Magnetic Properties Guide for Neodymium Magnets
Understand the key magnetic properties of neodymium magnets, including remanence, coercivity, BHmax, magnetic flux density, permeability, and temperature performance for industrial and engineering applications.
Osenc Magnets provides engineering-focused technical guidance for selecting NdFeB magnet materials used in motors, automation systems, magnetic separators, sensors, renewable energy equipment, and precision industrial assemblies.
What Are Magnetic Properties?
Magnetic properties describe how a permanent magnet generates, maintains, and resists changes to its magnetic field.
These properties determine:
- Magnetic strength
- Pull force performance
- Thermal stability
- Demagnetization resistance
- Magnetic circuit efficiency
Understanding magnetic properties is essential for selecting the appropriate neodymium magnet for industrial applications.
Main Magnetic Properties of NdFeB Magnets
Remanence (Br)
Coercivity (Hcb)
Intrinsic Coercivity (Hcj)
Maximum Energy Product (BHmax)
Magnetic Flux Density
Permeability
Curie Temperature
Each property affects magnet behavior under different operating conditions.
Remanence (Br)
What Is Remanence?
Remanence represents the residual magnetic flux density remaining in a magnet after magnetization.
It indicates how strong the magnet’s magnetic field is under open-circuit conditions.
Unit of Measurement
- Tesla (T)
- Gauss (G)
Remanence Formula
Br
Higher remanence generally means stronger magnetic field output.
Typical NdFeB Remanence Values
| Grade | Remanence (Br) |
|---|---|
| N35 | 1.17–1.21T |
| N42 | 1.29–1.32T |
| N52 | 1.42–1.45T |
Applications Requiring High Remanence
- EV Motors
- Separadores magnéticos
- Robotics
- High-Performance Sensors
Coercivity (Hcb)
What Is Coercivity?
Coercivity measures a magnet’s resistance to demagnetization.
It indicates how much opposing magnetic field is required to reduce magnetic flux to zero.
Unit of Measurement
- kA/m
- Oersted (Oe)
Coercivity Formula
Hcb
Higher coercivity improves magnetic stability in demanding environments.
Applications Requiring High Coercivity
- Motores
- High-Temperature Systems
- Automação Industrial
- Renewable Energy Equipment
Intrinsic Coercivity (Hcj)
What Is Intrinsic Coercivity?
Intrinsic coercivity measures resistance to irreversible demagnetization.
It is especially important for:
- High-temperature applications
- Strong opposing magnetic fields
- Dynamic motor systems
Intrinsic Coercivity Formula
Hcj
Why Hcj Matters
Higher Hcj values improve:
- Thermal stability
- Long-term magnetic reliability
- Resistance to magnetic field reversal
Maximum Energy Product (BHmax)
What Is BHmax?
BHmax measures the maximum magnetic energy density available within a magnet material.
It is one of the most important indicators of magnet performance.
BHmax Formula
BHmax
Unit of Measurement
- MGOe
- kJ/m³
Why BHmax Is Important
Higher BHmax values allow:
- Smaller magnet size
- Stronger magnetic field
- More compact motor designs
- Improved energy efficiency
Typical BHmax Values
| Grade | BHmax |
|---|---|
| N35 | 33–36 MGOe |
| N42 | 40–43 MGOe |
| N52 | 50–53 MGOe |
Magnetic Flux Density
What Is Magnetic Flux Density?
Magnetic flux density measures the strength of the magnetic field at a specific location.
Unit of Measurement
- Tesla (T)
- Gauss (G)
Flux Density Formula
B=Φ/A
Variables
- B = Magnetic Flux Density
- Φ = Magnetic Flux
- A = Area
Gauss vs Tesla
1 Tesla = 10,000 Gauss
Magnetic Flux
What Is Magnetic Flux?
Magnetic flux describes the total magnetic field passing through a given area.
Magnetic Flux Formula
Φ=B⋅A
Permeability
What Is Magnetic Permeability?
Permeability describes how easily magnetic fields pass through a material.
Permeability Formula
μ=B/H
Variables
- μ = Magnetic Permeability
- B = Magnetic Flux Density
- H = Magnetic Field Strength
Importance in Magnetic Circuits
Permeability affects:
- Magnetic flux flow
- Core efficiency
- Motor performance
- Electromagnetic system design
Curie Temperature
What Is Curie Temperature?
Curie temperature is the temperature at which a magnet loses ferromagnetic properties completely.
Typical NdFeB Curie Temperature
- Approximately 310°C–400°C depending on composition
Important Note
Operating temperatures should remain far below Curie temperature to avoid permanent magnetic degradation.
Temperature Coefficients
Magnetic properties change with temperature.
Example Relationship
B(T)=B0(1−αΔT)
Higher temperatures generally reduce magnetic field strength.
Relationship Between Magnetic Properties
Higher Remanence
→ Stronger magnetic field
Higher Coercivity
→ Better demagnetization resistance
Higher BHmax
→ Greater energy density
Higher Hcj
→ Improved thermal stability
Magnetic Properties by Grade
| Grade | Br | Hcj | BHmax |
|---|---|---|---|
| N35 | 1.17–1.21T | ≥955 kA/m | 33–36 MGOe |
| N42 | 1.29–1.32T | ≥955 kA/m | 40–43 MGOe |
| N52 | 1.42–1.45T | ≥955 kA/m | 50–53 MGOe |
Engineering Applications
Motor Applications
High BHmax and flux density improve motor efficiency and torque density.
High-Temperature Systems
High intrinsic coercivity reduces thermal demagnetization risk.
Separadores magnéticos
High remanence improves ferrous material capture performance.
Sensores
Stable magnetic properties improve signal consistency and accuracy.
Related Technical Resources
Guia de Níveis das Escolas Magnet
Compare magnetic strength and temperature resistance across NdFeB grades.
Guia de força de tração
Understand how coatings affect magnetic holding force.
Resistência à temperatura
Select the appropriate magnet grade for elevated temperatures.
Guia de orientação da magnetização
Learn about axial, radial, and multipole magnetization methods.
Perguntas frequentes
The most important property depends on the application. BHmax, remanence, and coercivity are commonly critical parameters.
BHmax measures the maximum magnetic energy density available in the magnet material.
Coercivity improves resistance to demagnetization, especially in high-temperature or dynamic environments.
Generally yes. Higher BHmax allows greater magnetic energy density and stronger magnetic performance.
Br measures residual magnetic strength, while Hcj measures resistance to irreversible demagnetization.
Magnetic properties are typically measured using hysteresis graph analyzers, gauss meters, and magnetic testing equipment.
Custom Magnetic Properties of NdFeB Magnets
Osenc Magnets provides custom NdFeB magnets, engineering consultation, and technical support for industrial magnetic systems worldwide.