Degradation of High Temperature Materials in Traditional and Modern Energy Systems

ICAER Conf, IITB, 10-12 December 2013

Ge Le1, Andrew Czerwinski2,4, BV Mahesh1,2, Manoj K. Mahapatra1, Prabhakar Singh1,

RK Singh Raman2,3

1 Center for Clean Energy Engineering, University of Connecticut, USA2 Department of Mechanical and Aerospace Engineering, Monash

University, Melbourne, Australia3 Department of Chemical Engineering, Monash University, Melbourne,

Australia4 Engineering and Materials Division, HRL Technology Pty Ltd,

Mulgrave, Victoria, Australia

Degradation of High Temperature Materials in Traditional and Modern Energy Systems

MOTIVATION

•Improving Efficiency and Environmental Impact of Traditional Systems, and

•Developing New Systems

Mitigation of Materials Degradation in New and Traditional Energy Systems

Degradation, Failure and Fracture. .

Major Issues in both New and Traditional Energy Systems

Oxidation-assisted Microstructural Degradation of Fe-Cr Alloys for Nuclear and Coal-fired Plant Steam Generators 2.25Cr-1Mo Steel Weldment (Cross-sections): Steam / 600 oC

Base Metal Heat Affected

Zone (HAZ)

•HAZ: extensive cavity formation at grain boundaries

•Creep resistance of HAZ is generally much inferior

Singh Raman, Metall Mater Trans A (several publications): 1995-2003

Improving Efficiency and Environmental Impact of Traditional Systems

• Higher Temp of Operation: Supercritical / Ultra-supercritical Plants (Steam Generators / Boilers)

• Novel / Smarter Approaches to Monitor Materials Degradation of High Temp Equipment

Challenges for Higher Temperature Materials:Advanced Fossil Fuel Power Plants

Unique Oxidation Test Facility: Loy Yang B Power Station, Australia

A joint facility of:

- Five Power plants in Vic state,- Vic State Govt,- Monash Univ,- HRL Technology,- Oak Ridge National Lab, USA

Testing Using Real Power Plant Steam

PhD project: 12,000 h data

Lab Test Facility for Oxidation Kinetics Data:Fossil Fuel Plant Steam Generators

Lab and Power Plant Oxidation Kinetics Data:Steam Generator 9Cr-1Mo Steel (T9)

Good agreement in plant and laboratory data

Lab and Power Plant Oxidation Kinetics Data:Steam Generator 9Cr-1Mo Steel (T92)

No good agreement in plant and laboratory data

Extrapolation of Plant Oxidation Kinetics Data:Steam Generator 9Cr-1Mo Steels

(T92: V+Nb+W, T91: V+Nb, T9: plain)

Mitigation of Materials Degradation inAn Alternative Energy System (e.g., SOFC)

- 70% cost of SOFC: Interconnection / BOP materials- Chromia evaporation: cell contamination

Suppression of Chromium Evaporation

Least Cr Evaporation from Aluchrom Alloy

Ge, Verma, Goettler, Lovett, Singh Raman, Singh, Oxide Scale Morphology and Cr Evaporation Characteristics of Alloys for Balance of Plant Applications in Solid Oxide Fuel Cells, Metallurgical & Materials Trans A, 44a (2013) 193 – 206.

Suppression of Chromium Evaporation: FIB

Ge, Verma, Goettler, Lovett, Singh Raman, Singh, Metall & Mater Trans A, 44a (2013) 193 – 206.

(Cr,Mn)3O4

Cr2O3

AISI 310S

Al2O3

Aluchrom:850 oC / 3% humidity

Aluchrom:950 oC / 12% humidity

Al2O3

Nicrofer 6025HT Ni, Fe, Cr mixed oxide

Cr2O3

Grain Boundary Corrosion is Expected to be Extremely Enhanced in the Case of

Nanocrystalline Alloys

Singh Raman et.al., J. Mater Sci Letters, 9 (1990) 353

Mitigation of Materials Degradation:Grain Size Effect

Oxidised 2.25Cr-1Mo steel (550oC)

Extensive Grain Boundary oxidation /

Notching / Grain detachment

Remarkable Oxidation Resistance due to Nanocrystalline (nc) Structure of Fe-Cr Alloys

