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Electrodeposition of NiW, NiWMo, and
NiMo Alloy Thin Films and
NiW Nanowires
Tetiana Bairachna Master of Science
Thesis Defense
Scientific adviser: Prof. E. J. Podlaha-Murphy
Chemical Engineering Department
Northeastern University
Boston MA 02115
August 15, 2011
Outline
1. Motivation: Why NiW, NiWMo, and NiMo?
Why NiW nanowires?
2. Literature search: what has been done before?
3. Experimental
4. Results:
Electrodeposition of NiW, NiWMo, and NiMo alloys
Electrodeposition of NiW nanowires
Mechanical robustness of NiW nanowires
4. Conclusions
6. Acknowledgments
2
3
Motivation: Why NiW, NiWMo, and NiMo alloys?
Why NiW nanowires?
1. Why NiW, NiWMo, and NiMo alloys? Outstanding
functional properties:
- thermal resistance
- wear resistance
- corrosion resistance
- microhardness
- magnetic properties
- catalytic activity towards hydrogen evolution reaction
2. Why NiW nanowires?
- to investigate properties on the nanoscale level:
structure, morphology, robustness
- to create new composite material
Literature search: what has been done before?
Literature search: references on NiW and NiMo electrodeposition 1. , Electrodeposition of alloys, Academic Press, New York ( )
2. and D. Landolt, J. Electrochem Soc., 143 (3), 885 ( )
3. and L. Kahlenberg, Quart. Rev. Am. Electroplaters' Soc., 19 (9), 41 ( )
4. C. G. Fink and F. L. Jones, Trans. Electrochem. Soc., 59, 461 (1931)
5. L. N. Gol'tz and V. N. Kharlamov, Zhur. Prikl. Khim., 13, 1326 (1936)
6. M. L. Holt and L. E. Vaaler, J. Electrochem. Soc., 94, 50 (1948)
7. J. Kashima and F. Fukushima, J. Electrochem. Soc. Japan, 15, 33 (1947)
8. T. H. Fleisch, J. W. Zajac, and J. O. Schreiner, Appl. Surf. Sci., 26, 488 (1986)
9. T. F. Fransevich-Zabludovskaya, A. I. Zayats and V. T. Barchuk, Ukrain. Khim. Zhur., 25, 713 (1959)
10. A. T. Vas'ko, Electrochemistry of tungsten, Tekhnika, Kyiv (1969)
11. O. Younes and E. Gileadi, Electrochem. Solid St. Let., 3 (12), 543 (2000)
12. T. M. Sridhar, N. Eliaz, and E. Gileadi, Electrochem. Solid St. Lett., 8 (3), C58 (2005)
13. N. Tsyntsaru, S. Belevsky, A. Dikusar, and J. P. Celis, Trans. Inst. Metal Finish., 86 (6), 301 (2008)
14. V.Vasauskas, J. Padgurskas, R.Rukuiža, H.Cesiulis, J. P. Celis, D.Milcius, I.Prosycevas, Mechanika, 72 (4),
21 (2008)
15. M. Donten, H. Cesiulis, and Z. Stojek, Electrochim. Acta, 50 (6), 1405 (2005)
16. N. Atanassov, K. Gencheva, and M. Bratoeva, Plat. Surf. Finish., 84 (2), 67 (1997)
17. I. Mizushima, P. T. Tang, and H. N. Hansen, M. A. J. Somers, Electrochim. Acta, 51,
6128 (2006)
18. M.D. Obradovic, R.M. Stevanovic, and A.R. Despic, J. Electroanalyt. Chem., 552, 185 (2003)
19. V. Kublanovskii, O. Bersirova, Yu. Yapontseva, H. Cesiulis, and E. Podlaha-Murphy,
Prot. Met. Phys. Chem. Surf., 45 (5), 588 (2009)
20. M. R. Pavlov, N. V. Morozova, V. N. Kudriavtsev, Zaschita Metallov, 43 (5), 503 (2007)
21. T. Nenastina, , M. Ved, V. Shtefan, and M. Sakhnenko, Func. Mat., 14 (3), 395 ( ) 4
5
Literature search: NiW microstructures
Electrodeposition of NiW microposts*
