An Ultimate Guide on Ferrites – Types and Applications

Ferrites are magnetic materials that are considered better than pure metals because of their wide range of properties, such as low cost, high resistivity, easy manufacturing, and superior magnetization. They are widely used in radar, audio & video, memory cores of computers, microwave devices, and satellite communication. Their high electrical resistance and low eddy current losses make them an ideal choice for a variety of industrial applications.

In this blog, we are going to explore everything that you need to know about ferrites such as their definition, use, types, properties, and applications. The information will help you make a better choice while you are using ferrites for your engineering or other business requirements.

What are Ferrites?

Ferrites are ceramic materials composed of iron oxide and metallic elements such as barium, manganese, nickel, and zinc. They have ferrimagnetic properties which means they can be attracted to a magnet easily. They are widely used for their magnetic properties reflected in their high magnetic permeability at high frequencies.

Earlier, they were manufactured for inductors and antennas only. So, they were available in a few select shapes and sizes. Now, the scenario has changed. Ferrites are manufactured in countless sizes and shapes and for a wide range of applications. They are predominantly used in three areas—home appliances, power applications, and Electromagnetic Interference (EMI) suppression.

How are ferrites different from other materials?

Ferrites differ from other ferromagnetic materials. They are not electrically conductive so they are highly used as magnetic cores in

• Transformers
• Inductors
• Permanent Magnets
• Computer memory elements
• Antennas
• Automotives
• Energy meter
• Welding machine
• Railways

Ferrites have both magnetic and electric properties. Some of them are

• High magnetic permeability
• High electrical resistance
• Low electrical losses
• Good chemical stability

Ferrites’ high permeability to magnetic fields is desirable for antennas while high resistance to electricity is desirable in transformers. This helps to suppress eddy currents while ensuring no core losses.

Types of ferrites

Ferrites are classified into two types based on their magnetic properties i.e.

1. Soft ferrites
2. Hard ferrites

1. Soft Ferrites

Soft ferrites are used in transformers and electromagnetic cores. They carry low coercivity so they can easily change their magnetization and behave like conductors. These ferrite components are widely popular in the electronic industry. They help to produce highly efficient ferrite cores (magnetic cores) for inductors, transformers, antennas, and other components with high-frequency range.

Common soft ferrites are Manganese-Zinc (MnZn) Ferrites & Nickel-Zinc (NiZn) Ferrites.

Applications of soft ferrites

• Television
• Telecommunication
• Medical devices
• Computer
• Other electronic systems

2. Hard Ferrites

Hard ferrites are produced using iron oxide and barium oxide. They carry high coercivity, so they are hard to demagnetize even in strong magnetic fields. Therefore their magnetization is considered permanent. These ferrites are used to produce permanent magnets for household appliances such as loudspeakers, refrigerator, and electric motors.

Common hard ferrites are Barium ferrites and Strontium ferrites.

Applications of Hard Ferrites

• Loud speakers
• Micro motors

Why are Ferrites used?

Ferrites are commonly used in the electronic industry. It includes use in transformers, inductors, personal computers, televisions, power supplies, electromagnets, and more. They offer the benefit of high electrical resistance that leads to low eddy current losses.

Also, by using ferrites in these electrical products, manufacturers improve their ability to prevent high-frequency electrical noise. Ferrites act as EMI/RFI filters to suppress the noise (Radio Frequency Interference) from entering or exiting the product. Thus, it eventually helps in improving the performance of the product and enhancing the customer experience.

How are Ferrites used in the industry?

Ferrites are often used in electronic devices such as television, inductors, transformers, and household appliances. They are pressed from a powdered precursor and then fired in a kiln. Owing to the sintering process, the mechanical and electromagnetic properties of the ferrite components are highly affected. They depend on time, temperature, and atmosphere.

After the sintering, ferrites shrink by a few percent. The shrinkage could be 10% to 17% in every dimension, depending on the specific type of ferrite. During manufacturing, it is highly important to maintain correct dimensional tolerances and prevent cracking and warpage that happen because of shrinkage.

Ferrites can also be in a solid or snap-in state while fitting properly around a cable. They work by forming a low-pass filter that prevents high-frequency noise. Large-sized ferrites are often used in the external cable of devices, while small-sized ferrites are used in individual circuit parts.

