These balls are made of rare earth alloy, mainly including NdFeB and SmCo, as well as barium and strontium ferrite. They are distinguished by their remarkable magnetic properties, although their mechanical strength is limited. By choosing Marteau- Lemarie, you benefit from more than 40 years of expertise and a stock available in France for quick delivery.
Chemical composition of the magnetic ball
| Element | type | Ni pct | Cu pct | Al pct | Dy pct | Co pct | Nb pct | B pct | Fe pct | Nd pct |
|---|---|---|---|---|---|---|---|---|---|---|
| % | NdFeB | – | 0,2-0,4 | 0,2-0,4 | 0,8-1,2 | – | 0,5-1,0 | 1,0-1,2 | 64,2-68,5 | 29,0-32,0 |
Physical characteristics of the magnetic ball
| Ownership | Value | Unit |
|---|---|---|
| Density | 7.55,8.3,4.95,7.2 | g/cm3 |
| Young Module | 156,138,165,150 | GPA |
| Thermal expansion coefficient | 7.9,10.5,12.9,11.7 | × 10−6 /°C |
| Thermal conductivity | 8.9,12,3.2,60 | W/m·K |
| Electrical resistivity | 1475,625,>10^5,580 | No·m |
| Specific heat | 502,356,700,502 | J/kg·K |
Diameters and grades available for magnetic ball
| Parameter | Value |
|---|---|
| Minimum diameter | 3 mm — 1/8′′ |
| Maximum diameter | 26 mm — 1′′′ |
Corrosion resistance of magnetic ball
Excellent corrosion resistance for AlNiCo alloys, good for SmCo alloys and ferrite, very low for NdFeB alloys (this is why they are often coated).
Applications of magnetic ball
Microphones, motors, sensors, aeronautical and military industry, medical and acoustic devices, magnets for display/decoration, jewellery.
