Post on 26-Jul-2021
GTT-Technologies Annual Workshop and User‘s Meeting
Herzogenrath-Kohlscheid (Aachen, Germany)
5th July, 2013
Phase Diagrams with FACTSage Speaking different Languages for Thermochemical Properties
Michael Auinger
Outlook
– Motivation
– Thermochemical Properties in Oxides
– Ellingham-Richardson Diagrams
– Stability Diagrams
– Thermochemistry of Oxides and Nitrides
– Nitrides in the System Iron - Chromium - Carbon
– Nitrogen and Oxygen in Iron - Silicon
– Summary
Oxidation Processes in Steels
scale (mainly ‘FeO’)
Grain Boundary Oxidation
Singheiser et.al., Materials & Corrosion 62 (2011) 504
The Problem
pictures from various internet sources and FACTSage
The Problem
pictures from various internet sources and FACTSage
Lost in Translation?
أنا أحب الديناميكا „ “الحرارية
„Μου αρέσει
θερμοδυναμική “
„我喜歡熱力學 “
„나는 열역학을
좋아 “
„Мне нравится
термодинамики “ „আমি তাপগমতমিদ্যা পছন্দ “
An Effective Solution
أنا أحب الديناميكا „ “الحرارية
„Μου αρέσει
θερμοδυναμική “
„我喜歡熱力學 “
„나는 열역학을
좋아 “
„Мне нравится
термодинамики “ „আমি তাপগমতমিদ্যা পছন্দ “
An Effective Solution
„I like thermo-
dynamics“ أنا أحب الديناميكا „
“الحرارية
„Μου αρέσει
θερμοδυναμική “
„我喜歡熱力學 “
„나는 열역학을
좋아 “
„Мне нравится
термодинамики “ „আমি তাপগমতমিদ্যা পছন্দ “
Part I
Thermochemical Properties
of Oxides
Ellingham Diagram
Oregon State University at www.oregonstate.edu (dl 02.07.2013)
Ellingham Diagram with FACTSage
2 Fe + O2 2 FeO
Tp
pRGGG
o
OOo
T
Feo
T
FeOo
T
22 ln22
,
)(
,
)(
,
)(
Ellingham Diagram with FACTSage
2 Fe + O2 2 FeO
Tp
pRGGG
o
OOo
T
Feo
T
FeOo
T
22 ln22
,
)(
,
)(
,
)(
Ellingham Diagram with FACTSage
2 Fe + O2 2 FeO
Tp
pRGGG
o
OOo
T
Feo
T
FeOo
T
22 ln22
,
)(
,
)(
,
)(
Ellingham Diagrams for Oxide Formation
Ellingham Diagrams for Oxide Formation
Ellingham Diagrams for Oxide Formation
Ellingham Diagram with FACTSage
2 Fe + O2 2 FeO
Stability Diagrams with FACTSage
2 Fe + O2 2 FeO
Stability Diagrams with FACTSage
2 Fe + O2 2 FeO
Comparison
Tp
pRGGG
o
OOo
T
Feo
T
FeOo
T
22 ln22
,
)(
,
)(
,
)(
o
O
Oo
T
Feo
T
FeOo
T
p
p
RT
GGG2
2
ln22
,
)(
,
)(
,
)(
Properties of Oxygen
Oxide Stability
0 250 500 750 1000 1250 1500 1750 20001250
1000
750
500
250
0
3/2 Fe + O2 = 1/2 Fe3
O4 2 Fe + O2 = 2 FeO
4/3 Cr + O2 = 2/3 Cr
2O3
2 Mn + O2 = 2 MnO
Si + O2 = SiO 2
Sta
ndard
fre
e e
nerg
y o
f fo
rmati
on o
f oxid
es
(-
Go =
-R
T l
n(p
O2
) /
kJ
mol-1
Temperature / °C
4/3 Al + O 2 = 2/3 Al
2O 3
0 K
O2
-25
-20
-15
-10
-5
0
Oxygen p
art
ial
pre
ssure
log(p
O2
)
Iron – Manganese – Chromium alloy
Figure: Spatial phase distribution in an Fe, 2 wt-% Mn, 0.8 wt-% Cr alloy after
oxidation at p(O2)= 3·10-22 bar and 700 °C for 120 min and ternary phase diagram.
