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30
0
-30
-900 -600 -300 0 300 600 900
40
20
0
-20
-40
-60
-1,5 -1,0 -0,5 0,0 0,5 1,0
quenching speeds (40 and 30 ms -1 ). From the relative intensities of the reflection (200) of the as-cast and annealed samples it
was concluded that they were textured. Thermomagnetic analysis curve for as-spun ribbons (40 ms -1 ) showed a broad
transition, in the range 300–600 0 C which corresponds to amorphous state, and three other transitions Tc 2 = 706 0 (5), Tc 3
=876 0 (5) and Tc 4 around T>1000 0 C, Fig 2. The last transition corresponds probably to α-Co . After annealing at 800 0 C for
15 min Tc 2 disappears, the 1:7 phase is know crystallized with Tc = 570 0 C, the phase with Tc 3 could be the 1:12 phase
favorable for annealing at relatively low temperature.
From the EDAX analysis it was found that the as-spun samples had a mean composition Pr(Fe 0.65 Co 0.27 Ti 0.068 ) 8.44 for the
ribbons produced with velocity of 30 m/s and Pr(Fe 0.67 Co 0.275 Ti 0.05 ) 9.43 (ribbons produced with 40 ms -1 ). The last composition
Magnetisation(Am 2 /kg)
150
75
0
-75
Pr(FeCoTi) 9.66
An. 850 0 C
v=40 m/s
-150
-20 -10 0 10 20
Magnetic field (kOe)
M(emu/g)
H(Oe)
-20 -10 0 10 20
Fig. 3 Typical hysteresis loop of Pr(Fe 0.664 Co 0.284 Ti 0.05 ) 9.66 annealing at 850 0 C for 15 min (on the left) and annealing at 700 0
C for 25 min(on the right).
Magnetisation (Am 2 /kg)
150
75
0
-75
-150
M(Am 2 /kg)
H(kOe)
Magnetic field (kOe)
is close to the nominal one, i.e. Pr(Fe,Co,Ti) 9.66 . The experimental data on Pr(Fe,Co,Ti,Cu,Zr) 9.66 annealed melt-spun ribbons
indicate the coexistence of α-Fe(Co) soft magnetic phase and the hard phases. The annealed ribbons have low coercivity
values attributed to the presence of the soft α-Fe(Co) phase (under certain experimental conditions) and non optimal grains
size. Fig. 3 show the hysteresis loop of Pr(Fe 0.664 Co 0.284 Ti 0.05 ) 9.66 annealed at 850 0 C for 15 min. The saturation
mangetisation is 116.6 Am 2 /kg and the coercivity is 250 Oe. The other samples of Pr(Fe 0.664 Co 0.284 Ti 0.05 ) 9.66 ribbons annealed
at 700 0 C present smaller values of coercivity and the maximum value of saturation magnetization is 152.0 Am 2 /kg for the
samples annealed at 700 0 C for 25 min, Fig 4. The nanocrystalline state can be achieved under special experimental
conditions during melt-spinning.
Fig. 4 The SEM micrograph of ribbons Pr(Fe 0.664 Co 0.284 Ti 0.05 ) 9.66 , annealed at 700 0 C-30 min, v=30 ms −1 in the left, in the
middle Pr(Fe 0.664 Co 0.284 Ti 0.05 ) 9.66 , annealed at 700 0 C –5 min, v=40 ms −1 ) c) Pr(Fe 0.564 Co 0.284 Cu 0.1 ) 9.66 , annealed at 700 0 C-30
min, v=40 ms −1
Acknowledgements: This work was done in the frame of the Bilateral Cooperation Romania–Greece, 2006-2007 of the
General Secretary for Research and Technology of Greece (GSRT),
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