Abstract: Disclosed is a surface modification technique for permanent magnetic materials. First, a sintered Nd—Fe—B magnet is immersed in a chlorine-containing solution to corrode its surface after the sintered Nd—Fe—B magnet is ground, polished and cleaned, so that atomic vacancies or gaps are produced at the grain boundaries in the surface layer of the corroded sintered Nd—Fe—B magnet; then, compound nanopowders coated on the surface of the sintered Nd—Fe—B magnet are implanted into the grain boundaries by laser shock peening to obtain a gradient nanostructure layer along the depth direction; at the same time, the surface nanocrystallization of the sintered Nd—Fe—B magnet and a residual compressive stress layer are induced by laser shock peening which remarkably improves the corrosion resistance of the sintered Nd—Fe—B magnet.

Abstract: Disclosed is a surface modification technique for permanent magnetic materials. First, a sintered Nd—Fe—B magnet is immersed in a chlorine-containing solution to corrode its surface after the sintered Nd—Fe—B magnet is ground, polished and cleaned, so that atomic vacancies or gaps are produced at the grain boundaries in the surface layer of the corroded sintered Nd—Fe—B magnet; then, compound nanopowders coated on the surface of the sintered Nd—Fe—B magnet are implanted into the grain boundaries by laser shock peening to obtain a gradient nanostructure layer along the depth direction; at the same time, the surface nanocrystallization of the sintered Nd—Fe—B magnet and a residual compressive stress layer are induced by laser shock peening which remarkably improves the corrosion resistance of the sintered Nd—Fe—B magnet.