* L. Namburi, Electrodeposition of Ni-W alloys into deep recesses, Thesis of Master of Science in
Chemical Engineering, B.Tech., Osmania University, 1999
Fig. 1. SEM image of a NiW micropost Fig. 2. SEM micrograph of Ni microposts
Electrolyte with NH4OH, pH 10
Temperature 70 oC
Recesses of 500 micron deep
Tungsten content less than 10 wt %
Goal – stronger Ni microposts
Fig. 3. SEM image of NiW microposts
Literature search: NiW nanostructures
6
Electrodeposition of CuNiW nanowires for magnetic applications*
* M. Gupta and , Electrodeposition of CuNiW alloys: thin films, nanostructured multilayers
and nanowires. J. Appl. Electrochem. 40 ( ) 1429-1439
Fig. 4. TEM image of multilayered
CuNiW nanowires Fig. 5. SEM micrograph of CuNiW
multilayers
Ammonia containing electrolyte, pH 8
Temperature 70oC
Highest tungsten content 33 wt.%
Alumina templates: 200 nm diameter and 60 µm length
Goals:
I. Determine conditions for depositing nanowires from thin
film NiW electrodeposition data
II. Develop conditions to deposit NiWMo thin films (not found
in literature) and compare to NiW and NiMo
III. Deposit NiW nanowires (not found in literature) and
investigate their robustness
7
Experimental'1
8
Electrodeposition into a
template: Whatman Nuclepore
Polycarbonate Track-Etch
Membrane
Potentiostat: Solartron SI
1287
Composition: XRF, Kevex
Omicron x-ray Fluorescence
Spectroscope
TEM and SEM Hummer sputtering system
Experimental’2
9
Au cathode Pt anode
SCE
Electrolyte:
Na2MeO4·2H2O 0.15 M
for NiW Me=W
for NiWMo Me=Mo+W
for NiMo Me=Mo
NiSO4·6H2O 0.1 M
Na3Cit 0.375 M
H3BO3 1 M
NaOH/H2SO4 for pH 7.0
Difference:
room temperature
no ammonia
polycarbonate membrane with pore size 10 to 100 nm
*Schematic from Maoshi Guan
Fig. 6. Schematic of the cell for the
electrodeposition of nanowires*
Cathode: gold film on the
bottom of the membrane,
Hummer sputtering system
Anode: Pt mesh
Reference electrode: SCE
Results
Part I
Electrodeposition of NiW, NiWMo, and
NiMo alloy thin films
Results: NiW alloy electrodeposition’1
W
Ni
Current efficiency
Fig. 8. Dependence of W and Ni
content in NiW alloys and current
efficiency in the range of applied
current densities of 10-700 mA/cm2
Fig. 7. Dependence of W and
Ni content in NiW alloys and
current efficiency
10
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60
Co
mp
on
ent
con
ten
t, w
t %
Cu
rren
t ef
fici
ency
, %
Current density, mA/cm2
0
20
40
60
80
100
0 100 200 300 400 500 600 700 800
Co
mp
on
ent
con
ten
t, w
t %
Cu
rren
t ef
fici
ency
, %
Current density, mA/cm2
Ni
W
Current efficiency
Higher j – lower W and CE
Results: NiW alloy electrodeposition’2
Fig. 11. Dependence of Log of partial current
density for Ni and W in NiW alloy
Fig. 10. Partial current densities for W and
Ni in NiW vs potential in the range of
applied current densities of 10-700 mA/cm2
Fig. 9. Partial current densities for W and
Ni in NiW alloy
0
0.4
0.8
1.2
1.6
2
0.8 1 1.2 1.4 1.6 1.8 2 2.2Par
tial
cu
rren
t d
ensi
ty, m
A/c
m2
Potential, -V vs SCE
2 5 10 20 30 40 50 Applied current density, mA/cm2
W
Ni
0
2
4
6
8
10
12
14
1 2 3 4 5 6 7Par
tial
cu
rren
t d
ensi
