What is an Alnico Magnet?

• Alnico Magnet Speakers
• Alnico Magnets Guitar
• Alnico Magnets Vs Neodymium Vs Ceramic Tesla
• Alnico Magnets Explained

Alnico Magnet Speakers

Applied Magnets is the #1 leading wholesaler of permanent rare earth industrial magnets, ferrite ceramic magnets, magnetic assemblies, magnet tools made with neodymium rare earth magnets, effective magnetic water treatment system made with the most powerful neodymium rare earth magnets and magnetic accessories and Magnetic Levitation Science Projects. Alnico magnets are ideal for corrosive and high heat applications up to 930°F (500°C). Dura can help optimize performance and cost with a variety of Cast and Sintered Alnico grades, including Alnico 2, Alnico 5, Alnico 5-7, and Alnico 8. Commonly used for various types of sensors.

Alnico magnets, composed of primarily aluminum (Al), nickel (Ni), and cobalt (Co), were developed in the 1940s. This class of magnet remains a preferred material because of its excellent temperature stability, high magnetic flux density, and resistance to corrosion.

Alnico magnets are manufactured through a casting or sintering process. The casting process allows the magnet to be manufactured into intricate and complex shapes. Sintered Alnico is made from a powdered mixture of ingredients that are pressed into a die under tons of pressure. The Sintering process allows for the magnets to be manufactured to tighter tolerances and higher mechanical strength.

• AlNiCo magnetic material is an alloy of Aluminum-Nickel-Cobalt which possesses excellent temperature stability and high residual induction. AlNiCo magnets have a low Coercive Force that limits their applications in many cases. Casting and sintering are two major processes used to manufacture the AlNiCo magnets.
• Alnico magnets are part of the permanent magnet family, and relatively high in magnetic strength. They offer excellent temperature stability & can be used at temperatures up to 1000⁰F (500⁰C). Because of their temperature stability and relatively high magnetic strength, they are commonly used for industrial applications such as rotating.
• Alnico permanent magnets are made up of alloys whose major constituents are iron, aluminum, nickel and cobalt, though other elements (e.g., copper and titanium) may be included in minor amounts. Grades of Alnico vary in cobalt content, which ranges from zero (Alnico 3) to 40% (Alnico 8).

Alnico Magnet Applications

• Guitar pickups
• Separators
• Sensors
• Radar
• Holding magnets
• Coin acceptors
• Motors
• Relays
• Controls

• Generators
• Receivers
• Telephones
• Microphones
• Bell ringers
• Loudspeakers
• Security systems
• And much more

Custom Alnico Magnet Shapes

Magnetic Hold is an alnico magnet manufacturer and supplier with capabilities to customize any magnet shape. We work with you to personalize your magnets for your application. Common magnet shapes include:

• Rods
• Bars
• Assemblies
• Horseshoe
• C-shaped
• Cylinders
• Rings
• Channels
• Arc
• Disc
• Block
• Sphere
• Plugs

Alnico Magnets Guitar

Cast Alnico Magnets

The most common Alnico cast magnets are in grades 1, 2, 3, 5, 6, 8, and 9. They are best suited for applications exposed to operating temperatures above 400 ° Fahrenheit. They maintain approximately 85% of their room-temperature strength up to 1000 ° F. They become completely demagnetized at approximately 1600 °F. For best results with Alnico 5 magnets, the length should be no less than 5 times the cross-section diameter or the diameter of a circle equal in area to the cross-section.

See the table below for cast Alnico magnet properties.

Alnico Magnet Grades & Properties

Br: Residual Induction
Gs: Gauss
Hc: Coercive Force
Oe: Oersted
˚C: Degree Celcius
MGOe: Mega Gauss Oersted

Alnico Magnets Vs Neodymium Vs Ceramic Tesla

Standard Tolerances (inches);
Rod - Diameter (±0.002), Length (±0.005)
Rectangle - Length & Width (±0.01), Thickness (±0.005)
Ring - Outside Diameter (±0.002), Inside Diameter (±0.02), Thickness (±0.005)

Sintered Alnico Magnets

They have marginally lower magnetic properties, but better mechanical properties, than cast Alnico. Their fine grain structure results in highly uniform flux distributions and mechanical strength. So they are suited for applications requiring short magnets.

See the table below for grades and properties of cast Alnico magnets.

Sintered Alnico Magnet Grades & Properties

Br: Residual Induction
Gs: Gauss
Hc: Coercive Force
Oe: Oersted
˚C: Degree Celcius
MGOe: Mega Gauss Oersted

Alnico Magnets Explained

Standard Tolerances (inches);
Rod - Diameter (±0.002), Length (±0.005)
Rectangle - Length & Width (±0.01), Thickness (±0.005)
Ring - Outside Diameter (±0.002), Inside Diameter (±0.02), Thickness (±0.005)

Magnetism Direction Options

• Square and rectangular Cast or Sintered Alnico magnets can be magnetized with two poles ('N' & 'S') through the length, width, thickness and multiple poles.
• Round Alnico magnet can be magnetized with two poles ('N' & 'S') the thickness, diametrically and with multiple poles.
• Ring Alnico magnet can be magnetized with two poles ('N' & 'S') through the thickness, diametrically and with multipoles. Contact us for the magnetism direction of irregular shapes.

