synthesis of metal hydrides employing vapor deposition technologies irmantas barnackas, prof.l....
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Synthesis of metal hydrides Synthesis of metal hydrides employing vapor deposition employing vapor deposition
technologiestechnologies
Irmantas Barnackas, prof.L. PranevičiusLithuanian Energy Institute
2006 01 20
Outline of the presentationOutline of the presentation
• Hydrogen storage: metal hydrides (Mg2NiH4)
• Experimental work
• Conclusion
The main goal of the workThe main goal of the work
To investigate the possibilities of formation of Mg-based alloys (Mg2NiH4), used for hydrogen storage, employing physical vapor deposition method.
Hydrogen StorageHydrogen Storage Compressed gas storage tanks Carbon fibers and nanotubes Metal hydrides
Mg hydrides• light weight• low manufacture cost• high hydrogen-storage capacity
Limitations• Slow adsorption kinetics• High de-hydriding temperature (~573 K)• Stability of the MgH2
The kinetics can be improved by alloying with Ni → Mg2Ni (the capacity to approx. 3.6 % and TDes ~ 553 K
MaterialH-atoms per
cm3 (x 1022)
% of weight that is
hydrogen
MgH2 6.5 7.6
Mg2NiH4 5.9 3.6
FeTiH2 5.9 1.89
LaNi5H6 5.5 1.37
Hydrogen Storage: Mg-Ni-H systemHydrogen Storage: Mg-Ni-H system
The phases of hexagonal Mg2Ni alloy:• α (Mg2NiH0.3)• β (Mg2NiH4)
The Mg2NiH4 hydride has two crystallographic forms:• a low temperature (LT1 and LT2) modification• a high temperature (HT) modification
For T > 510 K, Mg2NiH4 has a cubic structure (HT phase) which becomes monoclinally distorted below this temperature (LT phase).
Experimental technique: Experimental technique:
• to produce nanocrystalline Mg, Ni and Mg2Ni thin film materials using magnetron sputtering;
• to hydrogenate MgNi thin films in hydrogen plasma and under high hydrogen pressure and temperature (p,T);
• to study MgNi thin films de-hydrogenation kinetics using GDOES techniques;
• to analyze MgNi thin films properties of as-deposited, after hydrogenation and de-hydrogenation using XRD, SEM and GDOES methods.
Experimental technique: Experimental technique:
The scheme of experimental device of MgNi thin films for deposition and hydrogenation
in hydrogen plasma
Parameters of as-deposited Parameters of as-deposited
Mg, Ni and MgNi filmsMg, Ni and MgNi films : :IMg = 1 A, UMg = 400 V
INi = 0.3 A, UNi = 450 V
UBIAS = -100 V, IBIAS = 10-20 mA
Deposition time - 5 min;
Substrate temperature – 330 K
Film thickness – 1 - 3μm
Working gas – argon gas
As-deposited Mg film: - XRD and SEM analysis
10 20 30 40 50 60 700
500
1000
1500
2000
2500
3000
3500
4000 IMg
= 1 A, UMg
= 400 V
UBIAS
= 100 V, IBIAS
=20 mA
t = 5 min.
Substrate - quartz
Substrate
h-Mg(103)
h-Mg(102)h-Mg(101)h-Mg(002)
As-deposited Mg film
Inte
nsi
ty, a
rb.u
Diffraction angle, 2 theta
XRD diffractogram of as-deposited Mg film on quartz substrate
SEM micrograph of as-deposited Mg film on quartz substrate
As-deposited Ni film: - XRD and SEM analysis
30 40 50 60 70 800
50
100
150
200
250
300
350
400 INi
= 0.3 A, UNi
= 440 V
UBIAS
= 100 V, IBIAS
=10 mA
t = 5 min.
Substrate - quartz
c-Ni(200)
c-Ni(111)
Inte
nsi
ty, a
rb.u
.
Diffraction angle, 2 theta
XRD diffractogram of as-deposited Ni film on quartz substrate
SEM micrograph of as-deposited Ni film on quartz substrate
As-deposited MgNi film: - XRD and SEM analysis
10 20 30 40 50 60 700
500
1000
1500
2000
2500
3000IMg
= 1 A, UMg
= 400 V
UBIAS
= 100 V, IBIAS
=20 mA
t = 5 min.
INi
= 0.3 A, UNi
= 440 V
h-Mg2Ni(006)
h-Mg2Ni(003)
Substrate - quartz
As deposited Mg2Ni
Mg2Ni standard
Inte
nsity
, arb
.u.
