Transcript SANS investigation of materials for high

Small-Angle Neutron Scattering in
Materials Science
P. Strunz1, D. Mukherji2, G. Schumacher3, R. Gilles4 and A. Wiedenmann5
Nuclear Physics Institute and Research Centre Řež near Prague, Czech Republic
2 IfW, TU Braunschweig, Germany
3 Helmholtz-Zentrum Berlin, Germany
4 TU München, Forschungsneutronenquelle Heinz Maier-Leibnitz, Garching, Germany
5 ILL Grenoble, France
1


Outline:
SANS and its applications to materials science
Examples
– DT706 superalloy
– core-shell nanoparticles
– Porosity in thermal barrier coating
Projects supported by the European Commission under the 6th Framework Programme through the Key Action:
Strengthening the European Research Area, Research Infrastructures. Contract n°: RII3-CT-2003-505925 '
July 17, 2015
1
Small-Angle Neutron Scattering
– coherent elastic scattering on
inhomogeneities of the size ≈
10-20000 interatomic
distances (i.e. 10 Å - 2 mm) to
small angles (up to 15°)
2
Q: Scattering vector
(momentum transfer)
magnitude Q roughly
proportional to the
scattering angle
Scattering curve.
Evaluation:



Scattering Length Density ρ(r)


morphology
size
distance
orientation
volume fract.
Scattering contrast (Δρ)2
July 17, 2015
2
Small-Angle Neutron Scattering – data analysis
-0.006
-0.003
0.000
0.003
0.006
<320>
0.006
0.003
0.003
0.000
0.000
 
 d
 1

(
Q
,
Q
)
=
FF
x
y
 d
 V


-1
Qy (Å )
0.006
1.7E4 -- 3E4
9.59E3 -- 1.7E4
5.42E3 -- 9.59E3
3.06E3 -- 5.42E3
1.73E3 -- 3.06E3
979 -- 1.73E3
554 -- 979
313 -- 554
177 -- 313
100 -- 177
30830_32.CFG
-0.003
-0.003
-0.006
-0.003
or
0.000
-1
Qx (Å )
0.003
SCA433-5b1q
Ni superalloy
heat treatment:
solutionizing TM-15°C
= 1285°C /4h, AC
ageing at = 1100°C /0.25h, AC
=-32.7°,=0°,=30°
k  k0

 
1
FF 
V
Qz  0
F (Q)    r eiQrdr
v
30000
25000
0.006
gray scale: measurement
contour lines: fit
20000
y (Å)
azimuthal average
15000
10000
-1
d/d (cm sr )
100000
-1
10000
5000
1000
100
Scattering curve:
0
0

dependence
of scattering cross-section
d/d on momentum transfer Q
scattered
intensity I:
10
I ~ d/d 0.0001
0.001
-1


0.01
Q (Å ) Q approx. proportional
to scattering angle 2


5000
10000
15000
20000
25000
morphology
size
distance
orientation
volume fraction
30000
x (Å)
July 17, 2015
3
Why investigation of
matter using neutrons?
Properties of neutron





thermal neutrons: wavelength
1.8 Å (0.18 nm) and to velocity
2200 m/s

cold neutrons: typically 9 Å
and 437 m/s
no charge, weak interaction
with matter
magnetic moment
non-monotonic dependence of
scattering amplitude on at.
number (and even isotop)



interatomic distances and sizes
of nanostructures in condensed
matter similar to wavelength
often very small absorption =>
large depths (typically mm),
volumes, in situ studies
study of magnetic structures
isotopic contrast variation,
determination of “light” and
“neighboring” elements
July 17, 2015
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Applications: What can be investigated?


any structural, compositional or magnetic particle/inhomogeneity/
microstructural entity with size 1nm-2μm giving scattering contrast
structural biology (biological macromolecules)
– structure of biological macromolecular complexes e.g. DNA, protein, viruses; labeled subunits;
multiprotein complexes; stoichiometry of interactions, molecular weights; lipids.

chemistry and mesoscopic systems
– colloids; micelle systems and microemulsions; polymers; membranes; gels

solid state physics - microstructure
–
–
–
–
–
–
–
–
–
–
Alloys, ceramics, glasses
Porosity, voids, microcracks
Semipermeable membranes
Porosity in ceramics
Phase transformations
Precipitates in metals, inclusions
Precipitate formation/dissolution in alloys
Nanoscaled materials, nanoparticles
Interfaces and surfaces of catalysts
Impurities in silicon
magnetism

