neodymium(NdFeB) magnets, samarium cobalt(SmCo5, Sm2Co17)magnets, Alnico magnets, permanent rare earth magnets.

Q:What are neodymium magnets made from and how are they made?

A: Neodymium magnets are actually composed of neodymium, iron and boron (they are also referred to as NIB or NdFeB magnets). The powdered mixture is pressed under great pressure into molds. The material is then sintered (heated under a vacuum), cooled, and then ground or sliced into the desired shape. Coatings are then applied if required. Finally, the blank magnets are magnetized by exposing them to a very powerful magnetic field in excess of 30 KOe.

Q:Will my neodymium magnets lose strength over time?

A:Very little. Neodymium magnets are the strongest and most permanent magnets known to man. If they are not overheated or physically damaged, neodymium magnets will lose less than 1% of their strength over 10 years - not enough for you to notice unless you have very sensitive measuring equipment. They won't even lose their strength if they are held in repelling or attracting positions with other magnets over long periods of time.

Q:What are neodymium magnets used for?

A:Just about anything you can imagine! Please see our Uses Page for a list of some of the applications for these incredible magnets.

Q:Are your Neodymium Rare Earth Magnets RoHS compliant?

A: Yes, our magnets are fully RoHS compliant, meeting the European Parliament Directive entitled "Restrictions on the use Of Hazardous Substances" (RoHS). This Directive prohibits the use of the following elements in electrical/electronic equipment sold after 7/1/2006: cadmium (Cd), lead (Pb), mercury (Hg), hexavalent chromium (Cr(VI)), polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs).

Q:Why do I have to purchase and use licensed Nd-Fe-B magnets?

Sumitomo and Magnequench hold many patents on Nd-Fe-B magnets and magnetic materials. Use of sintered Nd-Fe-B permanent magnets, as the piece part magnet or as it's assembly, made by non-licensee is prohibited by the Patent Law of the United States of America. We already saw many users purchasing the Nd-Fe-B magnets from non-licensed vendors and causing severe legal problems. All of sintered neodymium-iron-boron (Nd-Fe-B) permanent magnets, which Stanford Magnets Company supplies, are licensed.

Q:Which are the strongest magnets?

A-The most powerful magnets available today are the Rare Earths types. Of the Rare Earths, Neodymium-Iron-Boron types are the strongest. However, at elevated temperatures (of approximately 150C and above), the Samarium Cobalt types can be stronger that the Neodymium-Iron-Boron types (depending on the magnetic circuit).

Q:How do I pick-up the magnets I need?

First, decide the shape and size of magnets, which can server you applications best. Then visit our webpages "How to Choose Permanent Magnet Materials" and "How to Choose a Grade" to decide the material and grade of the magnets you need. Next step is go to the page Quotation Request to fill up the form with the information on the magnets and quantity required. After you click the "Submit" button, we will receive your request and provide you with our price quotation. You can also fax your specifications and drawings to us at 949-362-1810.

Q:What are permanent magnets made of?

Modern permanent magnets are made of special alloys that have been found through research to create increasingly better magnets. The most common families of magnet materials today are ones made out of Aluminum-Nickel-Cobalt (Alnicos), Strontium-Iron (Ferrites, also known as Ceramics), Neodymium-Iron-Boron (Neo magnets, sometimes referred to as "super magnets"), and Samarium-Cobalt. (The Samarium-Cobalt and Neodymium-Iron-Boron families are collectively known as the Rare Earths.)

Q:Can I have a catalog of your magnets?

A:Unfortunately, we do not print Product Catalog. Please refer to above question to decide the magnets you need.

Q:Can I have a free sample of your magnets?

A:Our company's policy does not allow us to send out free samples. We keep our operation overhead low, so that we can offer our customers with our quality magnets at very competitive prices.

Q:How long will it take to receive your price quotation?

A:Usually take 1- 3 working days. However, if we are not able to supply the magnets you need, such as, either the size is too big, or the shape is too complicated, we may not provide you with our price quotation.

Q:How are magnets made?

Modern magnet materials are made through casting, pressing and sintering, compression bonding, injection molding, extruding, or calendering processes.

Q:Will magnets lose their power over time?

