Spark Plasma Sintering Nd-Fe-B Permanent Magnets with Good All-around Property

In present study,sintered Nd-Fe-B permanent magnets with different compositions were fabricated by using both Spark Plasma Sintering (SPS) technique and conventional sintering technique.Magnetic properties,mechanical properties,and chemical stabilities of the two kinds of Nd-Fe-B magnets are investigated. Compared with the conventional sintered magnets,SPS Nd-Fe-B magnets possess comparable magnetic properties,better corrosion resistance and mechanical properties.Microstructure observation shows that SPS magnet possesses unique microstructure due to the special sintering mechanism of SPS technique.In detail,the grain size of Nd₂Fe₁₄B main phase is fine and uniform,only a few Nd-rich phase forms along the grain boundaries of Nd₂Fe₁₄B,while most of them agglomerates into the triple junctions.Such mizrostructure modification restrains effectively the inter-granular corrosion and inter-granular fracture along Nd-rich phase in the SPS magnet.As a result,SPS magnets display better corrosion resistance and mechanical properties.