published in Mater. Sci. Forum 969 (2011) p.76
Part II
Gaseous Nitriding in the system
Fe – Cr – C
Nitriding of Fe, 1 wt-% Cr, 0.10 wt-% C and
Conditions: 48 h at 500 °C
p(NH3) : p(H2) = 100 (KN = 1 000)
Gaseous Nitriding Process
g´-Phase (Fe4N)
e-Phase (Fe2N)
Diffusion Zone
Theoretical Principles
Figure: Lehrer-Diagram of iron nitrides according to literature (left) and calculated
with the programme FactSage (right).
450 500 550 600 650 7000.01
0.1
1
10
-4
-3
-2
-1
0
1
2
g-Iron (fcc)
-Iron (bcc)
g'-Phase (Fe4N)
KN
= p
NH
3
/p1.
5
H2
temperature / °C
e-Phase (Fe2N)
log
10(p
2 NH
3
/p3 H
2
)
http://www.ipsenusa.com (dl 12.10.2010)
Iron – Chromium – Carbon alloy
published in HTM J. Heat Treatm. Mat. 66 (2011) p.100
Figure: Spatial phase distribution in an Fe, 1 wt-% Cr, 0.1 wt-% C alloy after gas
nitriding at KN= 2.4 and 500 °C for 48 h and phase stability diagram.
-10
-5
0
5
0.00 0.25 0.50 0.75 1.0010
-9
10-7
10-5
10-3
10-1
101
CrN
Cr2N
Cr 3
C2
Cr 7
C3
K
N =
p0
.5
o p
NH
3
/p1
.5
H2
xCr
/ (xCr
+xC)
Cr 2
3C
6
Fe + C + Cr3C
2
Fe + Cr
+Cr23
C6
Fe + C + CrN
Fe4N + CrN + C
Fe2N + CrN + C
log
10(p
N2
) /
bar
Binary Phase Diagrams
Binary Phase Diagrams
The System Iron – Nitrogen
Figure: Nitrogen Solubility in Iron at 1 bar (left) and binary Iron-Nitrogen phase
diagram, calculated with FACTSage (right).
H. Zitter, L. Habel Arch. Eisenhüttenwes. 44 (1973) 181.
The System Iron – Nitrogen
Figure: Nitrogen Solubility in Iron at 1 bar (left) and binary Iron-Nitrogen phase
diagram, calculated with FACTSage (right).
H. Zitter, L. Habel Arch. Eisenhüttenwes. 44 (1973) 181.
p1
The System Iron – Nitrogen
Figure: Nitrogen Solubility in Iron at 1 bar (left) and binary Iron-Nitrogen phase
diagram, calculated with FACTSage (right).
H. Zitter, L. Habel Arch. Eisenhüttenwes. 44 (1973) 181.
p1 p2
Part III
Gaseous Nitriding and Oxidation in the system Fe – Si
Nitriding of Fe, 1 wt-% Si
Conditions: 20 h at 550 °C (KN = 1 000)
4 h at 550 °C (KO ≈ 0.01)
Stability Diagram of Iron – Silicon
Figure: Stability diagram of an Fe, 1 wt-% Si alloy at 550 °C with respect to the
partial pressures of nitrogen and oxygen (SGTE Pure Substance Database).
