIP, changes in progress!)
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==General magnetic properties==
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===Curie temperature===
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The Curie temperature represents the temperature at which all magnetic crystal domains will realign randomly, effectively causing the magnet to lose all traces of magnetic force. This temperature is useful for removing the dangerous magnetic fields of stronger magnets.
  
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==Properties==
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===Magnetic field strength===
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===Chemical===
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The magnetic field strength is how much force the magnet can exert at a given size and magnetization. For example, a 1-pound 2"x2"x1" block of neodymium-iron-boron alloy, when fully magnetized, can lift over 500 pounds of weight.
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Neodymium oxalate is inert to most strong acids, including but not limited to concentrated [[Hydrochloric acid|hydrochloric]], [[Sulfuric acid|sulfuric]], and [[nitric acid]]s. In order to turn this into a usable neodymium compound, it must first be calcined to [[neodymium(III) oxide]].
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===Physical===
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==Types of magnets==
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Neodymium oxalate is a pink solid under natural light, and may acquire a yellow tinge under incandescent light.
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===Neodymium-iron-boron magnets===
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Neodymium magnets are composed of an alloy of [[neodymium]], [[iron]] and [[boron]] surrounded by a protective, oxygen-excluding metallic shell. See [[Neodymium iron boron magnet]] for more information. These magnets are approximately 27% Nd by weight. The typical range of Curie temperature for this alloy is 310 to 340 degrees C. These alloys may contain significant (>10%) amounts of [[cerium]], [[gadolinium]], [[praseodymium]], and other rare earths, as substituting these for Nd does not significantly impact the magnetic properties.
  
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==Preparation==
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===Samarium-cobalt magnets===
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Neodymium oxalate may be prepared from an acid-dissolved neodymium magnet by the addition of copious amounts of oxalic acid (available as wood bleach) and hydrogen peroxide (the more concentrated the better). At first, the precipitate will be either yellow or green, as iron oxalate coprecipitates. Upon addition of the hydrogen peroxide, however, the solution should fizz slightly, and in short order the yellow or green color of the precipitate should leach away. The iron is chelated into a vivid, emerald green complex in solution, and the neodymium oxalate remains insoluble as a pink or white precipitate.
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Samarium-cobalt magnets are composed of an alloy of [[samarium]] and [[cobalt]], typically surrounded by a protective metallic or Teflon shell. Some laboratory stir bars may use the SmCo alloy as the magnetic material owing to its higher temperature resistance than neodymium magnets. Two types of SmCo alloys are commonly made: SmCo<sub>5</sub> and Sm<sub>2</sub>Co<sub>17</sub>. The first is approximately 34% Sm by weight, and the second is approximately 23% Sm by weight. The typical range of Curie temperature for this alloy is 700 to 800 degrees C.
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===Alnico magnets===
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Alnico magnets are composed of an alloy of [[aluminium]], [[nickel]] and [[cobalt]], hence the name. These magnets' composition is not as tightly controlled as are rare-earth magnets', and as such the magnet composition can consist of a range of 8-12% Al, 15-26% Ni, 5-24% Co, 0-6% Cu, 0-1% Ti, and the remainder is Fe.
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===Ferrite magnets===
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Ferrite magnets are chiefly composed of a ceramic magnetic crystal form of [[iron oxide]], with trace additions of nickel, manganese, zinc, strontium, and/or barium to create a spinel crystal structure consisting of the compound AB<sub>2</sub>O<sub>4</sub>, where A is Fe, B is some 2+ cation such as zinc or barium, and O is oxygen.
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==Availability==
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Magnets can be cheaply purchased online or from the electronic stores. You can also salvage them from old machines, toys, electronics, though old ferrite and alnico magnets tends to become weaker with age, and they aren't very useful.
  
 
==Projects==
 
==Projects==
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=14145 Isolation of neodymium from magnets]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=14145 Isolation of neodymium from magnets]
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*[http://www.sciencemadness.org/talk/viewthread.php?tid=17986 Samarium from SmCo5 magnets]
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*Make a [[magnetic stirrer]]
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*Demonstration of diamagnetism (bismuth or pyrolytic carbon levitation)
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*Make a metal storage holder to hold ferromagnetic items
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*Make electricity from movement
  
 
==Handling==
 
==Handling==
 
===Safety===
 
===Safety===
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Neodymium is a heavy metal, and as such is toxic if ingested. Standard gloves should be safe to handle neodymium compounds with. Oxalates and oxalic acid are toxic by ingestion, and may lead to kidney stones and other deleterious side effects. The effects are somewhat mitigated by the fact that neodymium oxalate is inert and water-insoluble, however.
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Rare earths can cause heavy metal poisoning if ingested, but are otherwise safe to handle with basic PPE. Magnetized materials, however, can exert strong enough forces to injure the human body, and should thus be either demagnetized at their Curie temperature or kept away from other magnetic/ferrous materials.
  