– Magnetic/non-magnetic inhomogeneities
– Ferofluids
– Flux line lattices in superconductors

sample environment
–
–
–
–
–
–
orientation and deformation by shear flow
experiments under high pressure
magnetic field, electric field
mechanical load
high/low temperatures
adsorption facilities
July 17, 2015
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SANS  experimental technique
Pin-hole facility
Beam-stop
Vacuum chambers
neutron guide
neutron guides
velocity selector
exchangable
diaphragms
sample
detector
Typical range
Q: (0.001 – 0.3) Å-1
D: (3000 - 10) Å
SANS II facility of SINQ, PaulScherrer Institute (PSI) Villigen,
Switzerland
July 17, 2015
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Use neutrons (SANS) when:





1) bulk information or non-destructive testing is needed
2) sample cannot be prepared in the thin form necessary for
synchrotron without influencing the microstructure
3) absorption/scattering in sample-environment windows too
high for X-ray (in-situ experiments at extreme conditions)
4) scattering contrast for X-ray too low or does not allow to
resolve details (easier contrast variation for neutrons)
5) magnetic microstructure
Contrast variation
a
q
B
in D2O
in H2O
July 17, 2015
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SANS  magnetic scattering
a
Example of formula: scattering on
homogenneous feromagnetic particle
(M(r) = const.), polarized neutrons
Q

d
Q   cPVP F Q  2 Δ N2  Δ M2  2 PΔ N Δ M sin 2 a
d
B
isotropic
component
component modulated by sin2a
0.2
0.1
QY, nm
-1
Application:
0.0
• voids and precipitates
in ferromagnetic alloys -0.1
• radiation damage of
-0.2
-0.2
reactor vessel steels
• ferrofluids
• flux lines in superconductors
B
ΔN
ΔM
F(Q)
VP
cP
a
-0.1
0.0
QX, nm
0.1

0.2
P
... nuclear contrast
... magnetic contrast
... common formfaktor
... volume of one particle
... volume fraction
... Angle between Q a M
... beam polarization
-1
...
July 17, 2015
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Vortex lattice in type-II superconductors
K. Harada et al., Hitachi
Lab, Science 274, 1167
(1996)
• Higher magnetic field => field penetrates, flux is quantized into tubes
• Generally: vortices move => resistance
• Zero resistance <= enough flaws to "pin" the vortices: vortex lattice (2D)
• Nature of vortex lattice and role of pinning: investigation also by SANS
R. Gilardi et al.: Small Angle Neutron Scattering
Study of Vortex Pinning in High-Tc Superconductor
(La2−xSrxCuO4 (x=0.17, Tc=37 K). SINQ experimental reports 2003.
July 17, 2015
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Ni-base superalloys

High creep resistance

High-temperature applications

Two-phase microstructure:
–
g-phase matrix strengthened by g’
precipitates (size nm-mm)
– optimized by heat treatment
– essential for mechanical properties



