Structure, magnetic properties and corrosion behaviour of sintered Nd16Fe76−xCrxB8 magnets

Multi-layered electroless Ni–P coatings on powder-sintered Nd–Fe–B permanent magnet

“…Besides surface coating on the magnet, corrosion resistance could also be improved by alloying elements such as Al, Co, Cr, and Ni into the magnet [12,14]. Inevitably magnetic properties have to be sacrificed as the results of such an alloying process.…”

Corrosion studies on highly textured Nd–Fe–B sintered magnets

“…The effects of various materials parameters on the corrosion rate of Nd-Fe-B-based magnets have been studied, e.g. grain size [7], density [6], additives [8,9] and shift of the composition from the Nd-rich to the Fe-rich range [10].…”

Effect of DyF3 on the corrosion behavior of hot‐pressed Nd–Fe–B permanent magnets

“…The ferromagnetic Nd 2 Fe 14 B phase is surrounded by a Nd-rich phase. In aqueous solution, the Nd-rich phase dissolves preferentially due to its high oxidative reactivity and the galvanic coupling with the Nd 2 Fe 14 B phase [18][19][20][21][22][23][24][25]. Furthermore, hydrogen, which can evolve during the corrosion reaction is partially absorbed by the solid material and causes volume expansion.…”

“…Various additives were investigated regarding their effect on the corrosion behavior. For example, Co [20,22,[37][38][39], Cr [18], Cu [38,40] Al, Ga [38,41] change the composition of the intergranular Nd-rich phase and reduce its corrosion susceptibility.…”