10-9
10-7
10-5
10-3
10-1
101
10-10
10-5
100
105
1010
-10 -5 0 5
-45
-40
-35
-30
-25
-20
-15
-10
Fe
2N
Fe3O
4 + SiO
2
Fe3O
4 + Fe
2SiO
4
K
O =
pH
2O
/pH
2
KN = p
NH3
/p1.5
H2
Fe + Si
SiO2
Fe2SiO
4
Fe2O
3 + SiO
2
Si3N
4
Si2ON 2
Fe
4N
log
10(p
O2
) / b
ar
log10
(pN
2
) / bar
Simulation Results with ASTRID
Figure: Spatial phase distribution in Fe, 1 wt-% Si after gaseous nitriding for 20 h at
KN = 1 000 and oxidation for 4 h and KO ≈ 0.01 (ptot= 1 atm, 550 °C) .
Appl. Simul. of Thermodyn. Reactions and Interphase Diffusion
Ternary Phase Diagrams
Ternary Phase Diagrams
Ternary Phase Diagrams
Conclusions - The Problem
pictures from various internet sources and FACTSage
Conclusions – An Effective Solution
pictures from various internet sources and FACTSage
Conclusions – An Effective Solution
pictures from various internet sources and FACTSage
Conclusions – An Effective Solution
pictures from various internet sources and FACTSage
Acknowledgements
Dirk and Alexandra Vogel,
Else-Marie Müller-Lorenz,
Monika Nellessen
Prof. H. Danninger
Vera G. Praig, Markus Holzweber,
Kurt Piplits
Dr. D. Paesold
Bernhard Linder, Klaus Rendl,
Andreas Muhr
Funding
www.oberoesterreich.at (dl 03.07.2013)
Backup Slides
Additional Slides for the Presentation
Where we work…
Max-Planck-Institut
für Eisenforschung GmbH
Head: Prof. Dierk Raabe
Founded in 1917 from the “Kaiser Wilhelm Institute”
by Fritz Wüst.
3 Departments:
Computational Materials Design
Interface Chemistry and Surface Engineering
Microstructure Physics and Alloy Design
From where I am
Austria
Area: 83 879 km²
Inhabitants: ~ 8 405 000
Language: German
Capital: Vienna
Fisher’s Model of Diffusion
3
5
56
log3292.0
z
c
t
DDs GB
Whipple – Le Claire equation
3
5
56
log4704.0
z
c
t
DDs GB
Levine – MacCallum equation
I. Kaur “Fundamentals of … Boundary Diffusion” WILEY (1995)
Some Published Works on HT-Corrosion
Programme Algorithm
0.00 0.25 0.50 0.75 1.00-40
-35
-30
-25
-20
-15
-10
Fe2O
3 (hematite) + Al
2O
3
Fe3O
4 + FeAl
2O
4
oxyg
en p
ress
ure
log(
p(O
2)
/ po)
mole fraction aluminium xAl
Fe + Al
Fe + Al2O
3
'FeO' + FeAl2O
4
Fe + FeAl2O
4
Fe3O
4 + Al
2O
3
Al2O
3 + FeAl
2O
4
700 °C
element migration chemical reaction
tx,iTx,i
tx,ic.D=
dt
dcdiv
ASTRID, published in Oxid. Met. 76 (2011) 247
Data Handling
Al - total
Al
Al-Oxide
Figure: Spatial phase distributions of Fe, 2 wt-% Al (4.05 mol-% Al) after oxidation
at p(O2) = 10-22 bar for 60 min at 700 °C.
Al
Al2O3
FeAl2O4
Detail of a Grain Boundary
Figure: Spatial distribution of chromium oxides Cr2O3 and FeCr2O4 along a grain
boundary in Fe, 3 wt-% Cr after finished cooling from 650 °C.