ty, m
A/c
m2
Potential, -V vs SCE 10 50 100/200/350/500/700
Applied current density, mA/cm2
Ni
W
2.5
2.8
3.1
3.4
3.7
4.0
4.3
0 1 2 3 4 5 6 7
Lo
g o
f p
arti
al c
urr
ent
den
sity
[A/c
m2]
Potential -E, V vs SCE
Ni
W
@ 20<j<100 mA/cm2 jW>jNi
@ j>100 mA/cm2 jNij>W
11
Results: NiWMo alloy electrodeposition. Mo:W=1:1
Fig. 12. Dependence of W, Ni, Mo, and Mo+W
content in NiWMo alloy on applied current
density. Mo:W=1:1
Fig. 14. Dependence of Log of partial
current density for W, Ni, and Mo in
NiWMo alloy vs potential. Mo:W=1:1
Fig. 13. Partial current densities for W,
Ni, and Mo in NiWMo alloy vs
potential. Mo:W=1:1
Mo+W in NiWMo > W in NiW
Mo > W
j for Mo, Ni, and W ↑ @ -E > 5
12
1
1.5
2
2.5
3
3.5
4
0 1 2 3 4 5 6
Lo
g o
f p
arti
al c
urr
ent
den
sity
[A/c
m2]
Potential -E, V vs SCE
Mo
Ni
W
0
1
2
3
4
5
6
1 2 3 4 5 6
Par
tial
cu
rren
t d
ensi
ty, m
A/c
m2
Potential, -V vs SCE
10 50 100 200 350/500/700 Applied current density, mA/cm2
Mo
Ni
W
0
10
20
30
40
50
60
70
80
0 100 200 300 400 500 600 700 800
Co
mp
on
ent
con
ten
t, w
t %
Current density, mA/cm2
W
Ni
Mo
Mo+W
Fig. 15. Dependence of W, Ni, Mo, and
Mo+W content in NiWMo alloy on applied
current density. Mo:W=1:3
Fig. 16. Partial current densities for W, Ni, and
Mo in NiWMo alloy vs potential. Mo:W=1:3
Fig. 17. Dependence of Log of partial
current density for W, Ni, and Mo in
NiWMo alloy vs potential . Mo:W=1:3
j for Mo, W, and Ni ↑@ -E >6 V
0
1
2
3
4
5
1 2 3 4 5 6 7 8
Par
tial
cu
rren
t d
ensi
ty, m
A/c
m2
Potential, -V vs SCE
10 50 100 200 350 500 700
Applied current density, mA/cm2
Mo
Ni
W
Results: NiWMo alloy electrodeposition. Mo:W=1:3
0
10
20
30
40
50
60
70
80
0 100 200 300 400 500 600 700 800
Co
mp
on
ent
con
ten
t, w
t %
Current density, mA/cm2
W
Ni
Mo
Mo+W
1
1.5
2
2.5
3
3.5
4
0 1 2 3 4 5 6 7 8
Lo
g o
f p
arti
al c
urr
ent
den
sity
[A/c
m2]
Potential -E, V vs SCE
Mo
Ni
W
13
Fig. 18. Dependence of W, Ni, Mo, and
Mo+W content in NiWMo alloy on applied
current density. Mo:W=3:1
Fig. 19. Partial current densities for W, Ni,
and Mo in NiWMo alloy vs potential.
Mo:W=3:1
Fig. 20. Dependence of Log of partial current
density for W, Ni, and Mo in NiWMo alloy vs
potential. Mo:W=3:1
Mo:W=3:1 gives higher Mo+W than
1:1 and 1:3
Results: NiWMo alloy electrodeposition. Mo:W=3:1
1
1.5
2
2.5
3
3.5
4
0 1 2 3 4 5 6 7 8
Lo
g o
f p
arti
al c
urr
ent
den
sity
[A/c
m2]
Potential -E, V vs SCE
Mo
Ni
W
0
1
2
3
4
1 2 3 4 5 6 7 8
Par
tial
cu
rren
t d
ensi
ty,
mA
/cm
2
Potential, -V vs SCE 10 50 100 200 350 500 700
Applied current density, mA/cm2
Mo
Ni
W
0
10
20
30
40
50
60
70
80
90
0 100 200 300 400 500 600 700 800
Co
mp
on
ent
con
ten
t, w
t %
Current density, mA/cm2
Mo
Mo+W
Ni
W
14
Fig. 21. Dependence of W, Ni, and Mo content in
NiWMo alloy on the ratio of refractory metals
concentrations in the electrolyte.
c(Na2MoO4·2H2O) 0.0375, 0.075, and 0.1125. pH
5.0. Current density 100 mA/cm2. (Point
c(Mo)/c(W)=10 represents case with no W in the
solution)
Fig. 22. Dependence of deposition rate, deposition
potential, and current efficiency on the ratio of
refractory metals concentrations in the electrolyte.
