Post on 20-Mar-2016
description
Skupina Nanomateriálov a Aplikovaného Magnetizmu
Riešiteľský kolektív: Ivan Škorvánek Jozef Kováč Jozef Marcin Peter Kulík Jana Turčanová (PhD)
Riešená problematika 2007
magneticky mäkké a magneticky tvrdé nanokryštalické zliatiny pripravované z amorfných prekurzorov
nové materiály pre magnetickú refrigeráciu magnetické nanočastice na báze Au, Ag a prechodových
kovov
Grantové projekty (2007)
• VEGA 2/7169 Nové nanokryštalické magneticky mäkké a magneticky tvrdé materiály so zlepšenými funkčnými vlastnosťami (2007-2009)
• APVV-0413-06 (s FÚ SAV) Komplexné kovové zliatiny (2007-2009)
• COST P17 - Electromagnetic Processing of Materials, Improvement of functional properties of Fe- and Co-based nanocrystalline magnetic materials by heat treatment in magnetic field (2006-2009)
• Cex – NANOSMART Centrum Excelentnosti SAV pre Nanoštruktúrne Materiály (2007 – 2010)
CC Publikácie 20071. I. Škorvánek, J. Kováč, J. Marcin, P. Švec and D. Janičkovič, Magnetocaloric effect in
amorphous and nanocrystalline Fe81−xCrxNb7B12 (x = 0 and 3.5) alloys, Materials Science and Engineering: A 449–451 (2007) 460–463,
2. P. Baláž, L. Takacs, E. Godočíková, I. Škorvánek, J. Kováč and W.S.Choi, Preparation of nanosized antimony by mechanochemical reduction of antimony sulphide Sb2S3
Journal of Alloys and Compounds 434–435 (2007) 773–775 3. M. Deanko, M. Paluga, D.M. Kepaptsoglou, D. Muller, P. Mrafko, D. Janičkovič, E.
Hristoforou, I. Škorvánek, P. Švec, Pecularities of electrical resistivity during transformations in amorphous and nanocrystalline alloys, Journal of Alloys and Compounds 434–435 (2007) 248–251
4. I. Škorvánek, J. Marcin, J. Turčanová, M. Wojcik, K. Nesteruk, D. Janičkovič, P. Švec Field induced anisotropy and stability of soft magnetic properties towards high
temperature in Co-rich nanocrystalline FeCoNbB alloys, Journal of Magnetism and Magnetic Materials 310 (2007) 2494–2496
5. E. Godočíková, P. Baláž, L. Takacs, V. Šepelák, I. Škorvánek, E. Gock, Sb/FeS nano-composite prepared by mechanochemical reduction, Kovové Materiály, 45 (2007) 99-104
6. P. Kollár, D. Olekšákova, J. Fuzer, J. Kováč, S. Roth, K. Polanski, The magnetic properties of powdered and compacted microcrystalline permalloy, Journal of Magnetism and Magnetic Materials 310 (2007) 2609–2611
7. A.Zeleňáková, D.Olekšáková, J. Degmová, J. Kováč, P. Kolár, M. Kusý, P. Sovák Structural and magntic properties of mechanically alloyed FeCo powders, Journal of Magnetism and Magnetic Materials. Vol. 316, no. 2 (2007), p. e519-e522
Soft Magnetic Fe(Cr)-based alloys for magnetocaloric applications at RT
250 300 350 400
TC
dM/d
T
Temperature (K)
TC
200 300 400 500 600 700 800 900 1000 1100
0
20
40
60
80 Fe81
Nb7B
12
Fe77.5
Cr3.5
Nb7B
12
M
agne
tizat
ion
(Am
2 /kg)
Temperature (K)
Set of M(T) curves for annealed Fe81Nb7B12
0 100 200 300 400 500 600 700 800 9000
20
40
60
80
100
T = 5 K
T = 470 K
T = 300 K
Fe81Nb7B12
M (
Am
2 kg-1)
0H (mT)
Magnetic Entropy Change
250 300 350 400 4500,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
S (
JK-1kg
-1)
Temperature (K)
Fe81
Nb7B
12
as-quench 743 K/1 h 773 K/1 h
Fe77.5
Cr3.5
Nb7B
12
as-quench 723 K/1 h 800 K/1 h
Set of M(T) curves for Pr13Fe87
0 1 2 3 4 5 60
50
100
150
mag
netiz
atio
n (A
m2 kg
-1)
0H (T)
235
350
T = 5K
Pr13
Fe87
Magnetic Entropy Change for Pr13Fe87
240 260 280 300 320 3400
2
4
6
Sm (
JK-1kg
-1)
temperature (K)
5 T
4 T
3 T
2 T
1 T
Pr13
Fe87
Effect of heat treatment in longitudinaland transverse field vs Co-content in
(Fe1-xCox)81Nb7B12 (annealing at 773 K/1h)
-100
0
100
-3 -2 -1 0 1 2 3
-100
0
100
-3 -2 -1 0 1 2 3
x=0.5
x=0.66
Mag
netiz
atio
n (A
m2 /k
g)
x=0.75
ZF LF TF
H (kA/m)
x=1.0
Hard Magnetic FePtNbB-based nanocrystalline alloys
-6 -4 -2 0 2 4 6-80
-60
-40
-20
0
20
40
60
80
M (
Am
2 /kg)
FePtNbB 1279500°C/1h + 600°C/30 min
measured at 300 K
Hc FePtNbB / Hc FeNiNbB ~ 106 !!!
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