Diffusion between different Phases
http://adsjapan.blogspot.com and http://www.gettyimages.com
Figures: Shibuya (渋谷) crossing in Tokyo with green and red pedestrian lights.
single phase
cDJ A LJ A
g
g
RTLc
c
RTL oc
cLLJ A
D
general description
Modelling Segregation
[1] Blavette et al. Microsc. Microanal. 13 (2007) 464
Figure: Numerical simulation of segregation (left) and 3D atom probe tomography
of segregated boron atoms along the grain boundary in a NiAl superalloy [1] (right).
t = 0
t
concentration
Calculation of the Oxidation Depth
0 25 50 75
0.000
0.025
0.050
0.075
0.100
Rel
ativ
e ab
un
dan
ce
Oxidation depth in Sample x / µm
µ, s
0 25 50 75 100
0.00
0.25
0.50
0.75
1.00
Data: Data1_C
Model: SLogistic1
Equation:
y = a/(1 + exp(-k*(x-xc)))
Weighting:
y No weighting
Chi^2/DoF = 0.00721
R^2 = 0.99588
a 3.20455 ±0.00818
xc 29.5835 ±0.10386
k 0.22165 ±0.00442
Fra
ctio
n o
f m
etal
lic
Ch
rom
ium
Depth into Steel Sample x / µm
Cr- oxides metallic Cr
Multikomponentensysteme
Abbildung: Phasenverteilung einer industrienahen Legierungszusammensetzung
nach erfolgter Oxidation bei p(O2) = 10-22 bar und einer technischen Abkühlkurve.
Temperature Dependence
Diffusion equation
tx,icT,x,tx,iTx,i
tx,if+c.D=
dt
dcdiv
RT
Q
eD=D o
iTi
1200 1100 1000 900 800 7001E-19
1E-18
1E-17
1E-16
1E-15
1E-14
1E-13
volume diffusion
grain boundary diffusion
Dif
fusi
on c
oef
fici
ent
D /
m²
s-1
Temperatue T / K
Figure: Temperature dependence of phosphorous diffusion in iron.
I. Stloukal, C. Herzig, Z. Metallkd. 93 (2002) 88
Thermodynamic Principles
Figure: State diagram of water [2] (left) and schematic temperature evolution with constant heating (right).
[2] University of Bristol at www.enm.bris.ac.uk (dl 15.10.2010)
melting
boiling
Ice
temperatu
re T
time t
Efficiency of the Calculation
Figure: Distribution of Cr2O3 in Fe, 0.67 wt-% Cr at 700 °C after 90 min. Simulation
with InCorr (left) and with self-written programme (right).
300 FEM-points
Calculation time: 90 min
63 000 FEM-points
Calculation time: 120 min
25 µm
Berechnungsaufwand
Abbildung: Abhängigkeit der Rechenzeit zur Simulation des Oxidationsverhaltens
von Fe, 3 wt-% Cr bei verwendetem Kühlprogramm ab 650 °C (B).
bisher Elementarzelle Kanten Algorithmus gekreuzter0
25
50
75
100
Rec
henz
eit
t rel /
%
Algorithmus
Fine grained
C’ – regime B’ – regime A’ – regime
Coarse grained
C – regime B – regime A – regime
Grain Boundary Diffusion Regimes
Figure: Illustration of different diffusion regimes, depending on total diffusion time and ratio of DGB/D.
I. Kaur “Fundamentals of … Boundary Diffusion” WILEY (1995)
Experimental Set-up
N2
Ar
H2
Ar
H2
Dew-Point Sensor
H2O-Dosage
Gas Mixing Chamber
Reaction Chamber Gas Analysis
(H2O, O2-Content)
in Rev. Sci. Instr. (2013), accepted
Selective Decarburisation at 800 °C
Figure: Experimental parameters during selective decarburisation of Fe, 0.8 wt-% C
at 800°C in Ar / 2.5 vol-% H2 / H2O.
M. Auinger, V.G. Praig, et.al., Corros. Sci., submitted
Selective Decarburisation at 800 °C
Figure: Mass change during selective decarburisation of Fe, 0.8 wt-% C at 800°C
in Ar / 2.5 vol-% H2 / H2O.
