Electrodeposition of textured nickel on nickel alloy Hastelloy

Article abstract of DOI:10.1016/j.physc.2009.05.077

We proposed a new method fabricating low-cost and mechanically strong tapes for coated conductors. In this method, Hastelloy tape, which is a strong nickel alloy, is plated with a nickel film. A two-step plating was applied to obtain a textured

Full text of DOI:10.1016/j.physc.2009.05.077

Physica C 469 (2009) 1371–1373
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Physica C
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Electrodeposition of textured nickel on nickel alloy Hastelloy
M. Sugimoto a, , R. Teranishi , S. Ooue , M. Mukaida , N. Mori , K. Yamada ,
a
a
a
a
a
*
a
b
b
H. Fukushima , T. Izumi , Y. Shiohara
Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
a
b
Superconductivity Research Laboratory, ISTEC, 1-10-13, Shinonome Koto-ku, Tokyo 135-0062, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Available online 29 May 2009
We proposed a new method fabricating low-cost and mechanically strong tapes for coated conductors. In
this method, HastelloyÒ tape, which is a strong nickel alloy, is plated with a nickel film. A two-step plat-
ing was applied to obtain a textured nickel film. In the first step, a strike bath was used in order to plate a
nickel film on Hastelloy surface. In the second step, the film was plated in a low cost watts bath. We con-
trolled various plating conditions such as pH-condition, thickness, and current density in the watts bath
to fabricate a textured nickel film.
PACS:
8
8
1.15.Pq
2.45.Qr
The crystal orientation of the nickel films was characterized by an X-ray diffraction method (XRD) with
Keywords:
Hastelloy
Nickel plating
Strike bath
Watts bath
Cu K
a radiation. Preferred orientation of the film depends on pH of watts bath, nickel film thickness, and
current density. The optimal conditions for obtaining a textured nickel film are pH of 4.5 for the watts
2
bath, current density of 500 A/m , and thickness of 92
l
m. Finally, we succeeded in obtaining nickel films
with 96% c-axis orientation.
Ó 2009 Elsevier B.V. All rights reserved.
1
. Introduction
REBa Cu 7ꢀd (RE = Rare Earth elements, REBCO) coated con-
2. Experimental
2
3
O
A Hastelloy C-276 tape with 90 lm thick, 10 mm wide, and
ductors are mainly grown on substrates fabricated by means of a
Rolling-Assisted Biaxially Textured Substrates (RABiTS) method
and an Ion Beam Assist Deposition (IBAD) method [1,2]. In the RA-
BiTS method, fcc metal substrates are biaxially textured by heavy
cold rolling and annealing. Substrates fabricated by RABiTS method
are low cost, but mechanically weak, because basic material of the
substrate is composed by clean fcc metals.
20 mm long was used as a cathode electrode. One side of the
Hastelloy was electrolytic polished and the other side was coated
by an insulation tape. A nickel plate was used as an anode
electrode.
Both strike bath [5] and watts bath [6] were used to plate nickel
film on Hastelloy substrates. Compositions of these baths are
showed in Tables 1 and 2, respectively. First of all, the Hastelloy
2
On the other hand, substrates fabricated by an IBAD method are
tape was plated inversely at a current density of 500 A/m in the
strong. Inner layers (Yttria-stabilized zirconia (YSZ), Gd
2
Zr
2
O
7
strike bath for 30 s. Then, the tape was plated in the bath for
3 min to be deoxidized and plated nickel adhesion layers with
(
GZO) [3], MgO [4], etc.) in an IBAD substrate are biaxially textured
by an assisting ion beam on a Hastelloy. But this method is high-
cost due to their vacuum equipments, and inefficient for high
speed productive.
In this study, a new method is proposed which realizes a low-
cost and mechanically strong substrate for coated conductors.
We use Hastelloy substrates and plate biaxially textured nickel
films. High c-axis orientation of nickel films is discussed.
1.2 lm thickness. Next, the thin nickel film, obtained in the strike
bath, was thickened in the watts bath. We controlled pH-condition,
plating time, and current density in the watts bath to plate the tex-
tured nickel films. The pH of watts bath was adjusted with NaOH
3
solution of 10 mol/m from pH of 2.7–6.0. All nickel electro depo-
3
sitions were carried out in a glass beaker with 500 cm electrolyte
at about 40 °C.
Crystal orientations of the films were evaluated by using an X-
ray diffractometer h/2h scan with Cu–Ka radiation. In this study,
crystal orientation of the nickel film was estimated by a degree
of (2 0 0)Ni orientation, which was defined as follows:
*
Corresponding author. Present address: Mukaida laboratory, Department of
Materials Physics and Chemistry, Graduate School of Engineering, Kyushu Univer-
sity, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan. Tel.: +81 92 802 2979; fax:
81 92 802 2978.
r
200 ¼ F200=ðF111 þ F200 þ F220 þ F311
Þ
ð1Þ
ð2Þ
+
Fhkl ¼ Intensity ðcpsÞ=relative intensity
hkl
hkl
E-mail address: sugimoto07@zaiko10.zaiko.kyushu-u.ac.jp (M. Sugimoto).
0
921-4534/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.physc.2009.05.077