A-Modern magnet materials do lose a very small fraction of their magnetism over time. For Samarium Cobalt materials, for example, this has been shown to be less that 1% over a period of ten years.

Q:How do you measure the strength or power of a magnet?

A-Most commonly, Gaussmeters, Magnetometers, or Pull-Testers are used to measure the strength of a magnet. Gaussmeters measure the strength in Gauss, Magnetometers measure in Gauss or arbitrary units (so its easy to compare one magnet to another), and Pull-Testers can measure pull in pounds, kilograms, or other force units. Special Gaussmeters can cost several thousands of dollars. We stock several types of Gaussmeters that cost between $400 and $1,500 each.

Q:What are Magnetic Poles?

A-Magnetic Poles are the surfaces from which the invisible lines of magnetic flux emanate and connect on return to the magnet.

Q:What are the standard industry definitions of "North" and "South" Pole?

A-The North Pole is defined as the pole of a magnet that, when free to rotate, seeks the North Pole of the Earth. In other words, the North Pole of a magnet seeks the North Pole of the Earth. Similarly, the South Pole of a magnet seeks the South Pole of the Earth.

Q:What is your lead-time after I place a purchase order?

A:Usually take 2-3 weeks. If it is needed to make a mould, it may take a longer time. For a large production quantity purchase order, say ten thousands pieces, it may take a longer time.

Q:What is your minimum order in value?

A:$100.

Q:What is your minimum order in quantity?

A:One piece. However, please be advised that a larger quantity order always receives a lower price.

Q:What might affect a magnet's strength?

A-The factors can affect a magnet's strength: Heat, Radiation, Strong electrical currents in close proximity to the magnet. Other magnets in close proximity to the magnet.(Neo magnets will corrode in high humidity environments unless they have a protective coating.) Shock and vibration do not affect modern magnet materials, unless sufficient to physically damage the material

Q:What kind of payment do you accept.

A:Company’s checks, credit cards (VISA and MasterCard), personal checks and wire-transfer.

Q:How permanent is a magnet's strength??

A:If a magnet is stored away from power lines, other magnets, high temperatures, and other factors that adversely affect the magnet, it will retain its magnetism essentially forever.

Q:How is the strength of a magnet measured?

A:Gaussmeters are used to measure the magnetic field density at the surface of the magnet. This is referred to as the surface field and is measured in Gauss (or Tesla). Pull Force Testers are used to test the holding force of a magnet that is in contact with a flat steel plate. Pull forces are measured in pounds (or kilograms)

Q:Can you supply BH Curves, or Demagnetization Curves for your magnets?

A:Yes, we CAN posted Demagnetization Curves for our most common Neodymium magnet grades

Q:What are neodymium magnets? Are they the same as "rare earth"?

A: Neodymium magnets are a member of the rare earth magnet family. They are called "rare earth" because neodymium is a member of the "rare earth" elements on the periodic table. Neodymium magnets are the strongest of the rare earth magnets and are the strongest permanent magnets in the world.

Q:Can a magnet that has lost its magnetism be re-magnetized?

A-Provided that the material has not been damaged by extreme heat, the magnet can be re-magnetized back to its original strength.

Q:Can I make a magnet that I already have any stronger?

A-Once a magnet is fully magnetized, it cannot be made any stronger - it is "saturated". In that sense, magnets are like buckets of water: once they are full, they can't get any "fuller".

Q:Can I have a free sample of your magnets?

Our company's policy does not allow us to send out free samples. We keep our operation overhead low, so that we can offer our customers with our quality magnets at very competitive prices.

Q:How long will it take to receive your price quotation?

Usually take 1- 3 working days. However, if we are not able to supply the magnets you need, such as, either the size is too big, or the shape is too complicated, we may not provide you with our price quotation.

Q:What is your lead-time after I place a purchase order?

Usually take 2-3 weeks. If it is needed to make a mould, it may take a longer time. For a large production quantity purchase order, say ten thousands pieces, it may take a longer time.

Q:What is your minimum order in value?

$200.

Q:How can you tell which is the North Pole if it is not marked?

A-You can't tell by looking. You can tell by placing a compass close to the magnet. The end of the needle that normally points toward the North Pole of the Earth would point to the South Pole of the magnet.

Q:What are the different types of magnets available?

