Study On The Phase Transformation,Solidification Microstructure And Magnetic Properties Of Y-Fe-B Alloys

The rare-earth permanent magnet Nd-Fe-B has been widely applied in artificial intelligence and new energy vehicles due to its excellent magnetic properties and miniaturization,and the production are increasing gradually.However,there are many limitations in its applications under high-temperature,because of its low Curie temperature and low thermal stability in high-temperature applications.Dy and Tb are widely used in the production of Nd-Fe-B permanent magnets to improve their high-temperature magnetic properties,due to Dy and Tb gain great performance under high temperature.With the development of rare-earth permanent,the rare-earth resources such as Nd,Pr,Dy,and Tb have been used in large quantities,in the meanwhile,the high abundant rare-earth La,Ce and Y have been overstocked.In this work,the phase formation,microstructures and phase reactions of Y-Fe-B alloys were investigated experimentally.The effect of different Ce and Y content on the phase formation,microstructures and magnetic properties were investigated experimentally.And then,the effect of PrY-Fe-B melt-spun speed on the phase structures and magnetic properties were explored.The results of this work are follows:(1)The nominal composition of 6 at.%B and 11.7 at.%Y ingots were prepared via arc melting was investigated experimentally.In these ingots,with the increasing content of rare-earth Y element,the Y-Fe binary compounds increasing,and the phase which are 2:14:1 structure decreased.And in another way,with the increases of B content,the B-rich phase increases.The phase transition temperatures of YFe₂,YFe₃,Y₂Fe₁₇,Y₆Fe₂₃,Y_1.1Fe₄B₄,YFe₂B₂,and Y₂Fe₁₄B compounds were also determined based on the results of the alloy thermal analysis,which provided a theoretical basis for the study of magnetic properties.(2)The nominal composition of(Nd0.95-x Ce0.05Yx)14.5Fe79.3B6.2,(Nd0.90-y Ce0.10Yy)14.5Fe79.3B6.2 and(Nd0.85-z Ce0.15Yz)14.5Fe79.3B6.2(x,y,z=0.05?0.30)melt-spun ribbons were prepared via melt-spinning method was investigated experimentally.The effects of Ce and Y content on the phase structure and magnetic properties of the NdCeY-Fe-B alloys and the ribbons were explored.When the total content of Ce and Y is 0.25,the ribbon got the better comprehensive magnetic properties,and when the melt-spun speed also was 29 m/s.The composition of(Nd_0.75Ce_0.05Y_0.20)_14.5Fe_79.3B_6.2acquired the best magnetic properties in those ribbons.The comprehensive magnetic properties of the coercive force(H_cj),remanence(B_r)and maximum magnetic energy product(BH)max are 10.63 k Oe,8.16 k G and 12.19 MGOe respectively.(3)The effect of wheel speed on phase formation,microstructures and magnetic properties of(Pr_0.6Y_0.4)_14.5Fe_79.3B_6.2 and(Pr_0.6Y_0.4)₁₂Fe₈₂B₆ribbons with different speed(20?23?26?29?32m/s)were prepared by melt-spinning method was investigated experimentally.XRD results reveal that the melt-spun ribbons were composed of the main phase which were RE₂Fe₁₄B(Re=Pr,Y)and?-Fe minor phase.With the increase of the melt-spuning speed,when the speed is 23 m/s,(Pr_0.6Y_0.4)_14.5Fe_79.3B_6.2 gains the better comprehensive magnetic properties,and its remanence(B_r),coercivity(H_cj)and the maximum magnetic energy product(BH)_maxare 7.55 k G,10.20 k Oe and 11.96 MGOe respectively.(Pr_0.6Y_0.4)₁₂Fe₈₂B₆melt-spun ribbons gain excellent magnetic properties at the speed of 32 m/s,its remanence(B_r),coercivity(H_cj)and maximum magnetic energy product(BH)_maxare 10.35 k G,6.21k Oe and 21.20 MGOe respectively.Moreover,the relationship between the phase formation and magnetic properties of the melt-spun ribbons were explored.The magnetocrystalline anisotropy between the hard and soft magnetic phases of ribbons were verified experimentally.The experimental results show that.The reference for the development of high-abundance rare earth permanent magnets were provided eventually.