Cobalt is a very popular ferromagnetic metal that is utilized in many industries due to its vast range of applications.
It retained its magnetism and was mostly used in permanent magnets. Cobalt magnets are alloyed with aluminum and nickel and are generally used in medical devices, turbines, and motors.
In this article, we will discuss magnetism and the applications of cobalt and discover how cobalt gets its magnetic properties.
Is Cobalt Magnetic?
It’s true that cobalt has magnetic properties. Being a ferromagnetic metal, it can attract and get magnetized by powerful magnets. Ferromagnetic means attracted by magnets.
Furthermore, in the absence of attraction, it is possibly diamagnetic or paramagnetic. This is possibly because the electrons are unpaired in its outer most shell spin and point in the same direction, creating a magnetic substance.
What Makes Cobalt Magnetic?
The unique arrangement of cobalt’s electrons, which results in unpaired spins in its atomic structure, makes it magnetic.
Along with iron and nickel, cobalt is one of the several naturally ferromagnetic elements due to the strong magnetic field produced by these unpaired electron spins.
Factors Affecting Cobalt Magnetism
Temperature
The magnetism of cobalt varies substantially with its temperature. Below its Critical point of 1,115°C, cobalt is ferromagnetic, which means it can retain significant magnetic characteristics. However, as the temperature rises and reaches this limit, cobalt loses its ferromagnetic characteristic and becomes paramagnetic, meaning it can only be magnetized in the presence of an external field.
Crystal Structure
Cobalt’s crystalline structure influences its magnetic properties. Magnetic characteristics can be controlled by differences in crystal structure, resulting in distinct magnetic strengths.
External Magnetic Fields
Strong outside magnetic fields can enhance cobalt’s overall magnetic characteristics by causing its magnetic domains to align more consistently. Cobalt is advantageous in applications needing steady magnetization, including permanent magnets and magnetic alloys.
Impurities and Alloying
The addition of impurities or alloying components such as iron or nickel can alter cobalt’s magnetic characteristics. Some elements strengthen cobalt’s magnetism, while others weaken it based on the interaction of atomic structures.
Cobalt vs Ferromagnetism
Cobalt has ferromagnetism, which allows it to remain magnetized even without the presence of an external magnetic field. This feature results from unpaired electron spins in cobalt atoms, which provide a large magnetic moment. Cobalt, like iron and nickel, is one of the several naturally ferromagnetic elements, making it useful in magnetic applications.
Cobalt Curie Temperature
Cobalt’s curie temperature, which is also known as the Curie point, is approximately 1,115 °C (2,039 °F). Cobalt becomes ferromagnetic at temperatures below the Curie point and possesses the ability to magnetize and retain it even after an external magnetic field is removed.
Conversely, when the critical Curie temperature is exceeded, cobalt reaches paramagnetic behavior and ceases to exhibit spontaneous magnetization.
Cobalt Magnetic Permeability
The magnetic permeability of cobalt indicates its ability to create magnetic fields inside it under the influence of an outside magnetic field. Cobalt’s magnetic permeability is roughly more than that of non-magnetic materials but also substantially less than iron or nickel. Essentially, the magnetic pull of cobalt depends on a number of variables the crystal structure, temperature and impurity type.
Understanding Magnetic Moment of Cobalt
Cobalt’s magnetic moment is the atom’s natural magnetism, which comes from the spins of its free electrons being lined up parallel to each other. The magnetic moment of cobalt depends on how spin-free and angularly mobile its electrons are in their orbits.
Because cobalt has electrons that are not paired, it can make a small atomic magnetic moment. Every single electron that is not paired with a nucleus directly adds to the atom’s total magnetic moment, which in turn creates the overall magnetic field produced by the cobalt atom.
How to Permanently Magnetic Cobalt
Expose to a Strong Magnetic Field
Put cobalt in a powerful magnetic field. It becomes permanently magnetic when the external field gets removed because its magnetic domains align in the same direction.
Cool below Curie temperature
Maintain cobalt below its Curie temperature (1,115°C). Heating cobalt above this range breaks its magnetism; therefore, keeping it cool after magnetization allows for its permanent magnetism.
Alloy with Other Ferromagnetic Elements
Add iron or nickel to cobalt to strengthen its magnetic characteristics. Some alloys are more magnetic than cobalt alone.
Reduce Mechanical Stress
Strain can degrade cobalt’s magnetic domains, therefore minimizing mechanical stress. Stable, stress-free circumstances help cobalt compounds retain permanent magnetization.
Use Heat Treatment Processes
After magnetizing cobalt, careful heat treatment below the Curie temperature can “lock in” the magnetic domain alignment, enhancing its magnetism.
Shield from Demagnetizing Fields
Avoid demagnetizing or strong alternating magnetic fields that can damage cobalt’s magnetic domains. Proper shielding preserves cobalt’s magnetism.
Applications of Cobalt
Rechargeable Batteries
Lithium-ion batteries for gadgets, electric vehicles, and energy storage devices use cobalt to improve performance and longevity.
Magnets
Cobalt is required for high-strength permanent magnets in motors, speakers, and MRI scanners due to its ferromagnetic characteristics.
Aerospace Alloys
In aerospace, cobalt alloys are utilized in jet engines, gas turbines, and other important components due to their resistance to high temperatures and corrosion.
Medical Uses
Cobalt-60, a radioactive type of cobalt, finds utility in cancer treatment (radiotherapy) and medical device sterilizing due to its gamma radiation. MRI machines, which are used for medical images and diagnosis, are built within cobalt magnets.
Cutting and Drilling Tools
They are used for tough, heat-resistant cutting and drilling tools as well saw blades being carried out on heavy-duty machining operations where the stability is of great concern
Catalysts
Cobalt catalysts are utilized in the petrochemical industry to refine crude oil and synthesize fuel, resulting in more efficient production processes.
Does Cobalt Make Strong Magnets?
Cobalt does indeed make strong magnets. Because of their greater magnetic density and stability, cobalt-based magnetic materials like samarium cobalt (SmCo) and alnico are highly respected.
Neodymium magnets are a common industrial component utilized in many different applications.
Can Cobalt Become a Strong Magnet?
Yes, it’s definitely possible that cobalt will turn into a very strong magnet. When cobalt is properly magnetized, it appears to have interesting magnetic qualities, mostly when it is ferromagnetic. When a strong magnetic field is applied to cobalt and the magnetization process is carefully controlled, the material’s domain structure lines up, making a strong and lasting magnet.
Conclusion
In conclusion, cobalt has excellent magnetism and is most commonly used in many applications, such as batteries, magnetic motors, aerospace alloys, and health applications.
If you want to learn more about cobalt alloys, please contact our engineer team.