How do you know if you need to use ferrites?

Ferrites are used in electronic components to make sure that the products meet the criteria of EMI emissions set by regulatory bodies like the FCC. If you do early testing, you can determine if these ferrites can help you meet the criteria set by the regulatory bodies.

Manufacturers use ferrites so that they can suppress unnecessary RF energy and convert it into heat. While some others prefer to leave empty spacing in their designs to incorporate ferrites later on if required.

Major applications of Ferrites

Ferrites are very popular ceramic materials that are used with technologies ranging from hard magnets to microwave devices, household appliances to magnetic recording, etc. They have been in use for over 50 years and have shown considerable advancements in applications and fabrication technologies. Their growth is impressive and promising. If you use ferrites in bulk, it forms a group of magnetic materials and improves the performance of your equipment even more.

The applications of ferrites in the electronic industry are continuing to grow. With a wide range of geometries, continuous improvements in material characteristics, and cost-effectiveness, ferrites are a worthy choice for both conventional and modern-day applications. Here are some of the major applications of ferrites.

1. Inductors

Ferrites are widely used in a range of electronic circuits such as filters, impedance matching networks, low-noise amplifiers, and voltage-controlled oscillators. In inductors, they help with miniaturization and integration as ferrites are ideal for passive electronic devices. Their multilayer technology is suitable for the mass production of integrated devices as they allow high integration density.

Although multilayer capacitors arrived in the market several years ago, inductors came up only in the 1980s. To produce the inductance, a soft ferrite and metallic coil are used as primary components.

Ferrites need to be compatible with the integrated circuit manufacturing process to ensure a high permeability at the operating efficiency. Owing to spluttering, the ferrite films get high density, however, the composition is tricky to control accurately. Also, there’s a risk that the annealing process can achieve high temperatures.

If pulsed laser deposition is involved, high-quality ferrite films are produced and at higher prices. However, if a combination of sol-gel and spin-coating is used, then ferrite films are prepared easily at a lower cost but with slightly inferior quality.

2. Telecommunication

The demand for magnetic materials for high-frequency applications like telecommunications is skyrocketing. This happens because microwave technologies need higher frequencies and bandwidths that are up to 100 GHz.

As ferrites are non-conducting oxide materials, they allow the electromagnetic fields to pass through them easily, unlike the metals where the body of the material prevents the penetration of high-frequency fields. In the high-frequencies, the domain walls cannot follow the fields, and also the absorption of micropower takes place by dynamics.

3. Power Conditioning

Ferrites act as power suppliers for a range of devices such as TV, computers, video systems, peripherals, and small and medium instruments. They are mainly used in Switch Mode Power Supplies (SMPS). Under this, the power signal is rectified and then switched as regular pulses at a higher frequency. They are then incorporated in a ferrite transformer and then rectified to generate accurate power to the instrument. The power delivery and efficiency can be improved by increasing the working frequency of the transformer.

4. EMI Suppression

The increasing usage of electronic equipment such as digital cameras, digital interfaces in notebooks, and computers, scanners, and more has led to a rise in the demand for ferrite materials. Ferrites are used in these devices to suppress the noise caused by Electromagnetic Interference (EMI). Electromagnetic Interference means degradation in the performance of an electric device due to noise or electromagnetic disturbance. The fast development of wireless communications is increasing Electromagnetic Interference caused by electric and magnetic fields. This noise from electric devices is produced at higher frequencies than the circuit signals.

To avoid the noise or reduce it, ferrites are being used extensively. These ferrites act as EMI filters or low-pass filters and reduce the possibility of noise breaking out. They block the signals with frequencies that are higher than a particular value of frequency.

To build these EMI suppressors, several types of ferrites can be used, such as soft ferrites, ferromagnetic metals, and encapsulated magnetic particles.

5. Magnetic Sensors

Ferrites are used in magnetic sensors to control the levels of temperature. As ferrites have sharp and definite curie temperatures so they are ideal for this application. Positional and rotational magnetic sensors can also be developed using ferrites.

6. Magnetic Shielding

Ferrites are used in radar absorbing paint to make the aircraft of submarines invisible to the radar.