1. superallos are used at hightemperatures
2. they are processed before
the use at HT
=> investigation of HT microstructure
 Composition:
e.g. Cr 8.0, Co 4.0,
Mo 0.5, Al 5.7, W
9.0, Ti 0.7, Ta 5.7,
Ni balance; in wt%
July 17, 2015
10
20000
0.006
T=23°C
0.006-0.006
0 -- 0.100
-0.003
T=850°C
10000
20000
0.000
0.200 -- 0.300
0.100 -- 0.200
0.003
15000
0.006-0.006
0 -- 0.100
-0.003
T=1080°C
10000
0.000
5000
5000
0
0
0
5000
10000
15000
20000
25000
0
30000
5000
10000
15000
20000
25000
30000
-0.003
T=1120°C
0.000
0.003
15000
0.006
0.200 -- 0.300
0.100 -- 0.200
0 -- 0.100
10000
5000
0
0
5000
x (Å)
x (Å)
0.006-0.006
0 -- 0.100
10000
5000
0
0.200 -- 0.300
0.100 -- 0.200
0.003
15000
y (Å)
0.200 -- 0.300
0.100 -- 0.200
0.003
y (Å)
0.000
15000
y (Å)
-0.003
y (Å)
20000
-0.006
10000
15000
20000
25000
0
30000
5000
10000
15000
20000
25000
30000
x (Å)
x (Å)
-1
Qy (Å )
0.003
3.33E4 -- 1.35
8.2E3 -- 3.33E
2.02E3 -- 8.2E
496 -- 2.02E3
122 -- 496
30.0 -- 122
7.39 -- 30.0
1.82 -- 7.39
0.447 -- 1.82
0.110 -- 0.447
0.000
-0.003
0.900 -- 1.00
0.800 -- 0.900
0.700 -- 0.800
0.600 -- 0.700
0.500 -- 0.600
0.400 -- 0.500
0.300 -- 0.400
0.200 -- 0.300
0.100 -- 0.200
0 -- 0.100
30000
25000
20000
y (Å)
0.006
T=1160°C
T=1200°C
15000
melting
point:
1350°C
T=1340°C
T=1300°C
10000
5000
0
0
5000
10000
15000
20000
25000
30000
x (Å)
-1
Qy (Å )
0.003
0.000
-0.003
-0.003
0.000
0.003
0.006-0.006
-0.003
-1
Qx (Å )
SCA433
5b1/4
HT experiment
0.000
0.003
-1
Qx (Å )
0.006-0.006
-0.003
0.000
0.003
0.006-0.006
-1
size distribution
(volume weighted)
-0.003
0.000
0.003
0.006
-1
Qx (Å )
Qx (Å )
volume distribution (dimensionless)
-0.006
0.0005
volume distribution
0.0004
23
850
1080
1120
1160
0.0003
0.0002
0.0001
0.0000
1000 1500 2000 2500 3000 3500 4000 4500 5000
size
July(Å)
17, 2015
11
In-situ SANS investigation of hightemperature precipitate morphology in
polycrystalline Ni-base superalloy DT706
D. Mukherji, D. Del Genovese, P. Strunz, R. Gilles, A. Wiedenmann and J. Rösler
J. Phys.: Condens. Matter 20 (2008), 104220 (9pp)
new development of Ni-base superalloys:
- improving their microstructural stability
- preserving their good mechanical properties
=>
Need to know the microstructure during heat
treatment => the use of (in-situ) SANS
July 17, 2015
12
Ex-situ treated samples
DT706,
SANS
0.540 -- 0.600
0.480 -- 0.540
0.420 -- 0.480
8000
0.360 -- 0.420
0.300 -- 0.360
0.240 -- 0.300
0.180 -- 0.240
0.120 -- 0.180
6000
0.060 -- 0.120
0 -- 0.060
2500
y (Å)
y (Å)
2000
1500
0.900 -- 1.00
0.800 -- 0.900
0.700 -- 0.800
0.600 -- 0.700
0.500 -- 0.600
0.400 -- 0.500
0.300 -- 0.400
0.200 -- 0.300
0.100 -- 0.200
0 -- 0.100
0.900 -- 1.00
0.800 -- 0.900
0.700 -- 0.800 8000
0.600 -- 0.700
0.500 -- 0.600
0.400 -- 0.500
0.300 -- 0.400
6000
0.200 -- 0.300
0.100 -- 0.200
0 -- 0.100
y (Å)
3000
We can model well the data => insitu behavior can be well assessed
4000
0.900 -- 1.00
0.800 -- 0.900
0.700 -- 0.800
0.600 -- 0.700
0.500 -- 0.600
0.400 -- 0.500
0.300 -- 0.400
0.200 -- 0.300
0.100 -- 0.200
0 -- 0.100
8000
6000
y (Å)

