Dragica M. Minica

1

f
f
Kinetics of structural transformations of
Fe75Ni2Si8B13C2 amorphous alloy induced by
thermal treatment
S
Introduction Metallic glasses are kinetically
metastable and thermodynamically unstable
materials and undergo transformation to more
stable crystal forms at higher temperatures 1.
The change of structure can lead to change in
their technologically important properties, such
as the heat capacity, electrical resistivity,
volume and magnetic properties 2. This imposes
the importance of studying thermal properties and
kinetics of phase transformations induced by
thermal treatment of amorphous alloys. The
present paper is concerned with the
non-isothermal kinetics of multi-step process of
structural transformations of Fe75Ni2Si8B13C2
amorphous alloy in temperature range 293-1273 K
by resolution multi-step process to single steps.
Dragica M. Minica Ljiljana Mihajlovica A.Leksand
ra Gavrilovicb Lidija Rafailovicb Dušan M.
Minicc Corresponding author Tel
381-11-3336-689 E-mail address
dminic_at_ffh.bg.ac.rs aFaculty of Physical
Chemistry, University of Belgrade, Belgrade,
Serbia bECHEM Kompetenzzentrum für Angewandte
Elektrochemie GmbH, Wiener Neustadt,
Austria cMilitary Technical Institute, Belgrade,
Serbia
Experimental procedures The ribbon-shaped samples
of Fe75Ni2Si8B13C2 amorphous alloy were obtained
by standard procedure of rapid quenching of the
melt on a rotating disc. The thermal stability
of alloy and the structural transformations has
been investigated by the differential scanning
calorimetry (DSC) in a nitrogen atmosphere.
Results and discussion The Fe75Ni2Si8B13C2
amorphous alloy is stable up to 723K when the
multi-step of crystallization began giving the
overlapping crystallization peaks in the
temperature range of 790-860 K 3.
5 K min-1

20 K min-1
References 1. T. Kulik, Journal of
Non-Crystalline Solids. 2001, 287, 145. 2. A.A.
Soliman, S. Al-Heniti, A. Al-Hajry, M. Al-Assiri,
G. Al-Barakati, Thermochim. Acta 2004, 413,
57. 3. D. M. Minic, A. Gavrilovic, P. Angerer,
D.G. Minic, A. Maricic, Journal of Alloys and
Compounds 2009, 476, 705. 4. P. Budrugeac and E.
Segal, Rev. Roum. Chim., 2004, 49, 193. 5. L.A.
Perez-Maqueda, J.M. Criado, f. J. Gotor and J.
Malék, J. Phy.Chem., 2002, 106,
2862. Acknowledgements The investigation was
partially supported by the Ministry of Science
and Environmental Protection of Serbia, Project
142025.
Fig. 2. X-ray diffraction patterns the
as-prepared alloy and after thermal treatment at
given temperatures.
Fe3Si Fe3Si Fe2B Fe2B Fe15Si3B2 Fe15Si3B2
Annealing Temperature K Crystallite size nm Weight fraction wt. Crystallite size nm Weight fraction wt. Crystallite size nm Weight fraction wt.
780 800 823 923 1023 1123 1273 34 1 34 1 27 3 169 34 153 24 102 15 87 5 70 73 74 78 52 52 46 14 1 10 1 7 2 36 6 52 8 122 13 108 9 9 20 26 22 48 48 54 9 1 13 1 - - - - - 21 7 - - - - -
Fig.1 DSC curves at two heating rates a)
as-recorded b) resolved curves.
Overall values Peak 1 Peak 1 Peak 2 Peak 2 Peak 3 Peak 3
Kissinger Ozawa Kissinger Ozawa Kissinger Ozawa
Ea kJ mol-1 ln A 375.10.8 56.21.0 388.70.8 49.10.1 341.60.5 49.30.5 355.40.5 43.40.5 3308 4712 344.78 4112
The detail inspection of our results it was shown
the best linearity (R gt 0.995) for the set of
conversion functions denoted as An based on the
Avrami-Erofeev equation in general form where
n3/2, 2, 3, 4, concerning the process involving
the nucleation and nuclei growth. To confirm the
obtained kinetic model IKP method was associated
with the Perez-Maqueda criterion 4-5. The
kinetic triplets for every step were established
involving the conversion function
f(a)3(1-a)-ln(1-a)2/3 for all steps and
invariant kinetic parameters Ea 323 9 kJ
mol1, ln A 47 1.3 min1, for first step Ea
304 13 kJ mol1, ln A 43.1 1.8 min1, for
the second step and Ea 276 20 kJ mol1, ln A
38.4 5.0 min1, for the third step of
crystallization.

Fig.3 The application of Perez-Maqueda criterion
on the set Avrami-Erofeev equations for all four
heating rates.