A-There are 2 types of magnets: permanent magnets and electro-magnets. Permanent magnets emit a magnetic field without the need for any external source of power. Electro-magnets require electricity in order to behave as a magnet. There are various different types of permanent magnet materials, each with their own unique characteristics. Each different material has a family of grades that have properties slightly different from each other, though based on the same composition.

Q:What are Rare Earth Magnets?

A-Rare Earth magnets are magnets that are made out of the Rare Earth group of elements. The most common Rare Earth magnets are the Neodymium-Iron-Boron and Samarium Cobalt types.

Q:What is your minimum order in quantity?

One piece. However, please be advised that a larger quantity order always receives a lower price.

Q:What kind of payment do you accept?

Company’s checks, credit cards (VISA and MasterCard), personal checks and wire-transfer.

Q:What is your company's policy on Return?

Please visit the page General Terms And Conditions for detailed informaiton.

Q:How do I pick-up the magnets I need?

First, decide the shape and size of magnets, which can server you applications best. Then visit our webpages "How to Choose Permanent Magnet Materials" and "How to Choose a Grade" to decide the material and grade of the magnets you need. Next step is go to the page Quotation Request to fill up the form with the information on the magnets and quantity required. After you click the "Submit" button, we will receive your request and provide you with our price quotation. You can also fax your specifications and drawings to us at Can I have a catalog of your magnets.

Q:Can I have a catalog of your magnets?

Unfortunately, we do not print Product Catalog. Please refer to above question to decide the magnets you need.

Q:Can I have a free sample of your magnets?

Our company?ˉs policy does not allow us to send out free samples. We keep our operation overhead low, so that we can offer our customers with our quality magnets at very competitive prices.

Q:What does 'orientation direction' mean?

A-Most modern magnet materials have a "grain" in that they can be magnetized for maximum effect only through one direction. This is the "orientation direction", also known as the "easy axis", or "axis".

Unoriented magnets (also known as "Isotropic magnets") are much weaker than oriented magnets, and can be magnetized in any direction. Oriented magnets (also known as "Anisotropic magnets") are not the same in every direction - they have a preferred direction in which they should be magnetized.

Q:How long will it take to receive your price quotation?

Usually take 1- 3 working days. However, if we are not able to supply the magnets you need, such as, either the size is too big, or the shape is too complicated, we may not provide you with our price quotation.

Q:What is your lead-time after I place a purchase order?

Usually take 2-3 weeks. If it is needed to make a mould, it may take a longer time. For a large production quantity purchase order, say ten thousands pieces, it may take a longer time.

Q:What is the motor?

A: The motor is the battery power into mechanical energy to drive electric cars wheels rotating parts.

Q:What is winding?

A: The DC motor armature winding is the core part of the enameled wire wound copper coil. When the armature windings in the motor's rotating magnetic field generates electromotive force.

Q:What is the magnetic field?

A: In the permanent magnet or current that occurred around the magnetic force field, and those who can achieve the scope of the role of space or magnetic.

Q:What is the magnetic field strength?

A: The definition contains a 1 amp current in an infinitely long wire away from the wire 1 / 2 meters away, the magnetic field strength of 1A / m (amperes / m, the International System of Units SI); in the CGS System of Units (cm - g - s) China, to commemorate the contribution of electromagnetic Oster right to define 1 amp current carrying infinitely long wire at a distance of 0.2 centimeters distant wire field strength 10e (Oster), 10e = 1/4.103/m, the magnetic field H intensity is usually expressed.

Q:What is the amps Rule?

A: The right hand hold the wire, so straight in the direction of the thumb in line with the current direction, then four fingers bent under the direction of the line is around the direction of magnetic induction.

Q:What is the magnetic flux?

A: The magnetic flux is also called the magnetic flux: located in the uniform magnetic field has a magnetic field perpendicular to the plane, the magnetic field strength of the magnetic induction B, flat area of S, we define the magnetic induction intensity B and the area S of the product, called through the The surface magnetic flux.

Q:What is the stator?

A: There are brush or brushless motor part of the work will not be diverted. Wheel-hub with no tooth brush or brushless motor motor shaft is called the stator, this motor can be called unofficially sub-motors.

Q:What is the rotor?