Diffraction angle, 2 theta
XRD diffractogram of as-deposited MgNi film on quartz substrate
SEM micrograph of as-deposited MgNi film on quartz substrate
Plasma hydrogenationPlasma hydrogenation
Parameters of hydrogenation:Pressure – 100 PaBias voltage – -300 ÷ -3000 V Ion current from plasma – 70-400 mATemperature of sample holder 40 °CHydrogenation duration – 30-120 min.
The schematic presentation of the plasma hydriding
MgMg22Ni thin film saturated with hydrogen atomsNi thin film saturated with hydrogen atoms
H irra d ia tio n+
S u bs trate
B o un d arie so f n a no g ra in s
C ha n ne lsb etw e e n co lu m ns
C om p re ss ives tre ss
- H yd rog e n atom s
C om p re ss ives tre ss
H sa tu ratedsu rfa ce
.. ... ... ... ... . - H sa tu rated su rfa ce
10 20 30 40 50 60 700
500
1000
1500
2000
2500
3000
c-Ni(111)
h-Mg2Ni(006)
h-Mg2Ni(003)
P(H2) = 100 Pa
t = 1 hourIBIAS
=40 mAU
BIAS= 300 v
After hydrogenation in hydrogen plasma
As deposited Mg2Ni
Inte
nsit
y, arb
.u.
Diffraction angle, 2 theta
MgMg22Ni films after Ni films after plasma plasma hydrogenation: hydrogenation: - XRD and SEM analysis
XRD diffractogram of Mg2Ni film after plasma hydrogenation using dc power supply
SEM micrograph of Mg2Ni film after plasma hydrogenation on quartz
substrate (DC power supply)
10 20 30 40 50 60 700
500
1000
1500
2000
2500
3000
c-Ni(111)
h-Mg2Ni(006)
h-Mg2Ni(003)
P(H2) = 100 Pa
t = 1 hourIBIAS
=150 mAU
BIAS= 900 v
After hydrogenation in hydrogen plasma
As deposited Mg2Ni
Inte
nsit
y, arb
.u.
Diffraction angle, 2 theta
XRD diffractogram of Mg2Ni film after plasma hydrogenation using dc power supply
MgMg22Ni films after Ni films after plasma plasma hydrogenation: hydrogenation: - XRD and SEM analysis
SEM micrograph of Mg2Ni film after plasma hydrogenation on quartz
substrate (DC power supply)
10 20 30 40 50 60 700
1000
2000
3000
4000
5000
h-Mg2NiH
0.3(006)
h-Mg2Ni(006)
h-Mg2Ni(003)
h-Mg2Ni(003)
h-Mg2Ni(006)
P = 100 PaU
BIAS= 3000 V
t = 1 hour
After plasma hydriding Mg
2Ni
As-deposited Mg2Ni
Inte
nsity
, arb
.u.
Diffraction angle, 2 theta
XRD diffractogram of Mg2Ni film after plasma hydrogenation using AC power supply
MgMg22Ni films after Ni films after plasma plasma hydrogenation: hydrogenation: - XRD and SEM analysis
SEM micrograph of Mg2Ni film after plasma hydrogenation on quartz
substrate (AC power supply)
10 20 30 40 50 60 700
1000
2000
3000
4000
5000
LT m-Mg2NiH
4(220)
LT m-Mg2NiH
4(110)
h-Mg2Ni(003)
h-Mg2Ni(006)
P = 100 PaU
BIAS= 3000 V
t = 2 hour
After plasma hydriding Mg
2Ni
As-deposited Mg2Ni
Inte
nsit
y, arb
.u.
Diffraction angle, 2 theta
MgMg22Ni films after Ni films after plasma plasma hydrogenation: hydrogenation: - XRD and SEM analysis
XRD diffractogram of Mg2Ni film after plasma hydrogenation using AC power supply
SEM micrograph of Mg2Ni film after plasma hydrogenation on quartz
substrate (AC power supply)
Reactive sputtering inReactive sputtering in Ar+H Ar+H2 2 plasmaplasma
10 20 30 40 50 60 700
500
1000
1500
2000
2500
3000 UMg
= 160 V
UNi
= 320 V
Substrate - quartz
Mg2NiH
4 standard
Mg2Ni standard
c-Ni(111)
IMg
= 1 A,
INi
= 0.3 A,
t = 30 min.
P = Ar+H2
Ni standard
Inte
nsi
ty, a
rb.u
.
