The structures and magnetic properties of R,(Fe1-xSix)17 compounds (R=Dy,Y) were investigated by x-ray phase analysis and magnetic measurements. It is shown that Si substitution for Fe leads to a phase transition at x=0.2, and that the mean iron magnetic moment, ufe of R2(Fe1-xSx)17 compounds (R=Dy,Y) decreases as Si concentration x increases; moreover, there is a maximum of dependence Tc(x) at about x=0.16. It is found that the exchange interaction constant AFeFe inR2(Fe1-xSix) compounds (R=Dy, Y) increases with x increasing by means of means-molecular-field analysis of Tc 0 1994 American Institute of Physics.

A coupling model of pluralistic magnetic component R-T intermetallic compounds (R denotes rare earth, T denotes transition metal) has been proposed by means of the mean-molecular-field analysis. Using the model, the Curie temperature T, of (Sm1-x,Prx)2 Fe17 compounds has been cpmpared with the experimental values. It is found that the former are consistent with the later.