0

0.2

0.4

0.6

0.8

1

1.2

0 500 1000 1500 2000 2500 3000 3500

Wei

ght g

ain

per

unit

are

a, m

g/cm

2

time, min

microcrystalline (mc)nanocrystalline (nc)

mc, 30 min mc, 2 hr mc, 52 hr

nc, 30 min nc, 2 hr nc ,52 hr

Singh Raman, Gupta, Koch, Philosophical Magazine, 90 (2010) 3233

Oxidation (300 oC / Air) of nc and mc Fe-10Cr Alloys

Oxidised nc and mc Fe-10Cr Alloys

mc ncOxidised: 350oC / Air / 52h

nc and mc Fe-10Cr and Fe-20Cr Alloys Oxidized (300oC/120min): Cr Depth Profiles

0.0E+00

2.0E+06

4.0E+06

6.0E+06

8.0E+06

1.0E+07

0 100 200 300 400 500 600

Cou

nts

/sec

Time, sec

nc Fe20Cr

mc Fe20Cr

nc Fe10Cr

mc Fe10Cr

Cr - Profile

Singh Raman, Gupta, Corrosion Science, 51 (2009) 316

Our Nanocrystalline Fe-Cr Alloys Find Potential Application in Clean Energy Systems

Solid Oxide Fuel Cells (highest efficiency fuel cells)* High Cr alloys for Interconnect, Heat exchanger, Piping * Materials Issues: - 70% cost: Interconnection / BOP materials- Chromia evaporation: cell contamination

Rolls Royce Solid Oxide Fuel Cell

Effect of temperature on grain growth

• Rapid grain growth above 600 °C• Addition of Zr stabilizes the grain size even at 1000 °C !!

Mahesh, Singh Raman, Koch , J. Mater. Sci. 47 (2012), 7735-7743

MONASH Universit

y

MONASH Universit

y

Effect of Tamperature and Zr Addition on Grain Growth

- ARC Discovery and - North Carolina State University

Graphene: ‘Thinnest Known Corrosion Resistant Coating’

Graphene: Flat monolayer of sp2 hybridized carbon atoms arranged in a 2D honeycomb lattice

Single layer of graphite

Remarkable Mechanical Properties of Graphene

Young’s modulus: 1 TPa (steel ~0.2 TPa)

Stiffness: 1060 GPa

Graphene film vs Steel (similar thickness):

Graphene is 100 times stronger than the strongest steel

1 m2 graphene can bear 4 kg mass

Remarkable Mechanical Properties of Graphene Impermeable to most standard gases, including He

Impermeable to most fluids including small molecules

Inert even to most aggressive chemicals (e.g. HF)

Hydrophobic due to the non-polar covalent double bonds

Can Graphene act as a corrosion barrier?

Corrosion / Oxidation Resistance due to Graphene Coating

Chen S, Brown L, Levendorf M, Cai W, Ju S-Y, Edgeworth J, et al. Oxidation Resistance of Graphene-Coated Cu and Cu/Ni Alloy, ACS Nano. 2011 2012/01/26;5(2):1321-7

Graphene coated upper half of the

penny (Cu Alloy) does not corrode

Comparison of Corrosion Data from Different Groups

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

Po

ten

tial (V

) vs S

CE

graphene coated Cu

uncoated Cu

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Po

ten

tial

(V)

vs S

CE

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

-9 -8 -7 -6 -5 -4 -3 -2 -1

log i (A/cm2)

Po

ten

tia

l (V

) v

s S

CE

Prasai et al

Kirkland et al

Singh Raman et al

Anodic current density is an order of magnitude lower (in Na2SO4)

Ecorr has shifted towards more noble direction

Anodic current density is similar (in 3.5% NaCl)

Ecorr is more negative

Anodic current density is two orders of magnitude lower

(in 3.5% NaCl)

Ecorr is 40 mV more positive

Best corrosion resistance due to graphene coating

till date!

EIS of Graphene-coated and Uncoated Cu

1

100

10000

1000000

0.01 1 100 10000 1000000

Frequency (Hz)

|Z|

(Ω c

m2)

Graphene coated CuUncoated Cu

Confirmation of two orders of magnitude higher corrosion resistance due to graphene coating

Singh Raman, Banerjee.....Ajayan, Majumder et al, Protecting copper from electrochemical degradation by graphene coating, Carbon, 50 (2012) 4040.

External Collaborators: Raman Singh • Centre for Clean Energy Engineering (C2E2), University of

Connecticut,

• US Office of Naval Research (ONR), Naval Research Lab (NRL)

• North Carolina State University (Prof K Koch)

• Consortium of Five Power Generators in Vic state, and HRL Technology

• Rice University (Prof PM Ajayan)

• ETH, Zurich (Prof P Uggowitzer)

• Technion (Prof Dan Schechtman)

• Alcoa, BHP-Billiton

• Australian Vinyls

• DSTO, CSIRO, IITB-Monash Research Academy