| Nd3Fe29-x-0.9CoxMo0.9 (x= 4,8,12,14,16) alloy ingot and ribbons were prepared by melting quenching and a single roller melt-spinning of 20m /s method respectively,their structure and magnetic properties were examined by XRD,SEM and VSM measurement instruments。VSM results indicates that the saturation magnetizationσs and the residual magnetizationσr have not any obvious changes for Nd3Fe29-x-0.9CoxMo0.9 (x = 4,8,12,14,16) ingot samples with the Co content increasing , and the coercivity Hc are smaller。After annealing, the saturation magnetizations of all the ingot samples decreased respectively, and the coercivity were increased。the biggest coercivity was 5205Oe and the saturation magnetization is 122 emu/g (1T) when x=8 for the Nd3Fe29-x-0.9CoxMo0.9(x=4,8,12,14,16) ribbon samples。When annealing at 723K , the saturation magnetizationσs and the residual magnetizationσr were relatively decreased,and the coercivity was corresponding increased, the maximum coercivity is 5591Oe when x = 8, and the saturation Magnetizationσs is 65.15 emu/g。To reveal the relationship between coercivity and microstructure, Nd3Fe29-x-0.9CoxMo0.9(x=8) with a larger coercivity and Nd3Fe29-x-0.9CoxMo0.9 (x =16) with a lower coercivity were chosen to investigated by means of SEM and XRD。The results show that the main phase of the sample is 3:29 phase and the mixed phase is a small number ofα-Fe phase when x = 8;the main phase of sample is 2:17 phase when x=16。The internal grain size of x = 8 samples are more uniform,and for x = 16 samples , the internal grain size is very uneven,and there are some black dots in some places。To sum up:1,For the first time the samples with the main phase of 3:29 phase was prepared by melting quenching。2,It is found that the larger coercivity can be achieved through the appropriate amount of substitution of Fe with Co。3,The coercivity mechanism for the studied sample was the domain wall pinning model。4,Further work is in progress。...
|
PDF Full Text Request