... ,N50M,etc. b): Used in motor. c): coating can be NI, epoxy etc NdFeB magnet, rare earth magnet, strong magnet, permanent ... +cr coating. used in Motors.Our NdFeB magnet details.Coating: Ni, Zn, gold, sliver, epoxy, passivated and Zn3+CrGrades: N52, N50M, N45SH ... ferrite magnet: 6000T/year N48 block ndfeb magnet with color Zn coating