c(Na2MoO4·2H2O) 0.0375, 0.075, and 0.1125. pH
5.0. Current density 100 mA/cm2. (Point
c(Mo)/c(W)=10 represents case with no W in the
solution)
Mo:W=3:1 gives about the same amount of Mo in NiWMo alloy as for NiMo
Mo:W ratio also influences current efficiency CE– the highest CE 4 % @ Mo:W 1:1
Results: NiWMo alloy electrodeposition. Comparison
0
20
40
60
80
100
0 2 4 6 8 10
Co
mp
on
ent
con
ten
t, w
t %
c(Mo)/c(W), M/M
Mo+W
Mo
Ni
W 1
1.5
2
2.5
3
3.5
4
4.5
0 2 4 6 8 10
Cu
rren
t ef
fici
ency
, %
Dep
osi
tio
n r
ate,
mk
m/h
ou
r
Dep
osi
tio
n p
ote
nti
al, -V
c(Mo)/c(W), M
Deposition potential
Deposition rate
Current efficiency
15
Results: The behavior of W in NiW and NiWMo alloy
Fig. 23. Partial current densities for W vs
potential for NiW and NiWMo alloys (see Fig.
26 for detailed dependences for W in NiWMo
alloy)
Fig. 24. Partial current densities for W vs
potential for NiWMo alloy with varied
Mo:W ratio in the electrolyte
jW in NiW >> jW in NiWMo alloy → Mo inhibits W reduction
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0 1 2 3 4 5 6 7 8
Par
tial
cu
rren
t d
ensi
ty, m
A/c
m2
Potential -E, V vs SCE
Mo:W=1:3
Mo:W=1:1 Mo:W=3:1
0
0.5
1
1.5
2
2.5
0 1 2 3 4 5 6 7 8
Par
tial
cu
rren
t d
ensi
ty, m
A/c
m2
Potential -E, V vs SCE
W in NiW
W in NiWMo
16
Results: NiMo alloy electrodeposition
Fig. 25. Dependence of Ni and Mo content in
NiMo alloy on current density. pH 7.0
Fig. 26. Partial current densities for Mo and
Ni in NiMo alloy vs potential
Amount of Mo (80 wt %) in NiMo alloy
is higher than W (60 wt %) in NiW
alloy
For NiMo j for Ni and Mo ↑@ -E>5 V
Fig. 27. Dependence of Log of partial current
density for Mo and Ni in NiMo alloy vs potential
1.5
2
2.5
3
3.5
4
0 1 2 3 4 5 6 7
Lo
g o
f p
arti
al c
urr
ent
den
sity
[A/c
m2
]
Potential -E, V vs SCE
Mo
Ni
0
1
2
3
4
5
1 2 3 4 5 6 7Par
tial
cu
rren
t d
ensi
ty, m
A/c
m2
Potential -E, V vs SCE
Ni
Mo
0
10
20
30
40
50
60
70
80
90
0 100 200 300 400 500 600 700 800
Co
mp
on
ent
con
ten
t, w
t %
Current density, mA/cm2
Mo
Ni
17
The influence of pH and trisodium citrate concentration
0.5 M of Cit
0.375 M of Cit
0
10
20
30
40
50
60
70
80
90
Mo
83.3
16.7
81.1
18.9
Co
mp
on
ent
con
ten
t, w
t %
Alloy component
Ni
Fig. 28. Dependence of Mo and Ni
content on trisodium citrate
concentration when depositing NiMo
alloy. pH 7.0. Current density
100 mA/cm2
Fig. 29. Dependence of Mo and Ni
content on pH when depositing NiMo
alloy. Current density 100 mA/cm2
pH and Cit concentration do not
influence Mo content in NiMo
significantly, but lower pH (5)
provides higher current efficiency
0
20
40
60
80
100
3 4 5 6 7 8 9
Co
mp
on
ent
con
ten
t, w
t %
pH
Mo
Ni
18
Results
Part II
Electrodeposition of NiW nanowires
Results: NiW nanowires
Ni-W nanowires were deposited using both direct and pulse current
t
-i
t = 0 t
-i
t = 0 t
-i
t = 0
~~
t
-i
t = 0
~~
Direct current-time profile Pulse current-time profile
Time-on
Time-off 0
Applied current density -30...35mA/cm2
Applied current -9.82mA
Frequency
f=1/time-on
Duty cycle
γ=time-on/(time-on+time-off)
19
Dependences for Ni-W thin films were used to find conditions for nanowire deposition
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60
Co
mp
on
ent
con
ten
t, w
t %
Cu
rren
t ef
fici
ency
, %
Current density, mA/cm2
Ni
Current efficiency
W
Fig. 7. Dependence of W and Ni
content in NiW alloy and current
efficiency on applied current
density
Results: Deposition under direct current
20
Ni-W nanowire morphology turns out to be bumpy (pore shape? Effect of
deposition conditions?)