0 20 40 60 80 100 120 140-2.0
-1.5
-1.0
-0.5
0.0
mass c
hange
m / m
g c
m-2
time t / min
measurement from 27.04.2012
measurement from 26.04.2012
measurement from 04.08.2012
Fe, 0.8 wt-%C, 800 °C, Ar/2.5% H2, DP+13°C
M. Auinger, V.G. Praig, et.al., Corros. Sci., submitted
Selective Decarburisation at 800 °C
Figure: Cross section of Fe, 0.8 wt-% C after oxidation at 800 °C in Ar / 2.5 % H2 /
H2O for 60 min. The cross section was etched with 1 % HNO3 / Ethanol for 15 s.
M. Auinger, V.G. Praig, et.al., Corros. Sci., submitted
Selective Decarburisation at 800 °C
Figure: Evolution of the decarburised zone depth in Fe, 0.8 wt-% C after oxidation
at 800 °C in Ar / 2.5 % H2 / H2O. The solid lines represent theoretical results.
M. Auinger, V.G. Praig, et.al., Corros. Sci., submitted
Selective Decarburisation at 800 °C
Figure: Evolution of the mass change in Fe, 0.8 wt-% C during oxidation at 800 °C
in Ar / 2.5 % H2 / H2O. The solid lines represent the theoretical results.
M. Auinger, V.G. Praig, et.al., Corros. Sci., submitted
Ellingham – Formulas + FACTSage Pic
Text here
2 Fe + O2 2 FeO
Formation
)(TG
o
OOo
TFe
Feo
TFeO
FeOo
T
p
pRTGaRTGaRTG 22 lnln22ln220
,
)(
,
)(
,
)(
0!
Tp
pRGGG
o
OOo
T
Feo
T
FeOo
T
22 ln22
,
)(
,
)(
,
)(
d
2
)()()(22
O
T
Fe
T
FeO
T
y
FeFeO
o
OOo
T
Feo
T
FeOo
TaRTaRT
p
pRTGGG lnln2ln22 22
,
)(
,
)(
,
)(
ormationo
TG F,
)(
0
Properties of Nitrogen
figures from Landoldt-Börnstein (right) and FACTSage (left)
Nitride Stability
0 250 500 750 1000 1250 1500 1750 2000750
500
250
0
-250
2 Cr2N + N2
= 4 CrN
8 Fe + N2 = 2 Fe4
N
4 Cr + N2 = 2 Cr2
N
8 Mn + N2 = 2 Mn4
N
3/2 Si + N 2 = 1/2 Si 3
N 4
Sta
ndar
d fr
ee e
nerg
y of
for
mat
ion
of n
itri
des
(-
Go =
-R
T ln
(pN
2
) / k
J m
ol-1
Temperature / °C
2 Al + N 2 = 2 AlN
0 K
N2
-15
-10
-5
0
5
Nit
roge
n pa
rtia
l pre
ssur
e lo
g(p
N2
)
Theoretical Principles
0 250 500 750 1000
1E-5
1E-4
1E-3
0.01
0.1
1
10
100
1000
N2 + 3H
2 2 NH
3
Kp =
pN
H3
/ (p
3/2
H2
p1/
2
N2
) p
0
Temperatur / °C
N2 + 3H
2 2 NH
3
3
,
222
1
2
3NHNH Tp
05.1
!
2
3 pp
pK
H
NH
N
0
)(
2 p
KpK
Tp
NN
05.05.1)(
22
3 ppp
pK
NH
NH
Tp
02
1
2
3 !
)()()(223
N
T
H
T
NH
T GGG RT
GGG
Tp
oTN
oTH
oTNH
eK
)(,2)(,2)(,3 2
1
2
3
)(
Theoretical Principles
450 500 550 600 650 7002
3
4
5
6
7
102
103
104
105
106
107
g-Eisen (fcc)
-Eisen (bcc)
g'-Phase (Fe4N)
e-Phase (Fe2N)
log
10(p
N2
/p0)
Temperatur / °C
pN
2
/p
0
http://www.ipsenusa.com (dl 12.10.2010)
Figure: Lehrer-Diagram of iron nitrides according to literature (left) and stability
diagram calculated with the programme FactSage (right).