4000
4000
MST-1
2000
1000
DA-1
500
MST
2000
2000
ST
0
0
0
0
0
0
500
1000
1500
x (Å)
2000
2500
3000
Volume fraction 5%
0
2000
4000
x (Å)
20%
6000
8000
0
2000
4000
6000
8000
2000
4000
6000
8000
x (Å)
x (Å)
13%
24%
July 17, 2015
13
DT706: in-situ SANS (HT furnace)
1200
-4
1
0.1
800
700
600
12:00
24:00
Model:
10
1000
0.5 K/min
900
DT706
4 K/min
36:00
48:00
η
60:00
500
0
-100
84:00
72:00
and
γ’
1.5
1.2
y (mm)
-1
-1
d/d (cm sr )
Q
1100
4 K/min
20 K/min
measured, fit
1080°C
00:00
847°C
835°C, 1 min
835°C, 4 min
835°C, 38 min
835°C, 1 h 17 min
835°C, 8 h 45 min
835°C, 9 h 25 min
room temperature after
1000
100
temperature
Temperature (°C)
Aim:
Cooling rate (from solution
treatment temperature)
influence on precipitate
microstructure
azimuthal
average
0.9
0.6
0.01
1E-3
0.3
0.01
-1
Q (Å )
0.1
0.0
0.0
0.3
0.6
0.9
x (mm)
1.2
1.5 0.0
0.3
0.6
0.9
x (mm)
1.2
July 17, 2015
1.5
14
size - g '
1200
1400
1300
Size (γ‘)
1100
1000
800
900
600
800
700
400
after coolling rate 0.5 K/min
after coolling rate 2.3 K/min
after coolling rate 4 K/min
after coolling rate 20 K/min
200
0
00:00
04:00
08:00
12:00
16:00
20:00
24:00
600
500
400
28:00
Integral intensity:
determination at which
temperature η and γ’ start
to precipitate
0.014
Time (hours)
1353K, 1080°C
1400
0.5 K/min
0.006
Temperature
1134K
861°C
1000
0.005
800
Integral intensity
600
0.004
0.003
29:00
1138K
865°C
1160K
887°C
30:00
temperature (K)
1108K
1200
835°C
Integral intensity (rel.units)
0.007
0.010
time
32:00
1200
20 K/min
1133K
860°C
0.008
1000
800
0.006
600
0.004
20:00
24:00
28:00
400
Temperature
1163K
890°C
0.002
31:00
1108K
835°C
Integral intensity
400
200
33:00
1400
0.5 K/min
0.012
Integral intensity (rel.units)
size (Å)
Temperature
Temperature (K)
1200
1000
temperature (K)
1400
200
32:00
36:00
40:00
44:00
48:00
time
July 17, 2015
15
1500
0.35
0.30
Volume fraction × scattering contrast
1400
1300
DT706_1
cooling rate 4 K/min
1200
0.25
1100
0.20
1000
900
0.15
800
0.10
700
Temperature
600
GAMMA PRIME
0.05
500
ETA
0.00
00:00
04:00
08:00
12:00
16:00
0
20:00
Temperature (K)
Volume fraction × scattering contrast (rel.units.)
Volume fraction
0.5 K/min
• increase in η at γ’ expense
• EM supports this observation
Time (hours)
outcome

Evolution of size and volume fraction for various cooling
rates. γ’ size can be tuned using the in situ SANS results

