New Investigation Results of Crofer 22 APUEin Unternehmen ThyssenKrupp VDMvon ThyssenKrupp Stainless...

ThyssenKrupp VDMEin Unternehmen von ThyssenKrupp

Stainless

TKru

pp

W-E1/R.Hojda 06.07.2004

New Investigation Resultsof

Crofer 22 APU

Hojda/Singheiser/Quadakkers


Stainless

TKru

pp

W-E1/R.Hojda 06.07.2004

Development Challenges for Fuel Cell Materials

• Excellent High-Temperature Oxidation Resistance• Good Electrical Conductivity of the Oxide Scale• Thermal Expansion Similar to Ceramics (e.g. YSZ)• No Detrimental Reaction (Cr-Oxide Evaporation)• Adequate Strength at High Temperature• Easy Manufacturing• High Potential for Cost Reduction


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W-E1/R.Hojda 06.07.2004

Material Specification

Analysis: Fe / Cr 22 / Mn 0.8 / Ti 0.2 / La 0.2

Density: 7,67 g/cm3

Resistivity: 0,54 Ohm* mm2/m

Yield Strength: 300 – 400 MPa

Tensile Strength: 450 – 550 MPa

Elongation: 30 – 40 %

Properties/Workability similar to Ferritic Stainless Steels


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pp

W-E1/R.Hojda 06.07.2004

Coefficient of Thermal ExpansionForschungszentrum Jülich (IWV)

9·E-6

10·E-6

11·E-6

12·E-6

13·E-6

14·E-6

200 400 600 800 1000Temperature/ °C

2Ni/ZrO -Anode

Commercial 18%Cr Alloy(1.4742)

Commercial 24%Cr Alloy (Alloy 446)

Crofer 22 APU

Elektrolyte (8YSZ)

Cathode (LSM)

Ni Base Alloys

Coe

ffic

ient

of T

herm

al E

xpen

sion

(K- 1

)


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W-E1/R.Hojda 06.07.2004

Contact Resistance at 800°C in AirForschungszentrum Jülich (IWV)

1

10

100

1000

10000

100000

0 50 100 150 200 250 300 350 400 450Time [h]

Con

tact

resi

stan

ce [m

Ωcm

2 ]

preoxidation

Cr - ODS, Cr-5Fe-1Y 2O3

Semi-commercial JS-3

Crofer 22 APU DCU / DCVJEX / JEWJDA


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pp

W-E1/R.Hojda 06.07.2004

Scale Resistance Crofer 22 APU

0

0.005

0.01

0.015

0.02

0.025

0 50 100 150 200 250 300 350 400 450 500

Time (hours)

ASR

(ohm

.cm

2 )

800oC

700oC


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W-E1/R.Hojda 06.07.2004

Microstructures of Crofer 22 APU

800oC, 500h 700oC, 500h

Pt contactScaleCrofer22 APU

(Cr,Mn)3O4

Cr3O2

(Al,Ti,La)xOyMetal matrix

Note: Reduced Cr volatility due to (Cr,Mn)3O4 outer scale


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W-E1/R.Hojda 06.07.2004

SEM Cross-Section Crofer 22 APU 6000h/800°C/Air

Steel

Forschungszentrum Jülich (IWV)

Alumina

SilicaChromia

Cr/Mn-Spinel Mn-richregions


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W-E1/R.Hojda 06.07.2004

SEM Cross-Section of JS 3 (6000h/800°C/Air)

Steel

Chromia

Spinel

Mn-richintrusion

Ti-oxide


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W-E1/R.Hojda 06.07.2004

Comparison of Scale Formation JS 3 to Crofer 22 APU(6000h/800°C/Air)

JS-3 Crofer 22 APUBatch JDA

Steel

Cr2O3

(Mn,Cr)3O4

Mn-richintrusion

TiO2Steel

Cr2O3

(Mn,Cr)3O4

Mn-richintrusion

TiO2

Mn-richregions

Al2O3

Cr2O3

Steel

(Mn,Cr)3O4

SiO2

Mn-richregions

Al2O3

Cr2O3

Steel

(Mn,Cr)3O4

SiO2


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W-E1/R.Hojda 06.07.2004

Adjustment of Scale Formation on Crofer 22 APU

1000h/800°C/Air (cyclic oxidation)

Batch B (JZF)Batch A (JDA)


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W-E1/R.Hojda 06.07.2004

Discontinuous Oxidation of Crofer 22 APU

0

0.2

0.4

0.6

0.8

0 200 400 600 800 1000 1200 1400Time / h

Wei

ght c

hang

e / m

g.cm

- ² Crofer 22 APU, Batch A (JDA 4)

Crofer 22 APU, Batch B (JZF3)

JS3 (JEX4)


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W-E1/R.Hojda 06.07.2004

Specially designed Crofer 22 APU

• 22% Cr for Oxidation Resistance and low CTE

• 0.6% Mn addition for–Limitation of Cr evaporation–Good Conductivity of the Oxide Scale

• 0.1% La to improve Oxide Scale Adherence

Continuous Process Improvement Crofer 22 APU = JS-3 !

New Investigation ResultsofCrofer 22 APUDevelopment Challenges for Fuel Cell MaterialsMaterial SpecificationCoefficient of Thermal ExpansionContact Resistance at 800°C in AirScale Resistance Crofer 22 APUMicrostructures of Crofer 22 APUSEM Cross-Section Crofer 22 APU 6000h/800°C/AirSEM Cross-Section of JS 3 (6000h/800°C/Air)Comparison of Scale Formation JS 3 to Crofer 22 APUAdjustment of Scale Formation on Crofer 22 APUDiscontinuous Oxidation of Crofer 22 APUSpecially designed Crofer 22 APU

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New Investigation Results of Crofer 22 APUEin Unternehmen ThyssenKrupp VDMvon ThyssenKrupp Stainless...

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