Ceramic Magnet | Knowledge for Professional Buyers
The origin of ceramic magnets
Ceramic magnets (also known as ferrite magnets or hard ferrite) are developed at Philips Physics Laboratory in 1950s. They became commercially available in the 1960s due to its low cost and high magnetic performance. People call them ceramic magnets because 1) the sintering process of this magnet material is similar to ceramic and 2) both are electrically insulating. Permanent magnets really penetrated into our everyday life with the commercialization of hard ferrite. Prior to ferrite magnets, only AlNiCo magnets had dominated the permanent magnet market.
What makes ceramic magnets different?
Comparing to other permanent magnets, hard ferrite has a low maximum energy product of up to 5.5MGOe. However, its high coercivity and cost-effectiveness make it an ideal magnetic material for a variety of applications. Measuring by weight, it accounts for over 75% of the global permanent magnet consumption. Ferrite arc magnet is also an important component in electric motors.
- low cost
- high magnetic performance
- high temperature resistance (≤ 250℃)
- high resistance to demagnetization
How are ceramic magnets manufactured?
| Grade | Br | Hcb | Hcj | (BH)max | ||||
| mT | kGs | kA/m | kOe | kA/m | kOe | kJ/m3 | MGOe | |
| Y20 | 320-380 | 3.2-3.8 | 135-190 | 1.70-2.38 | 140-195 | 1.76-2.45 | 18.0-22.0 | 2.3-2.8 |
| Y22H | 310-360 | 3.1-3.6 | 220-250 | 2.77-3.14 | 280-320 | 3.52-4.02 | 20.0-24.0 | 2.5-3.0 |
| Y23 | 320-370 | 3.2-3.7 | 170-190 | 2.14-2.39 | 190-230 | 2.39-2.89 | 20.0-25.5 | 2.5-3.2 |
| Y25 | 360-400 | 3.6-4.0 | 135-170 | 1.70-2.14 | 140-200 | 1.76-2.51 | 22.5-28.0 | 2.8-3.5 |
| Y26H | 360-390 | 3.6-3.9 | 220-250 | 2.77-3.14 | 225-255 | 2.83-3.21 | 23.0-28.0 | 2.9-3.5 |
| Y27H | 370-400 | 3.7-4.0 | 205-250 | 2.58-3.14 | 210-255 | 2.64-3.21 | 25.0-29.0 | 3.1-3.7 |
| Y30 | 380-400 | 3.8-4.0 | 175-210 | 2.20-2.64 | 180-220 | 2.26-2.77 | 26.0-30.0 | 3.3-3.8 |
| Y30BH | 380-400 | 3.8-4.0 | 223-235 | 2.80-2.95 | 231-245 | 2.90-3.08 | 27.0-30.0 | 3.3-3.8 |
| Y30H-1 | 380-400 | 3.8-4.0 | 230-275 | 2.89-3.46 | 235-290 | 2.95-3.65 | 27.0-32.0 | 3.4-4.0 |
| Y30H-2 | 395-415 | 3.95-4.15 | 275-300 | 3.46-3.77 | 310-335 | 3.90-4.21 | 28.5-32.5 | 3.5-4.1 |
| Y32 | 400-420 | 4.0-4.2 | 160-190 | 2.01-2.38 | 165-195 | 2.07-2.45 | 30.0-33.5 | 3.8-4.2 |
| Y33 | 410-430 | 4.1-4.3 | 220-250 | 2.77-3.14 | 225-255 | 2.83-3.21 | 31.5~35.0 | 4.0-4.4 |
| Y35 | 400-440 | 4.0-4.4 | 176-224 | 2.22-2.8 | 180-230 | 2.26-2.89 | 30.3-33.4 | 3.8-4.2 |
| Grade | Br | Hcb | Hcj | (BH)max | ||||
| mT | kGs | kA/m | kOe | kA/m | kOe | kJ/m3 | MGOe | |
| C1 | 230 | 2.3 | 148 | 1.86 | 258 | 3.5 | 8.36 | 1.05 |
| C5 | 380 | 3.8 | 191 | 2.4 | 199 | 2.5 | 27.0 | 3.4 |
| C7 | 340 | 3.4 | 258 | 3.23 | 318 | 4.0 | 21.9 | 2.75 |
| C8 | 385 | 3.85 | 235 | 2.95 | 242 | 3.05 | 27.8 | 3.5 |
| C8B | 420 | 4.2 | 232 | 2.913 | 236 | 2.96 | 32.8 | 4.12 |
| C9 | 380 | 3.8 | 280 | 3.516 | 320 | 4.01 | 26.4 | 3.32 |
| C10 | 400 | 4.0 | 288 | 3.617 | 280 | 3.51 | 30.4 | 3.82 |
| C11 | 430 | 4.3 | 200 | 2.512 | 204 | 2.56 | 34.4 | 4.32 |
Physical Properties of ceramic magnets
| Ceramic Magnets – Typical Physical Properties | ||
| Property | Units | Value Ceramic (Strontium Ferrite) |
| Vickers Hardness | Hv | ~ 1160 (7 Mohs) |
| Density | g/cm3 | 4.5 to 5.1 |
| Curie Temp TC | °C | 450 to 460 |
| Curie Temp TF | °F | 840 to 860 |
| *Specific Resistance | μΩ⋅Cm | > 106 |
| Bending Strength | kN/mm2 | 0.05 – 0.09 |
| Tensile Strength | kN/mm2 | .02 to .05 |
| Thermal Expansion (∥) | °C-1 | +11.0 to +16.0 x10-6 |
| Thermal Expansion (⊥) | °C-1 | ‘+7.0 to +15.0 x 10-6 |
Neodymium vs. Ceramic Magnets
Strength: Neodymium magnets take the prize for sheer magnetic strength. If you need a magnet to lift heavy objects or generate a strong magnetic field, neodymium is your choice.
Durability: Ceramic magnets are more resistant to demagnetization due to high temperatures or external magnetic fields. They excel in applications where stability is crucial.
Cost: Neodymium magnets are pricier than ceramic magnets due to their exceptional strength. For cost-effective solutions, ceramic magnets are the way to go.
Applications: Neodymium magnets shine in applications that demand strong magnetic forces, such as electric motors and audio speakers. Ceramic magnets are preferred in applications like refrigerator magnets, motors, and generators.
Conclusion
Neodymium magnets offer unmatched strength but at a higher cost, while ceramic magnets provide cost-effective durability. so suitable options depend on your application’s requirements and budget.
Alnico vs. Ceramic Magnets, Choosing Between Alnico and Ceramic Magnets
Strength: Alnico magnets offer stronger magnetic fields compared to ceramic magnets. If you require a powerful magnet, Alnico may be the better choice.
Temperature Resistance: Alnico magnets excel in high-temperature applications, while ceramic magnets may lose some of their magnetism at elevated temperatures.
Cost: If cost-effectiveness is a priority, ceramic magnets are the more budget-friendly option.
Applications: Alnico magnets are often found in applications like electric guitar pickups, sensors, and various industrial settings. Ceramic magnets are commonly used in speakers, refrigerator magnets, and electric motors.
Conclusion
Alnico magnets offer superior strength and temperature resistance, while Ceramic magnets are a cost-effective and reliable choice for a wide range of applications. Carefully consider the requirements of your project to determine which magnet will best suit your needs.
About Tengye: Tengye supplies finest permanent magnet materials to world industry. We work closely with our customer from designing stage to mass production.