A: There are brush or brushless motor work rotating parts. Wheel-hub with no tooth brush or brushless motor shell is called the rotor, such a motor can be called the external rotor motor.

Q:What Brush?

A: There are brush motors inside the top surface of the commutation, motor rotation when the transfer of electrical energy through the phase detector transfer to the coil, as its main component is carbon, known as the Brush, it is easy to wear. Should be replaced regularly to maintain and clean up carbon deposit.

Q:What is a brush holder?

A: brush motor carbon brush inside the dress and keep the location of slot machine guide.

Q:What is the inverter?

A: There are brush motors inside, with insulation between the strip

Q:What is your minimum order in quantity?

One piece. However, please be advised that a larger quantity order always receives a lower price.

Q:What kind of payment do you accept

Company checks, credit cards (VISA and MasterCard), personal checks and wire-transfer.

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    Q:What does a magnet do?

    Attract certain materials - such as iron, nickel, cobalt, certain steels and other alloys; Exert an attractive or repulsive force on other magnets (opposite poles attract, like poles repel); Have an effect on electrical conductors when the magnet and conductor are moving in relation to each other; Have an effect on the path taken by electrically charged particles traveling in free space.

    Q:Why do I have to purchase and use licensed Nd-Fe-B magnets?

    Sumitomo and Magnequench hold many patents on Nd-Fe-B magnets and magnetic materials. Use of sintered Nd-Fe-B permanent magnets, as the piece part magnet or as it?ˉs assembly, made by non-licensee is prohibited by the Patent Law of the United States of America. We already saw many users purchasing the Nd-Fe-B magnets from non-licensed vendors and causing severe legal problems. All of sintered neodymium-iron-boron (Nd-Fe-B) permanent magnets, which YiLi Magnets Company supplies, are licensed.

    Q:Motor products are affected on the human body?

    According to Beijing Metro Line project Mentougou electromagnetic data on magnetic levitation, acoustic environment, environmental vibration test results showed that: the safety of magnetic and electromagnetic radiation from the human body is to a certain extent, but this parameter is also allowed in certain controllable range. However, further reports that, S1 electromagnetic maglev line data, the sound, vibration environment at this time results in line with national standards related to the implementation.

    According to the news reports, motor magnet, magnetic materials, magnetic components and other magnetic products on the human body have a certain impact. However, the impact to be controlled in a certain range. Lower body injury.

    Q:How does it work?

    Neodymium magnets also contain Iron and Boron, making them some of the strongest magnets in the world. Magnets of all types create a magnetic field, with both a north and south pole. The magnetic field created by the neodymium magnets is so strong; it will line up to match the magnetic north and south of the earth. It makes a great compass! On a more serious note, the large magnets are so strong that they may even be dangerous if not handled properly. A pair of these magnets will leap into a deadly embrace from over 6 inches apart and may knock chips off themselves from the force of the impact. You’ll be amazed at the super strength of the magnets, but we must warn you to be careful. Any type of magnetic media will be history in the presence of one of these large neodymium magnets.

    Q:What does it teach?

    Discover the magic of magnetic fields, friction, and the magnetic poles of the earth. U.S. dollar bills are printed with magnetic inks so that their passage from hand to hand can be traced. They are designed to prevent counterfeiting. Get a dollar and fold it in half. Hold the neodymium magnet near the bottom of the bill and notice how it attracts the iron. This could be a great magnetic demonstration for a science fair!

    Q:What are the differences between the different magnet formulations you sell?

    NdFeB (Neodymium-Iron-Boron) -- The most powerful 'rare-earth' permanent magnet composition known to mankind, and our specialty. This formulation is relatively modern, and first became commercially available in 1984. NdFeB magnets have the highest B, Br, and BHmax of any magnet formula, and also have very high Hc (see below for definitions). They are however very brittle, hard to machine, and sensitive to corrosion and high temperatures. Useful in the home, workshop, pickup truck, laboratory, wind turbine, starship and more. We carry both new and surplus stock in many sizes and shapes.In almost all magnet applications, NdFeB are the best choice for incredible strength and coercivity at a reasonable price! In power generation applications, NdFeB magnets can be expected to give 4-5 times the power output of ceramic magnets.

