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Samarium Cobalt Magnets

We safely say that we have a life on this planet. But what we do not often mention is that we have life only on this planet as far as we know. No other known place in the universe provides such a hospitable environment and all other necessary substance to sustain such varied forms of life in one place.

It is our one and only home. It is a definitive Pandora’s Box, concealing riches which have enabled mankind to reach such mammoth proportions of progress in everyday life. Till the 18-th century man lived in basically a simple way in comparison to today’s extravagance.

With the advent of the Industrial age, human population began to grow exponentially and hence man had to produce or manufacture goods on a very large scale and very fast. Hence man explored and started making use of Earth’s natural resources to meet his own demands.

The Pandora’s Box had been opened and it showered man with riches. Oil, coal, minerals, valuable stones, plants, water and metals: everything the Earth could provide was put into labor to serve man’s need. Such a magnificent gift is a rare earth magnet, especially one type of it called samarium cobalt magnet.

What  are Samarium Cobalt Magnets?

Samarium cobalt magnets are a type of rare earth magnets. It is not so rare, as the name suggests but is found abundantly.

They are made from an alloy of samarium and cobalt and are the second placed strongest magnets after neodymium magnets having higher temperature ratings. These magnets are very brittle, expensive and prone to cracking and chipping.

They are available in two variations or series : Series 1:5 (SmCo₅) and Series 2:17(Sm₂Co₁₇).

They are resistant to demagnetization, have good temperature stability but are subject to price variations in applications as cobalt pricing is highly market dependent. They were first developed in the 1970s.

Uses of Samarium-Cobalt Magnets

Due to their relatively less strong magnetism than neodymium magnets, samarium-cobalt magnets have found application in more sensitive fields.

The guitar producing legend, Fender, has been using the latest Samarium Cobalt Noiseless series of guitar picks in the American Deluxe Series of guitars from the famous designer Bill Lawrence. Beside in the highly competitive slot-car racing, high end electronic motors use this kind of magnets.

Other uses are in turbo-machinery and traveling-wave tube. One big advantage of samarium cobalt magnets is that they can be used in both very low cryogenic temperatures as well as very high temperatures.

But one must exercise caution while using such magnets as the strong magnetic fields may cause permanent damage to body parts.

Ceramic magnets are generally the most favored materials from which magnets are made. A ceramic magnet is made using powdered magnetic materials, such as iron oxide (Rust) and Strontium carbonate.

Ferrites having a high magnetic absorptiveness, which enables them to amass magnetic fields stronger than iron, are referred to as Ceramic magnets. Generally, they are inflexible and brittle usually appearing in the shapes of cubes, cylinders, motor arcs

The formation, uses and advantages

A ceramic magnet is obtained by the amalgamation of two main materials. Through a process called Sintering, they are heated and melted down to such a point where they adhere to each other. Once that happens, the material is cooled, condensed into a certain shape dried and then sintered one last time.

Magnets such as these hold benefits of longevity and cost. They tend to withhold their magnetic capabilities for long periods and are thus, also called as permanent magnets. The raw materials required for making magnets is easily available in abundance at cheap prices for mass-production, immensely reducing the costs.

This combination has proved to increase the reputation of this variety of magnet. Uses of ceramic magnets run the enterprise from the mundane to the technical. The flexibility of magnets and their capacity to ensure their magnetization is the key to all of these applications.

Ceramic magnets are exclusive because of their use in flexible fabrics, for ornamental purposes, crafts and other usages in homes, educational and industrial institutions. Ceramic magnets have a boat-load of uses. They are commonly found in Sound systems, automobiles, medical equipments such as MRI machines, DC motors and several magnetic powered machines such as holders, lifters and separators along with industrial assemblies and tools.

All magnets can be custom-made to suit individual needs and ceramic magnets are no exception. Whether you are a fabricator who needs a particular magnet mass produced, an institution looking to use magnets for a one time project, or an individual who needs a magnet for use in the home, ceramic magnets are easily adjustable and customizable for any type of job you have in mind.

