| With the development of rare earth resources,on the one hand,the high price of Pr-Nd brings greater cost pressure to the enterprise;on the other hand,a large number of Y,La,Ce which taken a high cost for separation and purification has been discarded waste,causing environmental pollution and inventory saturation.It is undoubtable that development and utilization of high abundance and low price rare matel,such as Y,La,Ce has important economic and strategic significance.La and Ce have been studied extensively and systematically.But there is no systematic study on the effect of Y substitution on the magnetic properties and micro structure of Nd-Fe-B melt-spun ribbons.In this paper,we prepared(Nd1-xYx)14.5FebalB6Co0.2 All Cu0.15(x=0,0.1,0.2,0.3,0.4,0.5)melt-spun ribbons,the optimum process of the preparation of Y instead of Nd-Fe-B melt-spun ribbons was systematically studied,and the effects of Y substitution on the magnetic properties,micro structure,coercivity mechanism and the interaction between crystalline were studied systematically.1.XRD,TMA and TEM results show that the ribbons mainly contains 2:14:1 phases,while the aggregation of the second phase can be observed in the grain boundary at the corner of x=0.1,v=15 m/s ribbons.As the substitution of yttrium increases,the grain size increases.The grain size of the v=25 m/s melt-spun ribbons increases from 18nm at x=0 to 89.2 nm at x=0.4.2.The magnetic properties of(Nd1-xYx)14.5 Febal B6 Co0.2 Al1 Cu0.15 melt-spun decreases with the increase of yttrium substitution.At the same component,with the increase of wheel speed,magnetic properties increased first and then decreased,optimum magnetic properties achieved at v = 25 m/s.When x increases from 0 to 0.4,remanence Br is 8.01,7.83,7.71,7.66,7.09 kGs,respectively;coercivity Hcj is 17.59,14.78,13.46,12.43,10.17 kOe,respectively.The influence of wheel speed on x=0.3 is relatively small,when the speed changes from 15 to 30 m/s,the change of the magnetic properties and micro structure for these ribbons is very little.With the increase of yttrium substitution,the Curie temperature of these ribbons decreases too.3.The coercivity mechanism of melt-spun ribbons was investigated by the initial magnetization curves and the small loops.The intrinsic coercive force Hcj= 17.6 kOe of x=0 was obtained at Hsat=18.5 kOe;the intrinsic coercive force Hcj= 10.17 kOe of x=0 was obtained at Hsat=12.5 kOe.For Hcj<Hsat,the coercivity mechanism of the ribbons is dominated by pinning type,the nucleation is enhanced with the increase of yttrium substitution according to the initial magnetization curves.4.According to the ? M curves,when the magnetization field is small,there is strong exchange coupling effect between the grains.The lowest peak value of the ribbons with x=0.1 is about 0.586.The ribbons with x=0.4 show the highest peak value of 0.984,which is a little bit larger than that of the ribbons without Y substitution.With the increasing of magnetization field,exchange coupling effect decreases while long-range magnetostatic coupling effect increases. |
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