start temperature of both η and γ’ determined

indication of growth of η at expense of γ’
July 17, 2015
16
Study of Ni3Si-type core-shell
nanoparticles by contrast variation
in SANS experiment
P. Strunz, D. Mukherji, G. Pigozzi, R. Gilles, T. Geue, K. Pranzas
Appl. Phys. A 88 [Materials Science & Processing], (2007) 277-284
electrochemical
selective phase
dissolution
Ni-Si alloy after two different heat treatments.
July 17, 2015
17
Extraction process
 3. Collection of
 1. Formation of
nano-sized
precipitates
structure in bulk
alloy by heat
treatment
 2. Separating the nano-
nano-particles
(ultrasound
vibrations)
structure from the bulk:
selective phase
dissolution
TU Braunschweig and
ETH Zurich
shell:
 Ni–Si or Ni–Si–Al alloys: Ni3Si particles covered by
amorphous shell made of SiOx
 bio-resistant => may be suitable for medical application
July 17, 2015
18
Shell formation
Possibilities :
 1. Depletion of Ni from Ni-Si solid
solution matrix and re-deposition
of Si on particle surface;
 2. Depletion of Ni from Ni3Si
precipitate surface.
SANS: motivation
method
 confirm core-shell structure
 comparison: precipitates in the
by an independent method
 indicate which mechanism of
shell formation takes place
bulk alloy and nanoparticles
 contrast variation (masking the
shell)
July 17, 2015
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Solid sample of Ni-13.3Si-2Al alloy
-1
10
1
Q
-4
2nd
population
3rd
population
0.1
4th
population
azimuthal average
0.01
1E-3
peak at low Q magnitudes:
dense population of precipitates
 four precipitate populations
necessary to describe the data
1st
population
0.01
1st population
0.1
1.5
1.5
1.2
1.2
0.810 -- 0.900
0.720 -- 0.810
0.630 -- 0.720
0.540 -- 0.630
0.450 -- 0.540
0.360 -- 0.450
0.270 -- 0.360
0.180 -- 0.270
0.090 -- 0.180
0 -- 0.090
0.9
0.8
0.60.6
0.4
0.3
0.2
0.0
0.0
0.0
0.0
3rd population
0.9
0.6
0.810 -- 0.900
0.720 -- 0.810
0.630 -- 0.720
0.540 -- 0.630
0.450 -- 0.540
nd population
0.360 -- 2
0.450
0.270 -- 0.360
0.180 -- 0.270
0.090 -- 0.180
0 -- 0.090
grey: precipitate
white: matrix
0.3
0.18
0.15
0.12
y (mm)
system of particles
 2nd population: an
extension of the 1st one
 3rd and 4th populations
in the channels between
the larger precipitates
y (mm)
 model: polydisperse 3D
y (mm)
-1
Q (Å )
y (mm)
-1
d/d (cm sr )
1000
100
 The inter-particle interference
large Q
medium Q
small Q
0.09
0.06
0.630 -- 0.700
0.560 -- 0.630
0.490 -- 0.560
0.420 -- 0.490
0.350 -- 0.420
0.280 -- 0.350
0.210 -- 0.280
0.140 -- 0.210
0.070 -- 0.140
0 -- 0.070
4th population
0.03
0.0
0.0
0.00
0.00 0.03 0.06 0.09 0.12 0.15 0.18
x (mm)
0.2
0.4
0.6
0.3 x (mm)0.6
0.8
0.9 1.2
x (mm)
1.5
0.3
0.6
0.9 1.2
x (mm)
1.5
 Polycrystalline alloy => isotropic =>
3D cross section averaged
July 17, 2015
20
nanopowder sample, contrast variation
100000
D2O: 100%
D2O: 80%
D2O: 67%
D2O: 32%
1000
-1
-1
d/d (cm sr )
10000
100
10
Q
-4
1
0.1
0.01
1E-3
36000
z (Å)
 model
0
24000
0
0.0275 -- 0.040
0.0150 -- 0.0275
0.00250 -- 0.0150
-0.0100 -- 0.00250
-0.0225 -- -0.0100
-0.035 -- -0.0225
-0.048 -- -0.035
-0.060 -- -0.048
-0.073 -- -0.060
-0.085 -- -0.073
4000
8000
12000
x (Å)
z (Å)
detail
1600
z (Å)
0.152 -- 0.180
0.124 -- 0.152
0.096 -- 0.124
0.068 -- 0.096
0.040 -- 0.068
0.0120 -- 0.040
-0.0160 -- 0.0120
-0.044 -- -0.0160
-0.072 -- -0.044
-0.100 -- -0.072
4000
2400
2000
0.152 -- 0.180
0.124 -- 0.152
0.096 -- 0.124
0.068 -- 0.096
0.040 -- 0.068
0.0120 -- 0.040
-0.0160 -- 0.0120
-0.044 -- -0.0160
-0.072 -- -0.044
-0.100 -- -0.072
population
8000
12000
1200
800
400
1st population
0
0
400
800
1200
1600
x (Å)
2000
2400
dispersed in various mixtures
of H2O/D2O
 all mixtures except 80% D2O:
the slope at medium-to-large
Q deviates from Porod law
 evolution with changing SLD
cannot be explained without
the presence of a shell
0.1
0.01
-1
Q (Å )
2nd
12000
 extracted nanoparticles
100% D2O
80% D2O
SLD of the shell: 49×109 cm−2
0
0
12000
24000
x (Å)
36000
July 17, 2015
21
 distributions in solid
sample compared to
extracted nanoparticles
volume distribution (dimensionless)
comparison:
precipitates vs.
nanopowder
1E-3
1E-4
Powder in 100% D2O
1st population (Core + Shell)
1st population (Core only)
2nd population (Core + Shell)
2nd population (Core only)
In solid sample
1st population
2nd population
3rd population
4th population
3rd
2nd
1st
population population
population
4th
population
1E-5
 displayed distributions:
1E-6
 the core and
10
 the core + shell
 1st and 2nd distributions (core) correspond
100
1000
size (Å)
well in size scale with the original populations
in the solid sample
 => indication that the particle core was not
attacked by the electrolyte during extraction
process
July 17, 2015
22
In-situ SANS Study of Pore
Microstructure in YSZ Thermal
Barrier Coatings
P. Strunz, G.Schumacher, R. Vassen and A. Wiedenmann,
Acta Materialia, Vol 52/11, 2004, pp.3305-3312
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23
Ceramic Thermal Barrier Coatings