The disadvantages of Ceramic Magnets

Despite all the pros, there are some cons to the magnets as well. However Mass production of these magnets limits the variety of shapes it can moulded into. Most commonly, they are available in bar, cube, discs and ring shapes.

In certain circumstances, the magnetic capabilities may need to be minimized or to bluntly put it, be turned off whenever necessary. The problem is this cannot be done with ceramic magnets.

Magnets are very “attractive” and interesting elements. One of the earliest natural forces that humans stumbled upon was most probably magnetism, although it has been relatively recent that the dormant potential of the properties of magnetic substances have been realized.

Many electronic devices and gadgets which have become so conventional today employ the marvel of semiconductors which cannot function without their magnetic counterparts. Rumor is that a goatherd from Crete called Magnes was the first to stumble upon lodestone (magnetite) when his iron hook was attracted a stone when he passed by it.

Ferrite Magnets or Ferrites are ceramic materials, compounds of iron, boron and barium or strontium or molybdenum, primarily obtained from iron-oxides such as Hematite (Fe2O3) or Magnetite (Fe3O4) apart from oxides of above metals. They are used to make permanent magnets, ferrite cores (the winding structures in transformers), and for several other applications.

Ferrites similar to most other ceramics are stiff and fragile. A ferrite magnet is the most rudimentary type of magnet, in contrast to more complicated magnets like Alnico magnets or Neodymium magnets (rare-earth magnets, the most powerful permanent magnetic material of which we are currently aware).Ferrite magnets are permanent magnets and also the most common magnets known to us since our childhood days, because they are easily affordable and immensely popular.

The Classification of Ferrite Magnets

Ferrite magnets, or ferromagnetic materials, are classified broadly into two categories on basis of a property called magnetic coercivity, or perseverance of internal magnetism: The two are Hard ferrites and soft ferrites.

The hard/soft reference is not regarding the actual hardness of the materials as they both are brittle in nature but rather their magnetic coercivity. Based on these properties, they can be employed in different applications. For instance, a hard ferrite magnet might be used in a radio or data storage devices.

A soft ferrite magnetic would be used as a transformer core or an electromagnet core. These magnetic variants come in several designs and shapes such as like disc, arc, cylinder, sleeve etc.

They are also fitted in audio speakers, rotary electric motors, hand-cranked  magneto generators, wiper motor, dc motor, automobile fans, locomotive fans, and several other  electronics components along with industrial assembly lines and load lifting/separating machinery.

The Applications  of Ferrite Magnets

Magnets have been very useful and have been utilized in innumerous everyday objects. Many of today’s technological advancements we benefit from nowadays employ magnets in one way or another.

For instance, magnets are transformed into magnetic strips where in information can be stashed. In Video and Audio tapes, sound and images are stored on the magnetic coating of the tape. Keeping these tapes near a strong magnet will destroy the data embedded inside it.

ATM’s, credit and debit cards also employ a strip of magnetic field on its back. This strip houses all the information that is necessary to access one’s bank accounts and personal information in lieu with the card. The technology in Microphones and speakers also require magnets to make them work.

By merging a permanent and an electromagnet, speakers carry the signals that generate a changing magnetic field that directs the shift of the magnetic fields that is accomplished by the permanent magnet. This returning force moves the cone of the speaker which produces the sound.

The microphone applies the same idea but in a reverse manner. Transformers also use them. Then there are the other uses for magnets that can be quite fun and amusing, such as the refrigerator magnets and also its use in the vernacular to explain attraction between two separate entities.

As far as human knowledge goes, to whichever wondrous depths of knowledge that our explorer minds have been to, this planet, Earth, is the only place in the whole universe with the capability to support life in it.

Comparatively this planet is but a speck of dust in contrast to other heavenly bodies or the space between them. Still this blue-green globe contains all the necessary substances to support such flourishing and varied life forms as are found all over the planet. It is the only home humankind has. It is a quintessential Pandora’s Box, concealing riches that have enabled mankind to reach such high levels of progress in everyday life with such rapidity and authority.

