A Sintered Ferrite magnet just similar to the permanent magnet. Powdered ferrite material follows sintering at higher temperatures. This makes the magnet harder and high-temperature resistive element.
Key Uses of Sintered Ferrite Magnets
Some of the highly notable applications of the sintered ferrite magnets include:
- Electric motors
- Sensors
- Actuators
- Speakers
- Magnetic latches
- Magnetic sensors
- Magnetic separators
- Magnetic couplings
- MRI machines
- Wind turbines
- Generators
- Magnetic bearings
Advantages
A number of benefits like the following contribute to the value of the sintered ferrite magnets:
- High Magnetic Strength: In comparison to many magnets, the sintered ferrite magnets feature higher strength.
- Cost-effective: These magnets are cost-effective, which helps you save money while you get the performance you need.
- Wide range of Applications: Embrace the versatility—they fit all kinds of uses.
- Good Resistance to Corrosion: They offer good corrosion resistance, making the structures last long in different environments.
Manufacturing Procedure of Sintered Ferrite Magnet
Multiple steps help you accomplish the manufacturing of the sintered ferrite magnet. The notable steps are:
1. Raw Materials Selection
The first step is the collection of raw material that goes into manufacturing. Key materials include iron oxide, barium carbonate, and strontium.
2. Grinding or Milling
To achive the fine and homogenous size of the particle you subject raw materials to grinding or milling.
3. Addition of Binders
The third step requires you to add binders. It may include the organic material or paraffin. The usage of binders help you bind the particles especially while compacting.
4. Precise Mixing
Next, homogeneously mix the raw materials along with the binder to prepare the precise mixture.
5. Compaction
Later in the fourth step, you deal with shaping the mixture. You can do so with isostatic pressing or dry pressing.
6. Injection Molding
On the contrary, you may prefer injection molding, which makes more complicated shapes and has higher accuracy.
7. Sintering
Next comes the important step of sintering. You put the compressed material into a thermostatically controlled furnace to heat it to a high temperature.
Heating: You slowly bring up the heated material to a temperature range of 1000-1300 °C.
Densification and bonding of ferrite particles: The heat causes the air particles to stick together. Consequently, there is an increase in density and strength.
Formation of crystalline structure: The material observes structural variations. The crystalline structure of the resultant structure is responsible for its magnetic characteristics.
Removal of binder (if used): In this step, you need to remove all binders added.
Control of atmosphere (nitrogen, hydrogen) to prevent oxidation: The atmosphere inside the furnace follows specific regulations to exclude oxygen, which may destroy the magnetic properties.
Cooling: The material is gradually brought to room temperature, and the crystal structure settles in.
8. Cutting
After sintering, you need to cut the material. You can do so by using the high-precision tools.
9. Follow Up Coating
You can coat your magnet products with different materials. This way you can ensure the perfect corrosion resistance as well as longevity.
10. Deal With Polishing
Next to increase the shine or to make your magnet smooth, you need to employ the polishing procedure.
11. Magnetisation
In the eleventh step put the magnet in a stronger magnetic field. Following this step, you can align the magnetic domain of ferrite magnets.
12. Inspection and Cleaning
Inspection and cleaning are essential to get rid of any contaminants if present. Through following this step you can ensure higher end quality.
Factors Influencing Properties of Sintered Ferrite Magnets
The purity and composition of the manufacturing materials influence the end properties of the magnets. Impurities can result in a change in magnetic properties. Be sure to use the best materials available.
Atmosphere, time, and temperature impact the conditions of sintering. Tune these parameters carefully for the required magnet properties. Higher temperatures and longer periods can increase the intensity of the magnet.
Particle size distribution is crucial. Smaller particles allow for higher density and magnetic properties. Uniform distribution is the basis for consistent results.
The pressure produced during compaction affects magnet density and strength. Compression under a higher pressure normally results in better compaction and stronger magnets.
Grain size and microstructure have an impact on magnetic properties. Weaker grains produce weaker permanent magnets. Control these factors to obtain the desired magnetic properties.
Magnetic Properties
Magnetic Strength
This magnet has a medium level magnetic strength. This is lower than some rare earth magnets.
Anisotropic/Isotropic: The magnets feature isotropic or anisotropic properties depending on the manufacturing process you use.
Physical Properties:
Color: Normally, it is black or dark gray in color.
Melting Point: The sintered silicon iron magnets have a high enough melting point (14500C), which makes them stable in high temperatures.
Temperature Resistance: They possess outstanding heat stability (3000C), which renders them usable in the most complex applications.
Corrosion Resistance: While they are corrosion resistant, these magnets may need coating for some of the applications.
Density: Sintered ferrite magnets are characterized by low density, which is one of their advantages in operation, but this compactness contributes to their strength and durability.
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