“Stated” diameter 100 nm - the actual diameter 90-250 nm
Bumps dimensions: width 57-60 nm, height 20-50 nm
Average tungsten content is lower than in thin films (up to 60 wt %)
Fig. 30. Sample 16: d=100 nm, DC, ω(W)=52.4±0.2 wt.%
15
Results: SEM images
Fig. 40. Sample 16: d=100 nm,
DC, ω(W)=52.4±0.2 wt.%
Scanning electron microscopy has
proven the bumpy morphology of the
nanowires deposited under direct
current
21
Results: SEM images
Fig. 41. Sample 16: d=100 nm, DC,
ω(W)=52.4±0.2 wt.%
22
From SEM: bumps width 140 nm
From AFM: bumps width 57-60 nm
Fig. 42. Sample 5: d=100 nm, PC, ton=1 s, toff=1.5 s, ω(W)=49.6±0.7 wt %
23
Results: Deposition under pulse current
Bumps dimensions: width 91-94 nm, height 23-29 nm
Tungsten content is lower than in thin films and when using
DC (52.4±0.2 wt.%)
Results: Deposition under pulse current
Fig. 43. Sample 7: d=50 nm, PC, ton=1 s, toff=1.5 s, ω(W)=50.4±0.5 wt.%
“Stated” membrane diameter 50 nm – actual 60-160 nm
Bumps dimensions: width 20-40 nm, height 17-21 nm
Tungsten content is lower than in thin films (up to 60 wt.%),
similar to that for 100 nm pore membrane PC (49.6±0.7 wt.%)
24
Results: Deposition under pulse current
25
Fig. 44. Sample 13: d=10 nm, PC, ton=1 s, toff=1.5 s, ω(W)=33.0±2.5 wt.%
“Stated” membrane diameter 10 nm – actual 35-40 nm
Bumps dimensions: width 15-16 nm, height 6-7 nm
Ni-W nanowires of this diameter are less mechanically robust: few are broken
Tungsten content is lower than in thin films (up to 60 wt.%) and that for 100 and 50 nm
pore membranes (49.6±0.7 and 50.4±0.5 wt.%): pH effect? Porosity? (different membrane
though)
Results: Variation in nanowire dimensions with change of
membrane diameter
26
Conclusions: 1. the bigger diameter – the bumpier structure
2. effect is not defined by the diameter only
Deposition mode Pulse current Direct
current
“Stated” membrane
diameter, nm 10 PC 50 PC 100 PC 100 DC
Actual nanowire
diameter, nm 35-40 60-160 70-245 90-250
Bump width, nm 15-16 20-40 91-94 57-60
Bump height, nm 6-7 17-21 23-29 20-50
Tungsten content, wt.% 33±2.5 50.4±0.5 49.6±0.7 52.4±0.2
Deposition time, hours 1.7 5.0 5.7 2.3
Results: Deposition under pulse current – different current frequency
Fig. 45. Sample 32: d=100 nm, ton=10 s,
toff=15 s, f=0.04Hz
Fig. 46. Sample 35: d=100 nm, ton=100 s,
toff=150 s, f=0.004Hz
27
Results: Variation in nanowire dimensions with change
of current frequency
Conclusion: The increase in frequency leads to the increase of
bump width and height
28
On-time/Off-time, s/s ∞ 100/150 10/15 1/1.5
Current frequency, Hz 0 (DC) 0.004 0.04 0.4
Bump width, nm 57-60 73-78 85-89 91-94
Bump height, nm 23-46 6-16 8-20 16-29
Tungsten content, wt % 52.4±0.2 51.5±0.8 54.0±1.5 49.6±0.7
Deposition time, hours 2.3 5.2 5.1 5.7
Results
Part III
Mechanical Robustness of NiW nanowires
Mechanical robustness of NiW nanowires from 100 nm membrane made by DC
Fig. 47b. TEM image of NiW nanowires
after ultrasonic treatment. Membrane:
Whatman Polycabonate 100 nm. Direct
current I=9.82 mA. Tungsten content
52.4 wt %
Fig. 47a. TEM image of NiW nanowires
without ultrasonic treatment. Membrane:
Whatman Polycabonate 100 nm. Direct
current I=9.82 mA. Tungsten content
52.4 wt %
29
Mechanical robustness of NiW nanowires from 100 nm membrane made by PC
Fig. 48a. TEM image of NiW nanowires
without ultrasonic treatment. Membrane:
Whatman Polycabonate 100 nm. Pulse
current I=9.82 mA, ton=1 s, toff=1.5 s.