    Ferrite (Ceramic) -- Also known as 'hard ceramic' magnets, this material is made from Strontium or Barium Ferrite. It was developed in the 1960s as a low-cost and more powerful alternative to AlNiCo and steel magnets. Less expensive than NdFeB magnets, but still very powerful and resistant to demagnetization. Useful everywhere. We carry both new and surplus in multiple shapes and sizes. Ferrite magnets are lower in power (B, Br, BHmax) compared to other formulations, and are very brittle. However, they have very high Hc and good Tc (see below), and are quite corrosion-resistant. A very cost-effective choice.

    AlNiCo (Aluminum-Nickel-Cobalt) for medium strength and excellent machinability. Developed in the 1940s and still in use today. They perform much better than plain steel, but are much weaker in strength (lower B, Br and BHmax) and must be carefully stored since they are prone to demagnetization. Contact with a NdFeB magnet can easily reverse or destroy the field of an AlNiCo magnet.

    SmCo (Samarium Cobalt)-- for high power and resistance to high temperatures and corrosion. Developed in the 1970s, these were the first so-called 'rare earth' magnets. They are almost as powerful as NdFeB magnets, and far more powerful than all the others (high B and Br). They are the most expensive magnet formulation, and usually only used where resistance to high temperatures (high Tc) and corrosion are needed. Also very brittle and hard to machine.

    Bonded (flexible)-- magnets are a rubberized formulation often seen on refrigerators and magnetic signs. Though they may be manufactured from any magnet formulation when powerdered and mixed with rubberizer, the result is always less powerful than a traditional sintered magnet of any formula. Used only where unusal and difficult shapes are needed.

    Q:How are your magnets measured and graded for strength, quality?

    Magnet Strength Measurements (B)--The units for measuring the field strength (flux density) of a magnet are Gauss or Tesla. 1 Tesla = 10,000 Gauss. The Earth's magnetic field is on the order of 1 Gauss. There are different ways to classify and measure field strength:

    B (flux density): This is the measurement (in Gauss or Tesla) you get when you use a gaussmeter at the surface of a magnet. The reading is completely dependant on the distance from the surface, the shape of the magnet, the exact location measured, the thickness of the probe and of the magnet's plating. Steel behind a magnet will increase the measured 'B' significantly. Not a very good way to compare magnets, since B varies so much depending on measurement techniques.

    Br (residual flux density): The maximum flux a magnet can produce, measured only in a closed magnetic circuit. Our figures for each magnet are provided to us by the magnet manufacturer. They are a good way to compare magnet strength...but keep in mind that a magnet in a closed magnetic circuit is not doing any good for anything except test measurements.

    B-H Curve: Also called a "hysteresis loop," this graph shows how a magnetic material performs as it is brought to saturation, demagnetized, saturated in the opposite direction, then demagnetized again by an external field. The second quadrant of the graph is the most important in actual use--the point where the curve crosses the B axis is Br, and the point where it crosses the H axis is Hc (see below). The product of Br and Hc is BHmax. If we have these measurements available, they are provided to us by the magnet manufacturer--very complicated and expensive equipment is needed to plot a B-H curve.

    Magnet Quality (BHmax): The quality of magnetic materials is best stated by the Maximum Energy Product (BHmax), measured in MegaGauss Oersted (MGOe). This is because the size and shape of a magnet and the material behind it (such as iron) have a large effect on the measured field strength at the surface, as does the exact location at which it measured. All of our Nickel-plated NdFeB magnets are grade N35 (BHmax=35 MGOe) and all of our Gold-plated NdFeB magnets are grade N45 (BHmax=45 MGOe). This gives about a 5% difference in strength, and a 150% difference in cost...it is wise to balance your magnet strength needs by cost too. Other magnets are measured the same way -- a grade 8 ferrite magnet (grade C8) has BHmax=8 MGOe.

    Coercivity (Hc): This measures a magnet's resistance to demagnetization. It is the external magnetic field strength required to magnetize, de-magnetize or re-magnetize a material, also measured in Gauss or Tesla.

    Q:How does temperature affect the behavior of a permanent magnet?

    Curie Temperature (Tc): This is the temperature at which a magnet material loses it's strength, permanently. Another useful number (if available) is Tmax, the recommended maximum operating temperature. Above Tmax (around 266 deg. F for most NdFeB magnets) a magnet will start ot lose its power, and at Tc all power is lost. If you need strong magnets that can be used at high temperatures, consider using Samarium Cobalt (SmCo) magnets.