With the advent of the Industrial age, human population began to grow exponentially and hence man had to produce or manufacture goods on a very large scale and very fast. Thus the Earth’s natural resources were called into action to supply the materials for building the cities and factories. Earth showered man with riches.

Oil, coal, minerals, expensive stones and metals: everything the Earth could give up was used to alleviate man’s living standard. One such gift is magnets, especially alnico magnets which are the strongest magnets among the non rare earth types.

How to make Alnico Magnets:

Alnico is actually an acronym for aluminium (Al), nickel (Ni) and cobalt (Co). They are iron alloys also containing copper and sometimes titanium. They are mostly used to make permanent magnets. In fact before the development of rare earth magnets in the 1970s, alnico magnets were the strongest type of magnets available.

They have excellent temperature stability, high induction residue and very high magnetic energies. They can be manufactured either by casting or sintering.

Cast magnets can be formed into various shapes, for example horseshoe magnets, which is not possible with any other type of magnets. There is a variation of cast magnets called the cast alnico 5 magnets which are the most of commonly used of all cast magnets and find a very wide range of applications.

Sintered alnicos on the other hand have weaker magnetic properties. Alnico magnets are very hard and brittle. Hence machining or drilling has to be performed with heavy machinery. They also have low coercivity and so are prone to demagnetization if not handled with care.

What are the uses of Alnico magnets?

Alnico magnets, being strong permanent magnets, are used extensively in industrial and consumer applications like electric motors, guitar pickups, microphones, cow magnets, travelling wave tubes etc.

Cast magnets are used mainly in meters, sensing devices, instruments and holding applications. One has to be careful while using them as they are prone to damage. In many areas stronger magnets like the rare earth magnets have superseded alnico magnets.

Knowing Alnico magnets

Alnico is an acronym referring to an alloy of Aluminium (Al), Nickel (Ni) and Cobalt (Co).It is basically an iron alloy which has Al, Ni and Co other than iron ore. It was first manufactured in Japan.

They are a category of strong permanent magnet with excellent temperature stability, high residual induction, and relatively high energy and are physically hard and brittle. Their shapes are mainly round and rectangle. However, many other shapes can also be manufactured using different foundry techniques.

Alnico has a low coercive force and can get easily demagnetized if it is not handled carefully. Despite that they can be pretty easily re-magnetized even if they lose partial magnetization.  Also some types of Alnico magnets are homogenous so they can be magnetized in any direction whereas the others are non-homogenous and therefore can be magnetized in only one specific direction. The latter have a greater magnetic capacity than the former.

One of the most useful properties of an Alnico magnet is that it is the only magnet that has useful magnetism even when heated red-hot. They are also one of the most stable magnets.

The creation of Alnico magnets

Alnico magnets can be produced by either casting or sintering process. The Manufacturing process of cast magnets is an elaborate one involving the pouring of a molten metal alloy into a mold and later treating the resultant material to heat in cycles. The magnet that is formed is dark grey in color with a rough surface.

However, machining of the surfaces can give them a shiny appearance like that of steel. Sintered magnets, on the other hand, are prepared by the compaction of fine grained Alnico powder by pressing and then produced compacted powder is sintered into a solid magnet.

Alnico is brittle, and therefore can easily chip or crack. To machine this material it is imperative to use special machining techniques. Cast Alnico materials contain some imperfections which can be exposed by finish machining.

According to the MMPA standard which provides specifications for Permanent Magnet Materials these magnets are mainly used for their magnetic properties rather than for physical use and hence it is imperative that during the manufacturing process some imperfections might creep in.

It is therefore recommended by the standard that these magnets not be used for structural purposes.

The applications of Alnico magnets

Alnico magnets are in wide use in the industry in sectors where strong permanent magnets are used. They are used in various appliances such as electric motors, loudspeakers, microphones etc.

However, in many applications they are being superseded by rare earth magnets, whose stronger fields and larger energy products allow smaller size magnets to be used for a given application.