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19-11-2010
Challenge the future
DelftUniversity ofTechnology
Magnetocaloric materials for Room-temperature applicationsEkkes Brück, Fundamental Aspects of Materials and Energy, TNW
2Magnetocaloric materials
Refrigeration
15% world energy consumption
Strong greenhouse gases
3Magnetocaloric materials
Magnetic refrigeration:
External magnetic field changes temperature of magnetic material
No CFCs, permanent magnets, easy scalable, high efficiency, low noise
Important parameters!
ΔT temperature change
ΔS entropy change
4Magnetocaloric materials
spins lattice
Basic magnetocalorics
E
Two energy reservoirs
5Magnetocaloric materials
E
Basic magnetocalorics
spins lattice
6Magnetocaloric materials
Develop energy-efficient refrigerator, operated in field of permanent magnet.
→ modern magnets ≤ 2.5 tesla
→ refrigerator regenerator design
→ Layered beds to increase T span
→ cycle frequency (power)
→ efficient heat-exchangers
7Magnetocaloric materials
2001 Model magnetic refrigerator
C. Zimm, Astronautics Co.
8Magnetocaloric materials
1.5T
9Magnetocaloric materials
Chubu and Toshiba Refrigerator 2003
(Gd, Dy) metal
Rotating magnet
0.76 T
Cooling power
60 W
T span 20 K
10Magnetocaloric materials
11Magnetocaloric materials
Okamura 2005, 2007
560 W @ 1.1T
12Magnetocaloric materials
Magnetocaloric airconditioner
Sari et al 2007
13Magnetocaloric materials
Tura & Rowe 2009
14Magnetocaloric materials
T (C0)
T (C
0 )
Increased T span with layered bed containing different materials with tailored Tc
15Magnetocaloric materials
Multimaterial regenerator
Rowe & Tura Int.J.Ref. 2006
16Magnetocaloric materials
Gd foil0.8 (P)48.8reciprocatingApril 2003Grenoble, FranceLab. d’Electrontechnique
Grenoble
Gd1-xDyx layered bed0.76 (P)1060rotaryMar. 4, 2003Yokohama, JapanChubu Electric/Toshiba
Gd1-xDyx layered bed0.6 (P)2740reciprocatingOct. 5, 2002Yokohama, JapanChubu Electric/Toshiba
Gd spheres; Gd5(Si,Ge)4 pwdr.b1.4 (P)23?reciprocatingMarch 4, 2003Nanjing, ChinaSichuan Inst. Tech./
Nanjing University
Gd spheres1.5 (P)2095rotarySept. 18, 2001Madison, Wisconsin, USAAstronautics
Gd & Gd1-xTbx layered bed2 (S)142reciprocatingJuly 2001Victoria, British Columbia
Canada
University of Victoria
Gd spheres4 (S)21100reciprocatingSummer 2000Yokohama, JapanChubu Electric/Toshiba
Gd foil0.95 (P)5?rotaryMay 2000Barcelona, SpainMater. Science Institute
Barcelona
Gd spheres5 (S)10600reciprocatingFeb. 20, 1997Madison, Wisconsin, USAAmes Laboratory/ Astronautics
Regenerator
Material
Magnetic Fielda
µ0H(T)
Max.
T
(K)
Cooling
Power
(W)
TypeAnnouncement
Date
LocationName
aMagnetic field source: S = superconducting magnet; P = permanent magnetbActual composition Gd5(Si1.985Ge1.985Ga0.03)
Room-temperature magnetic refrigerators
17Magnetocaloric materials
11 prototypes 2009
Frequ. Power ΔT magn. mater.
18Magnetocaloric materials
Giant MCE materials
1990 FeRh (Nikitin et al.)1997 Gd5Si2Ge2 (Percharsky & Gschneidner Jr.)1998 RCo2 (Foldeaki et al. )2000-2002 La(Fe,Si)13 (Hu et al., Fukamichi et al.) 2001 MnAs1-xSbx (Wada et al.)2002 MnFe(P,As) (Tegus et al.)2003 Co (S1-xSex)2 (Yamada & Goto)2005 NiMnSn (Krenke et al.)2009 MnCoGeB (Trung et al.)
19Magnetocaloric materials
0 1 2 3 4 50.0
0.5
1.0
1.5
2.0
2.5
M (
B/f.u
.)
B (T)
at 310 K
MnFeP0.46As0.54
For example
Magnetization processes
Materials with field induced first order phase transition.
20Magnetocaloric materials
La(Fe,Si)13 compounds
Cubic CaZn13 type of structure stabilized by addition of 10% Si(Kripyakewich et al. 1968)Invar type of behavior and unusual magnetic transition(Palstra et al 1983)Difficult to obtain single phase.
Gutfleisch et al 2004Meltspun almost single phase
21Magnetocaloric materials
Concentration dependence of Curie temperature and moment
Palstra et al. 1983
Tc increase with dilution
22Magnetocaloric materials
LaFe13 system
APL Zhang et al 2000Fujieda et al 2002
MCE decrease with dilution
23Magnetocaloric materials
PRB Fujita et al 2003
Tc increase with hydrogen!
Sharp transition maintained!
