Abstract:The effects of melt-spinning speed(v=15,20,25,30 and 35 m/s, respectively) and heat-treatment process on the magnetic properties and microstructure of melt-spun Nd26Pr3FebalCo4Ga0.42B0.92 ribbons were investigated. The ribbons show an obvious orientation when the speed v is less than 25m/s in the free side,which c-axis is perpendicular to the strip surface;the orientation decreases with the increase of melt-spinning speed. The grain can be refined by increasing the melt-spinning speed,when v < 25 m/s, the amorphous content increases obviously, the initial magnetization shows a one-step magnetization process,which demagnetization curve have good squareness;When v > 25 m / s, the initial magnetization changes to two-step magnetization process, and the demagnetization curve collapses obviously; The best magnetic properties are obtained when v=25 m/s,Br=0.91T,μ0Hcj=1.70 T,(BH)max=108.22 kJ/m3, After optimum crystallization annealing treatment, the amorphous content reduce significantly;all of the magnetic properties of ribbons have improved,the v>25 m/s imporve obviously, squareness and coercivity improve remarkable.The ribbon prepared at v=35m/s get the highest coercivity, μ0Hcj=2.10 T.The best magnetic properties are obtained when v=30 m/s,Br=0.91T,μ0Hcj=1.82 T,(BH)max=141.65 kJ/m3,The microstructure changes along with the thickness direction.The wheel side is composed of amorphous and fine grains,the free side is composed by larger grains.After the heat-treatment,the amorphous is reduced significantly.