Ferrite Magnets
Ferrite magnets are non-conductive aferromagnetic ceramic compounds derived from iron oxides such as Haematite (Fe203) or Magnetite (Fe304) and other metal oxides such as Barium and Strontium.
The first studies on this material date back to the 1940s, but actual applications were recorded only from the early 1950s.
As regards magnetic properties, Ferrites are often classified as “soft” or “hard” and are distinguished by low or high magnetic coercivity, acting as ferromagnetic cores in the first case and permanent magnets in the second.
They are suitable for low cost applications, where dimensions are not an issue.
They reach their maximum performance when used on:
- Brushed DC motors
- Brushless motors without special requirements
| FERRITE | ||
| Curie temperature | °C | 450 |
| Recoil permeability (µr) | – | 1.05-1.1 |
| Saturation field | kOe | 14 |
| Electrical resistivity | Ω m | > 104 |
| Compressive strength | N/mm2 | ~ 700 |
| Density | g/cm3 | ~ 5 |
| Flexural strength | N/mm2 | 55 |
| Tensile strength | N/mm2 | 50 |
| Hardness – Vickers | HV | ~ 500 |
| Young’s Modulus | N/mm2 | ~ 150 |
| Specific heat | kcal/kg.°C | 0.8 |
| Thermal conductivity | kcal/m/hr/°C | ~ 5 |
| Coeff. of thermal expansion // | 10-6/°C | 14 |
| Coeff. of thermal expansion_ | 10-6/°C | 9 |