LaFe13 system with hydrogen
24Magnetocaloric materials
260 280 300 320 3400
5
10
15
20
-S
(J/k
g K
)
T (K)
Gd metal LaFe11.4Si1.6H
LaFe11.4Si1.6H1.5 LaFe11.4Co0.5Si1.1 LaFe11.2Co0.7Si1.1
0-2T
Fujita et al Phys Rev B 67 (2003) Hu, et al, JAP 97 (2005)
25Magnetocaloric materials
Field driven 1st order metamagnetictransition around 200 K .
La(Fe,Si)13 cubic above magnetic transition
cubic below
volume change 1.5%. Low Tc can be increased by addition of Cobalt or Hydrogen.
Hysteretic transition: stability of hydrogenation?mechanical stability?
Summary La(Fe,Si)13
26Magnetocaloric materials
MnFeP1-xAsx
Hexagonal Fe2P type of structure
Bacmann, JMMM 1994
Space group:
P62m
Mn 3g sites
Fe 3f sites
P/As 1b&2c sites
_
27Magnetocaloric materials
Sample preparation
Starting Fe2P, Mn2As3, Mn & P
mechanical alloying
sintering 1000oC
annealing 800oC
28Magnetocaloric materials
Magnetization process near Tc
Field induced transition with small hysteresis
29Magnetocaloric materials
Temperature dependence of Magnetization
Step-liketransition
first order
but very littlehysteresis
30Magnetocaloric materials
Comparison of magnetocaloric effect in different materials
Entropy changeconcentrated inrelevant T interval Tegus et al. Nature 415
31Magnetocaloric materials
285 290 295 300 305 310 3150
1
2
3
4
5B = 1.45 T
MnFeP0.45As0.55MnFeP0.47As0.53
Mn1.1Fe0.9P0.47As0.53
T ad
(K)
T (K)
Direct measurements MSU
Adiabatic temperature-change
Sample dependence need for careful preparation
32Magnetocaloric materials
For active magnetic regenerator
0 1 2 3 cm
MnFePAs sintered
Extrudedgreen
Shaping of materials
33Magnetocaloric materials
200 220 240 260 280 300 3200
10
20
30
40
50
60
70
M (A
m2 /k
g)
T (K)
1
2
3
Mn1.1Fe0.9P0.78Ge0.22
0.1 T
Virgin effect and large hysteresis
Arsenic has bad reputation in kitchen
Sample with Ge replacing As
34Magnetocaloric materials
Sample with Ge replacing As
Melt-spinning
+ Ar gas pressure 1 atm.
surface speed of the wheel v = 40m/s+
ribbons were annealed for ± 10 min.+
Mn2-xFexP0.75Ge0.25 (x = 0.70, 0.76, 0.78, 0.80)+
35Magnetocaloric materials
Small thermal hyteresis, Tc = 288 K
Large MCE observed at low operation field
Sample with Ge replacing As
36Magnetocaloric materials
Challenges with Fe2P materials
As bad reputationGe expensiveSi or Al could be perfect
37Magnetocaloric materials
MnFe(P,Si) first samples
Large hysteresis
50 100 150 200 250 3000
10
20
30
40
50
M(A
m2 /k
g)
T(K)
1st cooling heating 2ndcooling
B = 50 mTsweep rate 2K/min
MnFeP0.6Si0.4
38Magnetocaloric materials
Toxic ingredients0.1 %Hex. – hex.150-340250-580
MnFe(P,As)(P, Ge, Si)
Fe corrosion sensitiveH uptake
1.5 %Cubic -cubic
200-330La(Fe,Si)13Hy
High purity Gdrequired
hysteresis
0.5 %Ortho. –monokl.
130-270Gd5Ge2+xSi2-x
CommentsVStruct.Tc
(K)Alloy
Comparison giant magneto-caloric materials
39Magnetocaloric materials
Availability
60t?WW prod=90t, avail 10t
?GaNi0.501Mn0.227Ga0.258
4000
4000
unlimited
WW prod=90t, avail 10t
?
1000
Estimated
availability
7000tLaManganites
LaMnO3
22000tLaLathanum alloys
La(Fe13-xMx)
No limitation for an
industrial productionnone
Manganese alloys
Mn(As1-xSbx)
MnFe(P1-xSix)
140tGeGadolinium Silicon alloys
Gd4(Si1-xGex)5
1000tGdGd metal
Total availability of
MC material
Limiting
ingredient
40Magnetocaloric materials
Classical Technology:
Temperature range < 200 °C not considered
Magnetocaloric Technology: 75% of Carnot Efficiency
High Temperature (600 °C)Permanent magnets XMC-materials X
Low temperature (<200 °C)Permanent magnets ✔MC-materials ✔Access to waste heat
Heat- to electric-power conversion
41Magnetocaloric materials
dBTMTdTcTdSdQ p
Heat input → temperature changemagnetization change
2222
dtdB
RSNRIWelect
42Magnetocaloric materials
Magnetocaloric power generation
43Magnetocaloric materials
Stack of materials in generator
44Magnetocaloric materials
Various machine concepts were developed in the past.Lack of suited magneto-caloric materials prohibited realization of these.The novel materials showing giant-magneto-caloric effects near and above RT can lead to realization.
Summary MC power generation
45Magnetocaloric materials
People involved in project in Delft
• Senior scientists: Jürgen Buschow, Niels van Dijk• Pos docs: Lian Zhang, Luana Caron, Cam Thanh Dinh• PhD students: Thanh Trung Nguyen, Zhiqiang Ou, Huu Dung
Nguyen, Jose Leitao• Technician: Anton Lefering
46Magnetocaloric materials
Thank you
?