Tungsten content 49.6 wt %
Fig. 48b. TEM image of NiW nanowires after
ultrasonic treatment. Membrane: Whatman
Polycabonate 100 nm. Pulse current
I=9.82 mA, ton=1 s, toff=1.5 s. Tungsten content
49.6 wt %
30
0
0.2
0.4
0.6
0.8
1
0 0.04
0.11
0 0 0.04
1
No
rmal
ized
qu
anti
ty o
f N
iW
nan
ow
ires
w
ith
len
gth
of
x
≤500nm 0.5-1µm 1-2µm 2-3µm 3-4µm 4-5µm 5-6µm
Fig. 49. Normalized quantity of
NiW nanowires with the length of
x after ultrasonic treatment.
Membrane: Whatman
Polycabonate 100 nm. Direct
current I=9.82 mA. Tungsten
content 52.4 wt %
Comparison: NiW nanowires from 100 nm membrane made by DC and PC after US
0
0.2
0.4
0.6
0.8
1
0 0 0
0.11
0 0.04
1
No
rmal
ized
qu
anti
ty o
f N
iW
nan
ow
ires
wit
h l
eng
th o
f x
≤500nm 0.5-1µm 1-2µm 2-3µm 3-4µm 4-5µm 5-6µm
Fig. 50. Normalized quantity of
NiW nanowires with the length of
x after ultrasonic treatment.
Membrane: Whatman
Polycabonate 100 nm. Pulse
current I=9.82 mA, ton=1 s,
toff=1.5 s. Tungsten content 49.6
wt %
Both made by DC and PC, NiW
nanowires from 100 nm
withstand US treatment
31
Mechanical robustness of NiW nanowires from 50 nm membrane made by DC
Fig. 51a: TEM image of NiW nanowires
without ultrasonic treatment. Membrane:
Whatman Polycabonate 50 nm. Direct
current I=9.82 mA. Tungsten content 54.6
wt %
Fig. 51b: TEM image of NiW nanowires
after ultrasonic treatment. Membrane:
Whatman Polycabonate 50 nm. Direct
current I=9.82 mA. Tungsten content 54.6
wt %
32
Mechanical robustness of NiW nanowires from 50 nm membrane made by PC
Fig. 52a: TEM image of NiW nanowires
without ultrasonic treatment. Membrane:
Whatman Polycabonate 50 nm. Pulse
current I=9.82 mA, ton=1 s, toff=1.5 s.
Tungsten content 50.4 wt %
Fig. 52b: TEM image of NiW nanowires
after ultrasonic treatment. Membrane:
Whatman Polycabonate 50 nm. Pulse
current I=9.82 mA, ton=1 s, toff=1.5 s.
Tungsten content 50.4 wt %
33
0.0
0.2
0.4
0.6
0.8
1.0
0.43
0.29
1.00
0.71
0.57 0.57
No
rmal
ized
qu
anti
ty o
f N
iW
nan
ow
ires
wit
h l
eng
th o
f x
≤500nm 0.5-1µm 1-2µm 2-3µm 3-4µm 4-5µm
Comparison: NiW nanowires from 100 nm and 50 nm membrane made by DC
NiW nanowires from 50 nm
membrane break more than those
from 100 nm membrane
0
0.2
0.4
0.6
0.8
1
0 0.04
0.11
0 0 0.04
1
No
rmal
ized
qu
anti
ty o
f N
iW
nan
ow
ires
w
ith
len
gth
of
x
≤500nm 0.5-1µm 1-2µm 2-3µm 3-4µm 4-5µm 5-6µm
Fig. 54: Normalized quantity of NiW
nanowires with the length of x after
ultrasonic treatment. Membrane:
Whatman Polycabonate 50 nm. Direct
current I=9.82 mA. Tungsten
content 54.6 wt %
Fig. 53: Normalized quantity of NiW
nanowires with the length of x after
ultrasonic treatment. Membrane:
Whatman Polycabonate 100 nm. Direct
current I=9.82 mA. Tungsten content
52.4 wt %
34
Mechanical robustness of NiW nanowires from 10 nm membrane made by DC
Fig. 55a: TEM image of NiW nanowires
without ultrasonic treatment. Membrane:
OsmonicsInc Polycabonate 10 nm. Direct
current I=9.82 mA. Tungsten content
35.2wt %
Fig. 55b: TEM image of NiW nanowires
after ultrasonic treatment. Membrane:
OsmonicsInc Polycabonate 10 nm. Direct
current I=9.82 mA. Tungsten content 35.2
wt %
35
Mechanical robustness of NiW nanowires from 10 nm membrane made by PC
Fig. 56a: TEM image of NiW nanowires
without ultrasonic treatment. Membrane:
OsmonicsInc Polycabonate 10 nm. Pulse
current I=9.82 mA, ton=1 s, toff=1.5 s.