 
===Storage===
 
===Storage===
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Neodymium oxalate can be stored safely in any container.
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Stronger magnets such as neodymium/samarium alloy magnets should be stored in soft foam padding, with spacers between individual magnets to avoid injury. Weaker varieties such as Alnico and ferrites can be stored anywhere.
  
 
===Disposal===
 
===Disposal===
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Neodymium oxalate should be converted into a less toxic form (such as the oxide, a refractory material) before being disposed of.
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Stronger magnets should always be demagnetized by heating before disposal to prevent injury.
  
 
==References==
 
==References==
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===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=14145 The trouble with neodymium...]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=14145 The trouble with neodymium...]
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*[http://www.sciencemadness.org/talk/viewthread.php?tid=8758 Rare earth metals, mischmetal, etc]
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*[http://www.sciencemadness.org/talk/viewthread.php?tid=14145 Isolation of neodymium from magnets]
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*[http://www.sciencemadness.org/talk/viewthread.php?tid=17986 Samarium from SmCo5 magnets]
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*[http://www.sciencemadness.org/talk/viewthread.php?tid=8758&page=2#pid126564 Rare earth metals, mischmetal, etc.]
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*[https://www.sciencemadness.org/whisper/viewthread.php?tid=29839 Best type of magnet for a stirrer/hotplate?!]
  
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[[Category:Equipment]]
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[[Category:Alloys]]
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[[Category:Magnetism]]
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[[Category:Readily available chemicals]]
 
[[Category:Chemical compounds]]
 
[[Category:Chemical compounds]]
 
[[Category:Inorganic compounds]]
 
[[Category:Inorganic compounds]]
 
[[Category:Lanthanide compounds]]
 
[[Category:Lanthanide compounds]]
 
[[Category:Neodymium compounds]]
 
[[Category:Neodymium compounds]]
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[[Category:Oxalates]]
 
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[[Category:Easily prepared chemicals]]
 

Revision as of 21:52, 3 March 2019

Stub.png This article is a stub. Please help Sciencemadness Wiki by expanding it, adding pictures, and improving existing text.

Magnets are a commonly-encountered form of material that can be useful to the amateur chemist.

General magnetic properties

Curie temperature

The Curie temperature represents the temperature at which all magnetic crystal domains will realign randomly, effectively causing the magnet to lose all traces of magnetic force. This temperature is useful for removing the dangerous magnetic fields of stronger magnets.

Magnetic field strength

The magnetic field strength is how much force the magnet can exert at a given size and magnetization. For example, a 1-pound 2"x2"x1" block of neodymium-iron-boron alloy, when fully magnetized, can lift over 500 pounds of weight.

Types of magnets

Neodymium-iron-boron magnets

Neodymium magnets are composed of an alloy of neodymium, iron and boron surrounded by a protective, oxygen-excluding metallic shell. See Neodymium iron boron magnet for more information. These magnets are approximately 27% Nd by weight. The typical range of Curie temperature for this alloy is 310 to 340 degrees C. These alloys may contain significant (>10%) amounts of cerium, gadolinium, praseodymium, and other rare earths, as substituting these for Nd does not significantly impact the magnetic properties.

Samarium-cobalt magnets

Samarium-cobalt magnets are composed of an alloy of samarium and cobalt, typically surrounded by a protective metallic or Teflon shell. Some laboratory stir bars may use the SmCo alloy as the magnetic material owing to its higher temperature resistance than neodymium magnets. Two types of SmCo alloys are commonly made: SmCo5 and Sm2Co17. The first is approximately 34% Sm by weight, and the second is approximately 23% Sm by weight. The typical range of Curie temperature for this alloy is 700 to 800 degrees C.

Alnico magnets

Alnico magnets are composed of an alloy of aluminium, nickel and cobalt, hence the name. These magnets' composition is not as tightly controlled as are rare-earth magnets', and as such the magnet composition can consist of a range of 8-12% Al, 15-26% Ni, 5-24% Co, 0-6% Cu, 0-1% Ti, and the remainder is Fe.

Ferrite magnets

Ferrite magnets are chiefly composed of a ceramic magnetic crystal form of iron oxide, with trace additions of nickel, manganese, zinc, strontium, and/or barium to create a spinel crystal structure consisting of the compound AB2O4, where A is Fe, B is some 2+ cation such as zinc or barium, and O is oxygen.

Availability

Magnets can be cheaply purchased online or from the electronic stores. You can also salvage them from old machines, toys, electronics, though old ferrite and alnico magnets tends to become weaker with age, and they aren't very useful.

Projects

Handling

Safety

Rare earths can cause heavy metal poisoning if ingested, but are otherwise safe to handle with basic PPE. Magnetized materials, however, can exert strong enough forces to injure the human body, and should thus be either demagnetized at their Curie temperature or kept away from other magnetic/ferrous materials.

Storage

Stronger magnets such as neodymium/samarium alloy magnets should be stored in soft foam padding, with spacers between individual magnets to avoid injury. Weaker varieties such as Alnico and ferrites can be stored anywhere.

Disposal

Stronger magnets should always be demagnetized by heating before disposal to prevent injury.

References

Relevant Sciencemadness threads

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