    Q:Will magnets corrode if used outdoors?

    NdFeB magnets are susceptible to corrosion. The 'Fe' in the name stands for Iron, and it rusts! Many of our magnets come with a Nickel, Zinc, Gold or Epoxy coating to protect them from moisture. If the coating is damaged (frequently the case with surplus magnets) the magnet could rust if exposed to water or humidity. If this is a concern to you, you can easily add another layer of protection by dipping the magnet in epoxy or plastic coating.

    Q:How are magnets manufactured? Can I make them at home?

    Manufacturing: NdFeB magnets are complicated to manufacture. The powdered NdFeB material is packed in molds, then sintered. The non-magnetized 'magnets' are then shaped to the correct size and plated. To magnetize them, they are placed in a very expensive machine that generates an extremely high-powered magnetic field for an instant, using high-voltage capacitor discharge and coils. The polarity of the finished magnet depends on how it was oriented in the magnetizing machine, and how the particles in the sintered mixture were oriented. So that makes home manufacture impossible. You CAN, however, make a simple steel magnet at home. Take a nail and stroke it with a strong NdFeB magnet 20 or 30 times, ALWAYS moving the magnet in only one direction on the nail. Presto, the nail will be magnetized, altough very weakly.

    Q:Can I cut, drill or machine magnets to my own sizes and shapes?

    Yes and no. AlNiCo magnets are very easy to machine in any way you wish. NdFeB magnets are by nature very hard and brittle. Although they can be cut, drilled and machined, it should ONLY be done by folks who are experienced with ceramics. If the magnets get over about 300 deg F, they will lose their magnetism permanently. They are flammable, and it is not difficult while grinding or machining to get them (or the chips and dusts from cutting) so hot hot they ignite. If they do ignite, the fumes are toxic and the material burns very fast and hot, like Magnesium! In our experience any machining of these magnets should be done with diamond tools under lots of coolant with good ventilation and the risk of fire in mind.

    Q:How can you ship magnets safely? Don't they affect airplane compasses?

    We take great care when packing orders to see that any magnetic fields are well contained within the box we send them in. We pack very carefully so the external magnetic fields cancel out, and we use steel box liners as needed to insure that every box is safe and non-magnetic to comply with national and international postal regulations. We also test each package before it goes out to be sure it complies with all regulations.

    Q:What safety issues should I be aware of when handling magnets?

    First of all, keep magnets out of reach of children! Although magnets can be wonderful toys and highly educational, these are 'adult' toys, and not for children. Small children should not be allowed to handle any of our magnets at all! Older children should handle them only under adult supervision, and wearing proper safety equipment (depending on the size and power of the magnets being used). Small magnets pose very little hazard, but large magnets should be handled with extreme caution. Surprise is the main issue -- most folks are not aware of how powerful large magnets are. Please thoroughly read and understand our Magnet Safety Warnings page before ordering!

    Q:What is a magnetic field? What are magnetic field lines?

    Magnetic fields are historically described in terms of their effect on electric charges. A moving electric charge, such as an electron, will accelerate in the presence of a magnetic field, causing it to change velocity and its direction of travel. This is, for example, the principle used in televisions, computer monitors, and other devices with CRTs (cathode-ray tubes). In a CRT, electrons are emitted from a hot filament. A voltage difference pulls these electrons from the filament to the picture screen. Electromagnets surrounding the tube cause these electrons to change direction, so they hit different locations on the screen.

    Q:How are magnetic fields measured?

    The strength of a magnetic field is measured in units of Gauss (G), or alternatively, in Tesla (T). In the MKS (metric) system of units, 1 T = 1 kilogram*ampere/second^2 = 10^4 G.

    For comparison, the magnetic field of the earth at the surface is on the order of 1 Gauss, where that of a Neodymium magnet is on the order of 10^4 Gauss. This means that Neodymium magnets produce magnetic fields tens of thousands of times stronger than those of the earth!

    Technically, Gauss and Tesla are units of magnetic induction, also known as magnetic flux density. (This term is described in an earlier question.) Quantitatively, the force on a charged particle q moving with velocity v is given by the vector equation F = qv x B, where B is the magnetic induction.

