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.

SiC nanorods were synthesized through carbothermal reduction of SiO by C nanocapsules (CNCs) or amorphous activated C (AAC). The synthesized nanorods were characterized by high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectrometry (EDS). The nanorods formed during a reaction between SiO and CNCs were straight. They displayed a preferential orientation of the growth axis; Which was either parallel or normal to the [111] direction. The nanorods formed during reaction between SiO and AAC consisted of straight and curled parts or chains of SiC nanoparticles. The straight parts were aligned in the [111] direction. A surface of the rod tip was covered with a thin amorphous layer, 1～3 nm thick; Containing Si; C and traces of O. Formation mechanism of the SiC nanorods was proposed.