Preparation:
– Air Plasma Spraying (APS),
– Electron Beam Physical Vapor Deposition (EB PVD)

highly porous material, pore microstructure determines properties
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24
10000
Set 47: heat treatment
-1
o
1000
-1
(set 47) treated
ex-situ at 1200ºC
for 0, 1, 10
and 100 hours
Cross section (I47ASZD)
Data path: z:strunz
File: 47_PSI_presentation
Graph: CrossSect
Sun, 16 Apr 20, 15:54
100000
d/d (cm sr )
TBC: samples
1000000
100
at 1200 C at air
47_A
(treatment 0 h)
47_B
(treatment 1 h)
47_C
(treatment 10 h)
47_D
(treatment 100 h)
10
1
0.1
0.01
1E-3
1E-3
Model:



1. large pores and
cracks (radius > 100 nm)
2. medium-size pores
(~20 nm)
3. nanometric
pores (1-10nm)
0.01
0.1
1
10
-1
Q (nm )

No thermal
exposure:
– hydrogen?
– extremely
small pores?
– combination?
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25
in situ: creation of nanopores
from ex-situ: there are nanopores after 1h at 1200 ºC

=> created between 400 and 1200ºC
Temperature (°C)

1200°C
1200
Temperature
1000
800°C
800
600
400
ex-situ
in-situ
200
0
00:00
04:00

08:00
12:00
100:00
nanopores
created at
800ºC
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26
ZrO2 TBC (plasma sprayed): nanometric pores
sample 2F (set 47), combined in- and ex-situ,
nanopores
volume fraction
0.0010
mean radius
0.0008
800°C
1000
6
5
800
4
Temperature
0.0006
600
3
0.0004
0.0002
1200
400
ex-situ
in-situ
200
2
ex-situ
0.0000
00:00
1
24:00 100:00
0
04:00
08:00
time (hours)
12:00
mean radius (nm)
Temperature (°C)
volume fraction (dimensionless)
0.0012


in- and exsitu
measuremen
t fit well
together
800ºC:
population
of nmsized
pores
created.

between 800°C and 1200ºC, this population is unchanged

annealing at 1200ºC: size increases, volume decreases
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27
SAS in solid state physics: use neutrons when





1) bulk information or non-destructive testing is needed
2) sample: cannot be prepared in the thin form necessary for synchrotron
without influencing the microstructure
3) absorption/scattering in sample-environment windows too high for X-ray
(in-situ experiments at extreme conditions)
4) scattering contrast for X-ray too low or does not allow to resolve
details (easier contrast variation for neutrons)
5) magnetic microstructure
Applications (not exhaustive list):

solid state physics - microstructure
–
–
–
–
–
–
–
–
–
–
Alloys, ceramics, glasses
Porosity, voids, microcracks
Semipermeable membranes
Porosity in ceramics
Phase transformations
Precipitates in metals, inclusions
Precipitate formation/dissolution in alloys
Nanoscaled materials, nanoparticles
Interfaces and surfaces of catalysts
Impurities in silicon
magnetism

– Magnetic/non-magnetic inhomogeneities
– Ferofluids
– Flux line lattices in superconductors
What can be determined?






Average particle size
Surface area (I ~ S/Q4)
Volume fraction
Particle shape
Internal structure (contrast variation)
Size distributions
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