Tungsten content 33.0 wt %
Fig. 56b: TEM image of NiW nanowires
after ultrasonic treatment. Membrane:
OsmonicsInc Polycabonate 10 nm. Pulse
current I=9.82 mA, ton=1 s, toff=1.5 s.
Tungsten content 33.0 wt %
36
Comparison: NiW nanowires from 10 nm membrane made by DC and PC
0.0
0.2
0.4
0.6
0.8
1.01.00
0.67
0.58
0.25
0.08
0.33
0.58
No
rmal
ized
qu
anti
ty o
f N
iW
nan
ow
ires
wit
h l
eng
th o
f x
≤500nm 0.5-1µm 1-2µm 2-3µm 3-4µm 4-5µm 5-6µm
Fig. 57: Normalized quantity of
NiW nanowires with the length
of x after ultrasonic treatment.
Membrane: OsmonicsInc
Polycabonate 10 nm. Direct
current I=9.82 mA. Tungsten
content 35.2 wt %
0
0.2
0.4
0.6
0.8
1
0.33
0.22
1.00
0.22
0.11 0.11
0.56
No
rmal
ized
qu
anti
ty o
f N
iW
nan
ow
ires
wit
h l
eng
th o
f x
≤500nm 0.5-1µm 1-2µm 2-3µm 3-4µm 4-5µm 5-6µm
Fig. 58: Normalized quantity of
NiW nanowires with the length
of x after ultrasonic treatment.
Membrane: OsmonicsInc
Polycabonate 10 nm. Pulse
current I=9.82 mA, ton=1 s,
toff=1.5 s. Tungsten content
33.0 wt %
NiW nanowires made by DC
break more than those made
by PC
37
Comparison: NiW nanowires from 10 nm membrane made by DC and PC
Fig. 59: TEM image of NiW nanowires
after ultrasonic treatment. Membrane:
OsmonicsInc Polycabonate 10 nm. Direct
current I=9.82 mA. Tungsten content
35.2wt %
Fig. 60: TEM image of NiW nanowires
after ultrasonic treatment. Membrane:
OsmonicsInc Polycabonate 10 nm. Pulse
current I=9.82 mA, ton=1 s, toff=1.5 s.
Tungsten content 33.0 wt %
38
Thin Films
NiW
• Deposit concentration of W in NiW is in a similar range (40-60 wt %) as other
literature reports (@ low –E)
• Our work shows that the iW has an unusual feature, increasing with –E, and then
decreasing, and increasing again at extremely high –E
NiWMo
• In an electrolyte of 1:1 MoO42-:WO4
2-, there is more Mo than W deposited
• The sum of Mo+W in the deposit exceeds the amount of W in NiW
NiMo
• Mo deposit content in NiMo is higher than W deposit content in NiW
Nanowires
• Nanowires grow with a bumpy morphology even under DC
• Their ease to break depends on
• Wire diameter
• DC vs Pulse (pulse deposition is better)
Conclusions
39
Acknowledgments
Scientific adviser: prof. Elizabeth J. Podlaha-Murphy
Committee members: Prof. Mukerjee and Prof. Goluch
William Fowle (TEM/SEM imaging)
Labmates: Alex Avekians, Mehdi Zamanpour,
Hana Kim, Savidra Lucatero,
Shaopeng Sun, Salem Zahmi
Chemical Engineering Department
College of Engineering
Northeastern University
Fulbright Association
40
Thank you for your attention!
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