Improved Corrosion Resistance of Co,Al-Alloyed NdFeB Magnetic Nanostructures Processed by Microwave Synthesis Techniques

Co,Al-alloyed NdFeB nanostructures were synthesized by microwave combustion, followed by the reduction-diffusion process. Al and Nd substitution of Fe improved the corrosion resistance of nanostructured Nd
₂₀
Fe
₅₄
Co
₁₅
Al
₃
B
₈
. The corrosion resistance value was comparable to those of sintered NdFeB magnets. X-ray diffraction and TEM revealed a multiphase system and the presence of Nd-rich phase. The 2 μm-thick Ni plating improved corrosion potential to -0.77 and -0.74 V, respectively, and current density to 329 and 144 μA/cm
²
, respectively. The 10 μm-thick Ni plating provided a high degree of protection against corrosion.