The improved oxidation resistance of Si-doped SmCo₇ nanocrystalline magnet

A drastic improvement in oxidation resistance of SmCo₇ nanocrystalline magnet was achieved by alloying silicon at 500°C. The maximum energy product (BH) max loss of SmCo6.1 Si0.9 nanocrystalline magnet was about 5.6% after oxidation at 500°C for 500 h, which was significantly less than 52.1% of SmCo₇ nanocrystalline magnet. A general mode was proposed to predict the (BH) max loss as a function of oxidation time at 500°C. The formation of SiO₂ oxide in the internal oxidation layer plays an important role in reducing the oxidation rate and oxygen diffusion coefficient, which leads to the enhancement of inherent oxidation resistance of SmCo6.1 Si0.9 nanocrystalline magnet.