7. Ferrite Electrodes

Ferrites are used in electrodes because they possess high corrosion resistance. They have accurate conductivities and are ideal for applications such as chromium plating.

Shapes of Ferrite Cores | Ferrite Core Types

1. E Cores

Pros

• Simple Assembly
• Wide range of sizes
• Economical

Cons

• No Self Shielding

Applications

• Power & Telecom Inductor
• Differential Inductor
• Inverter Transformer
• Power Transformer
• Broadband Transformer
• Converter Transformer

2. ER Cores (EER Cores)

Pros

• Economical
• Assures Minimum Winding Resistance
• Ensures Optimum Efficiency

Cons

• Less Expensive than E Cores
• Less Productive

Applications

• Differential Inductor
• Power Transformer
• Compact Transformers
• Switch Mode Power Supplies

3. ETD Cores

Pros

• Minimum Winding Resistance
• Optimum Efficiency

Cons

• Expensive
• Less productivity

Applications

• Differential Inductors
• Power Transformers

4. POT Cores

Pros

• Temperature Stability
• Lowest Leakage Inductance
• Self-Shielding Ability

Cons

• Gapping process is complex

Applications

• Broadband Transformers
• Narrow Transformers
• Telecom Inductors
• Power Transformers
• Power Inductors

5. ROD Cores

Pros

• Wide range of sizes
• Direct the magnetic component of radio waves

Applications

• RFID Tags
• Line Filters

6. PQ Cores

Pros

• Maximum Power Output
• Accurate dimensions to optimize volume

Cons

• Compatible with few hot spots only

Applications

• SMPS
• Power Inductor

7. EFD (EFF) Cores

Pros

• Excellent Flat Design
• Accurate Space Utilization

Cons

• Expensive

Applications

• Compact Transformers
• Compact Inductors

8. U Cores

Pros

• Low Leakage
• Efficient Voltage Isolation
• Ideal for Higher Power

Applications

• Power Transformers

9. RM Cores

Pros

• Ideal for savings

Cons

• Route winding for ensuring isolation

Applications

• Differential Inductors
• Filter Inductors
• Power Inductors
• Broadband Transformers

10. UR Cores

Pros

• Better Voltage Isolation
• Assures Low Leakage
• Available in various sizes and impedances

Applications

• Power Transformers

11. EP Cores

Pros

• Economical
• Self-Shielding
• Ideal design for maximum value

Cons

• Little Winding Space

Applications

• Power Transformers
• Differential Inductors
• Telecom Inductors

12. Toroidal Cores

Pros

• High Magnetic Efficiency
• High Breakdown Voltage

Applications

• EMI/ EMC Filter Choke
• Current Transformers

13. EI Cores

Pros

• Easy to assemble
• Economical

Cons

• No Self-Shielding

Applications

• Differential Inductors
• Power Inductors
• Telecom Inductors
• Inverter Transformer

14. PM Cores

Pros

• Self-Shielding
• Thermal Stability

Cons

• Few Sizes

Applications

• Differential Inductors
• Telecom Inductors
• Power Transformers

15. EPC Cores

Pros

• Effective Space Usage

Cons

• Slightly Expensive
• Few Sizes

Applications

• Compact Transformers

16. Planar (EI, EE) Cores

Cons

• High Cost

Applications

• Differential Inductors
• DC/DC & AC/DC Converter

17. Planar (EIH, EEH) Cores

Pros

• Wastes no space
• Ideal for gapped inductor cores
• Helps in tackling fringing losses

Cons

• High costing

Applications

• Differential Inductors
• DC/DC, AC/DC converter

Conclusion

Ferrites are the right choice of materials that come with customized solutions to meet your engineering requirements. With a variety of shapes and sizes, they can be the ideal choice for your business. Their use is growing these days in many industries and now is the right time to utilise their benefits for your products.

If you want to know more about ferrites or you are willing to buy them for your business, we would like to recommend you to visit Cosmo Ferrites. They are one of the leading suppliers of ferrites across the world who have been involved in the R&D, production, and supply of ferrites for many years. They can tell you about their most suitable applications and sizes. You can contact their team to have a consultation and discuss your queries.