Laser shock peening method for improving the corrosion resistance of sintered Nd-Fe-B magnet

• Main Authors: Wang, Changyu, Lu, Jinzhong, Luo, Kaiyu, Wang, Fang, Yin, Yefang, Xu, Xiaohong
• Format: Patent
• Language: English
• Published: 24.05.2022
• Subjects: BASIC ELECTRIC ELEMENTS; CHEMISTRY; ELECTRICITY; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; INDUCTANCES; MAGNETS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TRANSFORMERS

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.