Study On Microstructure And Magnetic Properties Of The Nd-Fe-B Permanent Magnetic Materials

Nd-Fe-B permanent magnetic material is called“the king of magnetic materials”,because of its high coercivity,remanence and maximum magnetic energy pruduct.In rencent years,due to its excellent performance,it has been widely used in the field of functional materials.In this paper,Alnico5 or Fe-Cr-Co alloy were added into Nd-Fe-B alloy to obtain composite magnetic materials,which provides a new idea to develop high performance permanent magnets.The Nd-Fe-B-type ribbons were prepared by arc-melting and melt-spining,and their characteristics were tested by the means of X-ray diffractometer,vibrating sample magnetometer,scanning electron microscopy,transmission electron microscope and other equipments.The efftcts of Alnico5 or Fe-Cr-Co alloy addition on microstructure and magnetic properties of Nd-Fe-B-type ribbons,prepared by different wheel speeds were main studied.The following results were paid more attention:1.The Nd₂Fe₁₄B+x%Alnico5?x=0,3,5,10?ribbons were melt-spun at a speed of 40 m/s.The Alnico5 alloy had remarkable effects on microstructure and magnetic properties,and the x=3 ribbons got the best magnetic properties of Hc=8341 Oe,Mr=61 emu/g and Ms=104 emu/g.2.By adjusting the roller speeds to control melt-spinning speed,Nd₂Fe₁₄B+3%Alnico5 ribbons with diffenent isomorphous state were prepared.The results showed that the rapid quenching rates significantly affect the crystallization process and magnetic properties of the magnet,and 40 m/s is considered to be the best quenching rate.3.The Nd_11.4Fe_81.2-xB_5.7+xAl_0.5Ni_0.4Co_0.7Cu_0.1?x=0,2,4?ribbons were prepared at a rapid quenching rate of 40 m/s,and the effects of B content on the microstructure and magnetic properties were investigated.The results showed that B element affects the glass forming ability of ribbons and phase composition,and the ribbons with x of2 got the best magnetic properties as follows:Hc=10768 Oe,Mr=60 emu/g,Ms=90emu/g.4.The Nd₂Fe₁₄B+x%Fe-Cr-Co?x=0,3,5,10?ribbons were fabricated by melt-spinning at a speed of 40 m/s.The Fe-Cr-Co alloy had remarkable effects on microstructure and magnetic properties of ribbons,and when x=5,the ribbons got the best magnetic properties:Hc=6066 Oe,Mr=63 emu/g,Ms=126 emu/g.