Electroless Ni-Co-P Coatings on Sintered Nd-Fe-B Magnets with Improved Corrosion Resistance
Electroless Ni-Co-P coatings have been deposited on sintered Nd-Fe-B permanent magnets by optimizing the bath composition and operating conditions. The corrosion resistance of coated Nd-Fe-B magnets was significantly improved and corresponding corrosion current density Icorr in 3.5 wt. % NaCl solution decreased by two orders of magnitude. Coated with 12μm-thick Ni-Co-P, Nd-Fe-B magnets possessed slight reduction in magnetic properties, with a modest loss of remanence (Br) by 3.9 % and coercivity (iHC) by 4.5 %.
Huibin Xu, Khiam Aik Khor, Shengkai Gong, Hongbo Guo
T. Y. Ma et al., "Electroless Ni-Co-P Coatings on Sintered Nd-Fe-B Magnets with Improved Corrosion Resistance", Advanced Materials Research, Vol. 75, pp. 53-56, 2009