NdFeB(Neodymium-Iron-Boron) This is the most powerful permanent magnet on the market, and it offers a great return for cost/performance. Neodymium magnets have the highest field/surface strength (Br), and offer high coercivity (Hc) at reasonable prices. However, b/c of their corrosive nature, they are usually produced by plating or coating after they are machined (nickel, zinc, etc.). Due to its exceptional magnetic strength, extreme caution is required during handling and assembly.
SmCo (Samarium Cobalt) SmCo5 and Sm2Co17 Expensive and extremely brittle, this alloy offers a unique combination of high levels as below: resistance to corrosion resistance to demagnetization (Hc) magnetic strength (Br) high operating temperatures (350°C) Similar to neodymium magnets, extreme caution/care is required due to its high magnetic force.