    Another common quantity of interest is the corecivity or corercive force of a magnet. Also measured in Gauss, the coercivity is the magnetic field required to demagnetize a material. For example, Neodymium magnets typically have a coercivity of about 12000 Gauss. Please note that the coercivity is the magnetic field required for de-magnetization. It is not actually a mesaure of the "strength" of the magnet, although the highly coercive magnets are usually quite strong.

    The maximum energy product is used to determine the quality of magnetic materials. This is typically measured in Megagauss Oersted (MGOe - quite a mouthful!). The maximum energy product basically determines what materials make the best magnets.

    Magnetic field strengths are measured with devices known as magnetometers, also called Gaussmeters.

    Q:Why are there so many odd units and terms used to describe magnetic fields?

    Keep in mind that magnetic fields appear any a large variety of contexts besides permanent magnets. Engineers and scientists regularly deal with magnetic fields in the study of electric circuits, motors, optics, and various other fields of technology. The power of the magnetic fields involved can vary a great deal, so many ways of measuring things have developed through the ages.

    Q:What was the first discovered magnetic material?

    The first known magnetic material is a naturally-occurring mineral deposit known as a lodestone. It was found that small rods constructed out of this material would always point north if permitted to swing freely (i.e., when suspended from a string.) This discovery was useful for early navigational systems on ships.

    Q:How are electricity and magnetism related?

    Magnetism and electricity are closely related phenomena. Electric charge is a fundamental property of matter. Matter is made up of electrons, neutrons, and protons. Electrons have a negative electric charge, while protons have a positive electric charge; neutrons have no electric charge. These tiny particles are the building blocks of atoms. An atom has a net positive electric charge when it loses one of its electrons, and a net negative electric charge when it gains an extra electron. On the other hand, magnetic charges do not exist - Magnetic fields are generated solely by moving electric charges.

    An example of the relationship between electricity and magnetism is the motor. In a motor, a voltage is applied across the terminals of a coil of wire. The voltage causes the electrons in the wire to move, which in turn generates a current. This current results in a magnetic field, which interacts with permanent magnets attached to the core of the motor, causing it to move.

    Another example of the relationship between magnetism and electricity is the Lorentz force mentioned previously. Perhaps the most significant relationship between electricity and magnetism is light, which is known to physicists as an electromagnetic wave. Light waves are oscillating patterns of electric and magnetic fields, propagating through space at the speed of light (3x10^8 meters/second).

    Light is the best known example, but microwaves, radio waves, X-rays, infrared and ultraviolet light are also electromagnetic waves.

    Electric and Magnetic phenomena are intricately described by a collection of physical laws, known as Maxwell's equations. Fully understanding these complex equations require a thorough knowledge of calculus and differential equations. For more information, take a course in electromagnetic theory from your local university. :-)

    Q:Why do magnets have poles?

    This is a physical property of magnetic fields. Magnetic fields are vector quantities, meaning they have both a magnitude and a direction. Many measurable physical phenomena are described in terms of scalar quantities, which have only a magnitude. An example of a scalar quantity is temperature; temperature has a magnitude (which you can measure with a thermometer), but no direction.

    On the other hand, magnetic fields are directional. In a magnet, the magnetic field vector always points from the north pole to the south pole. In the space around the magnet, the vectors vary in both direction and magnitude. This is the behavior you see when you dump iron filings around a bar magnet, for example. Vector quantities which vary in space are known as fields; thus we have the term magnetic field for the vector field surrounding a magnet.

    Q:How does a permanent magnet work?

    Some materials have a feature known as ferromagnetism. The prefix "ferro" refers to Iron, which is one such material. Ferromagnetic materials have the ability to "remember" the magnetic fields they have been subjected to.

    An atom consists of a number of negatively charged electrons, orbiting around a positively charged nucleus. These electrons also possess a quantity known as spin, which is roughly analogous to a spinning top. The combination of orbital and spin motions is called the angular momentum of the electron. Angular momentum is perhaps most easily understood in the case of the Earth: The earth spins about a central axis, which means it at has an angular momentum around that axis. The planets also have an angular momentum as they revolve about the sun.

