Samarium cobalt (SmCo), is a member of the lanthanide group on the periodic table. It is a close relative of neodymium. Both of them are called rare-earth elements. They are used to manufacture powerful and permanent magnets. A SmCo magnet is just as breakable as a neodymium magnet, namely Neo magnet. It should preferably be chipped or drilled prior to magnetization. Special diamond tools should be used for cutting or drilling operations. There is a lot of information that a prospective customer should know prior to buying samarium cobalt magnets. A simple guide is presented below.
1. How are SmCo magnets made
There are two methods for manufacturing these products. One method is called sintering. Super-fine samarium powder is molded into a solid thing through pressing. The first technique is called isostatic pressing. It entails unique rubber die that hosts SmCo powder as it is gently pressed with equal force in all directions. The isostatic method produces a solid material with higher magnetic properties but tinier in size. There is also an observation that isostatically produced parts have magnetic characteristics that boast lower uniformity. Compression bonding is another technique used to make SmCo magnets. During this process, a very special type of samarium powder is mixed with a plastic carrier substance. Then it is die-pressed and heated. The compression bonded components often have close tolerance thus demanding no machine finishing. What’s more, these parts can be transformed into more complicated magnet shapes. Compared to sintered magnets, compression bonded units have lower energy product.
2.Samarium cobalt: machining
As briefly mentioned above, SmCo is as brittle as the neodymium rare-earth magnet. It could cut and crack easily. Hence, users are not advised to use crude tools to machine samarium cobalt magnets. Special diamond tools should be used for grinding instead. Likewise, grinding work must be done with generous amounts of coolant to reduce the damage that could arise due to heat, such as fires (for flammable dust caused by grinding) or cracks. It’s wise to let professional machinists do the grinding work.
Just like neodymium magnets, SmCo magnets require very strong and high magnetic fields to reach saturation. Magnetization must, therefore, be done after assembling. To make assemblies special, adhesives that fasten brittle SmCo magnets are utilized.
Although a samarium cobalt magnet boasts a very strong magnetic field, yet it may crack or chip easily. The same case applies to neodymium rare-earth magnets. They are brittle and must all be handled with a lot of care. Proper handling can prevent personal injuries and hazards. These magnets should never be allowed to accelerate at a high speed to an attracting object. They could collide and shatter into particles. Kids should not handle SmCo magnet or any other rare-earth magnet as these can be very dangerous if swallowed or allowed to pinch the skin.
Since samarium-cobalt magnet contains a rare-earth element, it is rarely affected by high temperatures. A standard grade, however, should never be heated beyond 350゜C.
A SmCo magnet does not corrode, which is unlike a neodymium magnet, an alloy of neodymium, iron, and boron. Therefore it is not coated or plated.