1
372
M. Sugimoto et al. / Physica C 469 (2009) 1371–1373
Table 1
Composition of strike bath.
than that of the other nickel crystal planes in the adequate pH
condition.
Compounds
Concentrations (g/m3)
3.2. Degree of orientation
NiCl
HCl
2
ꢁ6H
2
O
24,000
8000
From the results of Fig. 1, it was found that the orientation of
nickel films depends on the plating time. Then relationships be-
tween orientation and plating time were examined in dital. We
examined additional four nickel films with plating times, films
Table 2
Composition of watts bath.
6
0–150 min (with thickness, from 61 to 153
plating time dependence of the nickel film orientation. In the plat-
ing time from 15 to 90 min (with thickness from 15 to 92 m), de-
lm). Fig. 2 shows a
Compounds
Concentrations (g/m3)
NiSO
NiCl
BO
NaOH
4
ꢁ6H
2
O
O
25,000
4500
3000
l
2
ꢁ6H
2
gree of nickel preferred orientation is proportional to the plating
time. While, in the condition of plating time over 90 min, the ori-
entation was saturated. In the plating time of 90 min, the degree
of nickel preferred orientation achieved 96%. Fig. 3 shows (1 1 1)
H
3
3
Suitable
3
. Results and discussion
.1. pH-condition and plating time
Fig. 1 shows the dependences of the orientation of nickel films
3
1
on both pH-conditions of watts bath and plating time. The plating
time was varied from 15 to 45 min for the watts bath. The current
density was fixed at 500 A/m . We carefully controlled the pH con-
0
.9
2
ditions. In the condition of pH from 2.7 to 4.0, the textured nickel
film was plated in the bath. In the low pH condition around pH = 2,
the potential of H was more electropositive than that of nickel,
2
then a nickel film was plated kinetically. In this condition, the cur-
rent efficiency was very low, resulting in very thin film with very
poor orientation. In the condition of pH from 4.0 to 5.5, the degree
of nickel orientation was saturated. It was found that this pH range
was well suited to plate the textured nickel films. The plating rate
in the condition of pH from 4.0 to 5.5 was calculated about
0.8
0.7
0
0
.6
.5
1
.02
According to a pourbaix diagram of nickel [7], Ni(OH)
in the watts bath for the pH = 6.7. In this case, it seemed that the
pH at the vicinity of the cathode raised locally by H generation,
then Ni(OH) appeared and a nickel film was flacked.
l
m/min. In the condition of pH = 6.0, nickel film was flaked.
2
is deposited
0
30
60
90
120
150
180
2
Plating time (min)
2
Finally, we adopted the watts bath condition of pH = 4.5 for la-
ter experiments. From a view point of plating time or plating nickel
thickness, the thick nickel films had high (2 0 0)Ni orientation. We
concluded that the growth rate of the Ni {1 0 0} plane was faster
Fig. 2. A relationship between nickel plating orientation and the long time nickel
plating.
1
0
0
0
0
.8
.6
.4
.2
0
1
5min
30min
5min
4
2
3
4
pH
5
6
Fig. 1. A relationship among nickel film orientation, pH-condition and plating time
for the plating in watts bath.
Fig. 3. A (1 1 1) pole figure of the plating time 90 min in the watts bath nickel film.

M. Sugimoto et al. / Physica C 469 (2009) 1371–1373
1373
1
.8
.6
.4
.2
0
0
0
0
0
2
2.2
2.4
2.6
2.8
3
Fig. 5. A photograph of nickel films on Hastelloy tapes. The upper side: deposit in
500 A/m . The lower side: burnt deposit in 5000 A/m .
2
2
log of current density
Fig. 4. A relationship between nickel orientation and current density. X-axis is the
common logarithm of the current density.
4
. Conclusions
The Hastelloy tape was plated with textured nickel film in the
strike bath and the watts bath. We controlled various parameters
such as pH-conditions, plating time, and current density in the
watts bath to make a textured nickel film. The high (2 0 0)Ni orien-
tation films were obtained in pH from 4.0 to 5.5. The longer nickel
plating time, the higher degree of nickel orientation was obtained.
Table 3
Current density and plating time.
Current density (A/m2)
Log of current density
Plating time (min)
100
250
500
750
2
600
240
120
80
2.40
2.70
2.88
3
2
When the current density was 500 A/m , degree of preferred orien-
tation was saturated over 90 min. At the current density from 250
2
to 1000 A/m , the smaller current density resulted in the higher
1
000
60
degree of nickel orientations. In this report, the best condition for
2
the watts bath was pH of 4.5, current density of 500 A/m , and
plating time of 90 min, and we obtained nickel films with (2 0 0)
orientation above 96%.
the pole figure of the nickel film with plating time of 90 min in the
watts bath. A high c-axis textured nickel film is obtained.
Acknowledgements
3.3. Current density in the watts bath
This work was supported by the New Energy and Industrial
Technology Development Organization (NEDO) through ISTEC as
the Collaborative Research and Development of Fundamental
Technologies for Superconductivity Applications, and Fukushima
laboratory’s members at Kyushu University.
An orientation of electroplates is reported to be controlled by
current density [8]. To increase the degree of nickel preferred ori-
entation, the optimal current density was searched and the results
are shown in Fig. 4. Each current density and plating time of the
plating conditions are showed in Table 3. Here, the relationship be-
tween current density and plating time were decided to make
equal electric quantity for each condition. If their current efficiency
were equal, their nickel film thickness was estimated to be equal.
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of 100 A/m was higher than activation overpotential, then an elec-
[
trodeposit was not preferredly plated. In addition, we tried to plate
(
2
a nickel film in 5000 A/m for 12 min. However, the film resulted in
[
a burnt deposit as shown in Fig. 5.