    Now, the angular momentum of an electron is a vector quantity, meaning it has direction. The motion of the electron produces a current, which in turn generates a tiny magnetic field in the direction given by the angular momentum. Thus an atom can behave like a dipole, meaning "two poles". The direction of the orbital and spin angular momentum of the electron determine the direction of the magnetic field for the electron and the entire atom, thus giving it "north" and "south" poles. Different atoms have different arrangements of electrons into their orbits, and thus have different angular momenta and dipolar properties.

    A ferromagnetic material is composed of many microscopic magnets known as domains. Each domain is a region of the magnet, consisting of numerous atomic dipoles, all pointing in the same direction. A strong magnetic field will align the domains of a ferromagnet, or in other words, magnetize it. Once the magnetic field is removed, the domains will remain aligned, resulting in a permanent magnet. This effect is known as hysteresis.

    Few materials are actually ferromagnetic; however, all substances have a diamagnetic nature. Diamagnetism means that the molecules within a substance will align themselves to an external magnetic field. The external magnetic field induces currents within the material, which in turn result in an internal magnetic field in the opposite direction. This effect is usually quite small and disappears when the external magnetic field is removed.

    Some materials are paramagnetic. This is the case when the orbital and spin motions of the electrons in a material do not fully cancel each other, so that the individual atoms act like magnetic dipoles. These dipoles are randomly oriented, but will align themselves to an external magnetic field. However, when the field is removed, the material is no longer magnetized. Again, this effect is typically small. Neither diamagnetic nor paramagnetic materials exhibit magnetic domains.

    The atomic behavior of magnetic materials is actually considerably more complicated than this, as it relies on the theory of quantum mechanics. Quantum mechanics is the theory of physics used to describe the behavior of tiny particles such as electrons; like electromagnetic theory, it is complex and involves advanced mathematics.

    Q:What are Neodymium magnets made of?

    Not just Neodymium! Neodymium itself is actually a element number 60 on the periodic table. Neodymium magnets are actually made up of a compound called NIB, for Neodymium Iron Boron (Nd2Fe14B). This compound is one of the strongest known ferromagnetic materials.Click here for more information about the element Neodymium.

    Q:How can I make a magnet levitate?

    Click on the links below to check out our experiments with diamagnetic materials and superconductors :Diamagnetic levitation Supeconductivity Experiments

    Q:Are your magnets graded for quality?

    All of of our new, Nickel-plated magnets have a grade of N35, which means a maximum energy product of 35 MGOe. Our new gold plated magnets are all grade N-45. We do not have ratings for any of our surplus magnets.

    Q:Why won't my perpetual motion machine work?

    Perpetual motion machines are one of the true holy grails of physics; unfortunately, perpetual motion machines do NOT EXIST according to the currently accepted theories. They are denied by the Three Laws of Thermodynamics, which are proven by statistical mechanics, which is derived from quantum mechanics, which has been verified experimentally enough that it would be silly to deny it!

    The First Law of Thermodynamics states that Energy is Conserved. This means that the total energy of a closed system must remain constant. The universe, considered as a closed system, thus has constant energy.

    Energy exists in many forms: as heat, kinetic (motion) energy, and potential (gravitational, electric, and magnetic) energy, to name a few. The energy can change from one form to another. It can also pass from one system to another. Still, the total energy of a closed system will always be constant. You can neither create nor destroy energy; it always moves elsewhere.

    The Second Law of Thermodynamics states that The entropy of a closed system must always increase. The entropy is a measure of the disorder of a system. If you consider the universe itself as a closed system, then the entropy of the universe must always increase. Therefore, the universe is continually moving towards a state of greater disorder!

    Consider a glass of water, sitting initially on a table. You decide to push it off the edge and it shatters into fragments. It is now in a more disordered state, so it has greater entropy. The process can never reverse itself; you can't reassemble the glass and put the water back in it.

    Now a perpetual motion machine has, by definition, moving parts. The motion results in the transfer of heat through friction and air resistance. This results in a loss of energy by the device; the First Law implies that the total energy of the universe is conserved, so the energy is actually being transferred elsewhere.

    Assuming you don't add energy to this system, its energy will continually decrease and its entropy will likewise increase. Eventually it will slow and stop. Therefore, there is no such thing as a perpetual motion machine.

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