MAGNETO-STRUCTIJRAL PROPERTrES OF Dy2Fe17Cx NITROGENATED ALLOYS

The nitrogenation of DY2Fe17Cx (with x= 0, 0.5, 0.75, 1.1 , 1.11, '2 and 2.5) alloys has been investigated using X-ray diffraction, calorimetric analySis and MOssbauer spectroscopy. In particular, the behaviour of C·doped Dy alloys, in both rhombohedral (x> 0.75) and hexagonal (x<0.7S) ~ases. during nitrogenation has been studied. It is known that nitrogen and carbon have dIffere nt effects on the magneto-structural properties of RE2Fe17 compounds; moreover, the two structure5 may behave dirferently and so influence the nilrogenation and earbonation proce:ms. X-ray diffraction showed that the diffusion of nitrogen is faster in alloys with la rger lattices, if the rare earth is larger {Sm or if carbon is present; in Dy alloys the diffusion of ni trogen appears inhomogeneous and depend.~ on carbon content. Higher temperatures (> 480 G°C) destroy the 2: 17 phase and fonn (l-Fe. Th.e hyperfine parameters of the alloys before and after nitrogenation have been detennined using Mossbauer spectroscopy and Mlem to be more sc n~ itive to C content in the hexagonal phase.