METALLURGICAL AND PHYSICAL STUDY OF PRASEODYMIUM DISILICIDES AND DIGERMANIDES

The series of disilicides and digermanides of praseodyme with the comp osition PrX2-x (X=Si or Ge) were investigated using X-ray diffraction, metallographic studies, electrical resistivity and magnetic measureme nts. The original result presented here is evidence of new phases that can be identified as ordered and disordered variants of the ThSi2 str ucture in digermanides. These phases have the same basic orthorhombic GdSi2-type structure as in disilicides. Consequently, the phase diagra m in the RX2-x region is presented and discussed with some focus on th e physical behaviour in relation to the two-phase equilibrium.