Diffraction angle, 2 theta
XRD diffractogram of MgNi film after reactive sputtering on quartz
substrate
SEM micrograph of MgNi film after reactive sputteringon quartz substrate
Hydrogenation of MgNi thin films in high hydrogenHydrogenation of MgNi thin films in high hydrogenpressure and temperature (p,T)pressure and temperature (p,T)
The schematic view of the hydrogenation cell for the studies of the adsorption properties
Parameters of hydrogenation: Pressure – 8 barTemperature – RT – 523 KHydrogenation duration – 30-120 min.
10 20 30 40 50 60 700
2000
4000
6000T = 523 K
Hydrogenation properties: P(H2) = 8 bar
After hydrogenation for 120 min.
After hydrogenation for 60 min.
After hydrogenation for 30 min.
As-deposited Mg
2Ni
Mg2NiH
4 standard
Mg2Ni standard
Inte
nsit
y, arb
.u.
Diffraction angle, 2 theta
MgMg22Ni films after hydrogenation in high hydrogen pressure and Ni films after hydrogenation in high hydrogen pressure and
temperature (p,T) : temperature (p,T) : - XRD analysis
MgMg22Ni films after hydrogenation in high hydrogen pressure and Ni films after hydrogenation in high hydrogen pressure and
temperature (p,T) : temperature (p,T) : - SEM analysis
a
b
SEM micrograph of MgNi film after hydrogenation in high hydrogen pressure and temperature (p,T) on quartz substrate:
a – after 30 min.; b – after 60 min.
MgMg22Ni films after hydrogenation in high hydrogen pressure and Ni films after hydrogenation in high hydrogen pressure and
temperature (p,T) : temperature (p,T) : - SEM analysis
SEM micrograph of MgNi film at different magnification after hydrogenation in high hydrogen pressure and temperature (p,T) on quartz substrate
Studies of deStudies of de--hydrhydrogenationogenation kinetics of Mg kinetics of Mg22NiHNiH44 thin films thin films
The schematic view of the de-hydrogenation cell for the studies of the desorption properties
XRD analysis of XRD analysis of Mg2NiH4 film after de-hydrogenation process
DeDe--hydrhydrogenationogenation kinetics of Mg kinetics of Mg22NiHNiH44 thin films: SEM and XRD thin films: SEM and XRD
SEM analysis of SEM analysis of Mg2NiH4 film after de-hydrogenation process
10 20 30 40 50 60 700
1000
2000
3000
4000
5000
Hydrogenation (p,T): T = 523 K t = 60 min.De-hydrogenation: T = 770 K t = 30 min.
After de-hydrogenation for 30 min.
After hydrogenation for 60 min.
h-Mg2Ni(200)
h-Mg2Ni(203)
c-Mg2NiH
4(311)
c-Mg2NiH
4(220)
c-Mg2NiH
4(111)
As-deposited Mg
2Ni
h-Mg2Ni(006)
h-Mg2Ni(003)
Inte
nsi
ty, a
rb.u
.
Diffraction angle, 2 theta
GDOES analysis of desorption of Mg2NiH4 thin film
Studies of deStudies of de--hydrhydrogenationogenation kinetics of Mg kinetics of Mg22NiHNiH44 thin films thin films
Basic parameters:
T = 770 K, t = 30 min.
ConclusionsConclusions1. 1-3 µm Mg, Ni and Mg2Ni thin films were successfully deposited on the quartz
substrates using magnetron sputtering.
2.2. Observed formation of amorphous phase during plasma hydrogenation using DC Observed formation of amorphous phase during plasma hydrogenation using DC power supply. It can be related to formation of the compressive stresses and power supply. It can be related to formation of the compressive stresses and defragmentation of the material. defragmentation of the material.
3.3. Formation of low temperature (LT) m-MgFormation of low temperature (LT) m-Mg22NiHNiH4 4 thin films after hydrogenation of thin films after hydrogenation of
MgMg22Ni in hydrogen plasma for 2 hours using AC power supplier is observed.Ni in hydrogen plasma for 2 hours using AC power supplier is observed.
4. After the hydrogenation of Mg2Ni thin films in hydrogen atmosphere, in high pressure and high temperature, Mg2NiH4 thin films were successfully formed.
5. SEM results show formation of “bubbles” on the surface during hydrogenation in (p,T). It can be related to the high temperature during hydrogenation and formation of the compressive stresses. These bubbles were lifted after de-hydrogenation and some parts of thin films were destroyed.