LACAME 2012

1. MÖSSBAUER SPECTROSCOPY AND X-RAY DIFFRACTION STUDY OF Fe100-xVx
ALLOYS PREPARED BY MECHANICAL ALLOYING
M. A. Rengifo Morocho1,*, D. Oyola Lozano1, Y. A. Rojas Martínez1 ,H. Bustos Rodriguez1
1Universiad del Tolima, Ciencia de Materiales y Tecnología en Plasma, A.A.546, Ibagué, Colombia.
*marengifom@unal.edu.co
Powders of Fe100-XVX system were obtained with mechanical milling process (MA) at X = 20, 40, 60 and 80 and with grinding times of
12, 48 and 72 hours. The samples were studied by the techniques of X-ray diffraction (XRD) and Mössbauer spectroscopy (ME). XRD
results showed the appearance of two phases of vanadium, which let the subsequent development of vanadium oxide (VO) and whose
presence is evident after 48h milling times with X = 40, 60 and 80. It was also found for the same concentration range and milling times
of 48h and 72h, the presence of phase of Fe-V. Both phases of VO and Fe-V are favored with increasing concentration of V and to a
lesser extent with grinding time. Mössbauer spectra also show the appearance of these paramagnetic sites with increased concentration
and of milling time. The variation of the crystalline parameters and the hyperfine parameters, allow a clear view of the concentration
ratio and the grinding time.
The powders of Fe100-xVx were obtained by the
technique of mechanical alloying to 12, 48 and 72
hours of milling time, from Fe (purity 99.999%) and V
(purity de99, 9999%) with X = 20, 40, 60 , 80 and
average ball-to-powder weight radio of 40:1. X-ray
diffraction spectra were obtained with a Cu Kα
radiation to 300<2θ<900 and Mössbauer Spectroscopy
spectra was done with a source of Cu57 at room
temperature.
XIII Latin American Conference on the Applications of the Mössbauer Effect (LACAME). Medellín (Colombia). Noviembre 11 al 16 de 2012
Experimental Description
Results
We can see for the different concentrations, that the
milling time have a influence in the crystal structure. We
have seen the presence of phases of VO and FeV, for
almost all concentrations, except to the low values. The
V is taking all the media oxygen. There is not presence
of Fe oxides
Figure 1. X-Ray pattern for different concentrations in
function of milling time.
The variations of crystalline parameters allows us to
observe the sample that is suffering amorphization
process product of the milling process with the milling
time. The grinding time facilitates the appearance of
additional phases of V, in this case of the VO phase.
X=20 X=40
X=60 X=80
X Ray Diffraction and Mossbauer Spectroscopy
Figure 2. Lattice parameter and crystal size for the
different milling times.
Figure 3. X-Ray diffraction pattern in function of
concentration.
Because of its paramagnetic character, the
concentration of V has a more direct effect on the
structural characteristics of system. In the initial stages,
the V is combining chemically with the Fe for produce
the FeV. The Mossbauer spectra show the Presence of Fe
in crystalline form and amorphous. The HFD is related to
FeV phase. Phases V and VO disturb the magnetic
environment of the Fe.
Conclusions
It was found the presence of FeV phase for all cases
except when the concentration of V was X = 20 and
the grinding time of 12 hours. The Fe phase is only
visible when the milling times and the concentrations
are short. The HFD is attributed to the FeV phase with
disordered Fe. The concentration of V has a more
direct effect on the crystallinity and magnetics
parameters.Figure 4. Lattice parameter and crystal size for the
different milling times.
Figure 5. Mossbauer spectra for different milling times
in function of concentration.
The variations of hyperfine parameters show that the
concentration is a strong effect on the magnetic
characteristic. The hysteresis loop show a high
dependence whit a milling time and concentrations.
Figure 7. Hysteresis loop for X=60 for 12, 49 and 72
hours of milling time.
Figure 6. Hyperfine field in function of milling time and
concentration.
12h
48h
72h
X=20 X=40
X=60 X=80
X=20 X=20
X=40 X=40
X=60 X=60
X=80 X=80
12h 12h
48h 48h
72h 72h