Alnico magnet was successfully developed in the 1930s. It is composed of aluminum, nickel, cobalt, iron, and other trace metal elements. Thanks to their high coercivity and high Curie temperature, Alnico magnets are widely used in many industrial and consumer products, such as motors, electric guitar pickups, microphones, sensors, speakers, traveling wave tubes, and so on. But how are Alnico magnets made, do you know? In this article, let’s take a deeper look at the process of producing Alnico magnets.

Before diving into our article, let’s figure out how many types of Alnico magnets out there.

Alnico magnets can be produced by two methods, one by sintering and the other, more generally, by using a casting process. The density and mass of the Alnico magnets made by casting are larger so they have better magnetic characteristics and performance compared with the ones produced by sintering. But sintered Alnico magnets are more economical to produce. Besides, both anisotropic and isotropic variations of Alnico magnets can be achieved by sintering or casting.

When larger Alnico magnets weighing tens of kilograms are needed, then they will nearly always be made by casting method. However, really small Alnico magnets that weigh grams rather than kilograms are usually produced by using the sintering process. Sintering is usually the process used when a high volume of magnets are required.

Without further ado, let’s take a look at the steps of producing these two types of magnets.

The Steps of Producing Cast Alnico Magnets

Step one – Foundry Furnace

Different grades of Alnico have different recipes in terms of the percentage of aluminum, nickel, cobalt, and iron used. Quantities of the individual elements are placed in an induction furnace and are melted at a temperature of above 1750 degrees Celsius. There is more aluminum added than required to form the final magnet because some of the aluminum is wasted as it melts at a lower temperature (usually around 680 degrees Celsius).

During the melting and before casting, samples are taken, cooled, and analyzed with an x-ray spectrometer to make sure that the exact ratios of materials are correct and to allow any last-minute adjustments to be made.

Step Two – Casting

Pour the molten material into a shell mold or a larger green sand mold. As the molten metal cools, the shell mold starts to burn, and when the magnet becomes cold, the shell almost disintegrates. A shell mold is made by using a pattern plate and a molding machine.

The size of the patterns is similar to the required magnet size, but with an additional allowance for shrinkage and machining size. The internal magnetic cavities are connected by runners and these runners allow molten metal to reach each magnet cavity. Once the magnet is cast, these runners will be scrapped and remelted.

Step Three – Fettling

After that, the newly cast magnets are harvested from the molds and are then fettled on grinding wheels in order to remove the runner gates.

Step Four – Heat Treatment

The magnets are then heated to a very high temperature and placed in a magnetizer so that they can begin to cool down in a very strong magnetic field. This process is called hardening the magnet.

Then place the magnets in large tempering ovens for several days to temper and stabilize the magnets.

The heat treatment stage of the process, together with the foundry mix of alloys, makes the magnetic material have temperature handling characteristics and final magnetic properties.

Step Five – Grinding

Magnets usually need to be ground to a tight tolerance. Because the magnets are very hard, this is done by grinding.

Step Six – Testing

You can use a hysteresis graph tester, a Gauss meter, or a flux meter to test Alnico magnets.

Step Seven – Coating/Painting

If a specific coating is needed, this is done at the end of the process. The poles of the magnets may be fettled in order to make them bright and shiny.

Step Eight – Magnetising

The magnets are inserted into a coil or solenoid magnetizer, and within one-fifth of a second, an electrical pulse will generate the necessary magnetic field to fully magnetize the magnets.

The Steps of Producing Sintered Alnico Magnets

Step One – Pressing

The raw elements must be finely ground by milling into fine particles before sintered Alnico magnets are produced. The powdered magnetic material is then pressed into a die under a pressure of several tonnes, which closely resembles the magnets’ desired shape.

Step Two – Sintering

After the powder has been pressed, the material is sintered at a temperature above 1200°C in a furnace in a hydrogen atmosphere. This process fuses all the compressed particles together to form a magnet.

Step Three – Cooling

Then the red hot material is cooled. At this point, the material will have anisotropic properties and a preferred magnetic direction if it is cooled in the presence of an external magnetic field, which makes it stronger. Otherwise, if no external magnetic field is applied, the resulting magnet will be isotropic without a preferential direction of magnetism.

Photoshop 2020 crack for mac. Step Four – Coating

Typically, sintered Alnico magnets do not need further shaping or machining because the dies they are pressed into is very close to the required magnet shape. If a specific coating is needed, this can be done at the end of the process, just before the final magnetization of the magnets. To make the poles of the magnets bright and shiny, they can be fettled.

Step Five – Magnetising

At last, the raw magnetic material is placed in a coil or solenoid magnetizer for magnetization and then within one-fifth of a second, an electrical pulse generates the necessary field required to fully magnetize the magnet.

Conclusion

Thank you for reading our article and we hope it can help you to find the answer to the question of how are Alnico magnets made. If you want to know more about Alnico magnets and other types of magnets, we would like to advise you to visit Stanford Magnets for more information.

As a leading magnet supplier across the world, Stanford Magnets has been involved in R&D, manufacturing, and sales of magnets since the 1990s. It provides customers with high-quality permanent magnets like neodymium magnets, SmCo magnets, AlNiCo magnets, and ferrite magnets (ceramic magnets) at a very competitive price.