Theoretical calculation on equation of state of Nd_2Fe_(14)B at high pressure

According to the Hugoniot date of element Fe and Nd(the mol ratio are 72.32% and 26.68%),we calculated the equation of state of the hard ferromagnet material Nd2Fe14B at pressure rang with 19 GPa～78 GPa based on the volume additive law,the results indicate that the theoretical calculation accord will with the experiments data and the average error of D-u and P-V relation is ±2.30% and ±9.12%,that indicated the method in the paper has practicability for this kind of metal compound such as Nd2Fe14B,and can also apply this method to calculate the equation of state of other solid mixture and compound.